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Underwater noise due to precipitation

Crum, Lawrence A.; Pumphrey, Hugh C.; Prosperetti, Andrea; Jensen, Leif Bjørnø

Published in: Acoustical Society of America. Journal

Link to article, DOI: 10.1121/1.2026824

Publication date: 1989

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Citation (APA): Crum, L. A., Pumphrey, H. C., Prosperetti, A., & Jensen, L. B. (1989). Underwater noise due to precipitation. Acoustical Society of America. Journal, 85(S1), S153-S153. https://doi.org/10.1121/1.2026824

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PROGRAM OF

The 117thMeeting of the AcousticalSociety of America

SheratonUniversity Innand Syracuse University ß Syracuse, New York ß 22-26May 1989

MONDAY EVENING, 22 MAY 1989 COMSTOCK AB, 7:00 TO 9:00 P.M.

Tutorial on AcousticalOceanography

Mauro Pierucci, Chairman Departmentof AerospaceEngineering and EngineeringMechanics, San Diego State University, San Diego, California 92182

T•I. Acousticaloceanography: Childof ocean . Herman Mealwin (Physics Department, Naval PostgraduateSchool, Monterey, CA 93943)

Soundpropagation is the preeminenttechnique for sensing,identifying, and communicatingunder the oceansurface. However, the extraordinaryspatial and temporal variability of the oceanhas frustrated under- wateracousticians for decades.The solution,of course,was to learnmore about the causesof thisvariability. Thetraditional oceanographic instruments do this rather crudely, and probably the best technique is to usethe acousticalbehaoior to characterizethe medium. Several years ago, ocean acoustics gave birth to acoustical oceanography.The acoustical oceanographer inverts the problem; he uses the seemingly capricious nature of soundpropagation to learnabout the ocean. The many successes of this young science range from the identifi- cationand counting of physicaland biological inhomogeneities, such as microbubbles, zooplankton, and fish, to theremote sensing of distantrainfall and sea surface roughness, deep sea mountains, rocks and sediments, as wellas the shapeand strength of immensechurning ocean eddies, hundreds of kilometersin extent.

TUESDAY MORNING, 23 MAY 1989 REGENCY B, 8:00 TO 11:45 A.M.

SessionA. NoiseI: Noiseof Air-Moving Devices

Louis A. Herstein, Chairman TracorApplied Sciences, Inc., 7945MacArthur Boulevard,Suite 214, CabinJohn, Maryland 20818

Chairman's Introduction-•8:00

Invited Papers

8:05 A1. Fan noisecontrol---Challenges andopportunities. Hsien-sheng (Jason) Pei (DigitalEquipment Corporation,30 ForbesRoad, Northboro, MA 01532) Fansused in thecooling of mechanicaland electrical equipment are often the major sources of noise.This paperreviews the past and current noise control activities in thefan industry and related trade and professional organizations.Technology trends are discussed. Research needs and priorities are identified. The impact of fan

Sl J. Acoust.Soc. Am. Suppl. 1, Vol. 85, Spring1989 117th Meeting:Acoustical Society of America S1 design(blade, housing, and motor) and fan manufacturing (materials and processes) on fan noise and system acousticalquality are discussed. This paper illustrates with examples that fan noise control is more a challenge for design,application, and manufacturing than an investigationof fundamentalaeroacoustic mechanisms. Theapproach is multi-disciplinaryand comprehensive in its treatment of eachintegration level--from bear- ingsand windings to motor,housing, and end-use equipment, thereby integrating noise control into fan design and manufacturingto achievetotal quality for tomorrow'smarket.

8:30

A2. A review of air-movingdevice noise: Mechanisms and measurementmethods. David M. Yeager (IBM AcousticsLaboratory, P.O. Box 1328,Zip 1103,Boca Raton, FL 33432) The predominantacoustic noise sources of electronicsystems are very often due to convectioncooling devices.A widerange of capacitiesof air-movingdevices (AMDs) areused in computersand business equip- ment,typically varying in totalflow rate from 0.01 to 1.0m3/s, and in staticpressure drop from 10 to 1000Pa. This reviewpaper will coverseveral aspects of air-movingdevice noise: ( 1) basicmechanisms of aerodynamic noisegeneration, especially in the contextof air-movingdevice noise, (2) measurementmethods of character- izing aeroacousticnoise sources on airfoils immersedin turbulence,(3) important parametersin assessing aeroacousticperformance, (4) standardizedmeasurement methods for determiningnoise emission levels of AMDs; ( 5 ) useof soundpower levels of AMDS for predictingoverall system noise levels; and (6) nonstandar- dizedmeasurement methods for quantifyingair-moving devices based on soundintensity techniques.

8:55 A3.Onprecisein-ductmeasurementoffan noise.WilliamB. Swim (DepartmentofMechanicalEngineering, TennesseeTechnological University, Cookeville, TN 38505)

Measurementof fan noiserequires extremely careful control of a multipleof variables--includingfan operatingpoint and testsystem configuration--to obtain useful results. Frequently, fan noisemeasurements arecontaminated by unrecognizedfan or testsystem changes and spuriousnoise sources. A newfan testsystem wasdesigned to eliminateextraneous noise sources and to providegood control of the fan and the testsystem. Thissystem uses round sheet metal ducts to connectthe testfan to inletand discharge anechoic terminations. Rotatingmicrophone probes, one in the inletand one in the discharge,are usedto measureinduct SPL while the fan'sair performanceis beingdetermined. Two testsystems, one with a meandiameters of 8 in. and the otherof 16in., havebeen built. Measurementshave been made on both axial and centrifugal fans of sizesfrom 6 to 20 in. Representativeresults of thesemeasurements and data from recent studies of microphoneprobe design and surfacemicrophone systems use for in-duct noisemeasurements will be discussed.Data will also be presentedon the influenceof tip clearanceon axial fan noise.

9:20

A4. Air-movingdevices and active noisecontrol. D. A. Olson, S.S. Wise (Digisonix Division, Nelson Industries, Inc., Stoughton,WI 53589-0200), L. J. Eriksson,and M. C. Allie (Corporate Research Department,Nelson Industries, Inc., Stoughton,WI 53589-0600) Activenoise control presents unique advantages for the reductionof noisefrom air-movingdevices. These includeexcellent low- performance, minimal flow restriction,and ease of installation.In thispaper emphasiswill be placedon the useof activenoise control for silencingdischarge noise from fans.A recently developeddigital system using adaptive signal processing will be described.Results will be presentedfrom a numberof centrifugaland vaneaxial fans. Application guidelines have been developed to ensurethat thesystem performanceis maximized.These guidelines will be presentedusing results from actualfield testing.

9:45--10:00 Break

S2 J. Acoust.Soc. Am. Suppl. 1, Vol.85, Spring1989 117thMeeting: Acoustical Society of America S2 ContributedPapers

10:00 Suppressionof shock-associated noise from improperly expanded turbu- lentjet flowsissuing from a plugnozzle operated at off-designpressure AS. sources of low-speedjet impingementon a largefiat plate. ratiosis shown to bemore effective than that for jet flowsfrom an equiva- Allan Powell(Department of MechanicalEngineering, University of lent contouredconvergent-divergent nozzle operated in the over-and Houston, Houston, TX 77204-4792) underexpandedmodes. Jetimpingement on a largefiat normalplate produces a noisyturbu- lentdivergent wall jet. Asin themore general case, the image flow in the platecan be postulated and the "three sound-pressures theorem" applied (neglectingdissipation effects): For long wavelengths ("compact" flow), theaerodynamic sound sources must be reducible to lateralquadrupoles 10:45 alone,with maximanormal to andin that plane.Additional (usually weak??) shear dipoles associated with theviscous traction forces lie in the AS. Excitationof finite andinfinite length cylindrical shells by internal planeof theplate. Specifically, the large scale axisymmetric unsteady flow sound fields. William C. Ward (Noise Control Laboratory, The associated with the flow that sometimes occur resembles a PennsylvaniaState University, University Park, PA 16802) periodicseries of ringvortices that approach the plate and then spread out,symmetrically. Regardless of the details of this symmetrical unsteady Cylindricalshells, such as industrial piping system components, are flow,the associated source field must be periodic annular distributions of efficientlyexcited by broadbandinternal noise at discretefrequencies be- the lateralquadrupoles and tractiondipoles; in the long-wavelength low the ring frequency.Two typesof excitationare recognized:finite (compact)low-speed case these degenerate into symmetricalpoint lengthpipe resonances that are visible in shortpipes, and coincident exci- quadrupoles,one lateral and one longitudinal, yielding "U • laws"for sim- tationthat hasbeen studied for longor anechoicallyterminated pipes. plesimilarity. Dissipation results in "U•-type" monopolesdue to heat Bothmechanisms occur to varyingdegrees in pipesof anylength, and addition fluctuations. bothrequire that the acoustic and structural wavenumbers be closely (or exactly)matched. Because ducts possess an infinitenumber of potential coincidencefrequencies, coincidence transmission (i.e., precisely matchedwavenumbers) is dominant in pipes.In the limit for longshells, both mechanismsare dampingcontrolled and approachthe samelevels. Experimental data for short and intermediate shells show that coinci- 10:15 dence transmission ("infinite shell") can be the sole cause of vibration over widefrequency bands where the densityof resonantmodes is low. A A6. Sound sources of high-speedjet impingement.Alan Powell simpletheory is usedto predictthe frequencyand amplitude of response (Department of Mechanical Engineering,University of Houston, peakscaused by bothmechanisms. [Work supportedby NSF.] Houston, TX 77204-4792)

For high-speedflows the sourceregion is oftennot compact and the low-speedarguments are invalid:Then the motionof the flow boundary may provideinsight as to the nature of the soundsources. (i) When a "two-dimensional"jet impingeson a largeflat plate,the sinuousjet puffs 11:00 from sideto sideat the plate,approximated by simplesources separated by the high impedancejet. (ii) The high-speededge tone is similar. (iii) A9. Modeling of fluid-injection effects on flow noise. George For smallplates sound will begenerated by the axially symmetric modula- H. Christoph (Martin Marietta Laboratories, 1450 S. Rolling Road, tion of the strength of the unstablestand-off shock wave. Then, (a) Baltimore, MD 21227) changesin flowyield the totalannular simple'source strength or (b) the Basedon Naval UnderwaterSystems Center [communicationswith nearlyconical boundary of the flow envelopingthe plate appearsto vi- E. Payne of NUSC] and Soviet [Sov. Phys. Acoust. 30(5), 394-397 brate sympatheticallyproviding an alternativesource model. Some re- (1984) ] water-tunneldata, the Corcos wall-pressure model was modified suitsof an alternateapproach are given, in whichthe boundary is consid- to includefluid-injection effects. Boundary-layer parameters were used to ered to be generatingthe evanescentwaves, partially scatteredat modelthe wall-pressurefrequency spectral density and the longitudinal impingementor radiatingat initiation. cross-spectraldensity. Using predictions from a Martin Marietta bound- ary-layercode, favorable comparisons were made to the NUSC measured boundary-layerprofiles and wall-pressurefrequency spectra. Excellent agreementwas obtainedfor both the effect of injection rate and the re- duced effectivenessof fluid injection with distancefrom the injection source.Calculated wavenumber spectra showed that at low 10:30 (lessthan about200 Hz) spectrallevels increased with injection,while at higher frequenciesspectral levels decreased. The predictedconvective A7. Suppressionof shock-associatednoise from improperly expanded jet peaksshifted to higher wavenumbersdue to the decreasein convective flows.Darshan S. Dosanjh(Mechanical and AerospaceEngineering velocitywith increasinginjection rate. The rmswall pressuresare shown Department,Syracuse University, Syracuse, NY 13244) to increasefor all fluid-injectionrates. The modelpredicts that the large Experimentalaeroacoustic investigations of the reductionof intense flow-noisereductions (over 20 dB) obtainedin water-tunnelexperiments noiseradiated by improperlyexpanded turbulent jet flowsare reported. will not be achievedin full-scaleapplications. The noiseintensity varies with thestrength of therepetitive shock struc- ture inherentlypresent in improperlyexpanded jet flows.To reduce shock-associatednoise levels, the neededweakening of the repetitive shockstructure is achieved when improperly expanded jet flowsissue ( 1) froma plugnozzle with eithera contouredplug or a conicalperforated 11:15 plugoperated at a rangeof above-criticalpressure ratios; (2) fromcoaxial A10. Modeling of pressare-gradient effects on flow noise. George nozzlesof differentconfigurations operated in the inverted pressure H. Christoph (Martin Marietta Laboratories,1450 S. Rolling Road, mode.Farfield acoustic results and the supporting optical records of these Baltimore, MD 21227) improperlyexpanded jet flowsare presented.Striking changes in sound pressurelevel spectra, overall sound pressure level directivity, and sub- A methodologyto predict the effectsof pressuregradients on flow stantialreductions in theintensity of shock-associatednoise are reported. noiseis presented.The methodwas developed from the pressare-gradient

S3 J. Acoust.Soc. Am. Suppl. 1, Vol.85, Spring1989 117thMeeting: Acoustical Society of America S3 data of Schloemer[J. Acoust.Soc. Am. 42, 93-113 (1966) ] and of Bur- that thesedifferences are due to the waythat the adverse-pressuregradi- ton [MIT Acousticsand Vibration Lab. Rep. 70208-9 (1973)] and im- ents are formed. plementedwith theCorcos wall-pressure model. Predicted boundary-lay- er parametersyield a wall-pressurefrequency spectrum for a particular flowcondition, thus allowing one to predictconditions where data do not exist.For increasingpressure flows, rms wall pressureswere predicted to 11:30 beunaffected for Burton'stest cases but increasedfor Schloemer'sexperi- All. Correlating fan performance parameters and noise. Egons ments.This apparentcontradiction is in agreementwith the experiments. K. Dunens (Control Data CorporationARH268, 4201 N. Lexington Also, it is shownthat erroneousconclusions result from a zero-pressure- Avenue, Arden Hills, MN 55126) gradientwall-pressure model. Computationsof wavenumberspectra in adversegradients gave higher spectral levels except in thevicinity of con- Computercabinet designers choose fans based on their air flow char- vectivepeaks where levels are noticeablylower, especiallyat the high acteristicsbut noiseconcerns often have a significantimpact on the final frequencies.For Burton'stest cases, frequency-spectral-density calcula- cabinetdesign. Many physicaland operatingparameters can impactthe tionsshowed increases at low frequenciesand reductionsat highfrequen- fan noise.The noiseemissions from a large numberof fans have been cies,although not as dramaticas Burton'sdata indicatedfor the most measuredusing ANSI S12.11-1987. Regression analysis is usedto evalu- severeadverse-pressure gradients. Wall-pressure levels were predicted to atethe correlation of thevarious parameters to thefan noiselevel in order increaseat all frequenciesfor Schloemer'sdata. The modelclearly shows to understandtrade-offs at the initial designstage.

TUESDAY MORNING, 23 MAY 1989 COMSTOCK B, 8:00 A.M. TO 12:00 NOON

SessionB. Physical AcousticsI: Nonlinear Acoustics

David T. Blackstock, Chairman AppliedResearch Laboratories, University of Texas,Austin, Texas78713-8029

Invited Paper

8:00

B1. Nonlinear behaviorleading to real rarefactionshocks and related phenomena.P. A. Thompson (RensselaerPolytechnic Institute, Troy, NY 12181)

Early calculationsby Bethe,Zel'dovich, and othershave suggested the possibilityof rarefactionshocks in fluidsand solids.Recent experiments have demonstrated the existenceof rarefactionshocks in rubber( Kolsky and Rader), quartz (Barker and Hollenbach), iron (Erkman, lvanov, and Novikov), fluids at near-critical states(Borisov et al. ), and in evaporatingmixtures (Chaves, Thompson et al. ). Analogousdiscontinuities are foundin secondsound in superfluidhelium. The assertionthat all rarefactionshocks violate the secondlaw is untrue,both in theoryand practice! Physical experiments infiuids leading to a single-phaserarefaction shock, or to a completerarefaction-evaporation shock have, until now not been realized. ingredientsfor real rarefactionshocks include a negativenonlinearity parameter Y', usuallysome degree of metastability,Chap- man-Jouguetconditions, and in the caseof fluids,a largemolar heat capacity(many moleculardegrees of freedom). Examplesand relatedphenomena are discussed.

ContributedPapers

8:30 erties of the evolution of a sinusoidalwavetrain including the formation and propagationof expansionshocks and sonicshocks. Analytical solu- B2. Nonlinearwavetrains in densegases with large specificheats. M. tionsare presented for the inviscidproblem and are comparedto numeri- S. Cramer(Department of Engineering Science and Mechanics, Virginia cal solutionsdescribing the dissipativeevolution. PolytechnicInstitute and State University,Blacksburg, VA 24061), W. Pelz (Departmentof MathematicalScience, University of Akron, Akron, OH 44325), and L. T. Watson (Departmentof Computer 8:45 Science,Virginia Polytechnic Institute and State University, Blacksburg, VA 24O61) B3. Nonlinear propagation of sound beams in various media. E. A. Zabolotskaya (General Physics Institute of the USSR Academy of Periodicwavetrains propagating in fluidswhose specific heats are Sciences, 117942 Moscow, USSR) largecompared to themolal gas constant are examined. In thedense gas regime,the fundamentalnonlinearity parameter 1 + B/2A of thesefluids Approximatenonlinear equations describing the propagationof finite maybecome negative. The present study examines the nonclassical prop- amplitudesound beams in liquids,isotropic solids, and crystalsare sug-

S4 J. Acoust.Soc. Am. Suppl.1, Vol. 85, Spring1989 117th Meeting:Acoustical Society of America S4 gested.The equations have been derived under the assumptions of small A problemof continuousinterest in underwatersound propagation is perturbationand slow variation of thewave shape, which are due to dif- the predictionof the scatteringproperties of bubbles.Two importantpa- fractionand nonlinearity.Diffraction is takeninto accountwithin the quasiopticalapproximation. Nonlinearity is consideredup to quadratic A methodof measuringthese parameters, which is a modificationof a termsfor thecases of wavepropagation in liquidsand crystals, as well as bubble-sizingtechnique developed by V. L. Newhouseand P.M. Shankar forlongitudinal wave propagation in solids.As for nonlinear propagation [J. Acoust.Soc. Am. 75, 1473-1477 (1984) ] is described.The method of transversewaves in an isotropicsolid, cubic terms in themagnitude of exploitsthe nonlinear,mixing property of resonantbubbles simultaneous- the perturbationare retained. ly exposedto soundfields of differentfrequencies. The resultsof measure- mentsof bubbleradius and resonancedamping coefficient are presented forrameters bubblesinthishaving problemresonance arethe frequencies bubble'sradiusless thanand damping approximately coefficient. 100 kHz. Extensionof the techniqueto smallerbubbles is discussed.[Work conductedfor the Naval CoastalSystems Center and fundedby the Naval 9:00 PostgraduateSchool. ]

B4. Finiteamplitude effects on the propagationof a pulsedsound beam in a dissipativefluid. KjelI-Eivind Fr4ysa (Departmentof Mathematics, The University of Bergen, 5007 Bergen, Norway), Jacqueline Naze Tj•tta, and Sigve Tj4tta (Applied ResearchLaboratories, The 9:45 Universityof Texas at Austin,Austin, TX 78713-8029and Department of Mathematics,The Universityof Bergen,5007 Bergen,Norway) B7. Generallinearized solutions of the equationsOf bubble pulsations. Timothy M. Crossand Robert D. Finch (Department of Mechanical The linearand nonlinear propagation of a pulsedsound beam genera- Engineering,University of Houston,Houston, TX 77204-4792) ted by a real sourcein a fluid is considered.The sourcecan be planeor weaklyfocusing. The investigationis basedon a linearand quasilinear Previousattempts to find linearizedsolutions of the equationsfor va- solutionof the Khokhlov-Zabolotskaya-Kuznetsovnonlinear parabolic por bubblepulsations [e.g., seeFinch and Neppiras,J. Acoust.Soc. Am. equation.Analytical and numericalresults are presented.The evolution 53, 1402-1410 (1973) ] assumedthat oscillationswould be the result of of the pulseas it propagatesfrom the sourceinto the farfield region is imposedsonic excitation. It wasshown by Nicholasand Finch [ 12th lnt. investigatedfor variouspulse forms. The specialcase of a sourcewith Cong. Acoust., Toronto, paper 14-2 (1986) ] that nonlinearsolutions of distributionexp( - x2/a:)r(t) (x radialdistance, t time) is investigated theequations in factoften showed exponential expansions or collapses.In in detail,with emphasison the role of diffractionand absorptionon the this paperit is shownthat if the governingequations are linearizedusing a self-demodulationof the pulse.The resultsare relatedto the problemof Taylorseries expansion, without assuming either oscillatory or exponen- scatteringof soundby sound.[Work supportedby the IR&D programof tial behavior,then there are regimesof bubbleradius in whichone or the ARL:UT and VISTA/STATOIL, Norway. ] otherof thesetwo is a necessaryresult. The simplecase of a bubblewith an insolublegas content in a nonconductingliquid is considered.There can then be shownto exist a critical radius,with a value given by 2c/3yP, where• is the surfacetension, 7/ is the ratio of specificheats, and P is the gaspressure. Below this size the behavior is exponential, above it, oscilla- 9:15 tory. The resultscan be interpretedin termsof the stabilityof an open- loop controlsystem. BS. Effects of absorptionon the scatteringof soundby sound.Corinne M. Darvennes, Mark F. Hamilton (Department of Mechanical Engineering,The Universityof Texas at Austin, Austin, TX 78712- 1063), JacquelineNaze Tj•tta, and Sigve Tj•tta (Applied Research Laboratories,The Universityof Texasat Austin, Austin,TX 78713-8029, 10:00 and Departmentof Mathematics,The Universityof Bergen,5007 Bergen, Norway ) BS. Effects of nuclei and host fluid parameters on the threshold for cavitation producedby pulsed . Christy K. Holland and The scatteringof soundby soundin a losslessfluid was discussed at an Robert E. Apfel (Engineeringand Applied Sciences,Yale University, earlier meeting[Berntsen et al., J. Acoust.Soc. Am. Suppl. 1 83, S4 Yale Station #2159, New Haven, CT 06520) (1988), and Darvennesand Hamilton, J. Acoust.Soc. Am. Suppl. I 83, S4 (1988) ]. Here, the effectsof absorptionare included.The Khokhlov- An experimentalapparatus has been developed to determinethresh- Zabolotskaya-Kuznetsovequation is usedto derive farfield asymptotic oldsfor eavitationproduced in a fluidby shorttone bursts of ultrasoundat resultsfor the sumand differencefrequency sound due to the noncollinear 0.76, 0.99, and 2.30 MHz [A. Atchley et al., Ultrasonics26, 280-285 interactionof real soundbeams radiated from displacedsources. There (1988) ]. A fluid jet wasused to convectpotential cavitation nuclei, such are two main contributionsto the nonlinearlygenerated sound in the hs 1-/zmpolystyrene spheres, contrast spheres, and whole blood con- farfield:the continuouslypumped sound and the scatteredsound. Weak stituents,through the focalregion of the insonifyingtransducer. Cavita- absorptionaffects neither the locationsnor the relativeamplitudes of the tion thresholdsmeasured with thissystem in waterand in a fluid with ten pumpedand scattereddifference frequency sound. Strong absorption at- timesthe viscosityof waterwill be presented.Cavitation was detected by a tenuatesthe pumpeddifference frequency sound faster than the scattered passiveacoustical technique that issensitive to soundscattered from cavi- differencefrequency sound. The scatteredsum frequencysound is always tation bubbles.Results from theseexperiments that permit the controlof attenuatedfaster than the pumpedsum frequency sound, and theremay nucleiand host fluid properties will becompared to an approximatetheo- be shiftsin the locationsof the maxima. Numerical resultsare presented ry that predictsthe onsetof cavitation [C. K. Holland and R. E. Apfel, for the case of Gaussianprimary beams. [Work supportedby ONR Trans. IEEE UFFC-36(2) (1989)]. [Work supportedby NIH, grant (CMD and MFH), IR&D Programof ARL:UT, and VISTA/STATOIL number 1RO 1-CA-39374. ] (JNT and ST).]

10:15

9:30 B9. Possible observation of chaos in acoustics. Bill D. Cook (Cullen College of Engineering,University of Houston, Houston, TX 77204- B6. Measurementof bubble propertiesusing a multi-frequencysound 4792) field. Anthony A. Atchley, Robert A. Perton, and Ernest R. Lineberger (Physics Department, Naval PostgraduateSchool, Approximately20 yearsago, I observedan acousticphenomenon that Monterey, CA 93943) couldhave been chaos. Not understandingwhat I wasobserving, I found

S5 J. Acoust. Soc. Am. Suppl. 1, Vol. 85, Spring 1989 117th Meeting: AcousticalSociety of America S5 that I couldmaintain experimental conditions to preventit from occur- Linear wave propagationin periodicallyinhomogeneous media is ring.I did soin orderto completethe taskat hand.The studyinvolved characterizedby the divisionof the frequencyspectrum into regions understandingwhat conditions subharmonics were generated in an ultra- knownas passhands and stop bands, the waves (chlled Bloch waves) sonicstanding wave cavity. Two air-backedquartz transducerswere associatedwith whichare propagated and attenuated, respectively. A dis- placedin a Eabry-Perotconfiguration with water: one transducer having persionrelation is derived for zeroth-orderpropagation in a rectangular a resonantfrequency of aboutI MHz; the otheralways being at lower waveguide,which is.periodically loaded with rigidly terminatedside frequency.Their separation was adjustable to be between 5 to 10cm apart. branches.This dispersionrelation exhibits both the characteristicband The i-MHz transducerwas driven with a variablefrequency oscillator. At structureand, in the low-frequencylimit, Korteveg-DeVriesdispersion. sufficientpower and at somedriving frequencies, subharmonics were ob- For thecase of finiteamplitude pure tone excitation, a quasilinearanalysis servedboth optically and with a piezoelectrictransducer. Upon the onset showsthat parametricuptonversion is effectivelyblocked regardless of of subharmonics,an opticaldiffraction pattern displayed lines in between whetherthe secondharmonic frequency resides in a passhandor a stop the linesnormally observed. A frequencyanalyzer connected to thepiezo- band, thoughthe blockingmechanisms are fundamentallydifferent. A electrictransducer showed subharmonics and the correspondingidlers. 25.4-mmX 38.I-mm)< 6-m waveguidewas built with 38.I-mm-decp side- Under somehigher power conditions, the opticalpattern became a smear branchesat 0.1 m intervals.Early measurementsshow dispersion, band andthe frequency analyzer display became uninterpretable. In retrospect, structure,and second behavior qualitatively similar to analytic I now believewhat I wasobserving was chaos. andnumerical results. Possible applications in the studyof travelingwave amplificationand cnoidal wave/solitonpropagation are investigated. [Work supportedby Officeof Naval Research.]

10:30

B10. Nonlinear aspectsof the acousticlevitation of compressiblespheres. CharlesC. Church (National Center for PhysicalAcoustics, P.O. Box 847, University,MS 38677) 11:15

The useof acousticlevitation cells has become increasingly popular in Bl3. Oseillatory motion near a shape edge. Charles Thompson bothbasic research and industrial materials processing. Most theoretical (Department of Electrical Engineering,Laboratory for Advanced studiesof theforces involved have assumed a linearresponse of thelevirat- Computation,University of Lowell, I UniversityAvenue, Lowell, MA ed object to the acousticfield. In this study someof the effectsof the 01854) nonlinearresponses of highlycompressible spheres (i.e., gasbuhbles in a liquid) on the time-averageradiation force are described.The results The problemof lineartransmission of soundover a sharpedge is one of showthat, for example,as the pressureamplitude increases ( I ) the radius the oldestin acoustics.However, only recently has interestbeen taken in at whichthe force changes sign decreases: (2) the positionsin thefield at the nonlinearattenuation properties of suchstructures. A theoretical which the forceis maximalshift relativeto the positionsof the maxima modelfor the scatteringand dissipationacoustics will be presented.In determinedusing linear theory for radii lessthan the fundamentalreso- particular,the role that vorticitygeneration and transportplays will be nance;(3) at a fixedposition in the field, harmonicresonance responses discussed. producelocal maxima in the acousticforce. The presenceof the higher- order harmonicresonances also may be seenin calculationsof the levita- tion numberfor a suspendedbubble. Implications for levitatedliquid dropswill be discussed.[Work supportedby NIH. ]

11:30 10:45 BI4. Effect of an acoustic wave on mean-flow stability. BI L The useof acousticallevitation to study the coalescenceof oil drops CharlesThompson and Martin Manley (Department of Electrical in water. Edward Gardner and Robert Apfel (Department of Engineering,Laboratory for AdvancedComputation, University of MechanicalEngineering, Yale University,2159 Yale Station, New Lowell, I UniversityAvenue, Lowell, MA 01854) Haven, CT 06520) The interaction between an acoustic wave and a mean flow near the The behaviorof emulsionscomposed of immiscibleliquids has been surfaceof a bluff body will be discussed.The baseflow solutionwill be the objectof manytheoretical and experimentalstudies [for review,see presented.A nonlinearanalysis will beused to findthe region of validityof Cben et al., AIChE J. 30, 622-630 (1984) ]. The coalescenceof a drop the linear stability solution.Nonlinear effectswill be shownto stabilize separatedby a film from its homophasehas beenstudied to explain the disturbancesoutside the stagnationpoint region. stabilityof emulsions;there have not beenexperiments, however, on free drops contactingother free dropsover long periodsof time due to the difficultyencountered in containingthe drops.Acoustical radiation pres- sureprovides a meansof controllingf•e fluid dropsand wasconsidered for applicationto the studyof coalescence.Hexane drops were trapped by a 4S-kHz in a resonant water column. The time two drop• remainedin contactbefore coaleseing was measuredfor both pure and surfactantstabilized systems. This time wasthen compared to theoretical 11:45 predictionsand nonacousticalcoalescence experiments. [Work support- ed by the Heyi Foundation.] BIS. Acoustic streaming generated by surface oscillations. Charles Thompson and Vineet Mehta (Department of Electrical Engineering,Laboratory of Advanced Computation, University of Lowell, One University Avenue, Lowell, MA 01854)

11.-00 The resultsof a numericalanalysis of acousticstreaming caused by the oscillatoryflow over a two-dimensionalboundary will be presented.The BI2. Finite amplitude acoustic propagation in a periodic structure. effecl of spatial and temporal irregularity will be addressed.The validity CharlesE. Bradley(Applied Research Laboratories, The Universityof of modelsof the oscillatoryand time-averagedboundary layer will be Texas at Austin, P.O. Box 8029, Austin, TX 78713-8029) explored.

S6 J. Acoust.Soc. Am. Suppl. 1, VoL85, Spdng1989 117thMeeting: Acoustical Society of America S6 TUESDAY MORNING, 23 MAY 1989 REGENCY A, 8:00 TO 11:35 A.M.

SessionC. StructuralAcoustics and Vibration I: RaymondD. Mindlin Memorial Session

Sabih I. Hayek, Chairman Departmentof EngineeringScience and Mechanics, Applied Research Laboratory, Pennsylvania State University, UniversityPark, Pennsylvania16802

Chairman's Introduction---8:00

Invited Papers

8:15

CI. One-way propagationmodels for linearly elastic solids.John J. McCoy (School of Engineeringand Architecture,Catholic University of America,Pangborn Hall, Washington,DC 20064) One-waypropagation models for acousticenvironments have proven to bee•icient and robustas bases for generalpurpose computer programs. The availabilityofa distortionalmode of propagationfor a linearlyelastic solidenvironment and the coupling of thismode with the dilatational mode, in thepresence ofheterogeneity or of lateralsurfaces of mediumdiscontinuity, introduce additional complexity that is not yet completelyunder- stood.In this talk, an alternativederivation of one-waypropagation models to that of givingalgorithmic prescriptionto a squareroot of a sumofa multiplicativeand a differentialoperator is presented.Also discussed are the difficultiesencountered for linearlyelastic solids. A numberof numericalexamples are provided.

8:40

C2. Constructionof a mathematicalmodel of the nonlinear,dynamic mechanical properties of unreinforeed masonry.Hugh D. McNiven(Department of Civil EngineeringScience, University of California,Berkeley, CA 94720)

Thispresentation reports the resultsof a studyof theconstruction of a mathematicalmodel for predicting the nonlinearin-plane behavior of clay brick masonrywalls when subjected to dynamicexcitations. The constructionconsists of twostages: first the development of theform of themodel and then the establishment of theparameter functions appearing in it usingexperimental data and system identification. In previouswork with systemidentification, it was learned that there are several advantages if the system to bemodeled is linear. The optimizationis easyand cheapbecause the iterationsminimizing the costfunction converge rapidly. Perhaps,even more important is the fact that the transferfunction itself is optimizedrather than the time responseof the modelto a particularinput, as is the casewith nonlinearmodeling. Experiments consist of subjectingtwin walls of masonryto earthquake excitations on the shaking table at theEarthquake Engineering ResearchCenter (EERC), Universityof Californiaat Berkeley.The experimentswere designed so that the structurewas subjected to a seriesof earthquakeinputs of increasingintensity, but so that consecutive intensi- tiesdiffered by a smallamount. As a result,the responseto an individualexcitation, even in the nonlinear materialdomain ( followingcracking), is almostlinear. It wasassumed that thewall wouldbehave isotropical- ly. Thesubsequent form of themodel left two parameter functions to beestablished, one describes elastic- plasticstresses and dependson strains;the otherdescribes viscous stresses and is a functionof strainrates. Experimentaldata and system identification, using a particularoptimization algorithm, showed that both the shearmodulus of themasonry and its associated damping factor are bilinear. The experimentaltime histories of accelerationand displacement were compared with those predicted by the completed model. Even in thehighly nonlinearrange of materialbehavior, the two responseswere unusually close.

9:05

C3. Electroelasticinteractions, biasing states, and precisioncrystal resonators.H. F. Tiersten (Rensselaer PolytechnicInstitute, Troy, NY 12180-3590) In the interactionof the quasistaticelectric field with deformableinsulators, the conditionof rotational invariancecauses a combinationof the electricfield and the deformationgradients to occur in the constitutive equationsalong with the finitestrain. Since the resultingsystem is intrinsicallynonlinear, the lineardynamic equationsare moregeneral than those of linearpiezoelectricity when a biasis presentand reduceto themonly in the absenceof a bias.Even in thesimplest case of stress-freethermal deformation, which is just aboutalways present,the more general equations arise when the fixed reference coordinates at thereference temperature are

$7 J. Acoust.Soc. Am. Suppl. 1, Vol. 85, Spring1989 117th Meeting:Acoustical Society of America $7 employed.The advantage of theuse of referencecoordinates, which cannot be employed within the usual linear theory,in the accurate calculation ofthe temperature sensitivity ofhigh precision contoured quartz resonators isshown. In thetreatment, the equation for theperturbation in eigenfrequencyof the piezoelectric solution due to a bias,which is obtainedfrom the moregeneral linear equations, is employed.However, both the biasing stateand the vibrational solution are obtained by solvingsystems of unbiasedlinear equations. The changein frequencyresulting from any bias may readily be calculated from the perturbation equation when the linear piezoelectricsolutiofi and biasing state are known. The importance of thephenomenon of energy trapping in crystalresonators is discussedand means of controllingit arenoted.

9:30

C4.Temperature measurements and photographic observations of evolving adiabatic shear bands. J. Duffy (Divisionof Engineering,Brown University, Providence, RI 02912) Experimentsaredescribed inwhich the local temperature and local strain distribution are measured during theformation of adiabaticshear bands in steels.The specimenemployed is a shortthin-walled tube loaded dynamicallyin a torsionalKolsky bar (split-Hopkinson bar). Local temperature isdetermined by measuring theinfrared radiation emanating at 12neighboring points on the specimen's surface, including the shear band area.Indium-antimode elements are employed for this purpose to givethe temperature history during defor- mation.In addition,high-speed photographs are made of a gridpattern deposited on the specimen's surface, thusproviding a measureof thestrain distribution at variousstages during shear band formation. The results providea picture of thedeveloping strain localization process, ofthe temperature history within the forming shearband, and of theconsequence loss in theload capacity. It appearsthat plastic deformation follows a three- stageprocess that beginswith a homogeneousstrain state followed by a generallyinhomogeneous strain distribution,and finally by a narrowingof thelocalization into a fineshear band. Experimental results are comparedwith predictionsof variousmodels.

9:55 CS.Mindlin's equations of plated, crystal Plates for thin-film stress prediction. P.C. Y. Lee(Department of Civil Engineeringand Operations Research, Princeton University, Princeton, NJ 08544) Whenan electroded, crystal plate is subjected toa steadyacceleration and/or a steady,uniform tempera- ture change,stresses are induceddue to bodyforces exerted on the plateand electrodes,and due to the differencesin thermal expansions between the'plate and electrodes. Based on Mindlin's first-order equations of platedcrystal plates [ R. D. Mindlin,Progress inApplied Mechanics (Macmillan, New York, 1963 ), pp.73-84, PragerAnniversary Volume], a setof sixcoupled equations isobtained in whichthe thin-film stresses induced bythe body forces and thermal expansions are taken into account. A principleof virtualdisplacement corre- spondingto theseequations isalso obtained. In a partiallyelectroded, circular crystal disk, the stresses due to steadyacceleration are calculated,and the changesof thickness-shearfrequencies due to thesestresses are predicted.

10:20 C6.Theoryofsuperpotentialsinagraded-indexdieleetricwaveguide. RajK.Kaul, ThomasR. Hoffend, Jr., RaymondP. McArthur (State Universityof New York at Buffalo,Buffalo, NY 14260), and Kenneth T. Burke(Seton Hall College,South Orange, NI 07079) Thispaper deals with the theoryof dielectricwaveguides in a graded-indexmedia. The theoryis first developedin terms of electrical and magnetic potentiais and a gaugecondition which is a generalizationof the Lorentzgauge used in classical electromagnetic theory for the isotropic, homogeneous medium. The existence of thesepotentials under the generalized Loren tz gaugein thecontext of a generalizedHelmholtz theorem are thenproven. Even though this generalize d gauge uncouples the governing equations, it does not lead to partial differentialequations inthe normal form. To alleviate this problem, superpotentials ofthe HertzJan variety are introducedand it isshown how equations governing the vector superpotential can be reduced to a formwhich is amenableto standardanalysis. Then several uniqueness theorems associated with thissuperpotential are proven.As an illustrationof the useof the superpotentialand its relativemerits, it is appliedto certain waveguideproblems in an inhomogeneousmedium with variablepermittivity.

S8 J.Acoust. Soc. Am. Suppl. 1, Vol. 85, Spring 1989 117thMeeting: Acoustical Society of America S8 10:45

C7.Surface effects on impact response oflattices. James Tasi ( Departmentof MechanicalEngineering, State Universityof New York, StonyBrook, NY 11794) Ananalytical and computational study is given for the influence ofsurface conditions onthe normal impact responseof twoidentical crystal lattices. Early studies prescribed kinematic assumptions for shockconditions at the surfacesof crystallattices. These are comparedwith morerecent analysis that usessolutions of the dynamicequations of motionfor surfacesto determinethe shock condition for impact.In theabsence of any surfaceimpurities, long-range attractive forces exist and result in adhesionof thetwo lattices; during which, largetensile oscillations are generated prior to theadvent ofa compressiveregion of impact.The existence of a monolayerof surfaceimpurity on eachlattice results in a moretraditional shock impact condition ifa slightly attractivelong-range van der Waals minimum is ignored. If thelatter is considered, a combination of adhesion and traditionalshock impact condition are foundto exist.Asymptotic solutions of the nonlineardynamic surfaceequations are given for impactresponse and related to theearly kinematic studies. [ Work supported by NSF. ]

C8. Abstract withdrawn.

11:10

C9. Characterizationof woodfor violins.Daniel W. Haines (Schoolof Engineering,Manhattan College, Riverdale, NY 10471 )

Thetop and back of a violinare among the most important components ofthe instrument, both acoustically andstructurally. Centuries ago luthiers identified spruce as the ideal wood of thetop and maple as the nearly unanimouschoice for the back.This situationholds true today.Why is this so?The answersrests in the mechanicalproperties of thesewoods, particularly the properties that characterize the behavior of thetop and backin flexuralvibration. Five fundamental mechanical properties that hold most of thekeys to the acoustical andstructural qualities of spruceand maple are ( 1) density,(2) Young'smodulus and ( 3) dampingof waves travelingalong the grain, and (4) Young'smodulus and ( 5) dampingof waves traveling acr_oss the grain. Shear distortionalso affects the behavior of the vibratingspruce top andmaple back even at low frequencieswell withinthe audio range. Wood selection criteria and the influence of mechanicalproperties on the quality of the instrument will be discussed.

S9 J. Acoust.Soc. Am. $uppl. 1, Vol.85, Spring1989 117thMeeting: Acoustical Society of America S9 TUESDAY MORNING, 23 MAY 1989 COMSTOCK A, 8:30 TO 11:55 A.M.

SessionD. EngineeringAcoustics I and Noise II: New Developmentsin SoundPower Measurement

Robert Hickling, Chairman National Centerfor Physical/Iconstics,University, Mississippi 38677

Chairman's Introductions8:30

Invited Papers

8:35

DI. Review of ISO and ANSl standardsfor the determinationof soundpower levels of noisesources using sound intensity measurements.Malcolm J. Crocker (Department of Mechanical Engineering,Auburn University, Auburn, AL 36830)

Soundintensity measurements ca•l now be usedto determineaccurately the in situsound power of machin- ery noisesources in the presenceof high levelsof backgroundnoise. Meetings of workinggroup ISO/TC43/ SCI/WG25 beganin 1982and a firstdraft standardwas produced in late 1985.Meetings of workinggroup ANSI S12-21began in 1983and producedfirst draft of a standardin 1984.The ANSI draft standardwas circulatedfor ballotingas a standardin 1987,and the ISO thirddraft wascirculated in 1988.Although the and ANSI draftsare similar,there are somedifferences. The ISO draft allowsprecision, engineering, and surveygrade determinations and requiresfour indicatorsto be measuredto decidethe gradeachieved. The ANSI draft only allowsengineering determinations of soundpower. The ISO draft only allowsfixed point measurements,while the ANSI draft allowseither fixedpoint or scanningmeasurements of intensityon a surfaceenclosing the source.Last year, 17 laboratoriesin North Americatook part in a roundrobin using the ANSI draft.

9:00

D2. Implementationof a secondgeneration sound power test for productiontesting of earthmovingequipment. Lorne W. Tweed (EngineeringDepartment, TT-I, Caterpillar,Inc., EastPeoria• IL 61630-0945) Caterpillarhas developedan automatedsound power measurementsystem that measuresthe noiseof constructionequipment before it leavesthe assembly plant. This paper describes the test system and gives the resultsof verificationtests conducted at variousmanufacturing plants around the world. The new system allowsCaterpillar to quicklyand accuratelyacquire the data necessaryto ensurethat their productsmeet noise requirements.

9:25

D3. An indoorsound-power test for light vehicles.Robert Hickling and Lee N. Bolen,Jr. {National Center for PhysicalAcoustics, University, MS 38677) There is a needto developsound-power tests as standards for the noiseof manufacturedproducts, such as automobiles.For uniformityof testing,the testshave to be independentof the test location.Sound-intensity measurementscan be used for this,as has been demonstrated in testswith sixautomobiles. The soundpower of eachvehicle was measured for differentloads and enginespeeds, using a semicirculararray of sound-intensity probesrotated around the vehicleon a dynamometerroll. The testswere conductedat Clark Laboratory Servicesin a largework areawith a hard floorand high ceiling, with partiallyabsorbent material on the walls. There were no room resonancesapparent in ibe A-weighted vehicle sound-powerspectra. Also, theoretical estimateswith point sourcesin a reverberantroom showedthat the presenceof the wallsand ceilinghas a negligibleeffect on theA-weighted sound power of the vehicles.Good agreement was obtained with a standard referencesource. The resultswith thesix vehicles indicated that thepeaks in narrow-bandsound-power spectra canbe used to identifynoisy components in a vehiclepower train. [ Work supportedby theUnited States Officc of Naval Research.]

'S10 J.Acoust. Soc. Am. Suppl. 1, Vol. 85, Spring 1989 117thMeeting: Acoustical Society of America S10 9:50 D4. Estimatingsound power from discretemeasurements of sound intensity on a hemisphere.W. WestonMeyer (MathematicsDepartment, General Motors Research Laboratories, Warren, M[ 48090- •0S5) ß[n theory, total sound power radiated froma noise source canbe determined byintegrating thenormal componentofsound intensity over an arbitrary enclosing surface S.In practice,one must settle for approxima- tion,taking the sound power integral to be a weightedsum of intensitymeasurements at certain strategically locatednodes, or meshpoints,onS. Whatare the strategic locations, what are the weights, and what level of accuracycan be expected? The present paper attempts to answer these questions for the particular experimen- talsetup described in a recentpublication [ R. Hicklingand L. N. Bolen,"Indoor system for efficient measure- mentof thesound power of lightvehicles," NCPA Rep. RH-01-88]. Here, S isa hemisphereH plus circular baseB--the latter a physicalboundary that is perfectly reflective. The mesh covers H butnot B: it appears rectangularincylindrical projection, with longitudes equally spaced. Strategic positioning istherefore amatter of latitudeseleclion. Several schemes are discussed based on differentnotions of optimality,lhe meansof calculatingweights for each scheme are shown, and numerical evidence iscompiled to indicatethat levels of accuracyattainable, by applying the quadrature formulas to varioustest functions (chiefly monopoles}. The rapidfiucluations that can occurin the soundintensity function and the reasonsfor thiscondition are also discussed.

10:15

DS. Low-frequencyproblems in thedetermination and application of equipmentsound power ratings. Peter K. Baade(Noise and Vibration Control, Inc., 171Brookside Lane, Fayetteville, NY 13066) Thereis a growingconcern with low-frequency noise in buildings.Sound power ratings for thesources involved,however, typically do not inc]ode any data below the ] 25-Hzo•lave band because the present series of ANSI standards(S [.30-S 1.35) and their ISO counterparts for the determination of sound power, while not settingany low-frequency limits, do not provideany information on the measurementuncertainties for fre- quenciesbelow the ]2$-Hz band. In reverberationroom measurements, there •re at leasttwo types of low-frequencyproblems: ( 1 ) difficultiesinobtaining a valid space average of the sound pressure and (2) effects of theacoustic impedance seen by the source on its sound power output. The published literature on the second typecontains conflicting information. This issue is importantnot only for standardizingequipment sound powerdeterminations, but also for theproper application of equipmentsound power ratings.

ContributedPapers

10:40 duringstridulation. Sound fields were measured for threespecies of crick- ets.Two speciesof mole crickets,Scapteriscus acletu.• and s. oicinus,call D6. ANSI roundrobin test on determinationof soundpower from sound from within burrows constructed in the soil. Sound fields of the mole intensity. U. S. Shirahatti, Malcolm J. Crocker (Department of crickets were hemisphericaland the power output averaged4 ttW MechanicalEngineering, Auburn University,Auburn. AL 36830}, and (3( = 22, range2-22/tW). Poweroutput wasdependent upon male size Richard J. Peppin(Scantek, Inc., Rockville, MD 20850) and moisturecontent of soilsurrounding the burrow. Efficiencyof sound Theuse of thesound intensity technique to determine the sound power productionwas estimated to beless than 0.2%. Soundfields of a speciesof outputof a sourcehas become very popular over the years. An American treecrickets, Oecanthus quadripunctatus, approximated that of a doublet NationalStandards Institute committee, ANSI S12-21,is currentlyen- source.Power output ranged from 2-17/•W (N = 6) and efficiencywas gagedin developinga suitable standard for makingsound power measure- estimated at about 1%. menIsusing the sound intensity technique. The draft versionof the pro- posedstandard permits the useof bothfixed point measurements and also continoushand scanning on theenclosed surface. To checkthe validityof thesound power measurements and to helpmake suitable changes to the 11:10 measurementprocedure, many optionaldata quality indicatorsare also includedin the draft_Recently, the workinggroup ANSl S12-21orga- Dg. Automated soundpower measurementsystem for indoor testing of nized a round robin test on a standardreference sound power sourceß motorvehicle noise. U.D. Dietschi(ClarkLaboratoryServices, 821 East Variousorganizations across the United Statesparticipated in the round Fronl Slreet, Buchanan, MI 49107) robin test.This papersummarizes and discussesthe soundpower mea- Indoornoise testing of motorvehicles poses advantages not offered by surement results obtained on the reference sound source. the conventionaloutdoor pass-by test method.The soundpower of a motor vehiclecan be determinedby measuringsound intensity over a surfaceenclosing the vehicle.Due to its geometricsimplicity, a hemi- spherewas chosen for this purpose.In orderto facilitateefficient measure- 10:55 mentof soundintensity on a hemisphere,large enough to enclosean auto- D7. Power out0ut and efficiencyof soundproduction by crickets. T. mobilesituation on chassisdynamometer rolls, a specialstructure was O. Forresl (National Center for Physical Acoustics, Universily, MS designed to carr• the intensity measurement probes.The structure was 38677] semicircularin shapemade up of two concentricsections. The inner sec- tion with the measurementprobes was hinged to theouter support struc- Male cricketsproduce calling songsthat function to attract mates. ture suchthat it couldbe loweredinto a positionproviding easy access to Soundis producedwhen membranesof the wingsare causedto vibrate the microphonesfor calibrationpurposes. Truss sections were used in the

Sl 1 d. Acoust.Soc. Am. Suppl. 1, Vol.85, Spdng! 989 1! 7th Meeting:Acoustical Society of America S11 constructionof the microphoneboom to presentas small an interference similarto the original spectrum. This method only applies to bandlimited to the soundfield as possible.The entirestructure was suspended at its steadysignals. apexand was driven by a steppermotor via suitable reduction gearing. Controlof thestepper motor was provided by a computerprogrammed to completeeither continuous sweeps of the hemisphere orin a discreteman- ner,stopping the microphone boom at equalangular increments. 11:40

DI0. An acousticintensity measurement simulation for evaluating•ound 11:25 powerdetermination standards. Frederic Laville, Jean-Luc Agnan, and Jean Nicolas (Groupe d'Acoustiquede l'Universit•dc Sherbrooke, D9. Application of Gerchberg's iteration algorithm to noise spectrum D•partcrncnt de G•ni½ M•canique, Univcrsit• de Sherbrooke, restoration. Mei Q. Wu and Malcolm J. Crocker (Department of Sherbrooke,Quebec J iK 2R l, Canada) MechanicalEngineering, Auburn University,Auburn, AL 36849) Work hasbeen done for severalyears on the standardizationof sound In noisecontrol engineering,there are many caseswhere a steady powerdetermination using acoustic intensity measurements. The ¾alida- noiseis overlapped by an impulsenoise. Some information about the noise tionof thestandards through testing is difficult because of thelarge num- sourcecan be obtained by analyzingthe frequency spectrum of thesteady ber of measurementconditions to be tested.To help overcomethis prob- signal.But whenthe impulsesignal is overlapped on thesteady signal, the lem,a computercode simulating the measurementhas been developed. spectrumof the combinedsignal is usuallydifferent for the spectrumof Whereaspast attempts have been limited to specialcases, the developed theoriginal steady signal. One way to removethe effect of the impulseis to codeis intendedto handlecases that integratemore of the industrial filter it off in the time domain.By doingthis, sometime samplesof the reality.The measurednoise sources as well as the extraneous noise sources steadysignal are removedalso. The spectrumof the filteredsignal may are modeledby any numberof monopolesfor whichthe userspecifies still be differentfrom the spectrumof the originalsteady signal. In this theirquantity, source strength, location, relative phase, and degreeof paper,Gerchberg's iterative algorithm was used to restorethe lost time coherence.This approach offers computational simplicity as well as the samplesand henceto restorethe spectrumof the steadynoise. Experi- possibilityto modelrealistic radiation patterns such as plate radiation. mentswere conductd on idealizednoise sources where the spectrum of the The proposedISO standard(ISO/DP 9614) isevaluated for a plateradi- steadynoise was known. From the experimentalresults, it is seenthat the atingin the presenceof backgroundnoise. Recommended corrective ac- spectrumrestored by Gerehberg'siterative algorithm coverges toward tionswere found appropriate for farfieldmeasurements and inapropriate the originalspectrum. After 25 iterations,the restoredspectrum is very for nearfield measurements.

TUESDAY MORNING, 23 MAY 1989 NEWHOUSE II, ROOM 254, 8:30 TO 11:55 A.M.

SessionE. PhysiologicalAcoustics I, PsychologicalAcoustics I, and SpeechCommunication I: Interactions betweenNeurophysiology and {Sponsored in part by the AFOSR}

ChristopherW. Turner, Chairman Departmentof CommunicationSciences and Disorders,Syracuse University, 805 S. CrouseAvenue, Syracuse, New York 13244

Chairman's Introduction--8:30

Invited Papers

8:35

El. Evolving ideas of co,blear soundanalysis and stimulus representationin hearing. Julius L. Goldstein (Central Institute for the Deaf, St. Louis,MO 63 ! 10) Classicalprinciples ofcochlear operation and function in hearingare undergoing major revision because of recentbiophysicai discoveries that normalcochlear sound analysis is largelydetermined by centrallycon- trollednonlinear motor responses from the outer hair cells and that neural temporal entrainment can represent monauralstimulus information. Helmholtz's psychophysically and anatomicallybased hypothesis of tono- topiccochlear analysis is fully supported,but revisionis requiredof the classicalmodel he inspired,of that analysisas a tonotopicarray of linearfilters passively monitored by short-memoryenergy detectors. Chal- lengesto theclassical model have been presented throughout the history of auditoryscience from psychophys- icalstudies of combinationtones, idiotones, masking, and periodicity pitch. Hence, it isproposed that psycho- physicscan now be exploited systematically and interactively with biophysicalknowledge to contributeto developingthe required revised cochlear principles. To getbeyond the establishment of correlationsbetween

S12 J. Acoust.Soc. Am. Suppl. 1, VoL85, Spring1989 117thMeeting: Acoustical Society of Amedca S12 psychophysicaland biophysical data for specific phenomena, models of somegenerality are needed for coch- learnonclassical responses and for psychophysicalmeasurement. It is proposedthat idealobserver theory providesa generalworking hypothesis that has been successful in filling the second need. A newsignal process- ing modelfor nonlinearand activecochlear frequency analysis was formulated to fill the first need.Two modelingstudies of the relationshipbetween psychophysics and physiologywill be describedin detailfor periodicitypitch and nonlinearmasking.

9:15

E2. Effects of duration on intensity discrimination:Psychophysical data and predictionsfrom single-cell response.R. R. Fay, W. P. Shofner,and R. H. Dye (Parmly Hearing Institute, Loyola Universityof Chicago,6525 North SheridanRoad, Chicago,IL 60626)

An ROC analysiswas performedon responsesof singleauditory-nerve fibers (goldfish) and cochlear nucleuscells (gerbil) in orderto predictintensity discrimination (in thegoldfish and human) as a functionof signalduration. To evaluatethat the meanand variabilityof spikecounts within singleunits account for psychophysicalperformance, spike number distributions were obtained ( N = 100) for severaldurations ( 20 to 400 ms) andlevel differences (0.54 dB) at a unit'sbest frequency. The percentcorrect performance based on spikecounts was found by generatingROC curvesfrom empirical distributions and computing the area under the ROC [P(A)]. Theoreticalpsychometric functions were compared with psychometricfunctions from humanand goldfishlisteners obtained using a 2IFC paradigm(human) and a ratingmethod in classical respiratoryconditioning (goldfish). The forms of theneural and psychophysical duration functions are similar in the mammaland the fish,but the fishshows higher thresholds compared with the humanand with the neurophysiologicalpredictions. In general,psychophysical performance is well modeledby the optimum processingof spikecounts from individual cells. [Work supportedby a CenterGrant from NINCDS.]

9:45

E3. Physiologicalcorrelates of forwardmasking in singlenerve-fiber and compound neural responses recorded fromthe auditory nerve. Evan M. Relkin,John R. Doucet,Robert L. Smith(Department of Bioengineering, Institutefor SensoryResearch, Syracuse University, Syracuse, NY 13244-5290),and Christopher W. Turner (Departmentof Communication Sciences and Disorders, Institute for Sensory Research, Syracuse, NY 13244- 5290) Maskingcan be defined as a reductionin thedetectability of onesound stimulus, the probe, due to the presenceofa secondsound stimulus, the masker. Reduction in detectabilitycan be quantified by measuring the increasein thresholdfor thedetection of theprobe tone. Most previous studies of thecorrelates of forward maskingin theauditory nerve have measured reductions in averagedresponses to theprobe produced by the masker.It isnot possible to relatereductions in averagedresponses to changes in detectabilitysince detectabil- ity dependson responsemagnitude and variance.However, two-interval forced procedures can be usedto measuredetection thresholds for spiketrains of primary,single nerve fibers [Relkin and Pelli, J. Acoust.Soc. Am. 82, 1679-169[(1987) ] andN• of thecompound potential (CAP) [Relkinand Smith, J. Acoust. Soc.Am. Suppl. 1 83, S98 (1988) 1. Relkin and Turner [J. Acoust. Soc. Am. 84, 584--591 (1988) ] showedthat thereare large discrepancies between behavioral thresholds and thresholds for singlenerve fibers for forward masking.Particularly at highmasker levels, thresholds for thedetection of theprobe in theactivity of single fibersare moresensitive than those measured behaviorally. Several hypotheses that mightexplain this discrep- ancyinclude the effects of spatial and/or temporal processing of theresponses ofsingle neurons. These hypoth- esesare beginning to betested using both single fiber and compound neural recordings. Forward masking of the CAP is moresimilar to behavioralforward masking than is forwardmasking in singleneurons, suggesting a spatialsummation effect. Methods for measuringperistimulus compound potentials have also been developed to investigatetemporal effects such as the relativeimportance of onsetand steady-state responses.

10:15-10:25 Break

S13 J. Acoust.Soc. Am. Suppl. 1, Vol.85, Spring1989 117thMeeting: Acoustical Society of America S13 10:25

E4. Physiologicalmechanisms of masking and intensity discrimination. Bertrand Delgutte (Research Laboratoryof Electronics,Massachusetts Institute of Technology,Cambridge, MA 0213% and Eaton- PeabodyLaboratory of AuditoryPhysiology, Massachusetts Eye and Ear Infirmary,Boston, MA 02114) Recentelectrophysiological studies in whichstimulus paradigms were designed to mimicthose of psycho- physicssuggest that a broadrange of psychophysicaldata on maskingand intensitydiscrimination can be simplyexplained by assuming that signal detection is primarily based on averagedischarge rate informal ion in auditory-nervefibers, provided that informationfrom high-thresholdfibers is takeninto account.These stud- iesfurther suggest that tone-on-tonemasking is due both to spreadof theexcitation produced by the maskerto thesignal place along the cochlea,and to suppressionof thesignal by the masker,with the relativeimportance of the two mechanismsdepending on maskerlevel and frequencyseparation between signal and musket.In particular,two-tone rate suppression is largelyresponsible for the upwardspread of maskingat highmasker levelsand for differencesbetween simultaneous and nonsimultaneousmasking techniques. New resultswill alsobe presentedon unmaskingdue to suppressionof the maskerby the signal,improvements in signal detectabilityby off-frequencylistening, and the role of olivocochlearefferents in signaldetection. [Work supportedby NIH Grant NS13126.l

10:55

ES. Interactionsbetween nearophysiology and sl•ech distrimination.Donal G. Sinex,Lynn P. McDonald, andJohn B. Mort (Universityof California,Los Alamos National Laboratory, Physiology Group, M882, Los Alamos, NM 87545)

Psychophysicalapproaches have provided much information about the processingof speechsounds by humansand alsoby laboratoryanimals. These studies establish the essentialfunctions of the auditorysystem thatmust be explained and define the limits over which they operate. However, processing mechanisms cannot bediscovered by psychophysicalapproaches. Details about mechanisms must come from neurophysiological studies.This view has guided this investigation of theprocessing of voiceonset time (VOT), a complexacoustic cuethat differentiatesbetween consonants such as/d/and/t/. The peripheralneural representation of¾OT syllableswas studied, asking which (if any) propertiesof the neuralresponses correlated with the resultsof psychophysicalexperiments conducted by Kuhl and Miller [J. Acoust.Soc. Am. 63, 905-917 (1978); 70, 340- 349 ( 1981) ]. The psychophysicalfindings provided a standardagainst which hypotheses about the representa- tionof VOT informationcould be evaluated. As a result,it waspossible to identifya neuralmechanism in the auditory peripherythal may contribuleto the formationof phoneticcategories based on voicing. [Work supportedby NS23242 from NINCDS. ]

11:25

E6. Problems and opportunitiesin extending psyehophysieal/physiologicalcorrelation into the central nervoussystem. Eric D. Young (Departmentof BiomedicalEngineering and Center for HearingSciences, The JohnsHopkins Universily, Baltimore. MD 21205)

Becauseauditory-nerve fibers form a relativelyhomogeneous population, it is possibleto build modelsthat accountfor psychophysicalperformance on thebasis of auditory-nerveresponse properties using rather direct assumptions.However, when this analysis is extended to theCNS, theproblems become more complex because of thediversity of differentresponse types and the multiplicity of parallelcentral pathways. At minimum,one is facedwith parallelanalyses of severalsystems. some of which may not be relevantto the psychophysical problembeing analyzed. One approach has been to usenatural stimuli whose behavioral significance for the animal is clear and to analyzebehavioral and physiologicalresponses to thosestimuli in the sameanimal. Examplesof successfulapplication of thisapproach are bat sonarand barn-owlsound localization. Another approachis to usethe propertiesof directionally selectivespectral shaping by the pinna to definestimuli with knownbehavioral relevance. Examples taken from the cat cochlearnucleus will be usedto illuslratethe issues raisedabove. [ Work supportedby Grant NS 12524from N INCDS/NIDCD. ]

S14 d. Acoust.Soc. Am. Suppl.1, VoL 85, Spring1989 117th Meeting:Acoustical Society of America $14 TUESDAY MORNING, 23 MAY 1989 AMPHITHEATER, 8:45 A.M. TO 12:00 NOON

SessionF. Architectural AcousticsI: Room Acousticsfor Film and TelevisionProduction, Post-Production, and Cinema Spaces

Elizabeth A. Cohen, Chairman CharlesM. Salter Associates,Inc., 930 MontgomeryStreet, San Francisco,California 94133

Chairman's Introduetion-•8:45

Invited Papers

8:50

Fl. Roomacoustics for THX • motion-picturetheaters. Tomlinson Holman (Schoolof Cinema-Television, Universityof SouthernCalifornia, Los Angeles, CA 90089-2211and LucasfilmLtd., Box2009, San Rafael, CA 94912)

TheTHX" SoundSystem is installed in over300 premium motion-picture theaters and dubbing facilities worldwide.An importantpart of the programis specifiedroom acoustics, including both local acoustical environmentof loudspeakersand global room acoustics issues including background and intrusivenoise control and reverberationtime criteria. Acousticalstandards established for this programwill be examined, and the methodsof measurementwill be explained.Time-honored techniques such as usingappropriate measurementmicrophones forthe sound fields encountered, aswell as time and space averaging, are applied in new,more portable, forms.

9:30

F2. Temporalversus spatial considerations in referenceloudspeaker systems. George L. At•gspurger (Perception,Incorporated, Box 39536, Los Angeles, CA 90039) Until recently,the performance of loudspeakersystems used for musicmixdown or cinemareproduction hasbeen specified in termsof on-axisonechoir frequency response or l/3-octroom response. Now, readily availabletest methodsallow measurementof delaycharacteristics as easilyas conventionalfrequency re- spouse.So-called "time-corrected" playback systems, in fact,exhibit a widerange of temporaland spatial behavior.Theoretical and measured data are presented that indicate strong interaction between spatial side effectsand listening room acoustics. Subjective and objective trade-offs are discussed for three typical playback situations.

10:10

F3. Electroacousticsin the OMNIMAX • theater---Challengeand opportunity. Alvis F. Wales (Sonics Associates,Inc., 237 Oxmoor Circle, Birmingham,AL 35209) IMAX'" andOMNIMAX'" filmshave significantly advanced the realismand impact of motionpicture presentations.Toderive full benefit from the giant screen, the theater acoustics and sound reproduction system mustbe equal in qualityto thepicture. Most IMAX andOMNIMAX theatershave seen new construction, whichpermits a higherlevel of acousticalperformance and noise control than most other cinemas. OMNI- MAX theaters,in particular,pose special acoustical problems because ofthe focusing effect of the dome screen, combinedwith the tendencyof architectsto choosean acousticallydifficult shape (such as a cylinder,a hemisphere,or even a sphere)for the enclosing building. To permitfull spatialand directional effects, the theateracoustics are designed to berelatively nonreverberant, leaving the "ambience" and sound "images" to becreated by the sound track rather than dominated by the theater acoustics. Particular attention is paid to the soundsystem in termsof frequencyresponse, dynamic range, and imaging capability.

S15 J. Acoust.Soc. Am. Suppl. 1, Vol.85, Spring1989 117thMeeting: Acoustical Society of America S15 ContributedPapers

Modem auditoriumacoustics measures have been successfully used to objectivelyassess changes to auditoria.This paperreports the useof the F4. The reflectionphase grating diffusor: A five-year progressreport. sametechniques to assessthe acousticalchanges introduced in hallsby Peter D'Antonio (RPG DiffusorSystems, Inc., i 2003 WimbletonStreet, threetypes of electroacousticsystems. These were: a film soundsystem Largo,MD 20772) and two different room acousticsmodification systems. The RAMSoft The reflectionphase grating diffusor, RPG, whichis basedon math- room acousticsmeasurement program was usedwith broadbandexpo- ematicalnumber theory sequences suggested by ManfredSchroeder, has nentialpulses as the sourcesignal. The programcalculates 12 different broughtto architecturalacoustics a missingdesign ingredient--broad- quantitiesin eachof sixoctave bands and permits an evaluationin termsof bandwidthwide-angle sound diffusion--and opened up many possibilities the needsfor bothspeech and music.While oneof the roommodification for acousticalconsultants and architects.The RPG diffusorsystem was systemswas not found to be very effective,the other producedconsider- firstintroducted into the recordingindustry in 1983and in theshort span able increasesin reverberationalong with somerelated effects. Reposi- of 5 yearshas becomea standardingredient in hundredsof forefront tioningof the film soundsystem loudspeakers was shown to improvethe recording/broadcastfacilities, worship spaces, corporate conference/te- performanceof the system. The results clearly demonstrate the value of leconferenceand A/V facilities,performing arts facilities, and homelis- objectiveevaluations of electroacousticsystems in rooms. tening rooms.A few installationsinclude The Oak Ridge Boys, Peter Gabriel, Whitney Houston,CBS Records,Telarc, DMP, Polygram,CBS- TV, NBC, CBC, BBC, WQXR, WFMT, HoustonGrand Opera, Chrysler Hall, Kentucky Center for the PerformingArts, Word of Faith Minis- tries, Crenshaw Christian Church, Clear Lake United Methodist Church, Duke University,SUNY, and Lakeland College.This presentationwill comprehensivelyreview the theoreticaland experimentalperformance characteristicsof theRPG andexamine a broadspectrum of applications. 11:20 Many casestudy photos and TEF timeand frequency response measure- mentswill be presented. F6. Electronicequipment noise in videofacilities. Timothy J. Foulkes (CavanaughTocci Associates,Inc., 327 F BostonPost Road, Sudbury, MA 01776)

Noisefrom electronicequipment is a significantproblem for many 11:OS videostudios and ancillaryfacilities. Frequent efforts to controlroom ventilationnoise are negatedby noisycomponents that mustbe located FS. Assessing electroacoustic systems with auditorium acoustics within the critical spacesthemselves. This paperwill reviewacoustical measures.J. S. Bradley and R. E. Halliwell (Institute for Researchin designconsiderations for a few recentcase histories. Measured data from Construction, National Research Council, Montreal Road, Ottawa, severalcompleted facilities and strategiesfor noisecontrol will be dis- Ontario K 1A 0R6, Canada) cussed.

11:3.5-12:00 Panel Discussion

TUESDAY MORNING, 23 MAY 1989 REGENCY C, 9:00 TO 11:35 A.M.

Session G. Underwater Acoustics I: Acoustic Fields

Stanley M. F!att6, Chairman PhysicsDepartment, University of California,Santa Cruz, California 95064

Chairman's lntroduction--9:fiO

Contributed Papers

9:05 throughmatched field processing (MFP}. Frequencydomain MFP G1. Matched field processingfor a movingsource. John M. Ozard, Gary (FDMFP) is very effectivefor a stationarysource. However, there is an H. Brooke, and Scott Tinis (Defence Research Establishment Pacific, implicit averagingover time in FDMFP throughthe useof the Fourier FMO Victoria, British Columbia V0S lB0, Canada) transform and a further averagingif the covariancematrix is formed. Consequently,if the soundsource is moving,the averagingof the time The detectionor localizationof a soundsource in a multipathor multi- dependentsignal will leadto an increasein ambiguityof the sourceposi- mode environmentis improvedby taking the multipathsinto account tion and a lossin array gain.When the sourceis moving,the received

S16 J. Acoust.Soc. Am. Suppl. 1, Vol.85, Spring1989 117thMeeting: Acoustical Society of America $16 signalcontains information about both source position and source mo- 9:50 tion.To takefull advantage of theinformation in the time sequence, MFP in thetime domain (TDMFP) wasimplemented. TDMFP is equivalent G4. Source localization: Matched field versusmatched mode. Synthetic to obtainingthe narrow-band gain and MFP gainin onestep through the and real data performance analysis. Sergio M. Jesus and Rachel useof a Fouriertransform modified by thepropagation. Simulated results M. Hamson(SACLANTUnderseaResearchCentre, I-19026LaSpezia, confirmthe improvedlocalization and arraygain of TDMFP compared Italy) to FDMFP for a movingsource. The presentstudy compares the matched field and the matchedmode techniquesfor passivelylocalizing a narrow-bandpoint source in a shal- low-water, range-independentenvironment. The matched mode tech- niqueis fully characterizedin termsof sidelobeambiguity performance androbustness against both system and environment parameter variation and mismatch.Comparative results are alsoshown for real data detection 9;20 of a cw sourceimmerged at differentdepths in a 120-mdepth channel usinga 62-m aperturevertical array. The resultsof thisstudy indicate that G2. A stable data adaptivemethod for matched-fieldarray processingin the matched mode method is much less sensitive to the environmental acousticwaveguides. C. L. Byrne,R. I. Brent conditionsthan the matchedfield method,and in particular,the resultis Mathematics,University of Lowell, Lowcll, MA 01854•,C. FcuilladcJ lessdegraded by th• effectsof partial watercolumn sampling (short ar- (SYNTEK, Inc.,2101 E. JcffcrsonStreet, Rockville, MD ray). Resultsobtained on realdata showedgood agreement with the cor- R. DelBalzo( Nava1OceanRescarch and Devclopment Activity, Stennis respondingtests from simulated data. However, a largesidelobe coverage SpaceCenter, MS 39529-5004) wasfound for somesituations leading to detectionlosses. Major causesof performancedegradation are the uncertaintyon thearray sensor position The presenceof a "modal noise"component 1cads to estimatorinsta- due to array motionand correlatednoise due, mainly, to surface-genera- bility whenCapoh'S maximum likelihood (ML) methodis appliedto the ted noise. proccssiogof data from a vertical array in an acousticwaveguide. The physicsof the waveguideforces signal vectors and noisevectors alike to be projectedonto the spanof the "mode" vectors,when the numberof sen- sors(N) exceedsthe numberof propagatingmodes (M). The instability occurswhenever the (singlesnapshot) N X 1 data vectorshave the form x = Us -F U¾ -F white noise,where the matrix U is N X M (samplingthe 10:05 normalmodes at the hydrophonelocations and independentof the actual acousticdisturbances present), and s and ¾ correspondto signaland am- GS. Broadband acoustic-field simulations from standard ray theory. bientnoise sources, respectively. This conditionarises in normal-mode StanleyM. Flattr, John Colosi,Timothy F. Dude,Galina Roynet,and andlocal normal-mode propagation. The dominant eigenvectors of R Jan Martin (PhysicsDepartment, University of California,Santa Cruz, (whereR isthe cross-spectral matrix) are sensitive to slightinaccuracies CA 95064) in the calculationof R • in waysthat affectthe performanceof the ML The completewave field over a smallregion around 1000 km froma estimator.Following transformation of the N X Nmatrix R to the M X M pulsedsource is reconstructedin two ways.First, all therays from the modalspace cross-spectral matrix T, Capoh'smethod is appliedto T to sourceto a verticalarray of receiversat 1000km are found,along with obtain the "reducedmaximum likelihood" (RML) estimator.This pro- their traveltimes, number of caustics,arrival angles, and intensities.The cedure,which is a developmentof thesector focused stability technique of patternof wavefronts in a spaceat a giventime is then reconstructed on a Steeleand Byrne [Proceed. ISSPA 87, 24-28 August 1987, Brisbane, closelyspaced grid surrounding1000 km by treatingthese rays in an Australia,pp. 408•12], largelyeliminates instabilities due to inaccurate appropriateway. Second, the parabolic equation method isused at multi- inversionof R. Simulationsare presentedfor a shallow-waterenviron- plefrequencies to synthesizea pulse. The twofields are compared. Final- ment to providecomparison between the ML and the RML estimators. ly, the effectof internal wavesis simulatedby useof the first method, Theseindicate that the degreeof instabilitydepends upon the level of introducingrandom fluctuations on the travel times and arrival angles of noise(both correlatednoise and white noise)and that a significantim- eachray. [Work supportedby ONR, Code1125OA.] provementin performancecan be expected by useof theRML estimator in both cases.

9:35

G3. A symmetrx•'en-rmalization method for matched-modesidelobe 10:20 reduction.Ge• B. Smit•nd George M.Frichter, IV(Naval Ocean Researchand evD•ent Activity, StennisSpace Center, MS 39529- G6. Acousticwave front distortionsat long rangesfrom internal waves. 5004) Timothy F. Duda and Stanley M. Flatt6 (Physics Department, Universityof California,Santa Cruz, CA 95064) Current matched-fieldresearch at NORDA is centeredon techniques thatattempt to matchmeasured and predicted modal amplitudes for im- In the absenceof small-scalevariations on s•und speedin the ocean,a proveddetection and localizationof acousticsources in shallow-water pulsedsource delivers a seriesof smoothwave fronts onto a verticalarray waveguides.Ambiguity functions generated by thesemodal estimators at longrange from the source (multiray propagation). Small-scale varia- displaya sidelobestructure that issymmetric about the true source peak. tions such as internal wavesinduce distortionson the wave fronts with This symmetryrepresents additional information about the signalloca- transversecorrelation function determined by the phase-structurefunc- tion, which can be usedto further enhancedetection. Here, a simplecorre- tion, whichis itselfcalculable by integratingappropriate functions along lationalgorithm is presentedwhich enhances the signalpeak and sup- the trajectoryof an undistortedray. Expressionsfor the phase-structure pressessidelobes by renormalizingeach point of theambiguity function in functionat smallseparations have been previously given in the form of accordancewith the symmetryaround that point.Since a renormalized arrival-anglespreads due to internalwaves, but these expressions are only ambiguityfunction retains the rangesymmetry of the original,the tech- for verticalreceiver separations up to about 100 m. Evaluationsof the niquecan (within limits) be applied iteratively. Computer simulations of phase-structurefunction for separationsup to severalkilometers are pre- a shallow-waterPekeris waveguide are usedto demonstratethe effective- sented,and particularrealizations of wavefront distortionsthat result nessof renormalizationwhen applied to both narrow-bandand frequen- from theseinternal-wave effects are shown.[Work supportedby ONR, cy-averagedmode matching. Code 1125OA.]

S17 J. Acoust.Soc. Am. Suppl. 1, Vol.85, Spring1989 117thMeeting: Acoustical Society of America S17 10:35 izedby a classicalrange-independent sound channel at 700 m. The search for the bestestimated profile is conductedby varyingthe soundchannel G7. Preliminary results from the 1988 Monterey Bay acoustic axisstrength and depth in themodified Munk equationwhile maintaining tomographyexperiment.JamesH. Miller (DepartmentofElectricaland a constantsound-speed profile at great depths.Differences between the Computer Engineering,Code 62Mr, Naval PostgraduateSchool, estimatedand measured profiles are less than ñ 2 m/s; thesound channel Monterey, CA 93943), James F. Lynch (Department of Ocean axisdepth is determinedwithin 20 m of the measuredaxis depth. Exten- Engineering,Woods Hole OceanographicInstitution, Woods Hole, MA sionof thisapproach to includemesoscale features and greaterrange is 02543), and Ching-SangChiu (Department of Oceanography,Naval discussed. PostgraduateSchool, Monterey, CA 93943)

An oceanacoustic tomography experiment was held 12-16 December 1988near Monterey, California. The objectivesof thisexperiment were to test a tomographicsystem to analyzethe effectsof oceansurface waves, 11:05 internalwaves, and complexthree-dimensional bathymetry on long- rangeacoustic propagation. An acousticsource with a centerfrequency of G9. Localizationschemes for beam-typesources. I. T. Lu (Department 224 Hz and sourcelevel of 177 dB wasplaced on a seamount30 km off of Electrical Engineeringand Computer Science/WeberResearch PointSur. Seven modified SOhObUoys (with anchor,bottom-mounted hy- Institute,Polytechnic University, Farmingdale, NY 11735) drophones,large capacity batteries, and large floats) were placed in Mon- tereyBay to receivethe acoustic signals at rangesof 35 to 60 km fromthe A time-harmonicisotropic source in stratifiedwaveguides can be lo- source.The SOhObUoyrf signalswere received,demodulated, and the calizedby performingmatched-field processing in "modespace." Be- acousticdata were recorded on shore. Oceanographic measurements were causethe range and depth information of thesource are contained only in taken (for comparisonwith the acousticallyderived results) with a sur- thephase and magnitude, respectively, of complexmodel amplitudes, the face wave frequency-directionalspectra buoy, surface wave frequency rangeand depthdata can be processedindependently. This is not true for spectrabuoys, CTD yo-yo'sfor internalwave spectra, ADCP, and con- beam-typesources. When propagating in a waveguide,an initiallycolli- ventionalhydrographic survey for sound-speedprofiles. Preliminary matedbeam undergoes diffusion after successivereflections and refrac- analysesand comparisonof the acousticand oceanographicmeasure- tionsand is convertedeventually into theoscillatory pattern of oneor mentswill be presented.An outlineof what the completeanalysis will moreguided modes. However, the upgoing and downgoing plane wave entailwill alsobe presented.[Work supportedby ONR andNaval Post- constituentsofa givenmode do not have the same excitation strength as in graduateSchool Research Council. ] the caseof isotropicsources. Here, localizationschemes of a Gaussian beamsource that is modeledvia thecomplex source point technique are considered.The beamdirection, beam width parameter, and waist loca- tionare determined in "modespace." The procedure isgreatly simplified if thesource is a well-collimatedbeam. [Work supported by NSF.] •,• •0Y'• l0:50 GS. Sound-speeddetermination using matched field processing techniques. C. Karangelen (International Business Machines Corporation,Manassas, VA 22110) andO. Diachok (Code 5120,Naval 11:20 ResearchLaboratory, Washington, DC 20375-5000} G10.Source localization by inversionof theparabolic equation method. Matchedfield processing isshown to beeffective for estimating sound SusanM. Bates(MS 171,Raytheon Submarine Signal Division, 1847 speedin a deep,range-independent ocean environment. The amplitude West Main Road, Portsmouth, RI 02871-1087) and Bruce J. Bates andphase of signalsfrom a distantsource measured on a largeaperture (Building1171, Naval Underwater Systems Center, Newport, RI 02841) verticalarray are sensitive to changesin soundspeed. This sensitivity is exploitedto infer the environmental sound-speed profile by matching pre- The inversesplit-step parabolic equation method is derived.Spatial dictedand measured amplitude and phase. A sound-speedprofile model is localizationof singleand multiple low-frequency harmonic point sources developedbased on a modifiedversion of Munk's canonicalsound field in a deepocean is demonstratedby usingsimulated pressure field mea- equation.This model is used to determinesound-speed profile using a 15- surementsfrom a verticalarray. In addition,the method is appliedto a Hz signalfrom a 240-m explosivesource detected on a 675-m vertical sourceextended in rangeand depth.This methodis solvedin a single array at a rangeof 50 km in a deep-waterPacific environment, character- iteration,unlike some inverse techniques that vary parameters.

S18 J.Acoust. Soc. Am. Suppl. 1, Vol. 85, Spring 1989 117thMeeting: Acoustical Society of America S18 TUESDAY AFTERNOON, 23 MAY 1989 REGENCY A, 1:00TO 4:50 P.M.

SessionH. EngineeringAcoustics II and PhysicalAcoustics II: Warren P. Mason Memorial Session

Harry B. Miller, Chairman Naval UnderwaterSystems Center, New London,Connecticut 06320

Chairman's Introductlon--l:00

Invited Papers

1:05

HI.Warren P. Mason(1900-1986), physicist, engineer, inventor, author, teacher. Robert N. Thurston,David A. Smith,Jane Baran,Kwok Cheung,and John Johnson(Bellcore, Room 3X-223, Red Bank, NJ 07701- 7040)

Warren Perry Mason, a Charter Member, Fellow, President,and Gold Medalist of the AcousticalSociety of America, consistentlyapplied his understandingof fundamentalsto explainphysical processes and create practicaldevices. As a physicist,he ledus to a betterunderstanding of fundamentaleffects in liquidsand solids. He made the first measurementof shearelasticity in liquidsand helpedestablish the type of motion that polymerchains can make.In solids,he contributedto quantitativeunderstandings of phonondrag on charge carriersin semiconductors,fatigue of metals,and damping of acousticwaves in metals,insulators, semiconduc- tors,alloys, and rocks.As an engineerand inventor,he led advancesin mufflersand noisecontrol, electrome- chanicalfilters for carrier-frequencytelephony, piezoelectric crystals and ceramicsfor electromechanical transducers,and semiconductorstrain gauges. With about200 patents,he is the mostprolific inventor in the historyof Bell Labs.As an authorand teacher,he wroteover 200 papersand 4 referencebooks that teach fundamentalconcepts, give completetensorial descriptions of numerousphysical interactions in crystals, describeresearch results, and guide the reader to therelated literature. This talk will sampleMason's contribu- tionsto physicalacoustics and will givean exampleof a communicationsdevice made at Bellcore,in which Masonwould surely have been interested, namely an acousticallytuned optical filter lB. L. Heftnetet al., Electron. Lett. 24, 1562-1563 (1988)].

1:30

H2. An equivalentcircuit appreciationof Warren P. Mason.Arthur Ballato (U.S. Army Electronics Technology& DevicesLaboratory LABCOM, Fort Monmouth,NJ 07703-5000) WarrenMason was a manof manyparts and prolific in themall. Onearea in whichhe exercised a decisive influencewas that of equivalentnetwork representations of electromechanical systems. This papersalutes Mason'saccomplishments inhelping to bridgethe disciplines ofacoustics and electronics. It begins with a brief discussionof analogsand describes the Butterworth-VanDyke circuit of a piezoelectricvibrator. This is where Masonstarted his productive work in the subject,introducing acoustic transmission lines, mechanical ports, andpiezoelectric transformers. Today, the Mason equivalent circuit is universallyused for bulkand surface acousticwave device characterization. It hasalso given rise to a varietyof alternativeformulations such as analognetworks, the KLM equivalentcircuit, and systems models, which are discussed.

1:55

H3. Piezoelectricceramic compositional development. Don Berlincourt(Channel Prod ucts, Inc., 21 Kenton Road, Chagrin Falls, OH 44022) The originalpiezoelectric ceramic material was unmodifiedbarium titanate. It waslittle usedexcept as compositionallymodified. The earliestwork was by W. P. Mason,and this led to improvedcharacteristics for sonartransducers and then to phonographcartridge applications. By the mid 1950s,lead titanate zirconate materialswere shownby B. Jaffeto have higherpiezoelectric coupling and applicationat a much higher temperature.Over the next 10 years, many modified compositions were developed. These led to muchim- provedsonar systems and ultrasoniccleaners and to applicationsin ultrasonicbonders, stereo phonograph cartridgesand evenprinters. The new compositionsalso made possible applications such as piezoelectric ceramicfilters, gas ignition devices, and camera flashbulb actuators. More recently,specialized ceramics have beendeveloped based on lead titanateand lead metaniobate,but major effortshave been directed to applica- tionsof lead titanatezirconate compositions, which now touchvirtually every homeand automobile.The history of compositionalstudies with ferroelectricceramics is reviewedand the types of characteristics achievedare summarized.The compositionaladditives and somegeneral principles to explaintheir behavior are discussed.

S19 J. Acoust.Soc. Am. Suppl.1, Vol. 85, Spring1989 117th Meeting:Acoustical Society of America S19 2:20

H4. Acousticalfilters in plane-wavefields. Richard K. Cook (4111 Bel Pre Road, Rockville, MD 20853)

Lumped-parameteracoustical filters were thoroughly described by Warren P. Masonin his bookon elec- tromechanicaltransducers and wave filters.Today, the filteringaction of open-endedcircular (standing- wave)tubes and of plane-parallelwaveguides is described. The descriptionis most simply in termsof thespatial wavefields of open-endedtubes and slots.These were first analyzed accurately by L. A. Weinstein(Vaynsh- teyn) in the 1940s-1950sfor bothacoustical and electromagnetic waves. The basicmathematical technique wasdetailed examination of thediffracted field as a waveemerged from the openend after propagation inside thewaveguide. The solutionsto thediffraction problems are applied, in acousticalengineering, to theaccurate analysisof openresonators, as well as to the analysisof probetubes used for measurementof soundfields. Earlier investigatorshad been able to do no morethan arriveat roughapproximations in the form of "end corrections"to the lengthof a resonatingcircular tube, fianged at its openend.

2:45

HS. Using piezoelectricfilm and ultrasoundresonance to determinethe completeelastic tensor in one measurement.J. D. Maynard (The PennsylvaniaState University, 104 Davey Lab, UniversityPark, PA 16802)

Theultrasonic and elastic properties of materials is conventionally measured using quartz, lithium niobate, etc.,transducers and a pulse-echotechnique with thetransducer driven at .Some problems include transducerringing, transducer bonding, parallelism of samplefaces, beam diffraction, and the necessityof remountingtransducers in order to measureall of theelastic constants. Usually these problems can be mini- mized,but, with samplesthat areonly a fractionof a millimeterin size,conventional ultrasound measurement becomesdifficult, if notimpossible. However, nearly all of theseproblems disappear ifa resonancetechnique is used,and all of the elasticconstants may be determinedwith a singlemeasurement. For the broadband responseand minimum loading by thetransducer required for a resonancemeasurement in a smallsample, polyvinylidenefiouride (PVDF) piezoelectricfilm asthin as9/xm is ideallysuitable. Small active areas and leadsare produced with metalizationpatterns on eachside of the PVDF film. For resonancemeasurements, electricalcross talk across the small sample is processed byfrequency modulating the drive and using phase sensitivedetection. Samples with dimensions of onlya fewhundred microns may be measured with large signal-to-noiseratios. [Work supportedby theOffice of NavalResearch and NSF GrantDMR 8701682.]

3:10

H6. Acousticcavitation 42 years after the Briggs,Johnson, and Mason paper.Robert E. Apfel (Yale University,Department of MechanicalEngineering, P.O. Box2159, New Haven,CT 06520) WarrenMason was one of theearly pioneers of high-powerultrasonics who studied its effectson liquids [Briggset al., J. Acoust.Soc. Am 19, 664-677 (1947) ]. One of theseeffects is acousticallyinduced bubble activity.Such activity can be desirable,as in ultrasoniccleaning, or undesirable,as with cavitationon sonar transducers.This talk will reviewthe basicphysics underlying the onsetof cavitation,the dynamicsof bubble motion,and the effectscaused by cavitation,with emphasison how to optimizeor minimizethese effects, dependingon theapplication. [Much of thiswork has been supported by theOtfice of NavalResearch and by the National Institutesof Health throughGrant 1R01CA39374. ]

3:35

H7. TheMason horn, extension and applications. D. N. Beshers(Henry Krumb School of Mines,Columbia University,New York, NY 10027) WarrenP. Mason,in the mid 1950s,introduced the invertedexponential horn as a concentratorof ultra- sonicwaves. In 1968,he publishedan extendedaccount of a steppedapproximation to theexponential horn. Part of the hornwas replaced by a half-wavelengthpiece that functionedas a mechanicaltransformer with a stepreduction in diameterat thequarter-wave point. The specimen was shaped like a dumbbellto give a mass- spring-massresonance with a furtherstep down in diameter.The resultwas a substantialreduction in areaand thusan increasein vibratorystress. The apparatusmay also be describedas a compositeresonant oscillator: Eachof the threeelements, transducer, transformer, and specimen,is at resonance.Mason developed the theoryof thisstepped horn only for perfect resonance, and allowed for damping only in thereduced part of the specimen.Here, his theory is extendedto allow for small deviationsfrom resonance,such as must occur in practice,and for dampingin theother elements. When the damping and the deviations from resonance are small,simple sum rules hold. Variations in specimendesign are also considered. Applications, past and future, will be discussed.

S20 J. Acoust.Soc. Am. Suppl. 1, Vol.85, Spring1989 117thMeeting: Acoustical Society of America S20 4:00

HS. Resonanceof a parallelepipedto determinesingle-crystal elastic constants up to 1800 K. Orson L. Anderson(Institute of Geophysicsand Planetary Physics, University of Californiaat LosAngeles, Los Angeles,CA 90024-1567) Theexperimental free oscillation spectrum of a rectangularparallelepiped specimen of a singlecrystal has beenobtained on corundumup to 1800K, usingbuffer rods to separatethe specimen from transducers. By inversiontechniques, a theoretical spectrum can be generated,which depends upon the elasticconstants, crystalsymmetry, and dimensions. Using computational techniques involving the inversion of largematrices, a setof elasticconstants isfound that produces a theoretical spectrum matching the experimental spectrum out to about40 modes.Using this technique,the mineralphysics laboratory of UCLA hasdetermined the elastic constantsCO and dCij/dT asfunctions of Twith goodprecision up to temperaturesfar in excessof theDebye temperature.Some of the resultsfor MgO include:the accuratedetermination of the Griineisenparameter to highT; the conclusion that (c)Cv/c)T)e = 0 at hightemperature (i.e., there is no perceptible anharmonicity in specificheat); and the findingthat the artharmonicparameters 6s and•5. r areindependent of Tat high T.

4:25

H9, Warren P. [Mason:Some brief encounters,some long memories. Louis R. Testardi (PhysicsDepartment, Florida State University, Tallahassee,FL 32306)

My introductionto the scienceof acousticsand my first meetingwith Warren Mason were nearly simulta- neousif notsynonomous events at BellLabs during the mid 1960s.Living in thehouse of thegiant has left some memoriesand helpedshape some personal views on the natureof humanachievement and the diversityof greatness.I'll recountsome of theways our pathscrossed over the ensuing 20 yearsand try to explainhow his influencewent beyondwhat I could haveimagined at that first meeting.

TUESDAY AFTERNOON, 23 MAY 1989 AMPHITHEATER, 1:00 TO 5:10 P.M.

SessionI. Noise III: Alalalicationof "Modern Spectral Analysis" Techniquesto Noise Problems

Patricia Davies, Cochairman Ray W. Herrick Laboratory,Purdue Unioersity,West Lafayette, Indiana 47907

J. Stewart Bolton, Cochairman Ray W. Herrick Laboratory,Purdue University,West Lafayette, Indiana 47907

Chairman's Introduction--l:00

Invited Papers

1:05

11. Tutorial: Signal processingmethods for machinery diagnostics.Richard H. Lyon (Department of MechanicalEngineering, Massachusetts Institute of Technology,Cambridge, MA 02139)

Conventionalmachinery monitoring systems rely mainly on signalenergy processing methods such as powerspectrum analyses in the frequencydomain and envelopeanalysis in the time domain.Other, lesswell- known, techniquescan be very usefulin extractingdiagnostic information from the vibrationor soundpro- ducedfrom the machineas it operates.These methods include ccpst ral analysisas an order analysisor deconvo- lution procedure,and am and fm demodulationusing the Hilbert transformto studyvariations in loadingor speedof rotationaldevices. They alsoinclude various system modeling methods such as Kalman filteringand functionalexpansions of the transferfunction. Illustrations of the useof thesemethods, and descriptionsof situationsin which eachmay be helpfulwill be presentedin this tutorial.

S21 J. Acoust.Soc. Am.Suppl. 1, Vol. 85, Spring1989 117th Meeting:Acoustical Society of America S21 1:40

I2. Time-frequency spectra for nonstationaryacoustic signals--The Wigher distribution, the evolutionary spectrum,the modifiedmoving window spectrum, and their interrelationships.$ennie Moss, Jong-Sik Lee, Panos G. Adamopoulos, and Joseph K. Hammond (Institute of Sound and Vibration Research, SouthamptonUniversity, Southampton $09 5NH, England) The time-frequencydescription of acousticsignals is a commonrequirement (applications include speech, sonagrams,frequency tracking, etc. ), and this appliesto transientsand nonstationarysignals (both random and nonrandom). Three time-frequencyspectra that are usedare the Wigher-Ville distribution,Pri½stley's evolutionaryspectral density, and Kodera's modification to themoving spectrogram. This paper will present:a summaryof the definitionsand computationof thesethree different time-frequency spectra; the modelingof acousticsignals due to propagatingsources in a formallowing prediction of time-frequencyspectra; develop- mentof theinterrelationships between the spectra; and theoretical and simulation results from time-frequency spectra.Examples of theapplication of all threeapproaches will beillustrated by usingfrequency-modulated signals.The signalswill modelsound as perceivedby an observerdue to a convectingacoustic source (i.e., includingDoppler, range, and directivityeITects). The sourcesignal will exhibitboth tonal and random components.

2:00

13. Median adaptive filtering for spectral line enhancement.Tarek I. Haweel and Peter M. Clarkson (Departmentof Electricaland Computer Engineering, Illinois Institute of Technology,Chicago, IL 60616) Adaptiveline enhancementusing the well-knownLMS algorithmis a techniquefor the enhancementof low-levelperiodic components of unknownfrequency in a backgroundof broadbandnoise. The LMS filter operatesby iterativelyminimizing a quadraticindex using an instantaneousestimate of the gradientof the quadraticperformance surface to updatethe filtercoefficients. Provided the adaptationrate is sufficiently small,the filter usually performs well. If theinput data are corrupted by impulsivenoise, however, the filter is badlydegraded, and the adaptive process may actually fail. This paper addresses this problem by defining a medianleast-mean-squares (MLMS) algorithmwhere the instantaneousgradient estimate of the LMS is replacedby thesample median of thatparameter. The MLMS filteris compared, through simulation, with the LMS andwith an alternative gradient smoother that utilizes the sam pie mean ( theALMS algorithm).Results demonstratethat the MLMS is largelyinsensitive to the presenceof impulsiveinterference and performs comparablywith the LMS and ALMS whenno interferenceis present.

2:20

14. Measurementof the equivalentpoint sourceposition for an arbitrary distributionof sources.S. A. L. Gleggand J. R. Yoon (Departmentof OceanEngineering, Florida Atlantic University,Boca Raton, FL 33431 )

In manyapplications, knowledge of theequivalent point source position of a sourcedistribution isrequired for noisecontrol calculations. For instance,the insertion loss of a noisebarrier depends on theheight of the noisesource above the ground, and some estimate of thismust be used at thedesign stage. The equivalent point sourceposition is defined as the location at whicha singlesource would be placed to givethe best representation of the acousticfield over the largestpossible solid angle. This paperwill describehow the equivalentpoint sourceposition can be measuredusing parametric methods. Least-squares estimators using a microphone array are shownto be of limited value,especially at low frequencies,and often the bestresults are obtained usinga two-microphonemethod. [Work sponsoredby the FloridaDepartment of Transportation.]

2:40-2:55 Break

S22 J. Acoust.Soc. Am. Suppl. 1, Vol.85, Spring1989 117thMeeting: Acoustical Society of America S22 ContributedPapers

2:55 a sphericalwave model then provides source bearing, range, and ampli- tudeestimation. However, even for largeantennas, the spatial resolution I5. Accuratespectral estimation of multiplesinusolds using an FFT. John of thisnearfield beamforming is limitedto a wavelengthfraction. To in- C. Burgess(Department of MechanicalEngineering, University of creasethe localizationaccuracy, especially for low frequencies,"high- Hawaii, Honolulu, HI 98622) resolution"methods should be used.This paperpresents, in thiscase, Accurateestimates of amplitude,frequency, and phase of multiple Capoh'smethod, also called adaptive beamforming. It's performances sinusoldsin a signalcan be obtained using a methoddescribed earlier [J. andresolving power are computed and validated through numerical sim- C. Burgess,J. Acoust.Soc. Am. Suppl.1 83, S9'.!(1988) ]. The FFT size ulations.They extendto the nearfieldcase the resultsusually found in a requiredfor specifiedspectral resolution is discussed,as well as some farfield situation. However, much more drasticallythan with plane computationalaspects. waves, experimental resultsshow that this method breaks down if the sourcemodel mismatches the wavefronts actually received. To avoidthis strongmodel sensitivity, a robustapproach, extending the spectralden- sity matrixsource subspace, is proposed.This methodyields correct esti- mationof theamplitude and position of sourcestoo close to beresolved by linearprocessing. This enhancementof Capoh'Smethod does not require 3:10 anaccurate source model. In addition,it hasa lowcomputational cost and I6. Interior idle noise in current model pffssengercars. Timothy is not nearfielddependent. [Work supportedby DCN. ] J. Foulkes(Cavanaugh Tocci Associates, Inc., 327 F BostonPost Road, Sudbury, MA 01776)

The author, a consultan[in ,became interest- ingin thevast differences in interiornoise levels between passenger cars in today's market. Octave-bandnoise levelswere measuredin 20 different 3:55 automobilemodels. In order to reducethe numberof variables,the mea- I9. Cancellationof noise in the presenceof signalsof short duration. surementswere limited to thedriver's position with thecar stopped and Vijay Raman, Osama A. Mohammed, Kang Yen, and Kurt Ramdin engineat idle. In the 31-Hz band,noise levels varied 20 dB betweentwo (Departmentof ElectricalEngineering, Florida International University, differentmodels by the samemanufacturer. The rangeof A-weighted Miami, FL 33199) levelsspanned only 8 riB.While the A-weighted sound levels as published by most consumermagazines provide some indication of relative loud- This work focuses on the active cancellation of acoustic noise in indus- ness,examination of octave-band levels shows radical differencesbetween trial environmentssuch as factories, airports, etc., by the useof earphones models.Some observations and conclusionsare drawnby an "enlight- with active components.An important considerationin this problemis ened" consumer. that undesiredcomponents (noise) shouldbe reducedwithout eliminat- ing certain desiredsignals. More specifically,the cancellationtechnique mustincorporate the significantconstraint that warningsounds and brief verbalexchanges must not be canceled. Achieving this goal is particularly difficult when the characteristicsof the desiredsignals resemble that of the noise. In the courseof this work, these researchershave usedthe fact that thesesounds are of relativelyshort duration, whereas the ambient 3:25 noiseenvironment is persistent,to formulate and evaluateappropriate I7. Measurementsof vehicle noisesource height for noise barrier design. signaldetection and adaptive noise-canceling schemes. The filteringalgo- StewartA. L. Gleggand J. R. Yoon (Departmentof OceanEngineering, rithm adoptedis a variation of the well-knownadaptive least-mean- FloridaAtlantic University,Boca Raton, FL 33431) squaresalgorithm. [Work supportedby the Florida High Technology and Industry Council.] The heightofa imisebarrier required to givea certaininsertion loss is stronglydependent on the elevationof the noisesource above the ground. Currently, noisebarrier designmethods assume equivalent point source heightsfor differenttypes of vehicles,but thesehave never been substan- tiatedby measurements.This studyused a microphonearray, with para- metricprocessing, to evaluatethe equivalentnoise source height of 100 4:10 differentvehicles. The resultsgive the noisesource position as a function of frequencybetween 200 Hz and 2.5 kHz. The relative importanceof I10. Sound power level and directivity pattern determination of a space engine,stack and tire noiseon thesource height is apparent.It wasfound shuttle solid rocket booster. Thomas S. Adams (Ebasco Services, that the equivalentsource on heavytrucks is at 1.2 m, mediumtrucks 0.7 Incorporated,145 Technology Park/Atlanta, Norcross,GA 30092) m, and smallvehicles 0.6 m, abovethe ground.[Work sponsoredby Flor- The soundpower level and directivity pattern of soundwere deter- ida Departmentof Transportation.] minedfor a spaceshuttle solid rocket booster motor during a horizontal testfiring at theMorton ThiokolWasatch Test Facility in Utah. Six Bruel & Kjaer type 2230 precisionsound level meterswere placedat 60-deg intervals around the rocket motor at a distance of 1000 ft, except the locationdirectly behind the nozzle (2600 ft). These analyzerswere used to determinethe overallsound-pressure level, between 20 and 20 000 Hz, at eachof the six locationsduring the test.Two Cetec-Iviemodel IE-30A 3:40 audiospectrum analyzers were used to determinethe shapeof the spec- I8. Nearfield high-resolutionsource localization. Paul Bertrand (Office trum at a one-thirdoctave band resolution.The equipmentwas turned on National d'Etqdes et de RecherchesA•rospatiales, BP 72, 92322 approximately2 h prior to the scheduledtest and wasunattended during Chfi.tillon Cedex, France) the test.Various adjustments were made to the data to accountfor topo- graphic and atmosphericeffects. The sound producedwas predominantly An exampie of passiveacoustic array processingconsists of localizing low frequency,and the directivitypattern exhibited major acousticlobes the emanatingmachinery noise sources along a shipshell. When possible, 60 degto bothsides of the line offire. A total overallsound power level of an efficientway to increasethe poor accuracyof this localizationis to 196dB wasdetermined. [Work fundedby NASA StennisSpace Center, movethe array Fresnelzone up to the sources.A linearbeamforming with Mississippi.]

S23 J. Acoust.Soc. Am. Suppl.1, Vol. 85, Spring1989 117thMeeting: Acoustical Society of America S23 4:25 where0i isthe angle of thesaw teeth, and A, isthe nth Fourier coefficient, whichis a functionof 0 andrepresents the amplitude of thecutting noise. I! 1. Resultsof a computerslmulation scheme for activenoise reduction. A conventionalcircular saw has a veryhigh noise level when n isequal to Kang Yen, Vijay Raman,Osama A. Mohammed,and Kurt Ramdin integermultiples of the numberof teeth.This highpure-tone noise level ( Departmentof ElectricalEngineering, Florida InternationalUniversity, can be reduced and distributed to other n values if the saw teeth are un- Miami, FL 33199) evenlyspaced. In thisresearch, an optimizationalgorithm is usedso that This paperpresents the resultsof a computersimulation scheme for A, isclose to beinga constant.Producibility of thenoise-suppression saws active noiseminimization in a random noise-cancelingheadphone. The hasbeen considered during design. Experiments have been conducted to noise-cancelingalgorithm was developedin a separatepaper by these verifythe newdesign. This work is veryhelpful in improvingthe working authors.The performanceof the noise-cancelingalgorithm has been test- environmentof the woodworkingfactory. ed via digitalsimulation of the actualnoise field distributions within the ear canal.Farfield conditions have been assumed by the modelingenvir- onmental noise field to be due to sources far from the cancellation headset. The ear is initially modeledas an axisymmetricpipe, and the resulting field is calculatedas a functionof the locationof noisecanceling sources. The resultsproved helpful in determiningthe appropriatelocations of the noice-cancelingsources in order to achievemaximum noise energy reduc- tion at a predeterminedpoint in the pipe. [Projectsupported by the Flor- 4:55 ida High Technologyand IndustryCouncil. ] I13. Noise measurementson machinery near a reflecting plane. J. B. Moreland and F. S. McKendree (WestinghouseR&D Center, 1310 BeulahRoad, Pittsburgh,PA 15235) Noisetest specifications for largeequipment often requires that the 4:40 measurementsbe madewith the equipmentout-of-doors resting on the ground(usually a smooth,paved surface), and with thesound level meter I12. Developmentof noise-suppressionsaws. T. I. Liu (Departmentof microphonepositioned between 1 and 2 m abovethe ground.Construc- Mechanical Engineering, California State University--Sacramento, tiveand destructiveinterference between the soundradiated directly from Sacramento, CA 95819) the equipmentand the soundreflected from the groundproduces a sound Conventionalwood-cutting saws have even-spaced teeth and there- field in which the variation of the A-weighted soundlevel with distance fore generatepure-tone noise in the cuttingprocess. For the samenoise from the unit doesnot exactlyfollow the "inversesquare law." The direc- level,the pure-tone noise is more annoying than a combinationof frequen- tionalcharacteristics of the equipmentunder test further complicate the cies.Thus an optimizationtechnique is usedto developnoise-suppression interpretationof thenoise measurements, so that usingsound levels at one sawsthat haveirregular spacing between adjacent teeth. The Fourierse- distance,together with the inversesquare law to predictthe soundlevels riescan be usedto expressthe cuttingnoise of the circularsaws: at otherdistances, will notbe very precise. This paper discusses the prob- lem of machinerynoise measurement made above a reflectingplane and how modernspectral analysis techniques can be usedto extractinforma- f(O)= f(O)+ •l•[nsin(n0i +•b,,), tion from the noise data.

TUESDAY AFTERNOON, 23 MAY 1989 COMSTOCK A, 1:00 TO 4:45 P.M.

SessionJ. PsychologicalAcoustics II and SpeechCommunication II: Hearing Impairment and SensoryAids

David A. Fabry, Chairman WalterReed Army Medical Center,Army Audiologyand SpeechCenter, Washington,DC 20307

Contributed Papers

1:00 tasks;(b) unusuallypoor performers have been exluded from samples of Jl. Discriminationabilities of impairedlisteners compared to the range normallisteners; and (c) normallisteners are oftencollege students, im- of variationin performanceof normal listeners.Bias Espinoza-Varas, pairedlisteners are typically more heterogeneous samples. In the present CharlesS. Watson,and SuzanneE. Patterson(Department of Speech studydiscrimination performance of 23 impairedlisteners was compared and Hearing, Indiana University,Bloomington, IN 47405) to the rangeof discriminationperformance exhibited by large (n > 100), fairly heterogeneoussamples of untrainednormal listeners. The tasksin- Discriminationabilities of sensorineuralhearing-impaired listeners cludeddiscrimination of frequency,duration, intensity, tonal patterns, havebeen compared in moststudies to averageperformance of small and nonsensesyllables, and were presented at sufficientlyhigh sensation samples(n_• 10) of selected,highly trained, normal listeners. Such com- levels( >•25-30dB SL). The rangeof normalperformance was defined as parisonsmay be biasedbecause: (a) They do not take into accountthe the interval betweenthe averagepsychometric function of the listeners broaddistribution of theperformance of normallisteners, that is, the large comprisingthe best 10% of the normal sampleand the functionfor the intersubjectdifferences exhibited by normallisteners on many auditory worst 10%. Performance of normal listeners was distributed over broad

S24 J.Acoust. Soc. Am. Suppl. 1, Vol. 85, Spring 1989 117thMeeting: Acoustical Society of America S24 rangesinall tasks. Performance ofimpaired listeners was clearly bracket- perceptioncues. One moderate and two severe cochlear-impaired subjects edby the range of normal performance inall of the nonspeech discrimina- identifiedsynthetic fricatives, with eitherfull cues(frication and transi- tiontasks. Variability ofimpaired listeners' performance inthe nonspeech tion)or frication cue alone, presented inclosed-set response tasks across a taskswas comparable tothat of normal listeners, and their psychometric widerange of presentationlevels. The results showed that hearing-im- functionswere uniformly distributed over the range of thosefor normal pairedsubjects yielded equivalent recognition performance to the nor- performance. malswhen given an equivalentdegree of audibilityfor thefrication cue, butthey obtained poorer-than-normal performance if only given an equivalentdegree of audibility for the transition cue. Considering the 20- to 25-dBintensity difference between the frication and transition cues, the difficultythat hearing-impaired subjects have in perceivingfricatives un- 1:15 dernormal circumstances may be due to two factors: the lack of audibility .I2. Useof the ArticulationIndex to assess"noise reduction" hearing in termsof fricationcue and the loss ofdiscriminability interms of transi- aids.David A. Fabry(Walter Reed Army Medical Center, Washington, tioncue. [Work supportedby SU SenateResearch Grant and Deafness DC 20307) and DianneJ. Van Tasell (Universityof Minnesota, ResearchFoundation. ] Minneapolis,MN 55455) TheArticulation Index (AI) wasused to evaluatea commercially available"noise reduction" hearing aid. First, a transferfunction relating calculatedAI to ratedspeech intelligibility was derived empirically for a groupof normal-hearingsubjects. This functionwas used to predict speechrecognition by 12 hearing-impairedsubjects wearing either the noisereduction hearing aid or conventional amplification. Subsequently, subjectsrated the intelligibility of connecteddiscourse presented under 2:00 bothaided conditions at five signal-to-noise(S/N) ratiosin speech- weightednoise. The AI transferfunction predicted speech intelligibility JS. A comparisonof speechdiscrimination with coehlear implants and accuratelyfor halfthe subjects. For the remainingsubjects, predicted tactile aids. A. E. Carney (Boys Town National Institute, Omaha, NE scoreswere typically higher than observed scores. If the effects of upward 68131), M. J. Osberger,A. Robbins,J. Renshaw,and R. Miyamoto spreadof maskingwei-e included in theAI calculations,these differences (IndianaUniversity School of Medicine,Indianapolis, IN 46223) wereminimized. For all subjects,speech intelligibility increased mono- tonicallywith AI. AI scoresand speech intelligibility ratings were similar Speechdiscrimination was assessed in threegroups of hearing-im- pairedchildren fitted with three different sensory aids: ( 1) single-channel betweenthe two hearing-aid conditions, suggesting that S/N ratiowas not House3M cochlearimplants; (2) 22-channelNucleus cochlear implants; increasedby thenoise reduction hearing aid relativeto conventionalam- and (3) TactaidII devices.Nine subtestsof a speechdiscrimination bat- plification.[Work supportedby NINCDS NS 12125.] tery wereconstructed, which focused both on suprasegmentaland seg- mentalspeech contrasts. A change/nochange task was usedto assess discrimination.A changetrial consistedof fourstandard stimuli followed by four contraststimuli; the no-changetrial had eightstandard stimuli. Hits andfalse alarms were tallied, and P(C)max was computed for each subjectfor eachsubtest. Results indicated that, in general,subjects with 1:30 Nucleusdevices had the highest mean P(C)•,a• acrosssubtests, followed J3. A differentapproach to thenoise/interference problem of thehearing bysubjects with 3M Houseand Tactaid II devices.However, intersubject impaired.Edgar Villchur(Foundation for HearingAid Research,P.O. variabilitywas high for eachdevice. In addition,differences between de- Box 306• Woodstock,NY 12498) vicesfrequently varied on individualsubtests. The ability of thistest bat- teryto revealdifferences between children's speech perception with differ- Speechhas been called an error-resistantcode becauseit contains ent sensoryaids will be discussed.[Work supportedby NIH manyredundant caes to its meaning.Tbesc cues provide a reserveagainst (NS24875). ] the lossof cues maskedby interferenceand allow normal listenersto understandspeech in noisyenvironments. Evidence from experiments withprocessed speech suggests that the special vulnerability of thehear- ingimpaired to interferenceisnot an intrinsicfeature of theimpairment but typicallyderives from a lossof perceptionof the redundantcues en- joyedby normallisteners. If suchis the case, restoring lost speech cues to the impairedlistener is likelyto bemore belpful against interference than increasingsignal-to-interference ratios. The lecturewill includea demon- strationof speechprocessed to simulatethe effectsof recruitmentand accentualedhigh-frequency loss, and the vulnerabilityof thisspeech to 2:15 interference.Lost cues will thenbe restoredby compensatoryprocessing (two-channelamplitude compression plus frequency shaping), which in- J6. Two-channelFFT techniquesfor measuringhearing aids with creasesthe intelligibility of thespeech in thepresence of interferenceeven adaptive signal processing.John R. Bareham (BrLiel & Kjaer thoughit decreasesthe signal-to-interferenceratio. Instruments,Incorporated, 185 Forest Street, Marlborough, MA 01752) Hearing-aidmeasurements made in testenclosures have traditionally utilized a sinusoidal method such as that of ANSI Standard S3.22-1987. Whilethis method works well with essentially linear aids, it givesmislead- ingresults with automatic gain control (AGC) aids.A newmethod using shapednoise has been under study in WorkingGroup S3-48. This works 1:45 wellwith aidshaving linear, AGC, or adaptivefrequency response char- ,.I4.On thedifficulty of frieativeperception by hearing-impairedsubjects. acteristics,but doesnot work with aidshaving speech versus noise dis- Fan-GangZeng and Christopher W. Turner (CommunicationSciences criminationbased on detectionof the modulationof the receivedsignal. and Disorders,Syracuse University, Syracuse,NY 13244-2280) This paperproposes an extensionof the shapednoise method that seems to work well with aidshaving modulation detection. The proposedmeth- By'comparing conditions under which both normal and hearing-im- od usesa combinationof pulsed,shaped noise and continuousbandlimit- pairedsubjects were presented with equivalentdegrees of audibilityfor ed noiseas the test signal.The analysisis by two-channelFFT methods. fricativeperception, the current study isolated the factorsof lackof audi- Examplesof appropriateand inappropriate measurement methods will be bility from that of lossof suprathresholddiscriminability of fricative- shownfor all typesof aidsmentioned above.

S25 J. Acoust.Soc. Am. Suppl. 1, Vol.85, Spring1989 117thMeeting: Acoustical Society of America S25 2:30 energyoutputs, each of whichdrives a vibrator.Although successful in laboratoryand classroom settings, the largenumber of vibratorsrequired J7. Implementationofprincipal components spectral analysis of speech makesthe implementation of wearableversions difficult. By performinga in a wearabletactile aid. T.J. Rahrer, T. A. Kwasniewski(Department principalcomponents analysis of thefilter bank outputs, the spectral in- of Electronics,Carleton University, Ottawa, Ontario K I S 5B6,Canada), formationcan be recorded in asfew as four parameters. A compact princi- and B. W. TansIcy(Department of Psychologyand Departmentof palcomponents analysis system has been implemented using digital sig- Systemsand ComputerEngineering, Carleton University, Ottawa, nal-processingtechniques. The systemconsists of a l/3-oct bandpass Ontario KIS 5B6, Canada) filterbank, high-speed energy detectors for each filter, logarithmic scaling ofspectral energies, and a principalcomponent calculator, all in software One commonconfiguration of a vibrotactilesensory aid for the hear- runningon a commercialDSP microchip.In thispaper, the principal ingimpaired is the vocoder scheme employing a bank of bandpassfilters componentssystem is comparedto the traditionalvocoder method, as that modelhuman audition. These systems result in 16 or morespectral well as to the pitch and formantextraction schemes.

2:45-3:00 Break

3:00 showthis processing tobe as good as additive noise in simulatingsensori- neuralhearing loss. [Work supportedby NIH.] ,18.Recognition of Thai consonantsby listenerswith normalhearing and noise-inducedhearing loss. Sumalai Maroonroge (11510 Ridge Run Drive, Houston, TX 77064), Igor V. Nabelek (Department of Audiologyand SpeechPathology, University of Tennessee,Knoxville, TN 36996-0740),and Anothai U-phanich(Speech and HearingClinic, RamathibodiHospital, Bangkok 10100, Thailand) 3:30

The purposeof thisstudy was to comparerecognition of Thai conso- J10. Modelinga ventedpush-pull hearing-aid fitting i, situ asa feedback nantsin listenerswith normal and noise-inducedhearing loss. The sub- control system. David A. Preyes and James R. Newton (Argosy jectsconsisted of 36 normal-hearingand 120hearing-impaired listeners Electronics, 10300 W. 70th Street, Eden Prairie, MN 55344) whosehearing loss starting at 3, 4, or 6 kHz. All subjectswere native Thais.The testmaterials were meaningful Thai monosyllabicwords re- For theinvestigation of acousticfeedback encountered with push-pull cordedby a femalespeaker. The testwas presented at 35 dB SL in quiet amplificationfor in-the-earhearing aids, a simulatedfitting wasconsid- and in noise (noise level was l0 dB below signal level). There was a ered a feedbackcontrol systemto includethe acousticleakage from the significantdifference between scores obtained by listenerswith normal hearing-aidreceiver traveling back to themicrophone. A GennumWS53 I hearingand those with noise-inducedhearing loss. Consonant recognition amplifierwas connected to an earmoldshell made for the right ear of scoresin quietand in noisewere also different. The overallscores from the KEMAR. This shell containeda Knowles EK 3024 microphone,a threegroups of noise-inducedlisteners were similar but the patternsof Knowles BKI613 receiver,and a 0.09-in.-diam by 0.8-in.-long vent hole. consonantrecognition were distinct for eachgroup and testcondition. Transfer functionmagnitude and phasewere obtainedfor the micro- Recognitionscores for stops,fricatives, and affricates were relatively low. phone,amplifier, receiver, for the open loop while breakingthe signal Aspiratedconsonants showed lower scoresthan unaspiratedsounds. path betweenmicrophone and amplifier,and for the closedloop, all with Confusionerrors occurred across both place and mannerof productions. maximumgain before onset of oscillation.The acousticfeedback transfer functionwas determinedby subtractingthe forward loop transferfunc- tion from the closedloop transferfunction. A circuit synthesisprogram was used to fit the transfer function measurement data into mathematical transferfunction expressions. Comparisons were made between the syn- thesized transfer functions and the measured transfer functions. 3:15

J9, Simulation of sensorineuralhearing loss. Paul Duchnowski and Patrick M. Zurek (MIT ResearchLaboratory of Electronics,Room 36- 3:45 761, 50 VassarStreet, Cambridge, MA 02139) Jll. Reducing the effects of target misalignment in an adal•tive Previouswork [Zurek and Delhorne, I. Acoust. Soc. Am. 82, 1548- beamformerfor hearingaids. Julie E. Greenberg,Patrick M. Zurek 1559 (1987) ] foundthat noisemasking, while degradingthe speechre- (MIT ResearchLaboratory of Electronics,Room 36-761, Cambridge, ceptionof normallisteners to resembleclosely that of the impairedlisten- MA 02139), and Patrick M. Peterson (BBN Laboratories, l0 Moulton ers, could only be usedto simulatelosses less than 70 dB. With greater Street,Cambridge, MA 02138) losses,the noiseis unacceptablyintense. In the presentsimulation, a vari- ationofVillchur's [J. Acoust.Soc. Am. 62, 665-674 (1977) ] system,the Previouswork [Petersonet al., Acta Otolaryngol.(in press)] has inputsignal is dividedinto 14 l/3-oct bandsand each band level (deter- shownthat a multimicrophoneadaptive beamforming system for hearing minedover a 20-mswindow) is comparedto the impairedthreshold at the aids reducednoise effectively at input target-to-jammerratios (TJRs) up centerfrequency of theband. For inputlevels below threshold, the signal to about0 dB. However,that beamformingalgorithm assumedthat the is attenuatedto essentiallyzero. Signalsin an X-dB range (X• 30 dB) target signalwas identicalat the microphones,and violation of this as- immediately above threshold are attenuated accordingto an expansive sumptioncaused degrading target cancellationwhen input TJR was mappingof input levelinto the rangebetween normal threshold and im- greaterthan 0 riB.The presentsystem uses a measureof intermicrophone pairedthreshold plus X dB. Signalsmore than X dB abovethe impaired correlationto estimateshort-time TJR andinhibits adaptation dynami- thresholdare passedunattenuated. The systemthus simulatesthe two cally when T JR exceedsa selectedthreshold. Computer simulations of a primarycharacteristics of sensorineuralhearing 1oss-•elevated threshold two-microphonesystem in anechoicand moderately reverberant environ- and recruitment.In pilot studies,this technique was used successfully to mentsshow that this methodreduces (speech) target cancellationwhen simulateconsonant reception of impaired listenersdescribed by Zurek the identicaltarget assumption is violated.The improvedsystem reduces and Delho?ne.To evaluatethe simulationfurther, new subjects(both noiseat both positiveand negativeinput TJRs ( ñ 20 dB), with target impairedand normal) are beingtested with bothsyllables and sentences misalignmentsup to 10deg. Additionally, this processing scheme reduces with variationsin overalllevel, signal-to-noise ratio, and frequency-gain the misadjustmentnoise caused by strongtarget signals in the adaptive characteristic.Intelligibility scores and SINFA analysesobtained thus far feedbackloop. [Work supportedby NIH.]

S26 J. Acoust.Soc. Am. Suppl. 1 ,'Vol. 85, Spring1989 117thMeeting: Acoustical Society of America $26 4:00 periodare calculated for eachspeech frame processed. This paper pre- J12. Effectof numberof channelson the performance of a multichannel sentsreal-time cepstral analysis as a completespeech analysis strategy for compressionhearing aid. E. William Yund and Krista M. Buckles the cochlearimplant. Cepstral analysis has long been known as an accu- (HearingLoss Research Laboratory, Veterans Administration Medical ratemethod for pitchextraction and tracking. However, it has Center,Martinez, CA 94553) notbeen previously considered for real-timesignal-processing applica- tions,due to thecomplexity of thecalculations involved. Taking advan- Previousresearch [E. W. Yund,H. J. Simon,and R. Elton,J. Rehab. tageof today'smicroprocessor technology, cepstral analysis has been im- Res.Der. 24, 161-180 (1987)] hasdemonstrated the effectivenessof an plementedusing the TexasInstruments TMS320C25 digital signal eight-channelcompression hearing aid for individualswith sensorineural processor.Results obtained with a 10-poleLPC analysis using the same hearingloss in the taskof speechdiscrimination in a backgroundof processorare compared with thoseof the proposedmethod. The results speech-bandnoise. In thepresent study, similar multichannel compres- arealso compared to a commercialsoftware package (ILS fromSTI) for sionsystems with 4, 6, 8, 12,and 16 channels were compared with each validation. otherand with linear (frequency equalized amplification) and unpro- cessed(fiat amplification) conditions. The results on 15hearing loss sub- jectsshowed increasing speech discrimination performance as the number of channelsincreased, although the differencebetween 4 and 8 channels was much greater than the difference between 8 and 16 channels. Con- firmingthe previous results, the performance advantage of themultichan- nelcompression conditions over the linear and unprocessed conditions wasgreater at lowsignal-to-noise ratios (S/N), e.g., + 5, 0, or - 5 dBas 4:30 opposedto + 10 or + 15 dB. [Work supportedby VA Rehabilitation Researchand DevelopmentService.] J14. Somefactors affecting recovery from poststimulatoryfatigue. I. M. Youngand L. D. Lowry (Departmentof Otolaryngology,Jefferson Medical Collegeof ThomasJefferson University, Philadelphia, PA 19107)

Recoveryfrom poststimulatory fatigue was measured on subjects with normal hearingand patientswith unilateralcochlear and retrocochlear 4:15 hearingimpairments. Ears were stimulatedby steadytones at various ,I13. Real-time cepstral analysis,speech feature extraction, for the intensitylevels for 3 min. Thresholdsduring the recoveryperiod were cochlear prosthesis.lbrahim J. Oedeon, Tad A. Kwasniewski,and obtainedat thestimulated frequencies by usingboth the steadytone only TimothyJ. Rahrer(Department of Electronics,Carleton University, and the tonesalternated between interrupted and steadytones. For all 1231Colonel By Drive, Ottawa,Ontario KIS 5B6, Canada) subjects,alternate presentation of tonesresulted in morerapid recovery to preexposurelevel than steadytone presentation.These resultsseem to Themost common speech-processing strategies for usein thecochlear indicatethat the off-timeof interruptedtones permits the fast recovery implantemploy multifeature extraction. For the proposedapplicatiou, from fatiguefor the auditorynervous system. It is presumedthat, by the firstthree formant frequencies and amplitudes along with the pitch varyingthe on-off ratio, a varietyof recoverypatterns may be measured.

TUESDAY AFTERNOON, 23 MAY 1989 NEWHOUSE II, ROOM 254, 1:00 TO 2:24 P.M.

SessionK. SpeechCommunication III: Timing and Stress in Phonemesand Syllables

Robert J. Porter, Jr., Chairman KresgeHearing ResearchLaboratories, 1100 Florida Avenue,New Orleans,Louisiana 70119

ContributedPapers

1:00 panyingdifferences in articulatordisplacement. Similarly, changing from K1. Final lengthening:A local tempochange. Jan Edwards (Hunter normalto slowtempo is effected by a decreasein peakvelocity for boththe Schoolof Health Sciences,425 East 25 Street,New York, NY 10010), openingand closinggestures, without any accompanyingdifferences in Mary E. Beckman, and Janet Fletcher (Ohio State University, articulatordisplacement. Thus final lengtheningcan be describedas a Department of Linguistics,204 Cunz Hall, 1841 Millikin Road, local slowingdown before the phraseboundary. Interestingly, two sub- Columbus,OH 43210) jectsdid not differentiatebetween the peakvelocity of final and nonfinal closinggestures at the slow rate, probablybecause they had reacheda This papercompares the articulatorycorrelates of lengtheningat lowerlimit on peakvelocity. However, these subjects did maintaina dif- phraseboundaries to thoseof slowingdown from normal to slowtempo. ferencein vowel period duration betweennonfinal and final syllablesat The velocity,displacement, and duration .of openingand closingman- 'theslow tempo. This resultsuggests that final lengtheninghas a directly dibulargestures of syllablesin intonation-phrase-finaland nonfinalposi- temporaltarget at a moreabstract level of specificationthan thearticula- tionwere examined for four speakers. The longer durations of phrase-final tory dynamics.[Work supportedby the National ScienceFoundation syllablesare due primarily to slower closing gestures, without any accore- under grantsIRI-8617873 and IRI-8617852.]

S27 d. Acoust.Soc. Am. Suppl. 1, Vol.85, Spring1989 117thMeeting: Acoustical Society of America S27 1:12 acousticaloffset of the followingvowel, in termsof their taskdynamic description,however, the phase relations between consonant and vowel K2. Vowel lengthand closureduration in word-medialVC sequences. gesturesshould remain the same. This would result in a reducedstiffness Stuart Davis and W. Van Summers(Speech Research Laboratory, of thevowel gesture for thesyllables containing consonant clusters. The Departmentof Psychology, Indiana University, Bloomington, IN 47405) observationsof the present study would also correspond to a reductionof Previousresearch has shown that Englishvowel length varies depend- stiffnessfor the vowel but the numerical data seem to contradict a stable ing on the voicingcharacteristic of the .followingconsonant. For stop phasingrelation. In connectionwith the psychoacoustic interpretation of consonants,closure durations also vary asa functionof consonantalvoic- theP-center phenomenon, an argument is made against a strictlyintrinsic ing.Generally, vowel-stop sequences containing voiced consonants show timinginterpretation (based on articulatory regularities) of theeffects of longervowel durations and shorterclosure durations than similar se- rhythmicalproduction/perception. quencescontaining voiceless consonants. These previous studies have fo- cusedon stressedvowels in monosyllabicor bisyllabicwords. Very little researchhas examined the effects of postvocalicvoicing on stresslessvow- els.In thepresent study, t,he influence ofpostvocalic voicing on vowel and closuredurations in VCV and VCV sequencesis studied.Subjects pro- ducedsentence pairs containing target words contrasting in intervocalic consonantalvoicing (e.g., adopt-atop,tabbing-tapping). Both stressed 1:48. andunstressed vowels tended to lengthenbefore voiced consonants. How- ever,the vowel-lengthening effect was not as consistent for stresslessvow- KS. Universal versuslanguage-specific aspects of voicing-dependent els as for stressedvowels. Closure durations were longer for voiceless vowel duration.Christiane Laeufer (RomanceLanguages, Ohio State stopsthan voiced stops after a stressedvowel. However, voicing effects on University,248 Cunz Hall, Columbus,OH 43210) closure duration were inconsistent after stressless vowels. The results All languagesshow vowels to be slightlylonger before voiced ob- haveimplications concerning perceptual cues for intervocalicvoicing and struents.A phonologicalrule of vowellengthening has been proposed for for issuesconcerning syllable-internal structure. [Work supportedby Englishbecause the variationseems to be muchgreater than in, say, NIH.] French.This comparison, however, has been based on studies that do not controlfor wordlength, syllable structure, or for whetheror not the lan- guageshave final alevoicing. A comparisonof voicing-dependentvowel durationin Englishand French monosyllables shows that phrase finally and mediallyunder focus, obstruent voicing is a significantfactor influ-

1:24 encingthe durationof precedingvowels in both languages.In unfocused medialposition, on theother hand, the difference between the durations K3. Articulatory consonantand vowel timing in rhythmically produced as a functionof consonantvoicing is muchsmaller. Moreover, if differ- syllables. Barbara K/ihncrt, Bernd Pompino-Marschall, and Hans encesin syllabificationare takeninto account,the languagesare even G. Tillmann (Institut fQr Phonetik und SprachlicheKommunikation, moresimilar. That is, in French, consonantstend to be resyllabifiedwith Ludwig-Maximilians-Universit•it,Schellingstrasse 3, D-S000 Munich 40, the followingsyllable, unlike in English.These results suggest that lan- FederalRepublic of Germany) guagesuniversally exhibit fairly similar physiologically conditioned voic- ing-dependentvariation in voweldurations. Under certain conditions, The resultsof experimentsusing simultaneous EMG recordingsfor includingword length,syllabic structure, stress, position in word, and consonantal(OOS) and vocalic gestures(ABD) in rhythmically pro- utteranceand speaking tempo, the differenceis enhanced,while in others ducedspeech are discussedin connectionwith an articulatorilybased it isobscured. Thus a generalphonetic account in termsoftlining control interpretationof the P-centerphenomenon. Three subjects produced se- is preferableto a language-specificphonological rule. quencesof fivemonosyllabic tokens of the form/Cak/(with/C/=/p/, /pf/,/pl/,/pr/,/pfl/) in time to a metronome.In contradictionto the hypothesisof Tuller and Fowler [Percept. Psychophys.27, 277-283 (1980) ], the data in thisstudy suggest that the timingof the articulatory vocalicgesture is not a directcorrelate of the P centerand, furthermore, not independentof the syllable-initialconsonants. In addition,although the acousticsyllable onset shows the well-known systematicdeviations from isochronydepending on the lengthof the initial consonantcluster, 2:00 the articulatoryconsonantal gesture clearly does not showa parallelsys- tematicshift to earlieronset. These results support the hypothesisthat the K6. An artieulatory studyof consonant-voweloverlap. Kenneth de Jong articulatorytiming pattern of monosyllabicutterances seems to be deter- (Department of Linguistics,Ohio State University, Columbus,OH minedon the basisof the phoneticstructure of the entiresyllable. 43210)

Fowler [Phonedca( 1981); J. Exp. Psychol.(1983) ] has proposed that speechproduction is a seriesof globalarticulatory movements asso- ciatedwith the vowelsof an utterance,upon which smaller,consonantal movementsare superimposed.A possiblearticulatory test of this theory modelsconsonants and vowelsas alternations between a relativelyclosed 1:36 and openvocal tract. Using the Wisconsinx-ray microbeamsystem, ar- K4. P centers, C centers, or what else? Bernd Pompino-Marschall, ticulatoryrecords were obtainedof Englishphrases with variedaccent Barbara Kiihnert, and Hans G. Tillmann (Institut fiir Phonetik und placementand alveolarconsonant sequences of varied duration. Analysis of one speaker'sproductions is now complete.When the data are pooled Sprachliche Kommunikation, Ludwig-Maximilians-Univcrsi½it, over all conditions,the total duration of the bisyllabicsequence and the Schellingstrasse3, D-8000 Munich 40, Federal Republicof Germany) timedifference between sonority peaks is stronglyrelated to the lengthof Somequestions concerning the underlyingnature of the so-calledP- the medialconsonants; there is no evidencefor articulatoryoverlapsi.e., centerphenomenon (the acousticanisochrony of rhythmicallyregularly vowel shorteningin the neighborhoodof long consonantsor shiftingof produced/perceivedsequences of monosyllables)are discussedin the sonoritypeaks toward longerconsonants. However, correlationswithin light of recentEMG data from experimentswith rhythmicallyproduced accenttypes uncover a strongshortening effect for accentedsyllables pre- /Cak/syllables (with /C/=/p/, /pf/, /pl/, /pt/, /pfi/). The differ- cedinglong consonants, along with a reduceddisplacement in the follow- encesbetween/p/vs/pf/syllables resemblethe timing differencesin the ing vowel.Thus any comprehensiveoverlapping consonant-vowel theory microbeamdata of Browman and Goldstein [ HaskinsSR-93/94, 85-102 of speechproduction must take into accountthe generalprosodic struc- (1988) ]. Whereasthey found a stabletiming relation betweenthe "ar- ture of the utterance.[Work supportedby the NationalScience Founda- ticulatory mean" of the initial consonants(termed C center) and the tion under grant No. IRI-8617852 to Mary Beckman.]

S28 J. Acoust.Soc. Am. Suppl. 1, Vol.85, Spring1989 117thMeeting: Acoustical Society of America S28 2:12 assumedto be neutralwith respectto both featuresunder study. The speakershowed no evidenceof time lockingor featurespreading of the K7. The timingof llp roundingand tongue backing for/u/. Gina M. Lcc onsetof lip roundingin/iC, u/-typetokens. Within thesame token types, (Departmentof Linguistics,Ohio StateUniversity, 204 Cunz Hall, 1841 therewas an absenceof tonguebacking activity during the productionof Millikin Road, Columbus, OH 43210) the consonants.However, other articulatoryphenomena are temporally fixed.The maximumdegree of roundingwas fixed relative to the acoustic A smallcorpus of x-ray microbeamdata wasexamined to test the onsetof/u/[as statedin G. M. Lee,J. Acoust.SOC. Am. Suppl.1 gl, S37 predictionsmade by two well-known views of anticipatorycoarticulation: (1987) ]. Thisis consistent with pastfindings involving EMG peaks[Hir- time lockingand featurespreading. Lip roundingand tonguebacking oseet al., Ann. Bull. RILP ( 1968, 1969) ]. The timing of the minimum associatedwith English/u/were investigated.The token typeswere degreeof backingwas also fixed. These findings may provideevidence for VC.¾ sequenceswhere V =/i, u/and C =/s, t/, and consonantsare the notion of a (static) target in speechproduction.

TUESDAY AFTERNOON, 23 MAY 1989 NEWHOUSE I, ROOM A1, 1:15 TO 5:00 P.M.

SessionL. Bioresponseto Vibration I and PhysiologicalAcoustics II: Structural and FunctionalAspects of Mechanotransduetion

StanleyJ. Bolanowski,Jr., Chairman Instituter or SensoryResearch, Syracuse University, Syracuse. New York 13244

Invited Papers

1:15

LI. Primaryand secondary meehanoreeeptors. S. J. Bolanowski(Institute for SensoryResearch, Syracuse University,Syracuse, NY 13244) A briefreview of thestructure and function of primary(i.e., lacking a synapse)and secondary (i.e., having a synapse)mechanoreeeptors willbe presented. The central theme of thisreview and the session in generalwill be"What can be learned about mechanotransduction in general, based on the similarities and differences of the two receptortypes?"

1:30

L2. Stretch-activatedion channelsas acousticaltransducers. Frederick Sachs (SUNY Departmentof BiophysicalSciences, Buffalo, NY 14214) Ion channelssensitive to membranedistortion have been demonstrated in nearlyall cells,from plantsto animals,in specializedsensory transducers, such as the crayfishstretch-receptor and, in traditionalmotor outputs,such as skeletal muscle. The channelsrespond to membranetension by opening with a probabilitythat (for low tensions)follows an exponentialin the squareof tension.The datacan be explainedwith a simple modelin whichtension does Hookcan work on thechannel raising its energy, which leads towards transitions to theopen state. Even in skeletalmuscle, the channels are sufficiently sensitive to tensionto serveas productive modelsof hair cell transduction.If auditorytransduction is due to stetchsensitive ion channelsin ciliary membranes,a ve• simpletraditional model of forcecoupling between stereocilia leads to thefollowing predic- tions IF. Sachs,"Biophysies of mechanoreeeption,"Membrane Biochemistry 6 (2), 173-195 (1986) ]: ( I ) tuftsare tapered in orderto providea regionof strainthat is first order in theangle of deflection;(2) channels maybe located over the cilia, but will onlybe turned on at thedistal tips in thestrained region ofmembrane; (3) for maximumsensitivity, the optimumnumber of channelsis on the orderof one/tip; (4) givena constant channeldensity, to maintainoptimum sensitivity at differentmean pressures requires some form of mechanical relaxationto theoptimal tension; (5) specializedtip linksconnected to channelsare not required since strain is appliedin theplane of themembrane; and (6) thechannels are sufficiently fast to accountfor theresponse time of the generatorcurrent and the transductionsystem is sufficientlysensitive to accountfor the observed psycbophysical"thresholds." [Work supportedby NIADDK-13195 andUSARO 22560-LS.]

S29 d. Acoust.Soc. Am. Suppl.1, VoL 85, Spring1989 117th Meeting:Acoustical Society of America S29 2:00

L3. Localizationand biophysical characterization of an adaptationmechanism in amphibianhair cells.Iohn A. Assad,Nir Hacohen,and David P. Corey (DepartmentoœNeurology, Massachusetts General Hospital, Boston,MA 02114and Howard HughesMedical Institute, Boston, MA 02114) Hair cellsof thebullfrog sacculus adapt to maintaineddisplacement stimuli in a mannerthat indicates an activemovement of the elasticelement that exertsstress on transductionchannels. Transduction and adapta- tion werepresent in dissociatedhair cellsstudied with whole-cell,patch-clamp recording and video micros- copy.The adaptation rate--as well as the position of theresting current-displacement [I(.Y) ] curve--depend- edon extracellularcalcium and on membranepotential, suggesting that calcium passes into the cytoplasmto reachits site of action.Following a stephyperpolarization, the adaptationincreased within milliseconds, suggestingthat the calcium site is withina fewmicrons of theion channels through which calcium enters. The voltagedependence of the restingI(.Y) curve,together with the "gatingsprings" hypothesis for transduction, predictsa 40-nmmovement of the bundleaway from the kinociliumwhen the cell is depolarizcd.This was observed.

2:30

EA. Actin in cochlearouter hair cells: A structuralbasis for cell shapeand motility. Norma Slepecky (Institutefor SensoryResearch, Syracuse University, Syracuse, NY 13244-5290) Thresholdsensitivity and frequencyselectivity in the cochleadepend on intactouter hair cellsand models to explainthese phenomena suggest that activemechanical processes, residing in outer hair cells,alter micro- mechanicalproperties of the basilarmembrane. Auditory sensoryhair cellsisolated from the innerear change their shapein responseto stimulationin oitro.Three areasof the cell havebeen suggested to be involvedin this form of cell motility: ( 1) the infracuticularnetwork of actin filamentsthat is seenas a centralcore; (2) the corticallayer of actinfilaments along the lateralwall; and (3) actinin the outerhair cellcytoplasm. The actin filamentsin the stereocilia,the cuticular plate, and the infracuticularnetwork are not involved,since mechani- callydisrupted cells lacking these structures still shorten.Actin filamentsalong the lateralwall arenot involved in shorteningsince outer hair cellmembrane ghosts do notshorten, however, they retain the ability to constrict sothe cellbecomes thinner. Shortening of outerhair cellsdoes occur in mechanicallydisrupted cells as long as they containsome cytoplasm. Thus shorteningof outer hair cellsrequires cytoplasmic components. lmmuno- cytochemicalstudies have demonstrated the presenceof microtubules,spectrin, calcium binding proteins, and actin in the outer hair cell. Stainingwith phalloidinindicates for the first time that actin is presentas short filaments,and, with transmissionelectron microscopy,filaments are seenas a network throughout the cyto- plasm.Thus actinmay providethe structuralbasis for maintainingcell shapeand for causingmotility.

3:00

LS. A model for mechanotransduetionin a Pacinian eorl•usele. Mark H. Holmes (Department of MathematicalSciences, RPI, Troy, NY 12180) andJon Bell (Departmentof Mathematics,SUNY at Buffalo, Buffalo, NY 14214)

A Paciniancorpuscle (PC) isa rapidlyadapting mechanoreceptor that resides in theskin and other tissues. The transductionprocess in the PC consistsof a mechanicalfiltering by the capsulethat surroundsthe dendrite,along with a receptormembrane component. A modelis described that accountsfor these.The layer structureof the capsuleis takenas formedfrom concentricelastic membranes with the interlamellarspaces filledwith a viscousincompressible fluid. From this the hoopstrain in the receptormembrane is found and this servesas the input to a receptormodel, which hasa strain-sensitiveactivation mechanism for the transducer conductance.The transientbehavior of thereceptor potential due to variouscompression stimuli to thecapsule isinvestigated. Of particularinterest is how the viscoelastic properties of thecapsule contribute to theadaptive behaviorof the PC. To this end the dependenceof the hoopstrain on the rate oœcompression and the imposed strain are discussedalong with the responseof the PC when the loading is removed.

3:30-3:45

Break

S30 J.Acoust. Soc. Am. Suppl. '1,Vol. 85, Spring 1989 117thMeeting: Acoustical Society ofAmerica S30 ContributedPapers

3:45 brin(68 kD) wasidentified by immunoblot. Both bands were present in coresprepared by treatingstereocilia with triton to removemembrane L6, Effectsof staticindentation on the input-output function of Pacinian and solubleproteins. Calmodulin (17 kD) and calbindin(28 kD) were corpuscles.S. J. Bolanowski,Jr. andC. M. Checkosky(Institute for SensoryResearch, Syracuse University, Syracuse, NY 13244and identifiedby immunocytochemistry orby comigration. The electrophore- tic patterndiffers substantially from that of brushborder microvilli, Departmentof Surgery,University of RochesterMedical School, Rochester, NY 14642) whichare structurally analogous; inparticular, the calmodulin-regulated, myosinlike110-kD protein of brush border was not detected in stereocilia. The receptorpotential (RP) of catPacinian corpuscles (PC) in re- sponseto sinusoidaldisplacements exhibit asymmetric, full-wave rectifi- cation.Furthermore, there are apparently two populations of PC, one moresensitive to stimuluscompression, the otherto withdrawal.These resultscan be explained by proposing that there are two groups of neutral 4:30 elementswithin PC, eachproducing a half-waverectified response but L9, Very highlevels of calmodulin(CAL) in outerhair cells(OHC) of summingin polarityopposition. The RP may thus be dependent upon the organ of Corti (OC). Kuniaki Takahashi, Isolde Thalmann, relativecontribution from the two groups. If true,then changes in theRP RuedigerThaimann (Departmentof Otolaryngology,Washington mayoccur with selective(de) activationof onegroup of elements.This University,St. Louis,MO 63110),Hans-Peter Zenner (Department of maybe testedby varyingthe static indentation of the vibratingprobe, Otolaryngology,University of Tiibingen,7400 Tiibingen,Federal notingthat small static indentations may permit only the most sensitive Republic of Germany), and Peter Kraus (Department of groupof elementsto be excited,revealing a half-waverectified RP. In- Otolaryngology,University of WQrzburg,8700 Wiirzburg, Federal creasingindentations should then produce concommitant changes in the Republicof Germany} RP shapeas the other group becomes activated. The experiments show that changesin staticindentation produces changes in the RP, the Usingimmunohistochemical techniques, Slepecky et al. [ Hear. Res. changesconsiderably more complicated than the hypothesis predicts. The 321, I 1-22 (1988) ] demonstrateda selectiveaccumulation of CAL, an resultsindicate that while the two-group hypothesis may still be correct, ubiquitouscalcium binding protein, in the inner hair cells (IHC) and the I-O functionof eachelement may not resemblea half-waverectifier. OHC of the OC. By quantitativepolyacrylamide gel electrophoresis,it [Work supportedby NS 23933.] wasfound that in chinchillaOC, CAL isby far thehighest in OHC, where levelsof 6%-8% of totalprotein are reached. For comparison, the highest knownaccumulation of CAL (in the headsof spermatozoa)amounts to 12%. CAL is considerablylower in IHC (about 1% ), and is not detect- ablewith usualprotein loads in other cell typesof the OC. CAL is also very low in stria vascularisand Reissner'smembrane. The relativedistri- 4:00 butionof CAL in theOC issimilar to thatof glycogen,where the exceed- L7. Bidirectional transductionby haircells. C. L. Searle, H. E. Seeker- ingly high levelof 600-mmol/kgdry weightis reachedin OHC [Thai- Walker, T. A. Wilson, and D. M. Freeman (Room 20C-014, MIT, mannet al., Laryngoscope80, 1619-1645 (1970) ]. This circumstantial Cambridge,MA 02139) evidencesuggests that activationof phosphorylasekinase may be an im- portantfunction of CAL in OHC, wherebyultimately energy for contrac- Giventhe two-portdescription of a haircell from Weiss[ Hear. Res.7, tion is mobilizedfrom glycogen.Most likely CAL-inducedactivation of 353-360 (1982) ], with the Davis modelfor the angle-dependentconduc- myosinlight chainkinase also takes place as part of the contractilepro- tancerepresenting the transductionchannels [Leong and Weiss,Hear. cess.[Work supportedby NIH and DRF. ] Res.20, 175-195 (1985)], and the data of Crawfordand Fettiplace[J. Physiol.364, 359-379 (1985) ], Howardand Hudspeth[Neuron 1, 189- 199 (1988)], and Holton and Hudspeth [J. Physiol. 375, 195-227 (1986) ], analysisshows that ( 1) the feedbackinherent in the two-port mustbe positive,and ( 2 ) degenerative(outward-flowing) channels must 4:45 be present.The staticnonlinear behavior of the system,and the smalland largesignal dynamics, have been studied. The systemdisplays Q multipli- L10.Significance of ami•o acid sequence in characterization of cationat low signallevels, bandwidth increase with signallevel, a com- unidentifiedmajor proteins of theorgan of Corti (OC).Isolde Thalmann pressirenonlinearity at CF, andcontinuous oscillations if theparameters andRuediger Thalmann (Department of Otolaryngology,Washington areslightly misadjusted--all well-documented physiological phenomena. University,St. Louis,MO 63110)

Previously,two low molecularweight, highly acidic proteins were discribedthat are presentat very highconcentrations in the OC and that are assignedthe tentativenames OCP-I and OCP-2 [Thaimann et al., Arch.Otorhinolarygol. 226, 123-128(1980) ]. Now aminoacid sequenc- 4:15 ingstudies of theseproteins have been initiated. Preliminary results show LB. Mechanicalpurification and protein constituentsof amphibianhair that the N-terminalsequence of OCP-2 is Pro-Gly-Ile-Lys-Leu-Gln-Ser- cell stereocilia.Gordon M. G. Shepherd,Barbara A. Barres,and David Ser-Asp-Gly-Glu-Ile-Phe-Glu-Val-Asp-X-X-Ile-Ala-Lys-Gln-. Among P. Corey (Departmentof Neurology,Massachusetts General Hospital, the advantagesof knowing the sequenceor primary structureare ( 1) the Boston,MA 02114and Howard HughesMedical Institute, Boston, MA primarystructure contains all the informationrequired for formationof 02114) thesecondary and tertiary structure; (2) comparisonwith sequencesof knownproteins allows determination of thedegree ofhomology, to obtain In orderto understandthe molecular basis for transductionand adap- cluesabout evolutionary history and degreeof conservation,and hints tationin hair cells,it is necessaryto knowthe identitiesand relationships about protein function (e.g., the "EF hand" in somecalcium-binding of proteinsin the mechanicallysensitive stereocilia. A rapidand specific proteins);(3) repeatingmotifs suggest structural role; (4) internalho- purificationprocedure has beendeveloped for stereociliaof the bullfrog rnologysuggests duplication (e.g., in calmodulin);(5) the natureof the sacculus, that relies on mechanical adhesion of the stereocilia to nitrocel- N-terminal residuegives clues about the turnoverof the protein;and (6) lulosepaper ( "bundleblot purification"). The highpurity and yield of the theamino acid sequence allows oligopeptides to besynthesized for obtain- preparationwere demonstrated by light and scanningelectron micros- ing antibodiesfor immunohistochemicalstudies and correspondingoli- copy.Electrophoretic separation of proteinsrevealed 12-18 majorbands. gonucleotidesto be synthesizedfor molecularbiologic studies. [Work Actin stainedwith phalloidinand wasa prominentband at 42 kD. Fire- supportedby NIH and DRF.]

S31 d. Acoust.Soc. Am. Suppl.1, Vol. 85, Spring1989 117th Meeting: Acoustical Society of America S31 TUESDAY AFTERNOON, 23 MAY 1989 COMSTOCK B, 1:30TO 4:45 P.M.

Session M. I: Acoustics of Percussion Musical Instruments

Uwe J. Hansen, Chairman Departmentof Physics,Indiana State University,Terre Haute, Indiana 47803

Invited Papers

1:30

M1. Vibration modesand tuningof xylophonebars. Ingolf Bork (Physikaliseh-TechnischcBundesanstalt, D-3300, Braunschweig,West Germany) The characteristicquality of xylophonesound depends bolh on theinharmonic structure of itsspectrum of partialsand on the orderin whichthe individualpartials decay. Subjective tests have shown that a systematic tuningof thefirst three partials improves the quality. A procedurefor thepractical realization of sucha tuning is described.With the helpof modalanalysis, it can be shownthat whentorsional vibration modes as well as bendingmodes contribute to soundradiation, the tuningbecomes more complicated.

M2. Pitchdistribution in bellchimes of theChinese Bronze Age. Lothat yonFalkenhausen (Department of Asian Languages,Stanford University, Stanford, CA 94305-2034) Pitchmeasurements on a numberof archaeologicallydiscovered graduated sets of two-pitchbells [cf. M. Chengyuan,Chin. Music 3(4), 81-86 ( 1980);4( 1), i 8-20 ( 1981); and4(2), 31-36 ( 1981); S. Shen,Sci. Am., 104--110(April 1987);T. D. Rossinget el., J. Acoust.Soc. Am. 81, 369-373(1988)] fromthe Shang(ca. 1500-1050BC) andZhou (ca. 1050-256BC) dynastieswere compared, and the patternsof pitchdistribution fromoctave to octavewere scrutinized. Over time, an increasingmastery of thetechnology of manufacturing two-pitchbells can be observed, especially regarding the ability of manipulatingthe twofundamentals on each bellin sucha waythat bothcould be usedin musicmaking. From WesternZhou (ca. 1050-771BC) onward, thepitch distributions of eachchime show a basicdivision into a lowerand a higherregister, the former at first manifestinga greater density of pitchesthan the latter. in thehigher register, the Western Zhou four-tone (mi- sol/la-do)pattern was later gradually enriched with additionalpitches. The everdenser distribution of pitches seemsto reflectthe development of bellchimes from a musicalinstrument of merelyaccompanatory nature to oneon whichmelodies could be playedin full, sometimesin morethan one tonality. Caution must be used, however,in generalizingfrom thesephenomena on the developmentof tonalscales in China.

2:30

M3. Modalstudles in a doublesecond Caribbean steel drum. UweJ. Hansen(DepartmentofPhysics, lndiana StateUniversity, Terre Haute, lN47803),ThomasD. Rossing,andScott Hampton (DepartmentofPhysics, NorthernIllinois University, DeKalb, I L 60115) Caribbeansteel drums characteristically contain several sections of separatelytuned areas imbedded in one quasihemisphericallyshaped drum head that is formedin theend of a 55-gallonsteel drum. The doublesecond panunder study for thisreport includes three A • sectionstuned in .Pitch and spectral content for each sectiondepend on sectiongeometry, mass distribution, and elastic properties. Section geometry is determined byhammer-embossed boundary delineation while mass and tension arc modified by selective hammering in the sectioninterior, which enables tuning of severallower partials harmonically. Spectral nearfield studies illus- trateharmonic content as well as departures from harmonicity in someof thenotes under study. Time average holographicinterferometry shows strong amplitude dependence of spectralcontent of notesand illustrates couplingbetween sections. Complications in usingimpact excited modal analysis due to noncoherentinput contributionsare discussed,and computer-animatedmodes are illustrated.

S32 J. Acoust.Soc. Am. Suppl. 1, Vol.85, Spring1989 117thMeeting: Acoustical Society of America S32 3:00 M4.Vibrationalmodesofdrumheadsinvarioustypesofdrums. ThomasD.Rossing (Departmentof Physics, NorthernIllinois University, DeKalb, IL 60115) Asvibrating systems, drums can be divided into three categories: those consisting of a singlemembrane coupledtoan enclosed aircavity (e.g., kettledrums); those consisting ofa singlemembrane open to the air on bothsides (e.g., tom toms, congas); and those consisting of two membranes coupled by an enclosed air cavity (e.g.,bass drums, snare drums). In kettledrums,the enclosed air raisesthe frequencies ofthe axisymmetric modeswhile air loadinglowers the frequenciesof themusically important modes with oneto four nodal diameters,and shifts them into a nearlyharmonic series. In two-headeddrums, coupling of the two heads throughthe air cavity results i•'mode pairs in which the heads move either parallel or antiparallel toeach other. Dipole,quadrupole• and other multipole symmetries are observed in the radiatedsound fields. Some drums, suchas the kettledrum and tabla, convey a strongsense of pitch;others such as the bass drum and snare drum do not.The senseof pitchmay be enhanced by loadinga portionof thedrumhead, as in the Indiantabla and mridanga.

3:30

MS. Calculationsof timpaninormal modes for arbitrarykettle shapes.Robert E. Davisand Arnold Tubis (Departmentof Physics,Purdue University, West Lafayette, IN 47907) A practicalboundary-integral-equation method is developedfor extendinga previousstudy of timpani normalmodes [ R. S.Christian eta/., J. Acoust. Soc. Am. 76, 1336-1345(1984) ] to thecase of rigid kettles that areazimuthally symmetric but have arbitrary contours. Room acoustics effects are ignored. Calculations and comparisonsof results with experimental data are carried out for variouskettle shapes including cylindrical, hemispherical,hemispherical with a cylindricalsleeve, hemiellipsoidal, and paraboloidal. It is foundthat the closenessof the musically important modal frequency ratios, f•: f•_•:f•: f4• to 2:3:4:5,can be quantitatively accountedfor by calculations of theeffect of air loading.These desirable ratios may be approximately achieved if V/Ira3 •> 1.08 and poa/c• 1.51,where Vis the kettle volume, a is the timpani membrane radius, Po is the mass densityof air, and•r is a realmass density of the membrane.The timpanispectrum depends weakly on the detailedkettle shape as long as these conditions are sal:isfied. An infiniterigid baffle in themembrane plane may be usedto greatlysimplify the calculationswithout having a significanteffect on the results.

ContributedPapers

4:00 two (3,0) modesthat have frequencies2.32-3.29 timesthe lowest(2,0) mode.The spectraof thesebells are comparedto thoseof other Chinese M6. Measuringthe characteristicproperties of mallets.Ingolf Bork bells, includingthose of the renownedZenghou Yi. (Physikalisch-TechnischeBundesanstalt, D-3300, Braunschweig,West Germany)

A measurementprocedure is describedthat makesit possibleto char- acterizedifferent types of malletsfor percussioninstruments. From spec- tral analysisof the impulsiveforce generatedby the mallet head, a fre- 4:30 quency range is obtainedover which each mallet optimally excites vibrations.The dependenceof thisoptimum range on the strengthof the M8. Modes of vibration and sound radiation from a snare drum. Zhao blowconstitutes a qualitycriterion that is alsosuitable for characterizing Huan and Thomas D. Rossing (Department of Physics, Northern pianohammers. Illinois University,DeKalb, IL 60115)

The orchestral snare drum is a two-headed instrument about 35 cm in diameterand 13-20 cm deep.Snares of metalor gut are stretchedacross 4:15 the lower (snare) head,which is generallythinner than the upper(batter) M7. Soundspectra of ancient Chinesebells in the ShanghaiMuseum. head.The drumcan be played with or withoutthe snares. Coupling of the Thomas D. Rossirig (Department of Physics, Northern Illinois two headsthrough the air enclosedby the shell resultsin modepairs in University,DeKalb, IL60115) and ZhuHong-Fan (Shanghai Museum, which the headsmove parallel or antiparallelto eachother. When struck 16 SouthHenan Road, Shanghai,People's Republic of China) near the center, the soundspectrum is dominatedinitially by a strong partial (typicallyaround 180-200 Hz) dueto parallel(01) motionof the Soundspectra were obtained from tenbells from the 5th- 12thcentur- two heads.This moderadiates energy rapidly, so after a shorttime, its iesBC bystriking them at theappropriate sui and gu locations.Although amplitudefalls below that of themodes with one or morenodal diameters. considerablydifferent in size,shape, and ornamentation,all the bells had Partials due to the latter modesdominate the spectrumwhen the drum is ovalcross sections and thusexhibited two-tone behavior IT. D. Rossinge! struck off-center. Dipole, quadrupole, and other multipole symmetries al., J. Acoust. Soc. Am. 83, 369 (1988) 1. Frequency ratios of the two are observed in the radiated sound field. Vibrations of the shell contribute fundamental(2,0) modesrange from 1.11-1.31 (181--473 ½). In most very little to the soundspectrum. [Research supported by Remo, Incor- spectra,it is possibleto identify two partialsmost likely associatedwith porated.]

S33 J. Acoust.Soc. Am. Suppl. 1, Vol.85, Spring1989 117thMeeting: Acoustical Society of America S33 TUESDAY AFTERNOON, 23 MAY 1989 GOLDSTEIN AUDITORIUM, 1:30TO 5:00 P.M.

SessionN. PhysiologicalAcoustics III and PsychologicalAcoustics III: InteractionsBetween Neurophysiologyand Psychoaeousticsand Others (PosterSession)

Evan M. Relkin, Chairman Institutefor SensoryResearch, Syracuse University, Merrill Lane, Syracuse,New York 13244

ContributedPapers

All posterswill beon displayfrom 1:30to 5:00p.m. (Viewinghours will alsobe extended into theevening. ) To allow contributorsan opportunityto seeother posters,contributors of odd-numberedpapers will be at their postersfrom 1:30to 3:00p.m. andcontributors of even-numberedpapers will theirposters from 3:00to 4:30p.m. Contributors are encouraged to leavetheir posters in placeuntil 9:45p.m. A cashbar will beset up in the eveningto facilitateinformal discussion,and the GoldsteinAuditorium will be closedat 10:00p.m.

NI. Physiological"release from masking."J. B. Mott, L. P. McDonald, N3. Frequency and duration discrimination by patients with central and D. G. Sinex (University of California, Los Alamos National auditorypathway lesions. Mary Ellen Thompsonand SharonM. Abel Laboratory, Life SciencesDivision, LS- 1 M882, Los Alamos, NM 87545) (Mount Sinai Hospital ResearchInstitute, Suite 843, 600 University Avenue, Toronto, Ontario MSG IXS, Canada) Psychophysical"release from masking" [ S.Buus, J. Acoust.Soc. Am. 78, 1958-1965(1985) ] is observedwhen the maskingexerted by stimuli The performanceof three groupsof patientswith centralauditory with equalpower but differentenvelopes is compared.Depending on the pathologyincluding subjects with lesionslocalized to the right temporal masker-to-probefrequency ratio, thresholds for flat-envelopemaskers are lobe,left temporallobe, and eighth nerve was compared using three psy- higherthan those for correspondingfluctuating-envelope maskers. A sim- chophysicaltasks. These included detection, frequency discrimination, ilar phenomenonwas previously reported for maskedthresholds based on and durationdiscrimination. Speech perception was measuredusing the rate responsesof chinchillaauditory-nerve fibers [J. B. Mott et al., Absts. Four AlternativeAuditory FeatureTest. The patientswere compared to a A.R.O. 12 (1989)]. Thoseresults were interpretedas suggestingthat groupof age-matchednormal control subjects and hospitalizedcontrol neuralactivity during periods of low maskerenergy was important for subjects.Except for patientswith acousticneuromas, all subjectshad detection.The presentstudy examined whether synchronized responses normal hearingacuity. Performancedeficits relative to normal were de- of auditory-nervefibers also contribute to "releasefrom masking."Syn- pendenton site of brain lesion,verified by CT and/or MR1 scans.The chronizedrates were measured in short-timewindows, centered on per- relationshipbetween the processing of frequencyand duration and speech iodsof highand low energyin the maskers'envelopes. Synchronized rate perceptionwill be discussed.[Work supportedby the MedicalResearch at theprobe frequency grew more rapidly as a functionof levelduring low- Counciland NationalSciences and EngineeringResearch Council. ] energywindows than high-energywindows. Statistical thresholds based on synchronizedbehavior will alsobe reported.[Work supportedby N1NCDS NS23242. ]

N2. Time-domainanalysis of auditory-nervefiber firing rates. Hugh N4. Auditory-nerve representation of communication signals in E. Seeker-Walker and Campbell L. Searle (Room 20C-014, M1T, backgroundnoise. loshuaJ. Schwartz,Michael Ferragamo,andAndrea Cambridge,MA 02139) Megela Simmons (Department of Psychology,Brown University, Providence, R1 02912) A time-domainanalysis of firing-ratedata from over200 fibersfrom the auditory nerveof cat hasbeen used to estimatethe formantsof syn- Anuranauditory-nerve fibers phase-lock to theperiodicity of complex theticspeech syllables. Distinct groupsof fibersare apparentin the neuro- acousticsignals, even though many of thesefibers do not synchronizeto gramsof the firing-rateresponses. The intervalsbetween peaks in the puretones at their bestfrequencies (BFs). In thisexperiment, the effects firing-rates of the fibers in each group are very similar, and reflect the of backgroundmasking noise on peripheral coding of both spectraland period of the formant that dominatesthe group'sresponse. Analysis of temporalstructure of the male bullfrog'sspecies-specific advertisement theseintervals confirms that they corresponddirectly to the formantper- call wasexamined. Synthetic advertisement calls with 21 components iods.It is concludedthat the cochlearfilters have much shorterimpulse (periocli'cityof 100 Hz) were digitally constructedand presentedvia a responsesthan the formantsto which they respond.The time-domain closed-fieldsystem against different levels of noise.Plots of averagedis- analysistracks the changesof lowerfrequency with morepreci- chargerate versusBF showpeaks corresponding to the periodicityand sionthan previousanalyses of the sameneural data [M. I. Miller and M. low-frequencyspectral energy in the signalwhen presented at noiselevels B. Sachs, J. Acoust. Soc. Am. 74, 502-517 (1983); S. A. Shamma, J. nearthreshold. These profiles change substantially in thepresence of high Acoust. Soc. Am. 78, 1622-1632 (1985)]. The direct representationof levelsof backgroundnoise. Plots of averagelocalized synchronized rate the formantperiod in the time domainis contrastedwith the diffusespec- (ALSR) againstBF are muchless influenced by noise.The datasuggest tral representationof the formant,the dependenceof spectralpeaks on thattemporal coding of thisnatural call is more resistant to noisemasking nonformantparameters, and the distortionof the spectrumby physiologi- than is a representationbased solely on dischargerate. [Work supported cal nonlinearities. by NIH. ]

S34 J. Acoust.Soc. Am. Suppl. 1, Vol.85, Spring1989 117thMeeting: Acoustical Society of America S34 NS.Relations between neural-count andintensity-jnd functions forsingle bullfrog.A low-noiseacoustic measurement system was developed for auditory-nervefibers. William S. Hellman(Department of Physics, recordingSOAKS in a readilyavailable species of frog.SOAKS were de- BostonUniversity, Boston, MA 02215) and Rhooa P. Hellman tectedin one of five anesthetized frogs during late autumn. The frequency (Departmentof Psychology,Northeastern University, Boston, MA of the emission was temperature dependent, increasing from 1612-1762 02115) Hz, with a changein bodytemperature from 22.1•-25.3 øC. The SOAE levelranged from -- 3 to + 4 dB SPL and was uncorrelatedwith tem- Theequation d'a(x) = AN(x),where x = 1/1o,is applied tophysio- logicalmeasurements reported byDelgutte | The Psychophyxics ofSpeech peratureover lhe range studied. SOAEs have been reported in Ranaescu- Perception(1987) ] forsingle auditory-nerve fibers. Intensity-jnd func- lents[A. R. Palmerand J.P. Wilson,J. Physiol.324, 66P ( 1981) I and tionsare derived for individualfibers with thenenral-eount function as Ranatemporaria [Wilson et al., in AuditoryFrequency Selectivity, edited input.The experimentally obtained neural counts are represented bya byB.C. J. Mooreand R. D. Patterson(Plenum, New York, 1986),pp. hyperbolictangent function, and the measured dependence of the count 39-46].The emissions inthese other species are also temperature depen- varianceon thecount is approximatedby a combinationof linearfunc- dent [P. vanDijk andH. P. Wit, 1. Acoust.Soc. Am. 82, 2147-2150 tions.Here, AN(x) can be obtained without approximation forarbitrary (1987)]. Experimentsare recommended to explore the possibility that valuesof Ax for a hyperbolictangent function; it can also be represented thepresence and incidence of SOAKSare seasonally dependent in this species.[ Work supported in partby N IH. ] bya Taylorseries inAx. The exact equation for AN(x) gives a U-shaped jndfunction inagreement with the numerical procedure used by Deigutte. Bycomparison, theTaylor series for AN(x) convergestothe exact solu- tionin fifthorder. [Partially supported by theRehabilitation Research andDevelopment Service of the VA. ] N9. Scatteredambient noise as an auditory stimulusfor fish. Peter H. Rogers, Thomas N. Lewis, Martha ]. Willis, and Scott Abrahamson(School of MechanicalEngineering, Georgia Institute of N6. Simulating pitch perceptionand sensitivity to phase using a Technology,Atlanta, GA 30332) peripheral auditory model. Ray Meddis and Michacl L Hcwitt In an earlierpaper [ P. H. Rogers,J. Acoust.Soc. Am. Suppl.I 79, S22 (Department of Human Sciences,University of Technology, (1986)], it washypothesized that one role of thefish's auditory system Loughborough,LEI 1 3TU, IgnitedKingdom) may be to detectand localizenearby fish by "imaging"ambient noise The abilityof ncurophysiologicalstudies to givcan adequateaccount scatteredby theirswim bladders. This is analogous to the role of thevisual of humanpitch perception was studied using a peripheralauditory model systemof mostanimals, where the relevantsignal is ambienllighl scat- comprising(a) outer-ear,low-frequency attenuation, (b} a setof 60 digi- teredby objectsrather than light emitted by luminousobjects. A classical tal filtersto simulatebasilar membrane frequency selectivity, (c) an array conditioningexperiment has been performed which indicatesthat the fish of inner hair cell simulators,and (d) a systembased on Licklidcr's [Ex- auditorysystem is capableof functioningin this manner.The ambient perlentis7, 128-133 ( 1951) ] theoryof pitch perceptionthat generates noiseis provided by a J-9transducer driven by Gaussian noise. Scattering runninghistograms of the time intervalsamong all spikesin fibersorigi- of thisnoise by the resonantswim bladder is simulatedby applyinga natingfrom adjacent sites on themembrane. The mostfrcqucntly occur- filteredversion of the noisesignal to a smallspherical projector. The ring time intervalswere taken to representthe periodof the perceived "targel strength"is bandwidthof the filter. The fish is conditionedto pitch,while the overall pattern of time intervalsrepresented the perceived respondto the presenceof the signalfrom the sphericalprojector. The timbre. Thc modcl was tested,giving satisfactoryresults, using a wide fish'sability to detectthis signal (as a functionof range,bearing, etc. ) is rangeof harmonic,inharmonic, and noisestimuli knownto give riseto taken to be a measureof its ability to detectscattered ambient noise. pitchperceptions as well asstimuli, whcrc the relativephase of the har- moniccomponents affects stimulus timbre. [ Work supportedby SERC.]

NI0. The amplitude-latencytrade-off demonstrates a temporalbasis for N7. Alternate-stateotoacoustic emissions as a basisfor episodic fineecho delay acuity in batsonar. J. A. Simmons,M. Ferragamo,and intermittentfinnitus. Edward M. Burns(University ofWashington, JG- C. F. Moss(Department of Psychologyand Section of Neurobiology, 15, Seattle,WA 98195) Divisionof Biologyand Medicine,Brown University, Providence, RI 02912) Thccorrelational evidence isso overwhelming that the vast majority ofoccurrences ofsevere, continuously present, tinnitus are not associated Echolocatingbats (Eptesicusfuscus) can perceive a changein echo withspontaneous otoacqustic emissions (SOAKS). Similarly, subjects delaysmaller than I/.rs in two-choice,echo-jitter discrimination tasks. withSOAKS are rarely subjectively aware of theirpresence, a fact that is Althoughthe bats emit short enough to avoidoverlap of stimulus notincompatible with theliterature on theadaptation of low-levelsinu- echoeswith incidental echoes, and although the transfer function of the soidalstimuli. However, OAE researchers have often speculated that un- delayelectronics reveals no amplitudeor spectralcues correlated with stableSOAKS could be the basis of intermittenttinnitus. This paper re- delay,it is difficultto believethat suchfine temporal is not basedon portson measurementsmade on one subjectduring an episodeof spectralcues. If thedelay of echoes isencoded by neural discharge timing intermittenttinnitus (reported by thesubject to be audiblein normal ratherthan from spectral information, perceived delay should shift ac- circumstances,loud,and extremely annoying), which demonstrate fairly cordingto theneural amplitude-latency trading function, which is -- 13 conclusivelythat the tinnitusin thiscase is associated with alternate-state to -- 18/•s/dBfor N•-.N4 responsesin Eptesicus. The apparent delay of SOAKs. echoesintbejitter task shifts by -- 16to -- 17#s/dB,demonstrating that thebats perceive the delay ofjittered echoes from their arrival time rather thanfrom some spectral consequence of the parlicular value of echo delay. Thecorresponding shift of the entire jitter psychometric function demon- stratesthat batsmay perceivethe phaseof echoesrelativc to emissions N8. Spontaneousotoacoustlc emissions in Rana caresblanc,the frominformation encoded in thetiming of neuraldischarges, asprevious- Americanbullfrog. T. J. Gcnnosa (Departmentof Biomedical ly proposedfrom coincidence of the jitter psychometric function with the Engineering,Boston University, 44 CummingtonStreet, Boston, MA cross-correlation function of echoes. 02215),H. F. Voigt(Departments of BiomedicalEngineering and Otolaryngology,Boston University, Boston, MA 02215), and R. BurLard (Departmentof CommunicationDisorders, Boston University,Boston, MA 02215) Nil. Perilymphvolume flow in the fistulizedcochlea. Naoki lnamura, Temperature-dependentspontaneous otoacoustic emissions Alec N. Salt, RuedigerThaimann, and Arti Vora (Departmentof (SOAEs)are reported for thefirst time in Ranacatesbiana, the American Otolaryngology,Washington University, St. Louis,MO 63110)

S35 J.Acoust. Soc. Am. Suppl. 1,Vol. 85, Spring 1989 117thMeeting: Acoustical Society ofAmerica S35 It hasbeen previously reported that in guineapigs the rate of peri- NI4, The P300 responseto verballypresented digits. Lawrence F. Molt lymphvolume flow is extremelylow ( < 2 nl/min) whenthe cochleais in (Department of ExceptionalStudent Education, Florida Atlantic thephysiological, sealed state. In thepresent study, flow rates were moni- Univcrsity,BocaRaton, FL33431) andRichard S. Saul(Audiology and toredwhen the otic capsulewas perforated. Flow wasmeasured by com- SpeechPathology Service, Veterans Administration Medical Center, paringdispersal of a tracer (ttimethylphenylammonium)in both direc- Miami, FL 33125) tionsalong scala tympani with ion selectivemicroelectrodes. Perforation of the cueblearapex produced a highrate of flow averaging0.4 pl/min. Latencyand amplitude functions for the P300component of the slow The ratewas reduced considerably when cerebrospinal fluid (CSF) pres- auditoryevoked potential were measured for 20 normalhearing adults. sure was releasedby openingthe dura at the foramenmagnum. Under Stimuliconsisted of digitizednumbers, 1-10 (excluding7), of 480-ms theseconditions, the mean rate of 6.9 hi/min. Blockageof the ouchlear duration.The method of presentationfor stimulipairs v•as in anoddball aqueductwas even more effective, reducing flow to a meanvalue of 1.4nl/ paradigmin which the frequentlyoccurring digit waspresented 80% of the time and the rarelyoccurring digit 20% of the time. Pairsconsisted of min. In the latter condition,the flow rate was not significantlydifferent from the normal, sealedcochlea condition. These resultsdemonstrate that acousticallysimilar or acousticallydivergent waveforms (e.g., 4-5 vs8-2, the highrates of flowin thefistulized cochlea atise from a nonphysiologic respectively).Evoked potentials wcrc recorded from Fz, Cz,and Pz sites. While both meanlatency and meanamplitude values differed among the entry of CSF into scalatympani through the cochlearaqueduct. For ex- perimentalpurposes, this nonphysiologic flow canbe reduced by releasing threesites, with thegreatest amplitude and shortest latency recorded from CSF pressure,or better still, by occludingthe cochlearaqueduct. [Work site Cz, differenceswere not statisticallysignificant. Similarly, mean am- supportedby NIH ProgramProject Grant No. POI NS24372.] plitudeand latencyvalue differences did not reachstatistical significance for acousticallysimilar versus acoustically divergent digit pairsat any of the three sites.

N15. Effectsof intensesound exposures and aspirin on overshoot.Craig N 12. A widedynamic range speech test for theevaluation of compression A. Champlinand Dennis McFadden(Departments of Psychologyand hearingaids. Arlene C. Neuman,Matthew H. Bakke,and Harry Levitt Speech Communication and Institute for Neurological Sciences (CUNY Graduate School,33 West 42 Street, New York, NY 10036) Research,University of Texas,Austin, TX 78712) Wide dynamicrange test materials have been developed for the evalu- Brieftonal signals were presented 2 or 190ms following the onset of a ationof compressionhearing aids. Anomalous sentences containing four 200-msbroadband masker. These two conditionsof signaldelay were monosyllabictest words per sentencewere recorded by a femaletalker. testedbefore and after a seriesof exposuresto a tone intenseenough to The fourtest words in eachsentence were then scaled (using a waveform inducetemporary threshold shifts (TTS). The differencein detectability editingsystem) to representfour different sound-pressure levels covering betweenthe short-and long-delaysignals (i.e., overshoot)was reduced a 30-dBrange (in 10-dBsteps). Performance on thisspeech material was when a TTS of at least 10 dB was induced, but not when smaller amounts comparedto a performance-intensityfunction obtained using monosyl- of TTS wereinduced. This reductionin overshootwas due to an improve- labicword lists at the samefour sound-pressure levels. Testing was done mentin the postexposuredetectability of the signaldelayed by 2 ms;the for a linearand two compression systems (compression ratio of 2.5, in- detectabilityof the signaldelayed by 190 ms was unchangedpre- and stantaneousattack time, releasetimes of 20 and 140 ms). For all three postexposure.Recovery from both the TTS and the reductionof the over- conditions,frequency shaping based on a half-gainrule was used.Ten shootfollowed slightly different time courses.Data are currentlybeing listenerswith sensorineuralhearing loss served as subjects. Results of the collectedfor the two conditionsof signaldelay before and after the pro- experimentindicated that the wide dynamic range test material was sensi- ductionof anaspirin-induced threshold shift. [Work supportedby NIH. ] tiveto thedynamics of thecompression system being evaluated, while the monosyllabicword materialspresented at discretelevels was not. [Work supportedby NIH Grant No. POl NS17764.]

N16. Comodulationmasking release for three types of modulatoras a function of modulationrate. Robert P. Carlyon, SCrenBuus, and Mary Florentine (CommunicationResearch Laboratory (226 FR), NortheasternUniversity, Boston, MA 02115)

NI3. Comparisonof long-term averagespeech spectrum at ear-level and To investigatethe dependenceof comodulation masking release standard recording positions. Leonard E. Cornelissc, Jean- (CMR) on the type and frequencyof modulator,thresholds were mea- Pierre Gagn•,and RichardC. Seewald(Department of Communicative suredfor a 4-kHz tone maskedby modulatedand unmodulatednoises. The maskers were a 400-Hz wideband of noise centered on 4 kHz Disorders,University of WesternOntario, London, Ontario N6G 1H 1, Canada) (NOCUE), the same noise with a 2700-Hz low-pass noise added (LPCUE), and a widebandnoise with a passbandbetween 3 and 6 kHz The long-termaverage speech spectrum (LTASS) wasobtained from (WBCUE). Eachmodulated masker was presented with severalmodula- ten maleand ten femaletalkers for two microphonepositions. Dual chan- tion frequencies,f,,s and three typesof modulators:a squarewave, a nel recordingsof speechwere recordedand played back for spectrum sinewave,and a low-passnoise. Thresholds were lower in the presence analysis.One channelrecorded the speechsignal obtained from a micro- thanin theabsence of modulationfor all modulatortypes, except when f, phoneplaced 30 cm directlyin front of the talker, while the secondchan- was high. The modulated-unmodulateddifference (MUD) decreased nel recordedthe speechsignal obtained from a microphoneplaced at the monotonicallywith increasingfe in all conditions.For any givenf•, talker'sear. A spectrumanalyzer (BK type 4132) was usedto compute MUDs weregreater for square-waveand low-pass-noisemodulation than the overalllevels and 1/3-octave-bandlevels. The analysesindicated sig- for sinusoidal modulation. The CMR, defined as the difference between nificant differences in overall and the 1/3-octave-band levels between the the MUD obtained in the NOCUE condition and that obtained in each two recordingpositions. The mcanoverall level at the positionof the car cuecondition, did not vary systematicallywithr, overthe rangestudied. was approximately6 dB higher than the overall level at the standard CMR wassmaller for sinusoidalmodulation than for eithersquare-wave recordingposition. Also, l/3-octave-bandanalyses indicated that the ear- or low-pass-noisemodulation. Although there was some variability across level LTASS consistedof more low-frequencyenergy and lesshigh-fre- listeners,low-pass-noise modulators that producedan f, of between32 quencyenergy than the LTASS recordedat the standardposition. The and 100 Hz resulted in substantial (5-9 dB) CMRs for all three listeners. implicationsof theseresults for heatingaid selectionwill be addressed. [ Work supportedby thePiggott-Wernher Fellowship and NIH. ]

S36 J. Acoust.Soc. Am. Suppl.1, Vol. 85, Spring1989 117th Meeting:Acoustical Society of America S36 N17. Masking patterns for comodulatedand uncomodulatednarrow- N20. Perception of pitch structure in pure-tone melodic sequences. bandnoises as a functionof maskerband separation. Rebecca M. Fischer NicholasOram and Lola L. Cuddy (Department of Psychology, and D. WesleyGrantham (Division of Hearingand Speech Sciences, Queen'sUniversity, Kingston, Ontario K7L 3N6, Canada) VanderbiltUniversity, 1114 19th Avenue South, Nashville, TN 37212) Musicallynaive subjects were tested in two experimentsinvestigating Maskingpatterns were determined for a pair of narrow-band(25 Hz the perceptionof pitchstructure in pure-tonesequences. Each sequence wide) noiseswhose envelopes were perfectly correlated, uncorrelated, or contained20 successivesamples from eithera diatonicor a nondiatonic negativelycorrelated. In one condition,noise bands were centeredat tonesetof seventones with probabilityof occurrenceof eachtone system- 962.5 and 1037.5 Hz in order to examine the effects of comodulation atically varied. Sequenceswere presentedin either of two frequency maskingrelease (CMR) whenpaired noise bands were within one critical ranges(262494 Hz, or 1047-1976 Hz). Frequencyrange was varied band;the secondcondition used noise bands centered at 887.5 and 1112.5 betweensubjects in experiment1 andwithin subjectsin experiment2. On Hz, a separationof greaterthan one critical bandwidth. Signal thresholds eachtrial, a sequencewas followed by a probetone, one of the 12chromat- weredetermined for a rangeof frequencies(750-1250 Hz) aboveand ic toneswithin the sameoctave as the sequence.Subjects rated the good- belowthose of themaskers in orderto examinethe processof CMR out- ness-of-fitof the probetone to the sequence.In bothexperiments, probe- sidethe immediatespectral region of the maskers.Preliminary data sug- tone ratings were positively related to probability of occurrenceof the gestthat CMR graduallydecreases as the signal is moved away in frequen- probetone in the sequence.Moreover, for sequencesgenerated from dia- cy from the center of either noiseband. A comparisonof CMR in tonic tonesetsand presentedin the high-frequencyrange, ratings also positivelyand negatively comodulated conditions is expected to shedlight reflectedthe tonalhierarchy implicated by the key of the toneset.[Work on the typeof mechanismsunderlying CMR within and acrosscritical supportedby NSERC. ] bands.

N21. Reaction time measures of phantom image recognition in stereophonic listening. H. Brazzil (Department of Mathematics, N18. Profile analysis by parallel distributed networks. James University of St. Thomas, Houston, TX 77006) and A. Yonovitz H. Howard, Jr., Jeffrey L. Harpster, and Maxwell H. Miller (Speechand Hearing Institute, Universityof Texas Health Science (Departmentof Psychology,The CatholicUniversity, Washington, DC Center at Houston, Houston, TX 77030) 20064) Intensitystereophony allows the listenerto perceivephantom images, Severalprofile analysis (spectral shape discrimination) phenomena whichmay be localized at anypoint on the imaginarysoundstage existing weresimulated using simple, three-layer, feed-forward, parallel networks. betweenloudspeaker pairs. Specification of the phantomimage typically As in previousstudies with human listeners,pairs of multitonal sounds relieson subjectiveevaluation by the listener.This studyutilized reaction wereused---one with all componentsat a uniform,background level and time to quantifythe ability of listenersto accuratelyidentify the image the other with a tonal signaladded in-phase to the centralcomponent. positionas a functionof frequency.Subjects were seated at 30-deginci- Networkswere trained to selectthe signal alternative in a 2AFC paradigm denceto eachloudspeaker in an anechoicenvironment. Each trial consist- usingthe generalizeddelta rule with error propagationand were then edof a pairof third-octavenoise bursts at oneof sixfrequencies (250-8000 testedunder various conditions. Background levels were varied randomly Hz). The first of eachstimulus pair was presentedwith no interloud- either betweenor within trials. In the former case,the network learned to speakerintensity difference (phantom center). The secondstimulus oc- compareenergy at the signalfrequency across the two sounds(intensity curredrandomly at phantomcenter, phantom left, or phantomright, and discrimination),whereas, in the latter case,it learnedto comparethe subjectswere instructed to correctlyrespond as quickly as possible in this distributionof spectralenergy within sounds(profile analysis). These three-choiceforced response task. Interloudspeakerintensity difference resultsmimic previousfindings with human listenersreported by Green for imagesoccurring left or right of centerwas 2, 4, or 6 dB. Longer and his colleagues[D. M. Green, ProfileAnalysis (Oxford U. P., New reactiontimes occurred for centerimage responses, independent of fre- York, 1988)1. In follow-upsimulations, improved profile analysis have quency.Shortest reaction times were obtained at 2 kHz, with increasing beendemonstrated when the frequencyrange of tonalcomponents is ex- latenciesoccurring at higher frequencies.Data suggeststhat phantom pandedand as the duration of the complexincreases to 100 ms. [Work imageidentification in stereophoniclistening is compromisedabove 2 supportedby ONR. ] kHz.

N22. Binaural signaldetectability in noiseamplitude-modulated (NAM} NI9. Spectral pattern discriminationin children, Prudence Allen and noise as a function of masker bandwidth. Mark Hedrick and D. Frederic Wightman (Waisman Center, University of Wisconsin, Wesley Grantham (Bill WilkersonHearing and SpeechCenter, l 114 Madison, WI 53705-2280) 19th Avenue South, Nashville, TN 37212)

This experimentused a video-game-basedadaptive forced-choice Thresholdswere determined for a 500-Hz tonalsignal in the presence paradigmto assessthe effect of noiseon theability of childrento discrimi- of a noiseamplitude-modulated (NAM) noise,where the carrier was a nateamong stimuli with differentspectral shape. The stimuliwere synthe- wideband Gaussian noise and the modulator was a 20-Hz-wide noise band sizedvowels and consonants,and tonal complexesthat had sinusoidally centeredat 20 Hz. The NAM noisewas filtered after modulationto pro- rippledspectra. Preschool children, school-aged children, and adults duceaband centered on the 500-Hzsignal. Both diotic (So) andinteraur- servedas subjects.In orderto encouragethe subjectsto basetheir dis- ally phase-reversed(S•r) signalthresholds were determined as a function criminationson spectralshape rather than on local energyconcentra- of maskerbandwidth (10-1000 Hz). When the maskerwas presented tions, the overall level of the stimuli was randomizedover a 20-dB range diotically, So thresholds(and to a lesserextent, S•' thresholds) first in- for eachpresentation. In general,the resultssuggest that spectralpattern creased,then decreasedas a functionof maskerbandwidth, thus showing discrimination ability for all stimulus typesimproves with age.The age at the effectsofcomodulation masking release at the wider bandwidths.The whichthe children'sperformance reaches adult levels varies with stimu- masking-leveldifference (MLD, i.e., the differencebetween So and S•- lustype. Moreover, noise has a particularlydeleterious effect on thespec- thresholds) increased as masker bandwidth decreased, as it did with a tral patterndiscrimination ability of the youngersubjects. [Work sup- random (unmodulated) noisemasker. When the maskerwas presented portedby DRF and the WaismanCenter Rowan Trust. ] such that the noise carrier was diotic but the noise modulators were inde-

S37 J. Acoust. Soc. Am. Suppl. 1, Vol. 85, Spring 1989 117th Meeting: AcOusticalSociety of America S37 pendentat thetwo ears,a sizableMLD stilloccurred (5-10 dB), but the at two sensationlevels (30 and 60 dB SL) monaurallyand binaurallyat MLD decreasedwith decreasingbandwidth. The decreasedMLD at small six repetition rates: 3.1, 9.1, 15.1, 27.1, 39.1 (the 40-Hz, or steady-state, bandwidthsresulted from the higher S•r thresholdswith this stimulus response),and 51. l/s. The responsesof young(under 35 years)and older than with a true diotic masker,which can be explainedby the slowly (over 60 years) subjectswere compared.The resultsrevealed that the fluctuatinginteraural intensity differences that this type of maskerpro- waveformsare similar for the two groups at differentrates, with the excep- ducesat narrowbandwidths. [Work supportedby NIH. ] tionof latencyprolongations, especially for the laterwaves (e.g., Pb at 50- 60 ms), in the oldersubjects. Furthermore, at the higherrates, the ampli- tudesof the waveformsof the older subjectsare largerthan thosein the younger group.

N23. Binaural frequency-followingresponse (FFR) to lateralization stimuli. B. B. Ballachanda and G. Moushegian (Department of Audiologyand SpeechSciences, Purdue University, West Lafayette,IN 47906 and Cailler Center-UTD, Dallas, TX 75235) N26. Binaural differencein rat. Maria Psaltikidouand Roger The cuesfor localizationor lateralizationare interauraldisparities of P. Oaumond(Bioengineering Program, Pennsylvania State University, time andintensity, and neurophysiological studies have elegantly demon- UniversityPark, PA 16802) stratedthat lower-brain-stemneurons, in conformitywith anatomicalob- The binaural difference (BD) is the sum of monaural acousticbrain- servations,are differentially sensitive to thestimulus parameters that me- diate binauralphenomena. Brain-stem responses were obtainedusing stem responses(ABRs) minus the binaural ABR. Its constructionim- low-frequency(500 Hz) stimuli in variouscombinations of interaural pliesoperation of a nonlinearelement with binauralinput. The BD in five phase(time) and interauralphase and levelpresented in-concert and in- ratswas studied using insert earphones that provided 60 dB of interaural oppositionthrough earphones. The findingsshow that theamplitudes and isolationmeasured in the occludedexternal meatus. Scalp to chin BD morphologiesof thevolume-conducted evoked FFR potentialsare differ- consistedof a double-peakedcomplex with a followingtrough occurring entiallyaltered as a functionof timeand level variables. There are signifi- duringpeaks IV andV of thesum of monauralABRs. BD magnitudewas cantreductions, for example, in theamplitude of the evoked responses due definedas the maximum peak-to-trough waveform amplitude. As stimu- to interauraltime differences. Furthermore, for in-concertand in-opposi- lusintensity increased, BD magnitudeincreased linearly with themagni- tion timeand levelstimuli, the amplitudechanges are distinctly different, tudeof ABR peakI. A bilaterallysymmetric stimulus generally yielded reflectingthe complexneuronal interactions at the levelof the brain-stem smallerBD magnitudethan did stimuliwith smallbilateral asymmetry nuclei and tracts. (8-dB interauralintensity difference, 64-/•s interauraltime difference). With largerasymmetry, BD magnitudedecreased. The linearincrease of BD magnitudewith ABR peakI magnitudeisconsistent with operation of an elementthat appliesa rectificationnonlinearity to the differenceof binauralsignals during peaks IV and V of the ABR.

N24. Comparisonsof between-and within-subject variability in repeated- measuredauditory brain-stemresponses (ABRs) in 5-6-year-old children.JanieceM. Lord-Maes and Judith L. Lauter(Departments of EducationalPsychology and Speech and Hearing Sciences, University of Arizona, Tucson, AZ 85721 )

In reportsto this Society,and publications[J. L. Lauter and R. L. N27. Effectsof homophasicand antiphasic stimulation on the binaura!ly Loomis, Scand.Audiol. 15, 167-172 (1986); Scand.Audiol. 17, 87-92 evoked auditory brain-stem responses. Vishakha W. Rawool and (1988)], resultsof repeated-measuresABR testingin youngadults have Bopanna B. Ballachanda (Audiology and Speech Sciences,Purdue beendescribed, indicating the variabilityof peakparameters, such as la- University,West Lafayette,1N 47907) tency and amplitude,provides information that absolutevalues of these This studyinvestigated the effects ofhomophasic and antiphasic stim- parametersdo not:contrasts in between-versus within-subject consisten- ulationon thebinaurally evoked auditory brain-stem responses (ABRs). cy, and by ear of stimulation.Seven 5-6-year-old children were tested in Ten normalsubjects were presented with two in-phase(binaural conden- eightweekly sessions for ABRs to right, left, and binauralclicks, and see sationand binaural rarefaction) and two out-of-phase(left ear condensa- adultlike patternsbased on nonadult values: (1) contrast in between- tion, right ear rarefactionand right ear condensation,left ear rarefaction) versuswithin-subject consistency; (2) peakdifferences; and (3) ear dif- stimulusconfigurations. The stimuliwere 100-/•s clicks delivered at 47 dB ferences.Preliminary comparison between these data, a studyon 10-year- SL (repetitionrate 5.6/s). The ABRs werepicked up betweenhigh fore- oldmales, and 15 young adults suggest that ABR variabilitymay be sensi- head (active) and left earlobe(reference), the hasionserved as ground. tive to auditory-systemdevelopmental changes that continuelong after The earlier of the latenciesobtained with homophasicstimulation was ABR absolutepeak latencies have achieved "adult" values.[Work sup- comparedwith the earlierof the latenciesobtained with antiphasicstimu- portedin part by AFOSR. ] lation.A subject-by-treatmentanalyses on thepeaks (P) andtroughs (N) of eachcomponent revealed significantly earlier latencies for theantipha- sic conditionfor componentsfIN (p<0.05), IIIP (p<0.025), V1P (p < 0.01) and VIN (p < 0.025). Similartrends were apparent in compo- nentsIVP (p<0.1), 1VN (p<0.2), and VP (p<0.1). No differences were observedfor components1P, IN, liP, and VN.

N25. Comparisonof rate effectson the auditorymiddle latency evoked response(MLR) in youngand elderly adults.Jody Newman Ryan and George Moushegian (Cailler Center for Communication Disorders, Schoolof Human Development,University of Texasat Dallas, Dallas, TX 75235)

Middle latency responses(MLR) are rate sensitivein infantsbut less N28. Human auditory localizationperformance in azimuth. Richard ratesensitive in adults.It hasbeen suggested that developmental factors at L. McKinleyand Mark A. Ericson(AAMRL/BBA, Wright-Patterson bothends of the agecontinuum may influence MLR [Jergeret al., Sero. AFB, OH 45433-0653) Hear. 9, 75-86 ( 1988) ]. Effectsof rate in the elderlyare unknown.This study was undertakento determinehow rate alters the waveformsof the Human auditorylocalization performance in the free-field,over head- MLR in elderlysubjects. Tone bursts of 500 and 2000 Hz werepresented phonesvia a simulatorand over headphones via a real-time,head coupled,

S38 d.Acoust. Soc. Am. Suppl. 1, Vol.85, Spring1989 117thMeeting: Acoustical Society of America S38 digitalauditory localization cue will bedescribed in thepre- study.The stimuliused were wideband pink noise,male speech bandlimit- sentation.In the headphoneconditions, the head position is monitored to ed to 3.5 kHz, femalespeech bandlimited to 6 kHz and octaveband noise updatethe sound source position relative to thelistener's orientation. The from 125Hz to 8 kHz. The meanmagnitude error and mean response time synthesizerpresents sounds over headphonesthat are perceivedto be were measuredat 72 randompoints for eachstimulus. Five male and five outsideof the listener'shead in the horizontalplane. The performance femalesubjects participated. A 4.8-degmean magnitude error and a 4.4-s experimentswere designedusing a within subject,repeated measure meanresponse time werecollected with the synthesizer.

TUESDAY AFTERNOON, 23 MAY 1989 REGENCY B, 1:30 TO 4:40 P.M.

SessionO. Structural Acousticsand Vibration II: Modal Analysis

S. P. Ying, Chairman Gilbert Services,P.O. Box 1498, Reading, Pennsylvania19603

Chairman's Introductiontl:30

Invited Papers

1:35

O1. Modal analysistechnology review. Paul McDonald and Garth Wiley (StructuralDynamics Research Corporation,2000 EastmanDrive, Milford, OH 45150) An overviewof currentexperimental modal analysis technology is providedwith considerationto its use withfinite element analysis. The implicationsof thisavailable technology to acousticapplications are included. Theadvantages and disadvantages of various practical modal analysis methods will becovered. A lookto the futureis provided in assessingthe influences of computationaland graphics advances anticipated in worksta- tionhardware. Various application examples will bereviewed to illustratemethodologies employed.

2:00

O2. CurrentandfuturetopicsinmodalanalysisattheUniversltyofCincinnati.RobertW. Rost(Department ofMechanical and Industrial •ngineering, University ofCincinnati, Cincinnati, OH 45221-0072) The Universityof Cincinnati,Structural Dynamics Research Laboratory, has been involved in thearea of modalanalysis for over20 years.Currently, there are 5 facultymembers and 15graduate students who work with UC/SDRL. UC/SDRL hasworked with the United StatesAir Force, NASA, General Motors, and many otherindustries on a varietyof researchand consulting topics. Current and future technology in the areaof modalanalysis will bediscussed. Current topics to be discussedwill includemulti-input/multi-output testing techniques,parameter estimation for multi-input/multi-outputtesting, and work station environment. Future topicsto bediscussed will includestep sine testing, active control, and new signal processing techniques.

2:25

03. Modal identificationfor hysteretlcstructure. Daniel J. Intoart (Departmentof Mechanicaland AerospaceEngineering, University of Buffalo,Buffalo, NY 14260) Thiswork describes a method of analyzingthe vibration response of a viscoelasticbeam. The equationof motionof the transversevibration of a beamwith viscousdamping and temporalhysteresis is given.Several methodsfor measuringthe constants of a givenhysteresis kernel are presented. One is based on a least-squares fit to datausing inverse procedures for partialdifferential equations. The second approach discussed isthat of introducingan auxiliary coordinate. This coordinate combined with a transferfunction model of thehysteresis effectyields a modalanalysis solution for theviscoelastic beam. It isshown that identification isthen possible by usingmodal analysis techniques. This theoreticalderivation is comparedwith testdata.

2:50

04. A newapproach to systemidentification in conjunctionwith digitallySwept MultiExciter SineControl. M. A. Underwoodand R. C. Stroud (SynergisticTechnology, Incorporated, 1333 Lawrence Expressway #410, Santa Clara, CA 95051) This paperdiscusses a new adaptive control technique that applies optimization ideas to thegeneral prob- lem of updatingan imprecisesystem Impedance Matrix, I, as part of the feedbackcontrol process that is associatedwith MultiExciter SweptSinewave Control. Extensionsof the approachto other MultiExciter problemssuch as waveform and random vibration control will alsobe explored. The effects on the ability of the AdaptiveControl Algorithm to converge by lowmatching of phaseand amplitude between the input channels, low coherencebetween the exciterdrive vectorand the controlpoint responsevector, and low input/output

S39 J. Acoust. Soc. Am. Suppl. 1, Vol. 85, Spring 1989 117th Meeting: Acoustical Society of America S39 dynamicrange are also analyzed. The effects of the above instrumentation errors on the optimization problem associatedwith experimental modal analysis are also explored as well as the potential benefits that an enhanced frequencyresponse matrix estimate, as a resultof theabove system identification process, can provide.

3:15

O5. Modal analysisof rotatingmachinery. S. P. Ying (Gilbert Services,Inc., P.O. Box 1498,Reading, PA 19603) Modalanalysis of rotatingmachinery and its supporting structure is discussed.This paper presents the naturalfrequencies, damping ratios, and mode shapes of variousmodes of rotatingmachinery systems such as fansand radar antenna foundations as examples. For a rotatingmachinery, it isnecessary to havea dynamic correctionfactor for the dynamic natural frequency of a rotor(critical speed). The dynamic correction factor for ventilationfans is presentedwith examples. The overall natural frequency of an entiresystem depends on thedynamic combination of therotor and its supporting structure. Ira heavyduty rotor bearing is used,the modefor the rotorhaving a rigidsupport becomes significant, which simplifies design, and the dynamic sensitivityof thesystem is reduced. For a largeindustrial fan, an earlyfoundation design is compared with an improvedfoundation design in laterstage from a modeshape viewpoint. Based on suggestions developed from modalanalyses, a supporting structure was improved, gear noise resulting from torsional vibration was elimin- ated,and a rotor resonantproblem was resolved.

ContributedPapers

3:40 4:10

06. Group delay and reverberationin multi degreeof freedomsystems. 08. Detection of global modesin a foundationand hull structural model Djamil Boulahbaland Richard H. Lyon (Departmentof Mechanical from drive point mobility measurements on the foundation. Engineering,M IT, Cambridge,MA 02139) Kevin McCoy and Richard H. Lyon (Departments of Ocean and MechanicalEngineering, MIT, Cambridge,MA 02139) Signalsthat lravel in multi degreeof freedom(dof) systemsexperi- encegroup delay that is a functionof systemgeometry, modal density, Closelycoupled modes of two connectedstructures may be considered damping,and signalprocessing procedures. This paperis interestedin to be "globalmodes," involving the combinedmotion of both structures. developinginverse filters for suchsystems for the purposesof mechanism Such modeswill accountfor the greatestenergy transfer betweenthe and structuraldiagnostics, and the dereverberationof responsesignals. structures,and it is thereforedesirable to find waysof detectingthem. The designof inversefilters is greatlyaided if the processcan beginwith This paper is interestedin the casein which it is convenientto make approximationsto the systemtransfer functions that arebased (at leastin measurementson only oneof the two structures,in thiscase a "foundation part) on conceptualmodels for the systemdynamics. In this paper,the model" that is connected to a "hull model." The foundation (a beam) is theoreticalbasis for suchmodels is outlined, including the effects of signal excitedby a shaker,and its drive point mobilityis measured.At certain processingprocedures. The variouselements of thesemodels that have frequencies,an interactionwith the hull (plate) modescan be detected. beentested experimentally, and the resultsof thesestudies will bepresent- This interactioncan be modified by using small massesto changethe ed. couplingbetween the structuresand the foundationresonances. In this way, the globalmodes can be separatedtruly from structuralresonances that simplyhappen to lie closeto eachother.

3:$5

07. Resonancecharacteristics of connectedsubsystems. Takeru Igusa, 4:25 Jan D. Achenbach, and Kyung-Won Min (Department of Civil Engineering,Northwestern University, Evanston, IL 60208) 09. A generalizedalq•roach to randomnoise synthesis. Keng D. Hsueh and RogerP. Hamernik (Auditory ResearchLaboratory, 107 Beaumont Resonancecharacteristics of a collection of linear subsystemsinter- Hall, StateUniversity of New York, Plattsburgh,NY 12901) connectedby waveguidesis examined.The propertiesof the subsystems aredetermined separately using modal or mobilityanalysis, and the topol- A generalizedapproach to the synthesisof Gaussianand non-Gauss- ogyof thewaveguide network is cast in matrixform using a wavepropaga- ian randomnoises having a preselectedamplitude spectrum has been de- tion approach.It isfound that harmonicresponses are described by multi- veloped.An applicationof the inversediscrete Fourier transform follow- valuedanalytic functions defined in thecomplex plane ( or a single-valued ing certainmanipulations in the frequencydomain allows both Gaussian functionon a Riemann surface). The excitation frequencyis represented (skewhess = 0 and kurtosis = 3) and non-Gaussian (variable skewness, by the unit circle and resonancesare poleslocated outside of the circle. kurtosis, and crest factor) random noisesto be constructed. The theoreti- The analyticform of the responsefunctions provide insight into the rela- cal backgroundand the resultsof a numericalsimulation will be present- tionshipsbetween the modesof eachinterconnected subsystem as well as ed, which demonstratethe functionalrelation between the variousspec- the relationshipbetween modal vibration and wavepropagation effects. tral manipulationsand the descriptorsof the synthesizedrandom noise. Theserelations are complicated by the factthat theinterconnecting wave- Analog signalswere synthesizedusing the abovemethod in conjunction guidesby themselvesintroduce new modesof vibration.The complexity with PC-basedinstrumentation. The resultsshow that the approachis of the problemis reducedby restrictingthe analysisto a windowof com- viable and that the synthesizedrandom waveformscan be easilytailored plen frequencies,whose width is determinedby the degreeof interaction to simulatea varietyof real-worldnoise/vibration signals, e.g., high kur- betweenmodes of the subsystemsand wave guides.The interactionis tosis(impulsive} industrial noises, helicopter noises, and missilevibra- measuredby parametersgeneralized from an earlierstudy of simplersub- tion signals.The applicationof sucha methodologyto acousticaltesting, systems[T. Igusa and A. Der Kiureghian,J. Eng. Mech. 101, 20-41 environmentalstress screening, structural testing, etc., will be discussed. (1985) I. [Work supportedby ONR.] [Work supportedby NIOSH. l

S40 J. Acoust.Soc. Am. Suppl.1, VoL85, Spring1989 117thMeeting: Acoustical Society of America S40 TUESDAYAFTERNOON, 23 MAY 1989 REGENCYC, 2:00TO 4:35P.M.

SessionP. UnderwaterAcoustics II: Scatteringand

ClarenceS. Clay, Chairman Departmentof Geologyand Geophysics,Uniuersity of Wisconsin,Madison, Wisconsin 53 706

Chairman's Introduction--2:00

ContributedPapers

2.-05 2:35

PL Acousticõaekseatter from an inhomogeneousvolume beneath a P3. Anglespreading of acousticenergy on bottombounce paths. Diana planar interface:Model and experiment.Paul C. Hines (Defense F. McCammon(Applied ResearchLaboratory, The PennsylvaniaState ResearchEstablishment Atlantic, P.O. Box 1012, Dartmouth, Nova University,P.O. Box 30, StateCollege. PA 16804) ScotiaB2Y 3Z7, Canada) A modelfor the spalialdistribution of bottomreturning energy has Mathematicalmodels of acousticscattering from the oceanbottom beendeveloped that relieson a combinationof surficialroughness and currentlyavailable, generally fail to predictbackscatter levels of sufficient sublayerroughnesses to producea non-Gaussianprobability distribution magnitude,for two limitingcases; as the bottombecomes increasingly of returns.Sediment inhomogeneities and sublayering are modeled by the smoothand as the grazing angle becomes small. A mathematicalmodel of artificeof assumingthat the rmsslope of thesurficlal layer increases with acousticbackscattering is derivedherein which attemptsto addressthese grazingangle. Deep regioninhomogeneities are modeledby choosinga shortcomingsfor the easeof a sedimentbottom. In the model,scattering high value of 22ø for the rms slopeof the basement.These simplifying resultsfrom fluctuationsin concentration,where concentration is rough- assumptionskeep the model inboundscomputationally and producethe ly definedas the waterto particleratio within the sediment.The model correctbehavior for anglespreading in both thick and thin sedimentre- allowsfor penetrationof the incidentwave into thebottom at subcritical gions.Excellent agreements are shownwith data. [Work supportedby grazing,and retransmissionof scatteredspherical waves through the NAVSEA. ] (planar) interface.The frequencyand grazingangle dependence of the acousticbackscatter are determined primarily by thecorrelation function of theconcentration fluctuations, while the magnitude is controlled by the mean-squarevalue of thesefluctuations. To complementthe modeling, laboratoryexperiments were performedto measurevolume backscatter from a smooth,water-saturated sand bottom at grazingangles from 10.- 2:50 50' for frequenciesof 25-200 kHz. Agreementbetween model and data is good.[ Workwas performed during post-graduate degree at theUniversi- P4, Crosscorrelation of the repeatedtransmissions of signalsscattered at ty of Bath, Bath, U.K.] a roughsea floor. C. S. Clay (Department of Geologyand Geophysics, Universityof Wisconsin-Madison,Madison, WI 53706)

Real measurementsof the crosscorrelations of repeatedtransmissions froma sourceship to a receiveron anothership must contend with drift- ing ships.Over a roughsea floor, the crosscorrelations depend on the geometryof theexperiments, the nature of theroughness, and transmis- 2:20 siontechniques. Green {J. Acoust.Soc. Am. SuppLI 68, S72 (1980)] describedmultiple transmission techniques that canreduce the effectsof P2. Acousticwave scatteringby inhomogeneousobstacles in layered receiverdisplacements between transmissions. Since it is easyto control media.I.T. Lu andH. K. Jung(Department of ElectricalEngineering/ driftingships in numericalcalculations, it wasdecided to usenumerical ComputerScience/Weber Research lnstitutc, PolytechnicUniversity, simulations.The wedgeassemblage and facet ensemble method were used Farmingdale,NY 11735) to computeimpulsive signals scattered at a roughbottom [C. S. Clay and Acousticwave scattering by homogeneousobstacles in layeredmedia W. A. Kinney,J. Acoust.Soc. Am. 83, 2126-2133 (1988)]. The results hasbeen studied by a newmethod that combines the hybrid ray-mode and show that one can expectcross correlations as high as 80%-90% for boundaryelement methods [ 1.T. Lu, IMACS Meeting,Princeton Univ., receiverdisplacements of 25 m betweentransmissions. [Research sup- March 1989].The latterhas been employed to formulatethe scattering portedby Officeof Naval Researchand the Geophysicaland Polar Re- processand the formerto providethe Grecn'sfunction of the layered searchCenter of the Universityof Wisconsin-Madison.] environment.Here, the new method is extendedto analyzewave scatter- ing by inhomogeneousscatterers by includingthe finiteclcmcnt method. By finiteelement method, the inhomogeneousobstacles are dividedinto small clements and the field on these elements are formulated in terms of a systemof algebraicequations. By employingthe boundary clement meth- 3:05 od, the fielddistribution along the boundariesof the obstaclesarc formu- PS. Computer simulation model useable for testing underwater lated in termsof integralequations which are subsequentlyreduced to communication techniques. Lee E. Estes, Gilbert Fain, and Paul algebraicequations. In the integralequations, one needs to computethe R. Caron(DcpartmentofECE, Southeastern Massachusetts University, Green'sfunction ofthe layeredenvironment for variousarrangements of North Dartmouth, MA 02747) locationsof sourceand receiver.The newly developedhybrid ray-mode methodis best suited for thispurpose because it combinesrays and modes A model,and its software implementation, that isdesigned to simulate self-consistentlywithin a singleframework and optimizesthe advantage the transmittedand ocean-degradedreceived signal of an acousticunder- of each.Numerical implementation illustrates these aspects. [ Work Sup- water transmissionis presented.The approachtaken for the modelis the portedby NSF. ] developmentof a stochasticimpulse response characterized by its rever-

S4 J. Acoust.Soc. Am. Suppl. 1, VoL85, Spring1989 117thMeeting: Acoustical Society of America S41 berationstatistics and decaytime and shape.A correlationtime for the 10-ø wereobserved for thesewastewater plumes. The data presented evolutionof the nonstationarycharacter of the impulseresponse is also demonstratethe degreeto whichthe soundpower reflection coefficient defined.Signal transmission and receptionis then modeledby processing for a distributionof scatterersis dependentupon the concentrationof signalsthrough two statisticallyindependent realizations of the impulse lhosescatterers, and showthe utility of the acousticalmethod in water- response.The tworealizations are stationary during a correlationinterval mass characterization. and are linearlysummed after weighingwith leap-froggedraised cosines. New realizationsare generatedfor eachcorrelation interval. Results ap- propriateto transmissionin a shallow-waterlong horizontal channel are presentedand compared with experimentalresults. [ Work supportedby the MassachusettsCenters of ExcellenceCorporation. ] 4:05

P9. Sound scattering by deformed cylinders of finite length. T. K. Stanton(Woods Hole OceanographicInstitution, Woods Hole, MA 02543)

3:20 An approximatesolution is derivedfor the scatteringof soundby P6. A normal-mode approach to simulation of very low-frequency circularcylinders of finitelength with a deformedaxis and composition reverberationin an Arctic environment.Thomas 3. Hayward (Naval profileand (cross-sectional)radius that vary arbitrarilyalong the axis. ResearchLaboratory, Code 5123, Washington, DC 20375) This solutionis a generalizationof previouswork IT. K. Stanton,.I. Acoust. Soc. Am. 83, 55-63 (]988) and T. K. Stanton, $. Acoust. SOc. A normal-mode-basedapproach to simulationof very low-frequency Am. 83, 64-67 (1988) ] wherethe scatteringby straightfinite cylinders of undeficereverberation in an Arctic environmentis presented.Acoustic uniformfluid and elastic material, respectively, were described. The new backscatteringfrom theice layer and theocean bottom is simulated using formulationis usedto calculatethe scatteringof soundat all frequencies a normal-mode-basedmodel, with undericeand bottom backscattering froma prolatespheroid with a highaspect ratio (ratio of majoraxis to representedby couplingof forward-and backward-traveling waves asso- minoraxis) anda uniformlybent finite cylinder of constantcross-section- ciatedwith the normalmodes. Results of simulationsperformed to test al radius.There is excellent agreement between the calculations involving the feasibility of associatedmethods for estimating backscattering the prolatespheroid and the exactspheroidal wave funclion solution. strengthsfrom reverberationdata are alsopresented. Furthermore,numerical integration of the deformedcylinder formula requiredfar lesscomputer time than calculatingthe exactsolution. The calculationsinvolving the bent cylinder are comparedwith backscatter datafrom preserved euphausiids (shrimplike marine organisms) and sug- gestthat the radiusof curvatureof the animalsplays a major role in the acousticscatter characteristics of the marineorganisms. For example,at 3:35 200kHz, thebackscattering cross section ofa 23-mm-longeuphaosiid will decreaseby 6 dB if the animal bendsby as little as 1.4 mm at the ends. P7. Observationson perturbationtheory of scatteringby surfacewaves. [ Work supportedby the ONR. ] Robert H. Mellen (Kildare Corporation, 95 Trumbull Street, New London, CT 06320)

First-order perturbationtheory of scatteringby surfacewaves is usuallyexpressed in termsof the wavenumberspectrum of the surface roughness.Bistatic reverberation is calculatedfrom the Braggcondition and coherenceloss by integrationover the wavenumberrange corre- spondingto real scatteringangles. An alternativeangular-spectrum ap- proachis presentedthat providesadditional insight into both the elemen- PI0. A comparison between the boundary element method and the tary acousticsand the nature of theapproximations involved. Scattering is superpositionmethod for the analysisof the scatteredacoustic fields from shown to be equivalentto dipole reradiationby a random ensembleof rigid bodiesand elasticshells. Rossel D. Miller ( NKF Engineering,Inc., coherentarrays of area n-L '-, where L iscorrelation length. Phase delay of 12200Sunrise Valley Drive, Reston,VA 22091), Hansen Huang (Code the excitationthen producesa scatterbeam pattern havinghorizontal RI4, Naval Surface Warfare Center, White Oak Silver Spring, MD broadsideand vertically steered endfire components. Some of the possible 20903-5000), E. ThomasMoyer, Jr. (CMEE Department,George hazards involvedin comparingpredictions with experimentare dis- WashingtonUniversity, Washington, DC 20064),and Herbert 0befall cussed. (Departmentof Physics,Catholic University of America,Washington, DC 20064)

The steady-stateanalysis of submergedrigid and elastic bodies using two approachesis presented.In the firstapproach, a combinedfinite ele- 3:50 ment/boundaryelement approach is used.The finiteelement program PS. Observations of acoustic backscatter from oceanic wastewater /qASTRA/q(NASA structuralanalysis) is usedto formulatethe structural outfalls. John R. Proni and W. Paul Dammann (National Oceanic and matrices.The StEngAS (surface integral equation radiated noise and anal- AtmosphericAdministration, AOML-OAD, Miami, FL 33149) ysis)program is then used to solvethe coupled fluid-structure interaction problem.A superparametricboundary element with ninenodes is used.In Narrow beamecho sounders were usedto characterizethe spatial thesecond approach, the superposition method is employed for modeling distribution of wastewaterplume malerial from six oceanoutfalls in the the fluid. The superpositionmethod employs a numberof point sources SouthFlorida area.Volume scattering strengths were computed and plot- movedinside the bodyto representthe fluid responseat the surface.This ted as a functionof depth and horizontal distancefor 200-kHz echoes. allowsthe fluid matricesto be formedwithout surface integration. For- Reductionin peakscattering strength with increasedrange from the out- mulationsfor the superpositionmethod are givenfor both the radiation fall locations correlated well with reduction in concentration of Rhoda- and scatteringproblems. The methodologiesare demonstratedfor the mine-WT dye introducedinto the undilutedwastewater at a concentra- scatteringof an infiniteset of planewaves from a submergedrigid sphere, tionof I ppm.Sound power reflection coefficients ranging from 10-*• to prolatespheroid, and elasticspherical shell.

S42 J. Acoust.Sec. Am. Suppl.1, Vol. 85, Spring1989 117thMeeting: Acoustical Society of America $42 TUESDAY AFTERNOON, 23 MAY 1989 NEWHOUSE II, ROOM 254, 2:45 TO 4:21 P.M.

SessionQ. SpeechCommunication IV: Synthesisand Coding

John G. Parker, Chairman RADC/IRAA, GriffissAir ForceBase, New York 13441

ContributedPapers

2:4S Thisapproach depends on assumptions and previously proposed con- clusions[ D. G. Childerset al., Proc.ICASSP 85, 748-751]. Somecorre- QI. Diagnostictests of segmentalduration models. Jan P. H. van Santen spondingvoiced phonemes are extracted from the source speech and tar- andJoseph P. Olive(AT&T BellLaboratories, Murray Hill, NJ 07974) getspeech to comparespectrum differences for vocal tracts of thesetwo Durationmodels map combinations of segmentalidentities and multi- kindsof speech.Vocal tract lengths mainly determine spectrum distribu- factoffalprosodie contexts onto the temporaldomain. Two newdiagnos- tions;they do not change greatly and are assumed to havethe same vary- tic teststhat focuson interactionsbetween contextual factors were applied ingtendencies from segment to segmentwhile terminal radiation, etc. to voweldurations measured in contextsvarying in severalprosodic fac- slightlyinfluence spectrum distribution. These imply that there is a non- torsand speaking rate. The firsttest concerns a distinction that cuts across time-varyingnonlinear frequency-shifting function obtained by compar- a widearray of models(e.g., additive, multiplicative): Which groups of ingcorresponding spectrum parts (especially formants) of corresponding factorsare functionallycombined? When factorsare functionallycom- phonemesforsource and target voices. Changes ofvocal tract areas based bined,constellations of valuesthat yieldidentical durations for oneseg- onphysiological acoustics and terminal radiations for two voices are as- ment shouldalso yield identical durations for othersegments. The data- sumedto have the sametendencies for influencingthe corresponding showedthat speakingrate cannotbe combinedwith other prosodic spectrafrom phoneme tophoneme. A non-time-varying filtering function factors,contradicting any generalizedversion of the incompressibility thereforeneeds to be fixed by amplitude comparison between correspond- model [D. H. Klatt, J. Acoust.Soc. Am. 59, 1208-1221 (1976)} that ing-phonemespectra for the frequency-shifted source and target voices. wouldcount speaking rate amongits prosodicfactors. The secondtest Sincethe glottal pulse shapes remain nearly the same, and any two kinds concernsmodes that would count speaking rate among its prosodicfac- of pitchchange with the same tendencies from segment tosegment, the tors.The second test concerns models that express duration as the sum of pitchconversion factor is determined from comparing the corresponding additiveand multiplicative terms, and can diagnose which terms are need- phonemesfortwo voices and an excitation model whose shape isclosest to ed,Results included that speaking rate is combined with segmental identi- thatof thetarget voice. During voice conversion, the spectrum of the ty intoa singlemultiplicative term. These results show the advantages of sourcespeech isprocessed with the above two functions and the excitation diagnostictests over the standard approach of modelfitting. modelis irapulsedby thepitch-converted target pitch from segment to segment.Areas of applications are:(a) restoringhelium speech; (b) mim- ickingvoice; and (c) preprocessingspeech for recognition.

2:57

Q2. A study of two standard speechintelligibility measures.Steven L. Greenspan,Raymond W. Bennett,and Ann K. Syrdal(AT&T Bell Laboratories,Naperville, IL 60566)

In the diagnosticrhyme test (DRT) participantsidentify each test 3:21 wordby ohosingone of two responsealternatives that differonly in their initial consonantsand only by a singlebinary distinctivefeature. Al- Q4. Improvedduration rules for text-to-speechsynthesis. Ann K. Syrdal thoughthe DRT is an acceptedindustry and military standardfor mea- (AT&T Bell Laboratories,IHP 1B-206,200 Park Plaza, Napervillc,IL suringinitial consonantintclligibility, other intelligibility measures may 60566) bemore appropriate when stimuli produce near maximum DRT scores. Moreover,the DRT incorporatesassumptions that may be valid for natu- Thedurations of phonemicsegments in an utterancesynthesized by ral speech,but are untestcd for high-quality,low-bit rate coded speech. In ruleare importantbecause they affect both intelligibility and prosodic particular,the DRT implicitlyassumes that segmentalintelligibility can quality.There are many factors that influence segmental duration, includ- be adequatelymeasured by examiningonly single feature confusions. To ingthe identity of thesegment, and cxtrinsic factors such as surrounding examinethis assumption, subjects were asked to identifythe initial con- segments,lexical stress, syntax, and speaking rate. Several approaches to sonantsof consonant-vowelsyllables. Multifeature confusions were far modelingthe combined effects of thecontributory factors have been pro- morecommon with coded speech than with naturalspeech. Moreover, the posed.Until recently, the duration rules of theexperimental AT&T dyad consonantidentification procedure reliably discriminated between speech synthesis-by-rulesystem have been primarily additive. Starting with a codingdevices that had near maximum,statistically indiscriminable minimumduration for eachsegment, duration was augmented incremen- DRT scores.These results suggest that open-responseidentification pro- tallyby eachcontributory extrinsic factor. However, in naturalspeech, ceduresmay be moresuitable than the DRT for evaluatinghigh-quality, the effectof an extrinsicfactor tends to vary dependingupon other con- low-bit rate coders. tributoryfactors. Analyses of naturalspee6h [H. S. Gopaland A. K. Syrdal,J. Acoust.Soc. Am. Suppl.I 82, S16 (1987)] indicatedthat Klatt'sincompressibility model was more accurate than strictly additive or multiplicativeapproaches. Consequently;a new duration rule program 3:09 wasdeveloped for theAT&T text-to-speechsystem, using an incompress- ibility approach.Comparative evaluations indicate that segmentdura- Q3. Voiceconversion and its applications.Pan Jianping (Department of tionsdetermined by the newduration rule system are more accurate and InformationTechnology in Education,East China Normal University, are preferredsignificantly more often by listenersthan durations deter- North ZhongshanRoad, Shanghai 200062, People's Republic of China) mined by the additive rules.

S43 d. Acoust.Soc. Am. Suppl. 1, Vol. 85, Spring1989 117thMeeting: Acoustical Society of America S43 3:33 3:57

OS. A speechsynthesizer for rule-basedsynthesis.Yukio Mitomc (C•C Q7. iy!: An algorithm for the silectral compressionof natural speech InformationTechnology Research Laboratories, NEC Corporation4- I- i signals. Richard R. Hurtig (Department of SpeechPathology and Miyazaki, Miyamae-ku,Kawasaki, 213 Japan) and Noriko Umeda Audiology,University of Iowa, Iowa City, IA 52242) { Depart.meritof Linguistics,New York University,719 Broadway, Room 505, New York, NY 10003) An earlierreport JR. R. Hurtig,J. Acoust.Soc. Am. Suppl.1 81, S78 (1986)] usingsynthesized syllables demonstrated that naive subjects can A newspeech synthesizer is proposedthat is suitablefor speechsyn- discriminateand identifyspectrally compressed vowel segments under thesisby rule. This synthesizeris basedon a source-filtermodel and auditoryand vibrotactileconditions. These findings are consistentwith consistsof two sources--aglottal source and a noisesource---and three theview that the identifi•:ation ofthe spectral shape of thespeech segment cascadefilters. Each sourcecan be connectedwith any of the filtersdy- may be independentof its frequencyrange. A computationalalgorithm namically.Each filter is used as a speechcomponent, which is produced as wasdeveloped to achievespectral compression of naturalspeech. The a sourcesignal filtered by a slowvarying system and has a limiteddura- algorithmincludes calculation of an n-pointFFT, paddingthe resultwith tion. The speechsignal consists of somecomponents overlapping each thespectrum of a Hammingwindow, calculation of a 2n-pointlEFT, and otherin time-frequencydomain. The experimentalsystem was developed outputtingthe first half of theresultant time domain signal. The sizeof the ona 32-bitpersonal computer. The softwaresystem has two subsystems,a paddetermines the amount of compressionachieved while the placement speechsynthesizer with a formatpattern interpreter and a speechanalysis of the paddetermines the directionof the frequencyshift. Naive subjects systemwith a speechdatabase. A formant pattern interpreterreads a had no difficultyrecognizing simple sentences in a closedset for speech formantpattern definition file, and a controlsspeech synthesizer routine. signalscompressed to 2500or 1250Hz bands.After a few hoursof listen- Speechanalysis is based on the maximumentropy method (MEM), anda ing, openset recognitionis achieved.The implementationof the algo- databasecontains 25 rain of recordedmale voice samples. Experimental rithm for sensoryaids will bedemonstrated. resultsshowed that thissynthesizer can easily realize the spectraldiscon- tinuity betweenphoneroes.

4.'O9

QS. Statistical tree-based modeling of phonetic segment durations. MichaelD. Riley (Departmentof Linguistics,AT&T Bell Laboratories, Murray Hill, NJ 07974)

3:45 Segmentaldurations are affectedby many factors:phonetic context, Q6. improved excitation prediction and quantization in optimal speakingrate, stress, word and phrasal position, etc. Regression trees [ L. amplitude multilmlse coders. Daniel Lin (International Mobile Breimanet al., Classificationand RegressionTrees (Wadsworth, Monte- MachinesCorporation, 2130 Arch Street,Philadelphia, PA 19103) rey,CA, 1984)] arewell suitedto capturingthese effects, since they ( ! ) statisticallyselect the most significant features, (2) permitboth categori- Improvementsto the excitationprediction and quantizationproce- cal and continuousfactors to be considered,(3) provide"honest" esti- durein optimalamplitude multipulse coders are described.The new pro- matesof their performance,and (4) allow humaninterpretation and ex- ceduresuccessively reoptimizes the pulseamplitudes and predictorgain plorationof their result. In particular,transcribed databases of 400 of the long-delaycorrelation filter as eachnew pulseis found. Further- utterancesfrom a singlespeaker and 4000 utterances from 400 speakersof more,the amplitudes and gain are requantized at eachstep so that the new AmericanEnglish were used to build optimaldecision trees that predict pulseamplitudes and locationscan correctfor the quantizationerrors in segmentdurations based on such factors.Over 70% of the durational the existingexcitation. To performthe joint amplitude-predictor•opti- variancefor the singlespeaker and over 60% for the multiple speakers mization,nonrceursive pitch prediction structure is usedin our analysis. were accountedfor by this methodwhen usinginformation only at the The predictoris implementedas an adaptivevector quantizer whose code- word level and below. These terms were used to derive durations for a bookis populated with pastexcitation sequences. This structure allows for text-to-speechsynthesizer and were found to give more faithful results a computationallyefficient closed-loop analysis procedure. The results than the existingheuristically derived duration rules. Since tree building showedthat at 9.6 kbps,the new technique achieved an average segmental and evaluationis rapid oncethe data are collectedand the candidate SNR of over 18.5dB. Informalsubjective tests indicated that the recon- featuresspecified, the techniquecan be readilyapplied to other feature structedspeech is toll quality. setsand to otherlanguages.

S44 J. Acoust.Soc. Am. Suppl. 1, VoL 85, Spring1989 117th Meeting:Acoustical Society of America S44 WEDNESDAY MORNING, 24 MAY 1989 AMPHITHEATER, 8:00 TO 11:00 A.M.

SessionR. Noise IV: EnvironmentalNoise and Impact on Hearing

David Lubman, Chairman HughesAircraft, Building618, MS H425, PostOffice Box 3310, Fullerton,California 92631

ContributedPapers

8:00 Jefferson Davis Highway, Suite 701, Arlington, VA 22202) and Alton Chavis (HQ TAC/DEEV, LangleyAir Force Base,VA 23665) R1. Canadian "National Guidelines for Environmental Noise Controlt Proceduresand Concepts for the Drafting of Environmental Noise Low-altitude,high-speed training operations are routinelyconducted Regulations/By-lawsin Canada." Deirdre A. Morison (Bureau of alongspecially designated Military TrainingRoutes (MTRs). Designof Radiation and Medical Devices, National Health and Welfare, Canada, newroutes and/or realignmentof existingroutes requires an environmen- Ottawa, Ontario KIA 0L2, Canada) tal assessmentto determinethe communitynoise impact. Nominally, air- crafton theseroutes navigate from pointto pointalong defined segments. TheseNational Guidelineshave been prepared for legislatorsat all Keyelements required for noise prediction are the frequency of flights,the levelsof government, provincial planners, municipalities, consultants, in- statisticalvariation of positionrelative to thenominal centerline, and the dustries,and designers.The intent is to providea commonbasis across operationalnoise emission levels of theaircraft. Noise measurements were Canadafor the assessment,measurement, and legislativecontrol of envi- conductedon threeroutes: one operated by the StrategicAir Command ronmentalnoise while, at the sametime, providing options to allowflexi- andtwo by theTactical Air Command.On eachroute, 20 automaticnoise bility of choiceto fit specificneeds. The NationalGuidelines may be monitorswere deployed on a 2- to 4-miarray across the route centerline. adoptedor modified,in entiretyand in part,into provincialor municipal Major findingswere: noise emission levels are fully consistent with predic- legislationor intocodes of practice.The NationalGuidelines are divided tionsfrom USAF's NOISEFILE database;aircraft tend to fly within the intotwo major parts. Part I, Conceptsand Procedures, details the various centralpart of a route;aircraft follow nominal tracks corresponding to optionsavailable in developinga noisecontrol program and includes a definedroute centerline or correspondingto prominentvisual references; sectionon LandUse Planning and Model Noise Control Legislation pre- the lateraldistribution about each track is Gaussian;and multipletracks sentingsound level objectives and moregeneral bylaws. The secondpart canexist. Noise events were infrequent (typically less than three or four of the documentcontains technical reference material, including a section perday), andthe highest L d,,measured was less than 65 dB. [Thiswork on instrumentspecification, measurement, and prediction,and another wassponsored by USAF AAMRL/BBE.] coveringnoise reduction techniques. Terms and interpretations,refer- ences,and technical support documents are included also. The texts of the technicalsupport documents are briefly summarized in thedocument and arereproduced on microfiche at theend of theNational Guidelines. The NationalGuidelines were prepared by the WorkingGroup on Environ- 8:45 mentalNoise on the Federal/ProvincialAdvisory Committeeon Envir- onmentaland Occupational Health, which intends to provideperiodic R4. ROUTEMAP modelfor predictingaircraft noiseexposure along revisions. militarytraining routes. Michael J. Lucasand KennethJ. Plotkin (Wyle Laboratories,2001 JeffersonDavis Highway,Suite 701, Arlington,VA 22202) A modeland PC-based computer program has bccn prepared to calcu-

8:15 latenoise levels along low-altitude, high-speed military training routes. Theprogram is designedfor useby environmental planning personnel R2. Publicreactlontolowlevelsofaircraftnoise.John E. Wesler (Wyle whoare familiar with MTR operationsand with noise,but arenot neces- Laboratories,2001 JeffersouDavis Highway, Arlingtou, VA 22202) sarilyexpert. The program provides options for selecting general types of operations(visual or instrumentnavigation), aircraft types and speeds, Severalrecent instances have raisedthe issueof public annoyance altitudes,and nominal track centerlines. Up to 20 track/altitude/aircraft fromthe noise of airplanesflying at relativelyhigh altitudes or at relative- typesmay be defined within a 20-mi-widecorridor. Aircraft on each track ly largedistances from the nearestairport. Public complaints have arisen havea Gaussianlateral distribution about the centerline.The program aboutairplane flights over northern New Jerseyas the result of changesin containsnominal standard deviations based on the type of operations,or flightpatterns associated with themajor New York airports,even though theuser may specify a site-specific value. Aircraft noise emission levels are in manyinstances those airplanes are flyingat 15000 ft or higher.Con- derivedfrom the USAF NOISEFILE database.The programcalculates cernshave arisen regarding the noiselevels on the groundfrom the new, L•q,L a.,and L a .... whereLd,m, isLa. with an adjustment toaccount for swept-blade,advanced turboprop airplanes when they are flying at cruise theonset rate of MTR aircraftnoise. Program output is available in tabu- altitudesof 30 000 ft and higher.Complaints about aircraft noiseover lar formor in graphssuitable for inclusionin reports.[This work was nationalparks have resulted in a Congressionalrequirement to 'measure sponsoredby USAF AAMRL/BBE. ] thosenoises and determinetheir severity.These noise levels do not meet the usualcriteria for annoyanceor interferencewith individualactivity, whetherin termsof averagelevel or singleevents. A betterunderstanding of the intrusiveeffects of low levelsof communitynoise is needed,espe- cially wherepresent in areasof relativelylow ambientnoise levels. 9:00

RS. Sonicboom spectra of Atlantislanding 6 December1988. Robert W. Youngand Frank T. Awbrey(Sea World Research Institute, Hubbs Marine Research Center, 1700 South Shores Drive, San Diego, CA 8:30 92109)

R3. The noise environment under low-altitude, high-speed military After circlingthe world 69 times,orbiter Atlantis came to a stopon aircraft training routes. Kenneth J. Plotkin (Wyle Laboratories,2001 Runway 17 of EdwardsAir Force Basein California,at 1537U on 6

S45 J. Acoust.Soc. Am. Suppl. 1, Vol. 85, Spring 1989 117thMeeting: Acoustical Society of America S45 December! 988.Some I 0 mi to thewest, and 4 min previousto landing,its 9:15 394-mssonic boom swept over our measurement site at latitude34.886øN, R6. Revision of a dosage-effectrelationship for the prevalence of noise- longitude118.036•/, elevationabout 2.5 kf abovesea level. When the related annoyance.Sanford Fidell (BBN Systemsand Technology, deceleratingAtlantis heading southeast passed nearest to the micro- Corporation,P.O. Box633, CanogaPark, CA 91304) phonesat lateralslant range of 100kit, it wasgliding at Mach 1 about48 kit aboveground. The peakflat soundpressure level of the sonicboom More than a decadehas passed since Schultz (1978) deriveda rela- was129 dB; the peakC-weighted sound pressure level, 125 dB; the peak tionshipbetween noise exposure and the prevalenceof annoyancefrom A-weightedsound pressure level, 110 dB. The flat soundexposure level the findingsof varioussocial surveys of communityresponse to general was118 dB; the C-weighted and A-weighted sound exposure levels of the transportationnoise sources. Numerous measurements of the prevalence initial transientswere, respectively, 102 and 84 dB. If soundexposure level of noise-relatedannoyance have been publishedin subsequentyears. A is wantedfor a 400-mssonic boom with primaryemphasis in the range least-squaresquadratic fitting function to a setof 427 datapoints (devel- 0.8-3 Hz, fiat soundexposure level is appropriate; with primaryemphasis opedby additionof 266 newdata pointsto the originalset of 161 data in the range10-50 Hz, C-weightedsound exposure level is appropriate; points)differs little from the third-orderpolynomial fit to the original with primaryemphasis in therange 80-1000 Hz, A-weightedsound expo- data set. [Work supportedby U.S. Air Force Noiseand SonicBoom surelevel is appropriate. ImpactTechnology Program under Contract F33615-86-C-0530. ]

9:30-9:45 Break

thresholdsat 24 kHz in'the left ear than in theright car. Measured L•q correlatedwith HTLs at 3-4 kHz. Playingin a symphonyorchestra ap- R7. EffeetsofehangingtheA-weightingde•igngoaI.GeorgeS. K. Wong pearsto presenta mildrisk of hearingdamage, but musiciansin everyage (Division of Physics,National ResearchCouncil, Ottawa, Ontario K I A groupdisplayed average hearing thresholds better than the general popu- 0R6, Canada } lation. The proposalby the InternationalOrganization for Standardization (ISO), documentISO/'I'C43/SCI N644, dated October 1988, to modify the A-weighteddesign goal by imposingadditional attenuation to imple- ment well-definedfrequency cutoffs at 20 Hz and at 16 kHz to ensure consistentA-weighted measurements isexamined. The meritof the above proposalis in doubtsince the high-frequencycutoff at 16 kHz eliminates bothaudible and high-frequency components and can result in underesti- mationduring A-weighted noise assessment, particularly when the noise is impulsive.The consequencesof the abovechanges are serious:Future databasesof A-weightedmeasurements will be incompatiblewith those from the past,and acousticalcommunities in everycountry will suffer financialloss due to the needto replacemost of their measuringinstru- mentsto complywith the proposedA-weighting. A betterapproach to ensureconsistent A-weighted measurement is to imposetighter toler- ancesin thehigh-frequency region of theA-weighting, such as those speci- 10:15 fied in ANSI Sl.4A-1985 amendment to ANSI Sl.4-1983. R9. Abstract withdrawn.

10:00

R8. Sound exposuresand hearing thresholdsof musiciansin a major symphonyorchestra. Julia Doswell Royster (Environmental Noise Consultants,Incorporated, P.O. Box 144,Cary, NC 27512-0144 ), Larry H. Royster(North CarolinaState University, Raleigh, NC 27695), and Mead C. Killion (EtymotieResearch, Elk Grove, IL 60007) Seventynoise dosimetry samples were obtained for musiciansduring rehearsalsand performancesof a major symphonyorchestra. Audio- gramswere obtained for 59 musicians.The L• duringmeasurement per- iodsranged from 76-102 dBA (median= 90dBA), correspondingtoon- 10:30 the-jobdaily equivalentvalues of 72-98 dBA (median = 86 dBA). Using R10. Review of the effects of noise on performance.Alice H. Surer the ISO 1999.2model, this exposure would be expected to produce5-8 dB (Bioaeoustiesand OccupationalVibration Section,MS C-27, Divisionof of NIPTS after 30 yr for typicalears ( 0.5 fractile) or 8-10 dB of NIPTS Biomedical and Behavioral Science,NIOSH, 4676 Columbia Parkway, for very susceptibleears (0.05 fraetile). The musicians'average thresh- Cincinnati, OH 45226) oldswere better than those for age-matched reference nonindustrial noise- exposedpopulations without occupationalnoise exposure,and only The effectsof noiseon job performanceare not aseasily discerned and slightly worsethan thosefor highly screenedpopulations representing predictableas other effects, such as those on hearingor speechcommuni- agingalone. However, audiogram patterns indicated a slightnotch, sug- cation.The extentto whichnoise affects performance depends on numer- gestinga contributionfrom NIPTS. Bilaterallyaveraged thresholds for ousnonacoustical factors, such as the subject'sbiological and psychologi- musiciansin differentinstrument sections were essentially equivalent, but cal state, as well as certain externalfactors. Despite theseand other violinistsand riolists grouped together showedsignificantly poorer difficultiesinvolved in comparingresearch results, a recentreview of the

S46 d. Acoust.Soc. Am. Suppl. 1, VoL 85, Spring 1989 117th Meeting:Acoustical Society of America S46 noiseand performance literature provides sufficient evidence to indicate For a givennumber of impulses,increases in intensityare normally adverseeffects under certain circumstances. The probabilityof perfor- associatedwith greater threshold shifts. The details of thisgrowth should, mancedecrements increases with increased{ I } noiselevel, {2} intermit- in principle,reveal something of the basicmechanisms responsible for the tency,(3} aperiodicity,(4) lackof controilability.(5} taskcomplexity, loss.Experiments have beenconducted in which the earsof 30 catshave (6) task duration, and {7) the addition of certain other stressors.The beenexposed to 50 impulseswith theirpeak energies located at 4000 Hz reviewwas sponsored bythe U.S. Army Human Engineering Laboratory, andwith peakp•essures ranging from 135-145dB SPL.Threshold shifts andperformed under the auspices of GallaudetUniversity. grewabout 7.0 dB for everydB increasein SPLabove 134 dB. Virtually the sameresult can be calculatedfrom data for the chinchillaear JR. P. Hamernik, J. H. Patterson,and R. J. Salvi,J. Acoust.Soc. Am. 81, 1 i 18- 10:45 i 129 (1987) ], whichmay indicatethat thisfunction is characteristicof mammalianears. On theother hand, exposures to otherimpulses in both Rll. Growthof thresholdshift from intenseimpulses: Implications for animalshave shown much lower ratesof growth;however, these differ- basicloss mechanisms. G. Richard Price( US Army HumanEngineering encescan be explainedby conductivenonlinearities in the middleear and/ Laboratory,Aberdeen Proving Ground, MD 21005-5001) or a limited rangeof growthof thresholdshift.

WEDNESDAY MORNING, 24 MAY 1989 REGENCY A, 8:00 TO 10:35 A.M.

SessionS. PhysicalAcoustics III and EngineeringAcoustics III: Recent Advancesin Thermoacoustic Engines

Thomas J. Hofler, Chairman PhysicsDepartment, Code 61HF, Naval PostgraduateSchool, Monterey, California 93943

Chairman's Introduetion-•8:00

Invited Papers

8:05

S1. A thermoaeousticallydriven orifice-pulse-tubecryoeooler. G. W. Swift (CondensedMatter and Thermal Physics,Los Alamos National Laboralory,Los Alamos,NM 87545), R.A. Martin (AdvancedEngineering Technology,Los AlamosNational Laboratory,Los Alamos,NM 87545), and Ray Radebaugh(National Institutefor Standardsand Technology,Boulder, CO 80303) The orificepulse tube is a variantof Stirling-cyclerefrigerator in whichthe cold, work-absorbing piston and crankshaftare replacedby a simpledissipative struclure. To date,the oscillatorypressure needed to drive pulse tubeshas been provided by complex,unreliable room-temperature pistons and crankshafts.In this presenta- tion, plansand designcalculations for drivingan orificepulse tube with a thermoacousticengine will be discussed.In thiscomposite device, heat flowing from a high-temperaturesource to a room-temperaturesink will generatehigh-amplitude acoustic oscillations in high-pressurehelium gas; these oscillations will powerthe orificepulse tube, thereby pumping heat from a low-temperaturesource to a room-temperalure•ink. Thus the deviceis a heat-drivencryocooler with no movingparts. in lhis plannedsmall laboralory device, it isexpected that a fewW of refrigerationat roughly80 K usingabout 2 kW of heatat 1000K will beproduced. The nature of the oscillatoryheat transferand time-averagedenthalpy flow in the variouscomponents of the engineand coolerwill alsobe discussed, comparing and contrasting the acoustic-frequency Stirling cycle in thecooler with the thermoacousticcycle in the engine.

8:35

S2. The dependenceof the experimentalperformance of a thermoacousticrefrigerator on geometry.T. Hofler and M. Suzalla {Departmentof Physics,Naval PostgraduateSchool, Monterey, CA 93943) The resultsof recentmeasurements on an experimentalthermoacoustic refrigerator will be presented.In simpleterms, thermoacoustic heat lransportis causedby the interactionof a high-amplitudestanding wave with a stationary"stack" (a stackof parallelplates having uniform plate spacing). The focusof thesemeasure- mentsis on theeffect changes in stackgeometry has on refrigeratorperformance as determined by temperature

S47 J. Acoust.Soc. Am. Suppl.1, VoL 85, Spring1989 117th Meeting:Acoustical Society of America S47 spanand thermodynamic efficiency. The experimental geometry variations consist ofchanging the position of thestack in thestanding wave and changing the spacing between adjacent plates in thestack. The results show thatrefrigerator performance isvery sensitive tothe location of thestack in the standing wave, as expected from thetheory ofN. Rott,but performance is muchmore sensitive to platespacing than predicted by thetheory. [ Worksupported by theOffice of NavalResearch and the Office of NavalTechnology. ]

9:05

$3. Optimizingimpedances in the travelingwave heat engine. Peter. H. Ceperley(Departments of Physics and Electricaland Computer Engineering, George Mason University, Fairfax, VA 22030} Thermalcoupling between solid surfaces and an acousticworking fluid in a regeneratoris essentialto the operationof a thermoacousticengine, while the associated viscous coupling, also between the surfaces and the workingfluid, is detrimental to theengine's performance and efficiency. The Prandlt number (roughly 0.7 for mostgases over a considerablerange of temperaturesand pressures)fixes the ratio of thesetwo typesof couplingfor a thermoacousticengine with a continuousregenerator. This ratio of couplings can be improved in severalways in travelingwave heat engines with shortregenerators [P. H. Ceperley,L Acoust.Soc. Am. 66, 1508-1513(1979) andP. H. Ceperley,$. Acoust. Soc. Am. 77, 1239-1244{ 1985)]. Thispaper will discussthe optimizationof the flow resistance and length of a shortregenerator and also resonant impedance enhancement usingsplit mode excitation [P. H. Ceperley,U.S. Patent 4,686,407 ( 1987} ] to significantlyreduce the viscous losseswhile maintaininggood thermal coupling.

9:35

$4. Vorticesas a naturalaeroacoustic engine. M. Kurosaka(Department of Aeronauticsand Astronautics, Universityof Washington,Seattle, WA 98195) In previousinvestigations, it was found that the so-calledRanque-Hilsch effect is inducedby a spinning acousticwave present in swirlingflows; the total temperaturewithin the vorticesbecomes acoustically separat- ed. Another similar examplefor the Karman vortex street or an array of vorticesformed a bluff body is presentedhere. The vorticesin the wakeare foundto havethe capacityto separatethe total temperature,and theseparation is significantly enhanced by acousticresonance. Here, vorticesbehave as a natural"compressor- turbine" cycle,its performanceimproved substantially by acoustics.

ContributedPapers

10:05 confinethe heliumfor yearswhile permitting electrical feed through will alsobe disclosed.[Work supportedby the Officeof Naval Research,Of- S5. Thermoacousticrefrigerator for spaceapplications. S. L. Garrett, ficeof Naval Technology,and the Naval PostgraduateSchool Research T. Hofier, M. Fitzpatrick, M.P. Susalla, R. Yolkeft, D. Harris Foundation.] (Physics Department, Code 61 Gx, Naval PostgraduateSchool, Monterey, CA 93943), R. B. Byrnes,C. B. Cameron (Space Systems AcademicGroup, Code 66, Naval PostgraduateSchool, Monterey, CA 93943),andF. M. Murray (JBL, Incorporated,Northridge, CA91324) 10:20

Long-lived,space-based cryocoolers with lowvibration levels are nec- S6. Source level limits for submerged thermoaeoustlc sound sources. essaryin a varietyof applications,including the coolingof infraredsen- Thomas B. Gabrielson(Naval Air DevelopmentCenter, Code 5044, sors and high Tc superconductors.A thermoaeousticrefrigerator de- Warminster, PA 18974) signedto functionautonomously in a SpaceShuttle Get Away Special {C;.Ag) canister will be described that has no sliding scal• and oldy 15 gm One application for thcrmoacousticengines is the generationof sound of reciprocatingmass. It is capableof coolingto 100 K belowroom tem- underwater.In theory, the engineresonator could either be floodedwith peraturewith a singlestage "stack" consisting of rolled plasticfilm and water and radiate directly into the surroundingwater, or the resonator shortlengths of 10-lbtest monofilament fishing line as the spacers.This couldbe gas-filled.The radiationperformance of a liquid-filledresonator presentationwill concentrateon the modificationsto the basicrefrigera- (takento be an open-endedtube} radiatinginto the sameliquid is well tor design(U.S. Patent No. 4,722,201,issued 2 Feb. 1988} that improve known;however, the openend of a submerged,gas-filled tube is almosta both its electroacousticand thermoacousticefficiencies. These improve- velocitynode, so a smallerfraction of the storedenergy "leaks" out as ments include the use of a helium-xenon gas mixture as the thermody- radiation.For the samepressure amplitude in both the liquid-filledand namicworking fluid and a neodymium-iron-boronelectrodynamic driv- gas-filledtubes, the particle speedis moch higher in the gas-filledtube, er with a titanium suspension.Custom electronic circuits necessary to and this morethan compensatesfor the smallertransmission coefficient controlthe refrigerator(microprocessor, bubble memory data recorder, into the surroundingliquid. In either case,limits to the acousticpower phase-lockedloops, automatic gain controls,amplifiers, multiplexed di- outputcan be calculated from the resonatorradiation efficiency and from ode thermometers,etc.) and specialfabrication techniques necessary to the peculiarrequirements of the thermoacousticengine.

S48 J. Acoust.Soc. Am. Suppl.1, VoL85, Spring1989 117th Meeting:Acoustical Society of America $48 WEDNESDAY MORNING, 24 MAY 1989 REGENCY B, 8:00 TO 10:05 A.M.

SessionT. UnderwaterAcoustics III and Structural Acousticsand Vibration Ill: CommonalityBetween the Fields of Underwater Acoustics and Structural Acoustics

John J. McCoy, Chairman Schoolof Engineeringand Architecture,Catholic University of America, Washington,DC 20064

Chairman's Introduction4:00

Invited Papers

8:05

TI. Radiation and scatteringfrom laminatedspherical shells. Henrik Schmidt (MassachusettsInstitute of Technology,Cambridge, MA 02139) Thesolution in termsof sphericalharmonics to acousticand elastic wave propagation problems in spheri- callystratified media is well established. However, except for very low ka values,a directnumerical implemen- tationis unstable.Propagator matrix approaches have been appli9d for moderateka values,whereas environ- menttransformations have been developed to representthe spherical stratification by a planestratification at higherka values,in particularin relationto long-rangeseismic propagation in the solidearth. Here, it is demonstratedthat, by introducinga proper normalization of the spherical Bessel functions, uncondition:•l stabilitycan be obtained by using the Global Matrix approach [H. Schmidtand F. B.Jensen, J. Acoust.Soc. Am. 77, 813-825 (1985) ]. ThisSAFARI codehas therefore been modified to treatpropagation in spherically stratifiedelastic media. The algorithm is stableat leastup to ka = 10•, allowingmodeling of stratifications alternatingbetween high- and low-speed layers, traditionally problematic for propagator approaches. Exam- pleswill be givenfor high-frequencyscattering from coated shells as well as simulations of arraysignal processingperformance in relation to structuralacoustics experiments. [Work supported by ONR. ]

8:30

T2. Three-dimensionalGreen's functionfor fluid-loadedthin elastic cylindrical shell: Formulationand solution.L. B. Felsen,J. M. He, and I. T. Lu (Departmentof ElectricalEnginering/Computer Science, WeberResearch Institute, Polytechnic University, Farmingdale, NY 11734) Thispaper treats sound radiation from a time-harmonicpoint pressure source located either inside or outsidea thin,homogeneous, infinitely long circular cylindrical elastic shell, which is immersedin different interiorand exterior fluid media. This Oreen's function problem is attacked by a combinationof themethod of separationofvariables and the method of images applied to an infinitely extended azimuthal (•) domain.The reducedone-dimensional problems in thecylindrical (r, •3,z) coordinatesare solved by generalspectral techniquesin termsof one-dimensionalcharacteristic Green's functions gr, ga,gz, whichdepend on oneor bothof thetwo complex spectral separation parameters (spatial wavenumbers) 2, and 2•,. While the one- dimensionalproblems inthe • andz domainsare straightforward, thepresence ofthe shell in the radial domain introducessubstantial complexity. The solution is obtained by defining the discontinuities in the pressure and normaldisplacement across the shell via recourse to thedynamical equations of motioninside the shell. The synthesisproblem is made unique through a completeanalysis of thespectral singularities g,.•.z in theirrespec- tivecomplex planes, which permits selection of appropriateintegration contours. A hostof alternativerepre- sentations,whose choice (concerning utility) is motivatedby theparameter range of interest,can be derived fromthe fundamental spectral form, and asymptotic reductions lead to a varietyof waveprocesses that have a cogentray acoustic interpretation. [Work supported by ONR.]

8:55

T3. Coherencetheory in volumescattering and structural acoustics. Mark J. Beranand JohnJ. McCoy (Departmentof CivilEngineering, Catholic University of America,Washington, DC 20064) In thispaper, the use of the two-point coherence function, defined for arbitrarily positioned points, to study wide-angievolume scattering problems in theocean and wave propagation in cylindrical shells subject to randomforcing is considered.Although the basic equations of thetwo phenomena are different, it will be shownthat the basicapproach developed 30 yearsago in opticsis a usefulway to studythese and similar problems.First, the theory of partialcoherence developed in optics for free-space propagation from random sourcesis reviewed.Then, the coherence equations for thecylindrical shell propagation case are formulated, andit is shownhow the equations may be solved when the two-point statistics of the forcingfunction are known.

S49 J.Acoust. Soc. Am. Suppl. 1, Vol. 85, Spring 1989 117thMeeting: Acoustical Society ofAmerica S49 ContributedPapers

9:20 loadingpertaining to seaice and low-frequency acoustics, which cannot be characterizedby simplifyingheavy or light fluid loadinglimits. An T4. Frequencywavenumber analysis of seismoacousticwaves in an ice approximationto theexact kernel of the Wiener-Hopffunctional equa- layer. G. Giellisand T. C. Yang (Naval ResearchLaboratory, Code tionis used here, which is valid in thismidrange fluid loading regime. The 5123,Washington, DC 20375) farfielddiffracted pressure is found,which includes a fluid-loaded,sub- Seismoacousticwaves traveling in an ice layer over a deepArctic sonic(relative to the water) flexural wavein the ice plate. Comparisons Oceanare studied using frequency wavenumber analysis. Ice-ridge-gener- are alsomade with thelocally reacting approximation to the inputimped- ated noisecan travel in the ice via ice-trappedwaves and water-borne anceof an ice plate.The combinedeffects of the ice leaddiffraction pro- wavescoupled to the ice. {Previous hydrophone data [ B.Buck and J. H. cessrepresent loss mechanisms that contribute to thetransmission loss in Wilson,J. Acoust.Soc. Am. 80, 256-264 ( 1986}] indicatedthat the noise long-rangeArctic acousticpropagation. originatedfrom the bottom of a ridge.}The data are simulated by a point sourcein thewater (for the water-bornewaves) and a pointsource in the ice (for the ice-trappednoise) using the SAFAaInumerical code with a 9:50 planarreceiver array of verticalaxis geophones. Frequency wavenumber analysisis applied to thesimulated data to determinethe wavenumber of Tr. Low-frequencySAW sensorsfor the detectionof shearstresses in the the variouswaves traveling in the ice.The methodologyand preliminary turbulentboundary layer. Yongrae Roh, VasundaraV. Vatarian, and resultsof thisanalysis will be reported. Vijay K. Varadan(Department of EngineeringScience and Mechanics, Research Center for the Engineeringof Electronic and Acoustic Materials, The PennsylvaniaState University, UniversityPark, PA 9:35 16802)

TS. Low-frequency diffraction from a free surface coupled to a To simulatea low-frequencySAW device,surface wave propagation semi-infinite elastic surface as modeled by sea ice properties. at the boundarybetween water and a thin film of PZT-SH on steelwas Peter H. Dahl (MIT/WHOi Joint Program in Oceanography/ investigatedextensively through numerical analysis. Two- and three-di- OceanographicEngineering, Department of Ocean Engineering, mensionaldispersion curves, attenuation mechanism, and displacement MassachusettsInstitute of Technology,Cambridge, MA 02139) and variationwere obtainedfor eachof the propagationmodes of all typesof George V. Frisk (Department of Ocean Engineering,Woods Hole the surfacewaves (Rayleigh, Scholtc,and Love) in the medium. The OceanographicInstitution, Woods Hole, MA 02543) energydistributions of the Rayleighand Scholtewaves have also been obtained.With theseresults, the optimumgeometry (crystal cut, propa- This paperdiscusses the solutionof a low-frequencyplane wave inci- gation direction, and nondimensionalwavenumber) for maximum dentupon a semi-infiniteelastic plate, such as an Arctic ice!end or free launchingefficiency was determined. The acousticfluid was replaced by a edge,using the Wiener-Hopfmethod. By low-frequencyit is meantthat turbulentflow, and the variationof the propagationvelocity of the SAW theelastic properties of the plateare adequately described by thethin plate due to turbulencewas investigated.These results show a new methodto equation.For example,in a floatingice sheet, this translates into frequen- distinguishthe effect of shearstress fluctuations from that of normalpres- cy-icethickness products that are •<150. A key issuehere is the fluid sure in a turbulent flow.

WEDNESDAY MORNING, 24 MAY 1989 GOLDSTEIN AUDITORIUM, 8:15 A.M. TO 12:00NOON

SessionU. SpeechCommunication V: Perception,Production, Analysis, Synthesis, and Coding (PosterSession)

Richard Pastore, Chairman Departmentof Psychology,SUNY at Binghamton,Binghamton. New York13901

ContributedPapers

All posterswill beon displayfrom 8:15a.m. to 12:00noon. (Viewing hours will alsobe extended into the eveningand through noon on Thursday. ) To allowcontributors anopportunity to seeother posters, contribu- torsof odd-numberedpapers will beat theirposters from 8:15 to I 0:00a.m. and contributors of even-numbered paperswill beat theirposters from 10:00to I 1:45a.m. Contributors are encouraged to leavetheir posters in placeuntil 12.00noon on Thursday. A cashbar will beset up in theevening to facilitateinformal discussion. The Ooldstein Auditorium will be closedat 10:00 p.m. and will reopenon Thursday morning.

UI. Abstract withdrawn. Estimationof formantcontours from continuousspeech is a difficult problemthat hasrequired either elaborate heuristic rules or complexhid- den Markov models.Under high noise levels,these methods deteriorate significantlybecause of the degradedperformance of the spectralestima- U2. Formant contour estimation in noise using a spectral estimation tor on which they are based.This paperproposes a methodof formant "confidence measure." T. V. Sreenivas and R. J. Niederjohn contourestimation using a measureof confidencefor the spectralpeak (Department of Electrical, Computer, and BiomedicalEngineering, estimation.At high noiselevels, most spectralestimation techniques re- Marquette University,Milwaukee, WI 53233) sult in largevariance and increasedspurious/missing peaks; however, it is

S50 d. Acoust.Soc. Am. Suppl.1, Vol. 85, Spring1989 117thMeeting: Acoustical Society of America S50 foundthat a broaddistribution of spectralenergy can be determined more Fundamentalfrequency (F0) normalizationis an effectobserved in reliablyusing filter-bank analysis. This spectral energy distribution is uti- vowelperception in whichthe F0 of the vowelplays a role in perceived lized to differentiateregions of high and low signal-to-noiseratio in the vowel quality. It was hypothesizedthat this perceptualeffect involves a spectrum(for whitenoise corruption), which in turn is usedto determine processin whichhearers adjust a perceptualvowel space when they detect a "confidencemeasure" for the spectralpeak estimation. The additionof a changeof speaker.A seven-stepvowel continuumfrom "hood" to thisconfidence information to the noisyspectral peak data of a speech "bud" wassynthesized at two levelsofF0 ( 120 and 240 Hz). Thesetwo utteranceresults in clearsegments of the formantcontour standing out continuawere presented to subjectsblocked by F0 leveland with itemsof from the remainingnoisy peak data. Usingthese segments as anchorre- differentF0 randomlyintermixed with eachother. In the mixedF0 condi- gions,an algorithmis developedto determinethe completecontours, tion, there was a largeshift in the identificationfunctions of the vowel within the constraintsof the knownspeech properties. [Work supported continuumas a resultof changing F0, whilethere was no effect ofF0 in the by NSF. ] blocked F0 condition. Analysis of the reaction time data showed that subjectsidentified the itemsmore slowly in the mixed conditionthan in the blocked condition and that this increase occurred for items that were precededby an itemwith differentF0 and not whensuccessive items had the sameF0. Thesedata suggestthat hearersadjust a perceptualvowel spacewhen they detecta changeof speaker.[Work supportedby NIH U3. Duration effectson vowel perceptionby hearing-impairedlisteners. Training CenterGrant No. 50-315-26to Indiana University.] J. Besing,M..l'. Collins, and J. Cullen (Division of Communication Disorders,Louisiana State University, Baton Rouge,LA 70803)

The effectof temporaldifferences on the identificationof voweltokens by hearing-impairedlisteners was studied using six hearing-impaired lis- U6. Target zones for synthetic vowels. James D. Miller and John teners.Stimuli were syntheticallygenerated and varied in durationof W. Hawks (Central Institute for the Deaf, 818 South Euclid, St. Louis, steadystate, durations of the initial and final transitions,and F 1, F2, and MO 63110) F3 location.Listeners were requiredto identify the given vowel token froma setoften possiblealternatives. In somecases, the hearing-impaired Usingalgorithms developed by thesecond author (JWH), hesynthe- listeners'responses were similar to a groupof normal-hearinglisteners sized 7703 vowel tokens such that the valuesofF0, F1, F2, and F3 uni- and, in somecases, they were very different and appeared somewhat idio- formlysampled locations in a planein the middleof the vowelslab of the syncratic.The hearing-impairedsubjects were different from eachother; auditory-perceptualspace [J. D. Miller, "Auditory-perceptualinterpre- further,the labeling performance was different within the same subjects tationof thevowel," J. Acoust.Soc. Am. (in press)]. Eachtoken was 400 acrossdifferent vowels. In addition,subjects with similaraudiograms per- msand had a rise-fallpitch contour. The tokenswere arranged in random formeddifferently from one anotheron somevowels and similarlyon orderand presented in groupsof 100to onelistener (JDM), whoidenti- others.These results and the particulareffects of the alterationsin the fiedeach token as [IY, IH, EH, EY, AE, AA, AH, AO, OW, UH, or UW] durationsof the variouscomponents will bediscussed. [Work supported and ratedthe clarityof eachtoken on a scalefrom 1 (poor) to 5 (excel- by NIMH.I lent). The sizesand shapes of the targetzones derived from these experi- mentswill be comparedto thosebased on measurementsof natural speech.The dataare, in general,consistent with theconcept of vowel targetzones as being large with irregular and abutting boundaries. [Work supportedby NINCDS.] U4. Linear transformations for vowel normalization. Stephen A. Zahorian and Amir J. Jagharghi(Department of Electricaland ComputerEngineering, Old DominionUniversity, Norfolk, VA 23529)

The resultsof an evaluationof multivariablelinear regression tech- U7. Detection thresholdsfor isolated vowels. Diane Kewlcy-Port niquesfor speaker normalization of voweldata for I l vowelclasses will be (Departmentof Speechand HearingSciences, Indiana University, presented.The databasefor thestudy consisted of thecentral vowel por- Bloomington,IN 47405) tionsof 2922CVC syllablesobtained from ten males,ten females, and ten children.Each stimulus was represented both by threeformants and in A seriesof experimentson thedetectability of vowelsin isolationhas termsof overallspectral shape, via the discretecosine transform coeffi- beencompleted. Stimuli consisted of three sets often vowels, one synthet- cients(DCTCs) of the magnitudespectra. In all classificationexperi- ic, onefrom a maletalker, and one from a femaletalker. Vowel durations ments,half the databasewas used to train the classifierand the other half rangedfrom 20-160 ms. Thresholds for detecting the vowels in isolation was used for evaluation. For the case of formants, the classification accu- wereobtained from well-trained,normal-hearing listeners using an adap- racyon theevaluation data was63.3% ifdifferentspeakers were used for tive-trackingparadigm. Detection thresholds for vowelscalibrated for trainingand testing (and thusno speakernormalization), 63.9% if the equalsound pressure at theearphones differed by as much as 20 dB across samespeakers were used in the trainingand test sets but withoutexplicit vowels.However, the same patterns of thresholdsobtained for the vowel normalization,and 75.2% with speaker-normalizeddata. The ratesfor setwere obtained for all voweldurations. An orderlydecrease in vowel the correspondingconditions, but with DCTCs as parameters,were thresholdswas obtained for increasedduration, as predicted from tempo- 58.0%, 66.1%, and 77.9%. Theseresults indicate a reductionin classifi- ral integrationfor puretones. Several different analyses have been con- cationerror ratedue to speakernormalization of 32.4%for the caseof ductedin an attemptto explainthe differential detectability for thevar- formantsand 47.3% for the caseof DCTCs. The speaker-normalization iousvowels within eachset. The mostdetailed of theseanalysis involved a techniquesare an extension of thetechniques reported in theliterature IS. modeldeveloped by Mooreand Glasberg (1987) for calculatingexcita- F. Disnet, J. Acoust. Soc. Am. 67, 253-261 (1980)]. These resultsalso tionpatterns and the corresponding loudness level in phons.While that extendour results reported at theFall 1987ASA Meeting[ S.A. Zahorian modelprovided improved explanatory power over other models tried, and A. J. Jagharghi,J. Acoust.Soc. Am. Suppl.1 82, S37 (1987) ] to a furtherrefinements of perceptualmodels of loudnesswill be neededto larger,more varied database and indicate that automatic classification of explainthese data. [Research supported by NIH andAFOSR. ] speaker-normalizedvowels is comparable to eitherspectral shape param- etersor formantsas initial features.[Work supportedby NSF. ]

US. Perceived modulation magnitudes of second-formant, center- frequencyvariations. L. S. Sullivan, R. J. Porter (Kresge Hearing US. F0 normalization and talker variability, Keith Johnson (Speech ResearchLaboratory, LSU Medical Center,New Orleans,LA 70112 and ResearchLaboratory, Department of Psychology,Indiana University, Departmentof Psychology,University of New Orleans,New Orleans,LA Bloomington,IN 47405) 70112), J. K. Cullen, and M. J. Collins (Kresge Hearing Research

S51 d. Acoust.Soc. Am. Suppl.1, Vol. 85, Spring1989 117th Meeting:Acoustical Society of America S51 Laboratory, LSU Medical Center, New Orleans, LA 70112 and an initialburst at onset.Adding a noiseburst to thebeginning of thetone Departmentof Speechand Hearing,LSU MedicalCenter, New Orleans, stimulusshifted the temporal-orderlabeling boundaries to significantly LA 70112) longeronset asynchronies that are consistentwith thosereported for VOT. Implicationsfor temporal-orderprocessing and speech perception Speechsignals convey information via rapidchanges in formantfre- will be discussed.[Work supportedby NSF. ] quencies.Listeners can reliablyjudge the relative"modulation magni- tude" of frequencymodulations [e.g., H. Fastl, Hear. Res., 59-69 (1982) ]. Listenerswere asked if theycould also judge modulation magni- tudefor center-frequency-modulated formants by presentingpairs of 500- msstimuli with centered,"notchlike" modulationsdrawn from synthetic continuawith varyingnotch duration (30-300 ms) or depth (50-500 UII. Phonetic and nonphoneticfusion in duplex perception.Lynne Hz). The first,reference, stimulus (either a low- or high-modulationex- C. Nygaard and Peter D. Eimas (Department of Cognitive and tremeof a continuum)was assigned a referencemagnitude (1 for low- LinguisticSciences, Brown University, Box 1978,Providence, R102912) modulation-referencetrial blocks;10 for high-). Listenersassigned a rela- Whenlisteners hear a syntheticconsonant-vowel syllable split with its tive "modulationstrength" (1 to 10) to the secondstimulus. Judged third-formanttransition presented to oneear andthe restof the syllable magnitudeappears as an unevenperceptual surface in the magnitude (the base)presented to the othercar, theyreport two distinctpercepts: A X depth X durationspace: Highest modulation strengths are heardfor nonspeechchirp sound in theear presented the transitionand a complete deep-longstimuli; deep-sbort stimuli have slightly lower judged magni- syllablein theear presentedthe base.The presentstudies investigated the tudes;shallow-long modulations are muchweaker; shallow-short modu- nature of fusionof informationyielding the phoneticpercept. By intro- lationsare the weakest.The possiblerelation between perceived modula- ducinga third-formanttransition into the base,fusion of informationin tion magnitudeand judgments ofarticulatory-phonetic differences will be the nonspeechpercept was also studied.In this case,listeners reported discussed.[Work supportedin partby NIH-NINCDS andthe Louisiana hearingboth a nonspeechchirp centrallylateralized and a complete,but Lions Eye Foundation.] nowclearer, syllable in the ear presentedthe base.Experiment 1 replicat- ed the originalphenomenon of duplexperception and demonstratedreli- ablephonetic and nonphoneticfusion of the isolatedand embeddedtran- sitions.In experiments2-5, fundamentalfrequency, amplitude, spectral composition,and onsettimes of the chirpwere varied relative to the base U9. The useof rate informationduring phoneticperception depends on that did or did not contain a third-formant transition. It was found that pitch continuity. Kerry P. G•en, Erica B. Stevens, and Patricia listeners'ability to detectthe additionalthird-formant transition differed K. Kuhl (Departmentof Speechand Hearing Sciences,University of for the phoneticand chirp perceptsfor eachof the four variables.These Washington,Seattle, WA 98195) resultssuggest that, as expected,the mechanismsfor the perceptionof Studieshave demonstrated that speakingrate providesan important speechand locationare different.Moreover, neither system captures all the available information and thus the fusion of information can occur in contextfor the perceptionof certainacoustic properties of speech.For both directions. example,syllable duration, which varies as a functionof speakingrate, has beenshown to influencethe perceptionof voice-onset-time(VOT) for syllable-initialstop consonants. The purposeof the presentexperiments wasto examinethe influenceof syllableduration when the initial portion of the syllablewas producedby one talker, and the remainderof the syllablewas produced by a differenttalker. A shortduration and a long UI2. Artieulatory and acoustic signaturesof selected monosyllabic duration/bi-pi/continuumwas synthesized with pitchand formant val- words. Ray D. Kent and Gary Weisruer (Department of uesappropriate to a femaletalker. When presented to listenersfor identifi- Communicative Disorders, University of Wisconsin-Madison, 1975 cation, thesestimuli demonstratedthe typical effectof syllableduration Willow Drive, Madison, WI 53706) on the voicingboundary: a shorterVOT boundaryfor the short stimuli relativeto the long. An/i/vowel, synthesizedwith pitch and formant At previousmeetings of thisSociety, acoustic signatures for selected valuesappropriate to a male talker,was added to the end of eachof the wordsfrom an intelligibilitytest have been described. The signaturescon- short tokensproducing a new "hybrid" continuum.Although the overall sistminimally of the formant trajectoriesof the syllablenucleus of each syllabledurations of the hybrid stimuli equaledthe original long stimuli, word. The formant frequencyinformation can be augmentedby other theyproduced a VOT boundarysimilar to theshort stimuli. In a follow-up acousticinformation, such as information on nasalmurmurs, stop bursts, experiment,two new/i/vowels weresynthesized. One had a pitchappro- silences,and fricationintervals. A majorgoal of this work hasbeen to priateto a femaletalker with formantvalues appropriate to a maletalker, determinethe interspeaker variance of thesignatures and to evaluatetheir whilethe secondhad a pitchappropriate to a maletalker and formants usefulnessin characterizingspeech disorders. This reportextends the re- appropriateto a femaletalker. These vowels were used to createtwo new searchto include articulatory data obtainedby x-ray microbeam.The hybrid continua.The resultsof this secondexperiment indicated that articulatorysignatures take the form of planarmotion paths of radiopa- continuityof pitchbut not of formantstructure appears to be the impor- que markersattached to the articulators.Articulatory data wereobtained tant factorin the integrationof speakingrate within a syllable.[Work from fivetalkers. Selected results will be presentedto illustratethe articu- supportedby NIH.] letcry signaturesand to showtheir relationshipsto acousticsignatures of thesame words. The primarygoal of thisreport is to describeintraspeaker and interspeakervariances as they relateto the possibilityof developing normatire standardsfor articulatory-acousticsignatures. [Work sup- portedin part by NIH.] UIO. Identificationof onsetorder for two-tonecomponents: Implications for voicing perception. Jody K. Layer and Richard E. Pastore (Department of Psychology,SUNY University Center at Binghamton, Binghamton, NY 13901) UI3. Consonant types and tone in Siamese revisited. John Drury A generalaccount of voicingperception for initial positionstop con- (DMLL, Cornell University, Ithaca, NY 14853) sonantsvarying in VOT hasbeen offered based on the identificationof onsetorder of componentevents. Pisoni [J. Acoust.Soc. Am. 61, 1352- This isa reportof a productionstudy of theeffects of consonanttypes 1361 (1977) ] reportedcategorical perception for nonspeechtonal stimu- and lexical tones on F0 before and after the release of the consonantal li, althoughthe exactboundary locations differed from VOT speechboun- gesturein thespeech of onespeaker of CentralThai. The studyis designed daries.The current researchreplicates and extendsthe Pisonistudy. La- to determinewhether the duration or magnitudeof the effectsof conso- belingtask boundaries were in agreementwith Pisoni,and a two-interval, nants on F0 varies consistentlywith the lexical tone of the syllablein forced-choice(2IFC) taskyielded boundaries even shorter than those for whichthe consonants occur. The mainfindings are that ( I ) segmentsthat the labelingtask. Most syntheticspeech stimuli varying in VOT employ depressF0 havea smallereffect on the F0 of lowertones than of higher

S52 J. Acoust.Soc. Am. Suppl. 1, VoL85, Spring1989 117thMeeting: Acoustical Society of Amedca $52 tones,while (2) segmentsthat elevate F0 haveapproximately the same mationwas investigated: vowel targets available in quasisteady-statesyl- effecton F0 for all tones;and (3) consonantshave only a briefeffect on lablenuclei; dynamic information contained in rapidlychanging formant post-releaseF0, as in previousstudy [J. Gandour,J. Phon.2, 337-350 transitions;and intrinsic duration information. Results indicated a re- (1974) }. The findingsare discussedin termsof a model in which the markablysimilar error patternacross conditions for bothnative and non- measurableF0 of an utterancecan be predicted by combiningsegmental nativesubjects, except for oneless-advanced subgroup of normariveswho F0/time functionswith prosodicF0/time functions. identifiedvowels in certainmodified conditions more poorly than vowels in an unmodifiedcontrol condition, suggesting that less-advancednorma- tives may needall possiblesources of informationto identify English vowelscorrectly. [Work supportedby NINCDS.]

U14. Assessingthe perception of foreignspeech sounds. Bernard Rochet (Departmentof RomanceLanguages, University of Alberta,Edmonton, Alberta T6G 2E6, Canada) U17. Perceptionof speakerage using a pairedstimuli technique. Richard This paper reports the resultsof a seriesof testsin which a set of J. Morris (Departmentof CommunicativeDisorders, The FloridaState synthetic/sVt/stimuli was presentedto nativespeakers of Standard University, Tallahassee, FL 32306-2007) and W. S. Brown, Jr. French and WesternCanadian English in order to assessthe effectof (University of Florida, Gainesville,FL 32601) phonemicinterference as a perceptualphenomenon. Each linguistic groupwas asked to categorizethe vowelportion of eachstimulus in terms Listenershave consistentlydemonstrated the ability to estimatethe of its L I phonologicalsystem, and, in a secondtest, in termsof its L 2 age of taped voice within a few yearsof the chronologicalage of the system.In addition,subjects were askedto rate each stimulusas to the speaker.In thisstudy, a pairedcomparison technique was used to deter- adequacyof its vowel as a member of its class.The resultsprovide a mine the consistencyof raters'judgments. The listenersrated the age of representationof the subjects'perceptual categorizations of a subsetof the voicesfrom two age groupsof speakers.Both intrajudgeand interjudge vowel spaceof their native and their target languages(English/u/and consistencywere determined.The speakersfor the studyconsisted of ten /U/, andFrench/u/and/ii/). Analysisreveals that English/u/is char- women who were 20-30 yearsof age and ten women who were 75-90 . acterizedby significantlyhigher F2 valuesthan its Frenchcounterpart, years.of age.A 3-ssustained/a/at comfortable frequency and intensity andthat fewsubjects at thebeginner or theintermediate level perceive L 2 levels was used as the stimulus for the listeners. The listeners were 22 phonemesin the sameway as L 2 nativespeakers; for most,the acoustic undergraduatestudents who ratedthe secondvoice in eachpair relativeto specificationsofL 2 vowelsmatch closely those oftheir L 1 vowels,or are the first one. The voiceswere rated as sounding"much older," "older," intermediatebetween the L I andL 2 values,in keepingwith the notionof "the sameage," "younger,"or "much younger"than the first voice.A phoneticlearning. multiplecorrelation statistical paradigm was usedto analyzethe data. The resultswill bediscussed in relationto theoriesof agingspeech produc- tion and perception.

U15. Categorizationof nonspeechstimuli. Xiao-Feng Li, Jody K.Layer, and Richard E. Pastore (Department of Psychology, SUNY-- UI8. Source characteristics: A study of hand clapping. Stuart Binghamton,Binghamton, NY 13901) A. Tousman,Richard E. Pastore,and Steven Schwartz (Department of Psychology,SUNY--Binghamton, Binghamton, NY 13901) A numberof studieshave claimed that a continuumconsisting solely of auditorychirps or bleatsproduces uniform chance labeling and dis- The presentresearch evaluated the capabilitiesof listenersto deter- criminationperformance. However, when theseauditory continua are mine sourcecharacteristics from acousticsignal properties. Repp [J. addedto an appropriatesyllable base, they producea categoricallyper- Acoust. Soc. Am. 81, 1100-1110 (1987) ] demonstratedthat naive listen- ceivedplace continuum. The current studydemonstrates that practice ershave some ability to determinethe source characteristic of handposi- allowssubjects to categoricallyperceive these auditory continua in a man- tiongiven the acousticsignal of a clap.The purposeof thishand clapping nerequivalent to that reportedfor speechplace continua. Three sets of 16 experimentwas ( 1) to moredirectly assess the capabilities of naivelisten- sinusoidalstimuli were synthesizedwith 40-ms initial transitionsthat ers to determinesource characteristics, (2) to determinethe physical wereanalogous to the secondformants of syllables.The startingfrequen- aspectsof the acousticsignal that are highlycorrelated with the source, cy of the transitionsvaried in 15 equalsteps from 1140to 2420 Hz. The and (3) to train subjectsso that performancecould be improved.The durationof the final steady-stateportion of the stimuliwas 190,40, or 0 productionphase of the experimentconsisted of recordingclaps in five ms [bleats,short bleats, and chirps]with total durationof 230, 80, or 40 differenthand positions. The perceptualphase consisted of a withinclap- ms,respectively. The study consisted of 4 practicedays with initialtesting per same/differenttask with listenersasked to judgewhether the hand on each day, and followedby 2 days of reevaluationof labelingperfor- positionwas the same ( neverphysically identical) or different.Half of the mance.[Work supportedby NSF.] listenerstested received feedback. Preliminary results indicate that naive listenerscould distinguish hand position from only a few clappers.Fur- thermore,training over 360 trials wasonly marginallybeneficial in im- provingperformance. Results will bediscussed in termsof differentmeth- odsof assessingand improving listener performance. [ Work supportedby U16. The role of spectral,temporal, and dynamic cues in the perceptionof BRSG programgrant. ] English vowels by native and nonnative speakers.Salvatore Miranda (Departmentof Linguistics,University of Connecticut,U-145, Storrs, CT 06269-1145) and Winifred Strange (Departments of CommunicationSciences and Disordersand Psychology,University of SouthFlorida, Tampa, FL 33620) U19. Perceptual units of the infant cry. Taeko Tsukamoto (Konan Previouscross-language studies have demonstrated that differentlan- Women'sCollege, Morikita-machi, Higashinada-ku, Kobe, 658 Japan) guagesmay utilizedifferent phonetic features to signalphonemic distinc- and Yoh'ichi Tohkura (ATR Auditory and Visual PerceptionResearch tions.This studyinvestigated which phonetic features are utilizedby lan- Laboratories,lnuidani, Seika-cho,Kyoto, 619-02 Japan) guagelearners perceiving speech in thetarget language and if theacoustic parameters that specify the features are proce•ed in the same way by Perceptualunits for categoryidentification of infant cries have been nativeand nonnative speakers. Native speakers of Englishand students of studied.Three cry categoriesdiscussed in this paperare the hungercry, Englishas a secondlanguage (ESL) identifiedAmerican English vowels the call cry (i.e., cry callingfor infant-motherinteraction), and the anger that were electronicallymodified to vary systematicallyin the type of cry. The originalsamples have been classified into thesethree categories. acousticinformation available. The role of threetypes of acousticinfor- In orderto generatestimuli to beused in the perceptualexperiments, each

S53 J. Acoust.Soc. Am. Suppl. 1, Vol.85, Spring1989 117thMeeting: Acoustical Society of America S53 of the cry samplesis firstsegmented into single-segment units according U22. Accuracy and reliability of formant frequency measurementsin to breathgroups of the cry samples.Next, the single-segmentunits are infant CV-like utterances.Raymond O. Daniioff, Naneye C. Roussel, combinedwith eachother in temporalorder to generatetwo-, three-,five-, and Creighton J. Miller (163 Music and Dramatic Arts Building, and seven-segmentunit stimuli.In additionto the multisegmentunit LouisianaState University, Baton Rouge, LA 70803-2606) stimulithus obtained, the single-segment units and the three original sam- plesare usedas one-segmentunit stimuliand full-segmentunit stimuli, The accuracyand reliabilityof measurementsof infant formant fre- quencieswere investigated.A total of 40 CV-type tokens(C = labial- or respectively,in the perceptualexperiments. In identifyingthe cry stimuli, subjectsare instructedto makea forcedchoice among the threecry cate- velarlikestop closant, V =/i/-iike or/e-like vocaliesegment) were se- lectedfrom recordingsof voealizationsof two infants,ages 2-4 months. gories.The experimentalresults show that categoryidentification rates aregreatly dependent upon the number of segmentsmaking up each stim- The tokenswere of goodacoustic quality and weretaken from recordings ulus. However,the identificationrates are temporarilysaturated at two- of postfeedingmother-child interactions. Formant frequencymeasure- segmentunits in the call cry and at three- to five-segmentunits in the mentswere made from bothsingle FIT crosssections using a 10-mssam- hungerand anger cries. This factindicates that the unitswith two to five plingwindow and averaged, time-advanced • spectra.Time-advanced segmentsare the perceptualunits. Temporal duration of the perceptual FFTs were computedusing three successive FITs taken at 2.5-msright- unitsacross all threecategories is similar (i.e., about6-8 s). ward shiftsof the 10-mswindow. Three investigatorsindependently mea- suredformant frequencies in all tokens.Wideband 500-Hz spectrograms ofeachtoken were used to establish baseline values of formant frequencies for comparisonwith measuredFFT values.Inter- andintraobserver reli- ability wasalso determined. U20. Respiratoryresponse to oral flowand pressure perturbations during speech.Anne Putnam Rochet(Department of SpeechPathology and Audiology, University of Alberta, Edmonton, Alberta TrG 0T2, Canada), KathleenE. Morr (Departmentof Dental Hygiene,Idaho StateUniversity, Pocatello, ID 83209), and DonaldW. Warren (Dental U23. Fundamentaland formant frequenciesin an adolescentpopulation. ResearchCenter, University of North Carolina,Chapel Hill, NC 27514) SusanR. Merino and TerraneeM. Nearey (Departmentof Linguistics, Evidencefor the regulation/controlhypothesis of Warrenfor speech Univcrsityof Alberta,Edmonton, Alberta T6O 2E7, Canada) aeromechanics[Cleft PalateJ. 23, 251-260 (1986) ] wasobserved in nine Althoughmeasurements ofchiidren's, adult male's,and female's vow- normal men who produced/p,x/and/si/under conditionsin which a elsare readilyavailable in the literature,few studiescan be found that deal translabialdevice released intraoral pressure during/p/, and bite Mocks with the resonancesof the adolescentvocal tract. The adolescentpopula- openedthe anterior bite artificially during/s/. Intraoral pressures,oral tion.is of interestbecause of the variationin vocaltract lengthsthat it flows,and respiratoryvolumes associated with utterancewere the depen- providesand the consequenteffects of thisvariation on the formantfre- dent variables.For/p/, intraoralpressure decreased and translabialair quenciesof the vowels.Recordings were made of I I vowelsproduced by leakageincreased as bleed orifice area increased, but meanpeak intraoral 30junior highschool sludents, 16 male and 14female, between ! 1 and 16 pressurenever fell below4 cm H20. For/s/, meanoral flow increased yearsof age.The studentswere attendingthe sameschool and were all slightlyas the anteriorbite wasopened, but meanpeak oral pressuredid nativespeakers of the samedialect. Measurements of the fundamentaland not vary significantlyfrom control values.Mean flow on the postconso- formantfrequencies were taken from two tokensofeach i I vowelsfor all nantal vowelsdid not vary significantlyacross the experimentalcondi- of the speakers.A preliminaryanalysis of the data will be presented. tions.There wereno significantdifferences among mean inspiratory vol- umes within or acrosstranslabial bleed conditions, nor within or across bite-Mockconditions. Expiratory volume increased significantly as bleed orificearea increased, but not asbite-block size increased. These data may reflectthe regulationcontrol options inherent in eachcondition. The res- piratorysystem alone could be reliedupon to maintainintraoral pressure U24. The application of frequency-domainadaptive filters to speech within requisitelimits for speechduring the bleedconditions; during the enlmncement.Tarek I. Haweeland PeterM. Clarkson(Department of bite-blocktrials, speakerscould employ increasedrespiratory drive, Electricaland ComputerEngineering, Illinois Instituteof Technology, structuraladjustments of the sibilantorifice, or both, to compensatefor Chicago,IL 60616) seromechanicalperlurbation introduced by theblocks. [ Work supported Severalauthors have appliedthe time-domainleast-mean-squares by AHFMR. I adaptivefilter to the problemof (voiced) speechenhancement. General- ly, theseefforts have achieved only limited successdue, in part at least,to the nonuniformconvergence of the adaptivefilter when faced with fre- U21. Accuracy and reliabiUty of formant frequencymeasurements in quencycomponents of highly disparatespectral power (the so-called synthetic infant CV syllables. Naneye C. Roussel, Raymond "eigenvaluedisparity" problem ). This problemis addressedby employ- G. Daniloff, and CreightonJ. Miller ( 163 Music and Dramatic Arts ing the normalizationcapacity of the frequency-domainadaptive filter Building,Louisiana State University, Baton Rouge, LA 70803-2606) (FDAF). The first part of this paperdeals with the analysisof the FDAF for strictlyharmonic signals (this reflectsthe quasiperiodicnature of An investigationof the reliabilityand accuracyof measurementof voicedspeech). It is shownthat the behaviorof the filler for eachweight infantformant frequencies was conducted. Four factorsknown to render of the FDAF can be describedby a lineartransfer function relating the formantmeasurement difficult--pitch inflection, glottal noise, jitter, and desiredinput to the outputsignal. It is furthershown that the productof nasalization--wereincorporated into synthesizedCV (C =/b,d/, V the input powerand the feedbackcomponent (in each frequencybin) =/i,a,e/) syllablesappropriate to 3-month-olds.The syllableswere of determinesthe stabilityand convergenceof the filter. Normalizationcan high intelligibilityand quality.Three fundamentalfrequency contours be achievedby adjustingthis product for eachweight. Simulations com- (standard rise/fall. rising.flat), three F0 levels (325, 375, 425 Hz), four paring time- and frequency-domainapproaches have shown that the voice/noiseratios ( + 20, + 5, 0, -- 15), threefrequency jitter rates( 250, FDAF enhancersignificantly improves performance. 500,750), and onedegree of nasalcoupling were used. Formant frequen- cy measurementswere made in two waysfor eachtoken: ( I ) as single FIT crosssections using a 10-mswindow and (2) as averaged,time- advancedFIT spectra.In the secondcondition, three successive FF•s takenat 2.5-msrightward shifts of the 10-mssampling window were aver- U25. The intelligibility of digitally high-passfiltering the discretedigital aged to producethe FFT spectrumfor measurement.Three observers frequencies in amplitude- and time-quantized speech. Edward independentlymeasured F I, F2, and F3 and resultswere comparedto M. O'Brien (BicengineeringProgram, Texas A&M University,College synthesisparameter values. Inter- and intraobserverreliability was also Station, TX 77843-3120) computed.Results are discussed with regardto theinfluence of consonant placeand voweltype upon accuracy in eachof the four conditionsof Speechwas first amplitudequantized into two levels,depending on waveformperturbation. whetherthe speechsignal was above or belowa 0-V reference.Time quart-

S54 J. Acoust.Soc. Am. Suppl. 1, Vol.85, Spring1989 117thMeeting: Acoustical Society of America S54 tizationwas next accomplished using clocking rates of 25, 16.7,10, and the useof VQ and its relationto F0 for conveyinglinguistic and nonlin- 6.25kHz. Thus only discrete digital frequencies remain in theprocessed guistic distinctions. [Work supported by NIH Grants NS 07237, waveform.Having the speechin a digitalformat makes it amiablefor HD 1994, NS 24655.] furtherprocessing. Determining the discrete digital frequencies is rela- tivelystraightforward and these can then be displayed onto the skin using electricalstimulation to implement a tactile hearing aid. Since only a finite numberof electrodescan be used,the effectof high-passfiltering the quantizedspeech was investigated using seven' normal-hearing subjects. U28. Inte!ligibilityof speechproduced in noiseand while wearingan Phoneticallybalanced monosyllabic words were usedas the testtokens. oxygenmask. Z. S. Bond(Department of Linguistics,Ohio University, With no high-passfiltering, the percent word intelligibilities were 91%, Athens,OH 45701) and ThomasI. Moore (ArmstrongAerospace 86%, 77%, and 54% for quantizingrates of 25, 16.7,10, and 6.25 kHz, MedicalResearch Laboratory, Wright-Patterson AFB, OH 45433) respectively.Several filters were tested for each quantizing rate. However, 70%word intelligibility (considered adequate for conversational speech) A numberof laboratories have described relatively systematic changes wasobtained with only 15, 11, and 9 discretedigital frequencies remaining in theacoustic-phonetic structure of speechproduced in thepresence of in thefiltered speech for quantizing rates of 25, 16.7,and 10 kH2, respec- noiserelative to that producedunder more benign speaking circum- tively. stances.At leastsome of thesechanges may be attemptsto makespeech clearerand moreintelligible. In orderto evaluatethe intelligibilityof speechproduced in variouscircumstances, a male talker speaking isolated wordsin quietand in thepresence ot'95 dB SPLof pinknoise was record- ed.Speech samples were collected both with and without an oxygen mask. The peakamplitudes of eachword were normalized, and the words were U26. Voicequality in males:A multidimensionalscaling study. Marylou mixedwith pink noiseand presentedfor identificationto 45 nativeand to PausewangGeller (Department of Speechand Hearing Sciences, l0 nonnativeEnglish speakers. The orderof relativeintelligibility was the IndianaUniversity, Bloomington, IN 47405) samefor bothgroups. Speech produced while listening to noisealone was Thepurpose of thisstudy was to investigatethe perceptual dimensions most intelligible.Speech in the laboratoryand in maskconditions was thatlisteners use in discriminatingmale voices, and how these dimensions considerablyless intelligible. The noise+ maskcondition led to margin- relateto perceptualrating scale judgments. Results were compared to ally the leastintelligible speech. [Work supportedby AFSOR. ] earlier researchusing female voices. Listeners were 18 certifiedspeech pathologistswho judged the dissimilarityof sentencesproduced by 20 males(20-26 yearsof age). The listenersalso evaluated each voice on 17 perceptualrating scales (e.g., high pitch-low pitch,clear-hoarse). Re- sultsof the multidimensionalscaling (MDS) analysisproduced a four- U29. Speechintelligibility as a function of environmentand speaking dimensionalsolution. A stepwiselinear regression related the perceptual style. Karen L. Payton, Rosalie M. Uchanski, and Louis D. Braida attributesof speechrate and vocalpitch to the firsttwo dimensions,while (R.L.E. 36-747 MIT, 50 VassarStreet, Cambridge, MA 02139) thesecond two dimensionswere best explained by descriptorspertaining to quality (e.g., pleasant,smooth, melodious). Compared to the MDS Sentencesspoken "clearly" have beenshown to be more intelligible analysisof femalevoices, the varianceaccounted for wasreduced, sug- thanthose spoken "conversationally," both for hearing-impairedlisteners gestingmore randomvariability among male voices,or that thesevoices in a quiet background[Picheny et el., I. SpeechHear. Res. 28, 96-103 were more difficult for listeners to rate in a consistent manner. Combined (1985)] and for normal-hearinglisteners in a noisebackground [R. M. resultsfrom both investigations suggest that theperceptual dimensions Uchanski,Ph.D thesis,MIT (1988) ]. This studyexamined the effectsof that listenersuse in discriminatingamong male voicesmay not besubstan- noiseand reverberationon the intelligibility of thesetwo speakingstyles tially differentfrom the dimensionused in discriminatingamong female for listenerswith normalhearing. Six environmental conditions were test- voices. [Researchsupported by BRSG Grant S07 RR07031, DRR, ed: three reverberationtimes (ancchoic, T = 0.18 s, and T = 0.6 s) by two NIH.] levelsof noise( + osand 0 dB S/N). As the environmentaldegradation increased(calculated from the STI), intelligibilityscores decreased for both speakingstyles. However, clear speechwas more intelligiblethan conversationalspeech for eachcondition. Further, the clear speechscores declinedat a moregradual rate than the conversationalscores as the STI decreased.Envelope spectra of clearand conversational speech are being U27. Variations in measuredvoice quality related to linguistic and examinedto derivea predictorof intelligibilitythat includesthe charac- nonlinguisticfactors. Gerald W. McRoberts (Haskins Laboratories,270 teristicsof both the speechsource and the acousticenvironment. Crown Street, New Haven, CT 06511 and University of Connecticut, Storrs, CT 06268) and Alice Faber (Haskins Laboratories, 270 Crown Street, New Haven, CT 06511 )

Voice quality (VQ) in Englishhas generallybeen treated as a supra- U30. Speaker identity verification of spectrally ambiguous and segmental,not varying across individual speech segments. Ladefoged [in distinguishablespeech. Robert J. Logan (Departmentof Psychology, VocalFoM Physiology,edited by Blessand Abbs(1983) ] hasmeasured SUNY--Binghamton,Binghamton, NY 13901), Timothy C Feustel, the spectralcorrelates of VQ differencesin languagesin whichboth VQ George A. Velius (Bell CommunicationsResearch, 435 South Street, and tone (F0) are phonemicallycontrastire. Since VQ variation is not MRE 2E 236, Morristown, NJ 07960), and Richard E. Pastore contrastivein English,it is in theoryavailable to enhanceother linguistic (Department of Psychology,SUNY--Binghamton, Binghamton,NY contrasts,or may vary asa functionof nonlinguisticfactors, such as fati- 13901 ) gue or affect.Following Ladefogcd,VQ was measuredas the difference betweenthe amplitudeof F0 and the amplitudeof the mostintense har- Feustelet el. [J. Acoust.Soc. Am. Suppl.l 83, S55 (1988) ] evaluated monicin F 1 usingdiscrete Fourier transform spectra. Two separatecor- performanceof humansin a speakeridentity verification (SIV) taskwith poraof utterancesby subjectswithout known voice pathology were ana- the intentof improvingthe performanceofa LPC-cepstralbased verifica- lyzed.One corpus compared qualitatively similar stressed and unstressed tion algorithm.This studyuses the generalmethodology and signalpro- vowels(Vs) producedby a singlespeaker in "fresh"and "fatigued"cir- cessingtechniques developed by Feustelet al. to further investigatethe cumstances.The other comparedutterances produced by two trainedac- nature of potentialinvariant acousticinformation (within a speaker)used tors in contrastivelyand normally stressedconditions, and simulated by humansto verify a speakeftsidentity. Subjectswere presentednatural positiveand negativeeffective conditions. These analyses suggest that this speechor modified natural speechstimuli drawn from a corpus of spec- measureof VQ differentiatesbetween Vs in ( 1) stressedand unstrcssed trally distinguishableand spectrallyambiguous utterances. The results conditions,and (2) normallyand contrastively stressed conditions. How- suggestthat humanscan useinformation from boththe glottal (source) ever,it did notdifferentiate between Vs in freshand fatigued conditions or waveformand spectralenvelope. Overall, the glottalwaveform provides in the simulated affective conditions. The results are discussed in terms of more reliable information. The results will be discussed in this context.

S55 J. Acoust.Soc. Am. Suppl.1, Vol. 85, Spring1989 117th Meeting:Acoustical Society of America S55 U31. Speech recognition using codebookstrained from a synthesized U34. An algorithm for distinguishingbetween voiceless stops and seed. L. A. Smith, B. L. Scott, L. S. Lin, and .I.M. Newell (Scott voicelessfrlcatives. LaDeana F. Wcigelt, Steven.I. Sadoff,and James Instruments Corporation, 11I I Willow Springs Drive, Denton, TX D. Miller (Central Institute for the Deaf, 818 South Euclid, St. Louis, 76205 ) MO 63110)

Speechsounds generated by a simplewaveform synthesizer were used An algorithmhas been developed for the purposeof voicelessstop/ to createa 16-vectorcodebook for vectorquantization (vq). This code- fricativcdistinction in word-initialposition using three mcasurcsof the bookwas used as a seedfor trainingover the TI-20 isolatedword database, waveform:zero crossings, e.nergy, and derivative ofthe energy over time whichwas then used to testthe resultingcodebooks using speech recogni- (termedrate of risc,ROR). The ROR is usedas the primaryclassifier tion. The databasewas split into two setsof speakersand two codebooks whileenergy and zerocrossings are usedto discardspurious, irrelevant werecreated for eachset, one trained on onepass over the speech and the peaks.Peaks in ROR areconsidered in orderof magnitudefor relevance othertrained iteratively. All codebookswere trained adaptively, resulting to the stop/fricativedistinction. The resultingalgorithm was treated on in codebooksof 31 vectors--16high-energy and 15 low-energyvectors. 720 CVC tokens(four malespeakers, four female speakers, three stops Recognitionwas performed using a conventionalDTW algorithm.The and an affricatc[P,T,K,CH], five fricatives[S,SH,F,TH,H], and ten baselinerecognition accuracy (using no vq) was97%; the accuracyfor vowelcontexts [IY,IH,EH,AE,AA,AH,AO,UH,UW,ER] ). Data from the 16-vectorsynthesized codebook was 91.8 %. Accuracyusing trained twomale and two female speakers (360 tokens)were used as a training codebooksranged from 94% ( two-sidedvq ) to 95.1% (one-sidedvq with set, and the remainingdata (360 tokens) were usedas a test set. The a normalizedmatch distance).Crossing speaker sets (resulting in overallsuccess rate was 96.8%. [Work supportedby AFOSR.] speaker-independentcodebooks) yielded 94.9% recognitionaccuracy. The resultsindicate that speechsynthesis can be usedto decreasethe trainingneeded to developmultispeaker and speaker-independentcode- books.

U35. Pattern processingof stopconsonants: Part II. L. Garrison-Shaffer (Division of Humanitiesand SocialSciences, Penn State University-- U32. Improvementsto a speaker-independentalgorithm. Brian Scott, The BchrcndCollege, Station Road, Erie, PA 16563) Lisan Lin, Mark Newell, and Lloyd Smith (Scott Instruments Corporation,1111 Willow SpringsDrive, Denton,TX 76205) Theroles off 1,F2, andvowel environment instop consonant pattern processingwere investigated using interaural transfer and selective adap- In May 1988,a speaker-independentrecognition algorithm was de- tation.Previous results indicate that differentpatterns may exist for pro- scribedat the 115thMeeting of the AcousticalSociety of America [Scott ccssingof stops,depending upon whether the stopoccurs in a front or etal., J. Acoust.Soc. Am. Suppl.1 83, S55(1988) ]. Thealgorithm yield- backvowel environment [L. Garrison,J. Acoust.Soc. Am. Suppl.I 83, ed95.4% recognitionaccuracy on the 20-wordTI databaseobtained from S70(1988) ]. Suchpattern processing may reflect differences in theplace- the NationalBureau of Standards.The systemhas since been adapted for mentoff 2 relativeto F 1.This experiment systematically manipulated the useover the telephone. In sodoing, a newdatabase was developed consist- relationshipsbetween formants as well as vowel environment for CV syl- ingof 16words (zero-nine, oh, yes,no, cancel, terminate, and help) as lables.These manipulations resulted in sixstimuli that were used as adap- spokenby 11 malesand I 1 femalesfrom various locationsacross the torson a [ba]-[da] testseries. One adaptor shared its vowelpercept country.Although small ( 1001utterances), the database represented a ( [ba]) andthree other adaptors shared vowel category (back) with the significantchallenge as comparedto the one obtainedfrom the NBS. testseries. Finally, two adaptorswere from a front vowelcategory. The Therewere fewer training passes per word, more speakers, and therewas resultswill be discussedin relationto how formantrelationships and considerablymore noise in the database.Initial tests on this database vowelenvironment affect pattern processing of stopconsonants. [Work yieldedaccuracies of approximately60%• Four majorenhancements to supportedby NINCDS.] the algorithmimproved the accuracyon thisdatabase to 95.3% Two of the enhancementscompensate for time alignmentproblems inherent in bothlinear and nonlinear time normalization routines through the useof prosodyand redundancy.The other two enhancementsinclude the ex- traction of additional features and better use of variances. Results indicate that acceptablespeaker-independent recognition can be obtainedwith minimaltraining and processor requirements, given effective normaliza- U36.Acoustic features of nasalconsonants inVC contexts.Yingyong Qi tionroutines during the front-end signal processing. and RobertAllen Fox (Divisionof Speechand HearingScience, The Ohio StateUniversity, 324 Derby Hall, 154North Oval Mall, Columbus, OH 43210-1372)

Theacoustic features of thenasals [m,n] in CV syllablesand [m,n,•j ] U33. APS: An environmentfor acoustic phonetic research.Gordon in VC syllablesin Englishwere first analyzed and comparedusing cep- S. Watson(Centre for SpeechTechnology Research and Department of strally smoothedrunning FFT spectra.Clear differencesbetween nasals Artificial Intelligence,University of Edinburgh, 80 South Bridge, in CV andVC syllableswere obtained. For example,the spectral energy EdinburghEHI 1HN, Scotland) transitionsfrom vowelto nasalin VC syllableswere found to be muchless dramaticthan in CV transitions.Next, giventhe recentinterest in the Continuousspeech recognition systems based on acousticphonetic efficacyof auditoryrepresentations in speech recognition schemes, the featuresdemand characterization of the relationshipbetween phonetic nasalsin VC contextswere examinedin termsof auditorytransformed segmentsand their acousticvalues. This paperdescribes a softwareenvi- running spectra.Several features of interestwere obtained:The spectra ronmentfor exploringthis relationship. The softwaresystem is knownas weregenerally dominated by thesecond formant and, when the preceding APS--acousticphonentic research with S (the standardUNIX statistical vowelwas a lowvowel, nasal place of articulation was distinguished by the package).APS implements a languageformalism for describingsegments secondformant transition, which converged to 16-17 ERB for [m] and of speech,forming an interfacebetween the domainof phoneticsand a 19-20 ERB for In]; [•] wascharacterized by little formantmovement. rich speechdatabase. APS enables the automaticretrieval of all tokensof a Consistentnasal place features were not foundin the contextof the vowels givensegment type togetherwith their acousticparameter values in a [ i ] and[ u]. Finally,since the antiresonances ofa nasalmay provide place phonemiccontext specifiedby the user: For example, using ^Ps, it is of articulationinformation, the systemzeros of the nasalswere analyzed possiblein a singleinstruction to perform statisticaloperations (e.g., usingparametric spectral analysis based on the autoregressivemoving mean,variance) on the durationsof all word-finaloral stopsfollowing average(ARMA) process.Results indicated that the antiresonancesof stressedvowels IT. H. Crystal and A. S. House, J. Acoust. Soc. Am. 83, nasalsin a VC syllablecould be consistentlyestimated by a two-stepAR 1553-1573( 1988}]. The motivationfor APSand the principlesof its de- approximationmethod that could bc used to distinguishreliably between signare describedand examplesof its usageare given. [m] and In].

S56 J. Acoust.Soc. Am. Suppl.1, Vol. 85, Spring1989 117th Meeting:Acoustical Society of America S56 U37.ESPRIT: A signal processing environment with a visualprogramming showsthat the systemmay be veryuseful for analysisof the speechof interface.Robert T. Gayreft, John A. Biles,Harvey Rhody (RIT patientswith neurological and laryngeal diseases aswell as the analysis for ResearchCorporation and RochesterInstitute of Technology,75 musicalsounds. Results from analysis of pathologicvoices agree with HighpowerRoad, Rochester,NY 14623), and JamesHillenbrand thoseof Kasuyaet al. [ "PreliminaryExperiments on Voice Screening," in (SpeechPathology and Audiology,Western Michigan University, Proceedingsof the Symposium on VoiceAcoustics and Dysphonia, Got- Kalamazoo, MI 49008) land,Sweden (August 1985) ] andLaver et al. ["An AcousticScreening Systemfor theDetection of LaryngealPathology," J. Phon.14, 517-524 ESPRIT(Explorer speech processing system from the Rochester Insti- (1986)]. tuteof Technology)is an integratedspeech research development envi- ronmentthat runs on the TI Explorer,optionally augmented by theTMS- 320based Odyssey DSP board. The goal of ESPRITis to providespeech scientists,linguists, and engineersan intuitiveenvironment in whichto collect,process, and display speech signals. ESPR•T'S module editor allows userswho are not programmers to drawdata-flow programs made up of U40. Effects of changesin stressand in rate of speechon vowels. built-inand user-defined speech processing algorithms, display functions, Marlos Fourakis(Central Institutefor the Deaf, 818 SouthEuclid, St. andstandard utilities. ESPRIT'S display editor allows users to manipulate Louis, MO 63110) thegraphical displays that result from running these programs to zoom, The effectsof changesin stressand in rateof speechon theacoustic scroll,rearrange, take precise measurements, and performa varietyof characteristicsof American vowels as produced by nativespeakers in real otheroperations. While ES?RIT provides standard signal processing algo- words were examined. The words were embedded in a carrier sentence. rithms(FFT,LPC) anddisplays (waveforms, spectrograms, waterfalls, Subjectswere instructedto producefour repetitionsof the carrier sen- spectralslices), users who develop their own Lisp or TMS 320programs tencefor eachtest word undereach of fourconditions: (a) slow,(b) fast, can easilyinstall them to replaceor augmentthe standardsoftware. (c) stresson thetest word, and (d) stresson an attacheddummy syllable. [Worksupported by Rome Air DevelopmentCenter under Contract No. Therewere 32 tokensper vowel for eachspeaker. The utterancesof one F30602-87-D-0090. ] malespeaker have been completely analyzed and plotted in an auditory- perceptualspace [J. D. Miller, "Auditory-perceptualinterpretation of thevowel," J. Acoust.Soc. Am. (in press)]. The voweltarget zones de- scribedby Miller correctlyclassify 85% of thevowel data, regardless of stressand rate conditions; and with minormodifications, the accuracy of U38. Effectsof treestructure and statistical methods on broad phonetic classificationis improved. Data for onefemale speaker will alsobe pre- classification.James W. Delmege(RIT ResearchCorporation and sented.Furthermore, measurementsof sentence,word, and isolatedvow- RochesterInstitute of Technology,75 HighpowerRoad, Rochester, NY el durationswill be presentedfor bothspeakers. [Work supportedby 14623),James Hillenbrand (Speech Pathology and Audiology, Western NINCDS.] MichiganUniversity, Kalamazoo, MI 49008), and RobertT. Gayvert (RIT ResearchCorporation and Rochester Institute of Technology,75 HighpowerRoad, Rochester, NY 14623) The goalof thisproject was to developa systemfor assigningindivid- ual framesof a speechsignal to oneof fourbroad phonetic categories: U41. Speaker-independentword recognition with Lombard speech. Brian vowel-like,strong fricative, weak fricative, and silence.Classification re- A. Hanson,Ted H. Applebourn,and GregoryR. De Haan (Speech sultswere compared from a K-meansclustering algorithm and a maxi- TechnologyLaboratory, 3888 State Street, Santa Barbara, CA 93105) mumlikelihood distance measure. In additionto thecomparison of statis- To investigatethe robustness of a smallvocabulary, speaker-indepen- tical methods,this study comparedclassification performance using dent word recognizertrained on normalspeech, testing was done using severaltree-structured, decision-making techniques. Training and test Lombard speech.The Lombard databasewas collectedfrom talkersex- dataconsisted of variouscombinations of 98 utterancesproduced by five posedto 85 dB SPL whiteGaussian noise played through headphones. maleand fivefemale speakers. Results showed very little differencebe- Recognitiontests utilized a hiddenMarkov model recognizer with sepa- tweenthe K-meansand maximumlikelihood methods. However, the na- rate codebooksfor staticand dynamiccepstral features [Gupta et al., in tureof thedecision tree had a significanteffect on theperformance of the Proc.IEEE ICASSP-87,697-700 (1987)]. The front-endanalysis used classifier.[Work supportedby Rome Air DevelopmentCenter and the eitherstandard linear prediction (LP) or a versionof perccptuallybased Air ForceOffice of ScientificResearch as part of the NortheastArtificial linearprediction. {This PLP hasfiltering functions with 3-dB bandwidths IntelligenceConsortium (Contract No. F3060285-C-0008)and by Red- of I Bark, a correctionto Eq. (3) in Hermanskyet al. [Proc. IEEE cornLaboratories, Victor, NY.] ICASSP-85,509-512 (1985)].) The effectsof the analysistechnique, analysisorder, distancemeasure (cepstral or weightedcepstral), and spectralfeatures (static, dynamic, or integrated) were studied. The utility of staticand dynamicfeatures differed greatly according to the analysis methodand distance measure. For example,for low ( 5th)-order PLP, the dynamicfeatures alone performed much better than either static or inte- U39. Microcomputer system for analysis of the verbal behavior of patients with neurological and laryngeal diseases.Maurice Yunik, gratedfeatures. Alternatively, for high ( 14th)-orderLPC with weighted cepstraldistance, the dynamicalfeatures alone performed much worse Boyan Boyahoy, and Budi Rahardjo (Department of Electrical thaneither static or integratedfeatures, yet contributed to improvedrec- Engineering,University of Manitoba, Winnipeg,Manitoba R3T 2N2, Canada) ognitionrates with integratedfeatures.

The microcomputersystem for verbalbehavior analysis is built on the basisof theIBM-PC. It consistsof twoparts: hardware and software. The hardwareis the condensermicrophone and a two-channelADC board, including:amplifiers with adjustablegain; two Besselanalog filters with U42. Acoustic-phonetic analysis of stress-inducedspeech. John cutofffrequencies of 800 Hz and6 kHz;and two ADCs allowing sampling W. Gordon(Boeing Aerospace Company, P. O. Box3999, Mail Stop82- rateup to 40 kHz. Thesoftware is a programpackage which allows high 58, Seattle, WA 98124) precisionpitch detection by means of theautocorrelaton function; finding theseparate pitch periods by meansof amplitudeselection and parabolic The LincolnLaboratories stress speech database (LLStyle) hasbeen interpolation;pitch period perturbation; number of subharmonic-to-fun- usedto test variousspeech recognition algorithms that might be usedin damentalfrequency power; separation of segmentswhere the signalis conditionssuch as stressfulenvironments, under which the input speech strictlyperiodic; realization of spectralanalysis over these segments by canbe expected to vary from its trainednorm. To facilitatethe correlation meansof fast Fourier and fast Walsh transforms;and evaluationof the of performancedegradations with speechvariabilities, the entire LLStyle degreeofhoarseness from the spectra. Preliminary experimental research database(consisting of over 10 000 utterances) was transcribed. The pro-

S57 J. Acoust.Soc. Am. Suppl. 1, Vol.85, Spring1989 117th Meeting:Acoustical Society of America S57 gramSEARCH was then used to gatherstatistics of variousacoustic-pho- shape,tongue rotation, and asymmetry. The present study used two quite netic parameters.Grouping these statistics according to speakingstyle differenttechniques (x-ray microbeamand ultrasound)in a comparative hasprovided some insight into whichparameter changes cause problems studyof tonguemovement. A singlesubject repeated/VCVC/combina- in generalfor machinerecognition. The analysisof individualwords has tionsof/s/,/1/,/i/,/a/, and/o/. The phonetalceffects of the consonants helpedto explainwhy certainassumptions made by somerecognizer stra- ontongue shape were examined, as were the allophonic effects of thethree tegies(for constrainingthe searchspace) are invalidwhen appliedto vowels.Tongue minus jaw movements(ultrasound) were compared to variablespeech. tongueplus jaw movements(XRMB). The data indicatedthat tongue rotation,which was quite common, occurred about a fulcrumwhose locus wasshifted or obscuredby jaw movement.Other resultsindicated that therewas considerable expansion/contraction of the tonguesurface dur- ing speech.In addition,the surfaceof the tonguemoved at nonuniform U43. Recognitionof prosodiccontrasts in literal and idiomaticutterances rates that were both physiologicallyand phonemicallybased. by native and normatirespeakers of English.Diana Van Lancker (Departmentof Neuroscience,University of North Dakota Medical School,Fargo, ND 58102) Abilitiesof threegroups--native English speakers, fluent nonnative Englishspeakers, and advanced students ofEnglish asa secondlanguage U46. Relationship of recorded EMG signals to within- and cross- (ESL)--to identifyliteral (L) andidiomatic (I) meaningsof ambiguous utterance acoustic variation. Alice Faber (Haskins Laboratories, 270 sentences(e.g., "He wasat theend of hisrope" ) weretested. Tape-record- Crown Street, New Haven, CT 06511) and Lawrence J. Raphael ed utterancesproduced by twospeakers with eitherintended L or I mean- (Herbert H. Lehman College,Bronx, NY 10468,The Graduate School, ingswere presentedsingly and in contrastlyepairs; listeners judged City University of New York, New York, NY 10021, and Haskins whethereach stimulus expressed an L or an I meaning.Native speakers Laboratories, 270 Crown Street, New Haven, CT 06511 ) performedsignificantly better than fluent nonnative speakers on both sin- Analysis of simultaneousacoustic and EMG recordingsof one gleand paired presentations, while the ESL speakersperformed at chance speakerof New York Englishproducing/•pVp/utterances under several on both tasks.Linguistic training was associated with greateraccuracies conditions shows differences between inter- and intrautterance interac- in the nativebut not in the fluentnonnative speakers. Acoustic analyses tions.For threeanterior genioglossus insertions ( # 1--• 3) and oneposte- hadindicated that L and I utterancesdiffered significantly on measuresof rior insertion(#4), the peak activationamplitude relevant to articula- fundamentalfrequency (F0), numberof pitch contoursper utterance, tion of the vowel was measured.Amplitude differencesreliably lexicaland overallutterance durations, and pausing.I utteranceswere differentiatedtarget vowels. For vowel/musclepairs with significantam- higherin F0, andhad fewer contours, shorter durations, and fewer pauses plitudes,activity duration and phasing of thepeak within the activity were thanthe L utterances.The resultsreplicate the original finding that native alsomeasured. Despite strong correlations among the peakamplitudes speakerscan discriminate L from I meaningsfrom prosodiccues alone for the anterior insertions, these measures differed in their correlations [ Van Lanckeret al., J. SpeechHear. Res.24 ( 1981) ], and furtherindicate with measuresofF0, F 1, and F2, both within and acrossutterances. Over- that performanceon the testwas not attributableto a listeningstrategy all, F2 correlatedbest with # l/duration, F 1with :• 2/amplitude,and F0 and that nativecompetency significantly affects abilities to processthese with #2/amplitude. For/I/, intertokenF2 variationcorrelated best with prosodiccues. • 3/phasing,F 1with # 2/amplitude,and F0 with # 3/phasing.The pos- terior •4/duration correlated best with/uw/F 1 and F0. These results suggestboth the importanceof applyingsimilar intertoken analysis tech- niquesto largerdata setsand the advancesin understandingof subgcs- tural articulatorycontrol likely to result.[Work supportedby NIH.] U44. Digital processingof laryngeal images: A preliminary report. Raymond H. Colton, Janina K. Casper, David W. Brewer (Departmentof Otolaryngologyand CommunicationSciences, SUNY Health ScienceCenter at Syracuse,Syracuse, NY 13210), and Edward G. Conture (Department of Communication Disorders, Syracuse University, Syracuse,NY 13210) U47. Volume determination using .Ncil S. Rothman (The JohnsHopkins Applied Physics Laboratory, Laurel, MD 20810) A low-costmicrocomputer (Amiga 1000} and softwarewere used to digitizeand analyzeslides, high-speed films, and videotapesof laryngeal Cavitiesof irregular geometrycan be modeledas Helmholtz resona- images.The imageswcrc digitized with a 320 horizontalX 200 vertical tors providedthey adhereto specificdimensional limits. If the character- pixel resolutionand at 16 grey levels.Various algorithmswere usedto istics of the entrance region or "neck" of a cavity are held fixed, its reso- analyze the images,which includedcolor equalization,color merging, nant frequencywill be a functiononly of its volume.This propertyof a cdgcdetection, and histogramanalysis. An exampleis presentedwhere Helmholtz resonator enables the determination of the volume of various thearea of a noduleand thearea of the glottisarc measured using some of cavitiesthrough resonant frequency measurements. Using an electronic the processingtechniques and comparedto similar measurementsob- feedbacktechnique and hand-heldadaptor, this methodologyhas been tainedby hand.The qualityof thedigitized images obtained with thislow- applied to determinethe volumesof both simple and complexcavities costsystem is very good.Simple image processing techniques, commer- includingcastings of humannasal passages. The aim of this researchis the cially available,are well suitedto the analysisof laryngcalimages and developmentof a laboratorysystem of measurementof nasalpassage vol- shouldpermit more sophisticated processing of movementof structures umein livehumans. This will allowthe determination of volumechanges within the larynx. resultingfrom variousstimuli and providefurther insight into the heat and masstransport phenomena that occurin upperrespiratory airways.

U45. A comparisonof x-ray microbeamand ultrasoundmeasurements of the tonguesurface during speech.Maureen Stone (Departmentof U48. New architecture for sub-band coding. Takashi Yazu and RehabilitationMedicine, Room 6S235, Building 10, National Institutes Makoto Morito (ResearchLaboratory, OKI ElectricIndustry Co., Ltd., of Health, Bethesda,MD 20892) 550-5Higashi-asakawa-cho, Hachioji-shi, Tokyo, 193Japan ) Trackingpoints on the tonguesurface provides unique information Most sub-bandcoders (SBC) have beenrealized by quadrature-mir- aboutits movement, such as surface expansion/contraction, differences in ror filter (QMF) with frequencyshift and low-passfilter (LPF). How- rateof movementalong the tonguc's surface, and X-Y tongueposition. ever,the QMF methodhas the followingproblems: (i) Bandseparation is Scannedimages of the tongue surface provide different but equally unique limited to the powerof 2; (ii) arithmeticerrors are accumulatedbecause information,such as posterior and anterior tongue relationships, tongue of the cascadeconnection of QMF; and (iii) it is necessaryto adjust the

S58 J. Acoust.Soc. Am. Suppl.1, Vol. 85, Spring1989 117th Meeting:Acoustical Society of America S58 timedelay if the number ofQMF connections isdifferent. Thispaper County, Catonsville, MD 21228), and Silvio P. Eberhardt (Jet presentsa new architecture for SBCwith flexible band assignment, less PropulsionLaboratory, Pasadena, CA 91109) arithmeticcalculations, and small storage memory. In thisSBC architec- ture,a finiteimpulse response filter (FIRF) isused instead of theQMF. Previousresearch suggests that many lexical errors in thespeechread- Thecenter frequency of eachband is selected according to theequation ing of sentencescan be explainedin termsof visualphonemic errors. F•/F• = D *n/m, whereF• isthe sampling frequency of theinput signal, However,description and quantification of perceptualerrors at thepho- F•.is the center frequency of thek th band,D isthe decimation factor, and nemiclevel requires specification of stimulus-to-responsealignments. Be- m, n areintegers. According to thisrelationship, frequency shift and the causespeechreading produces numerous errors, including phoneme in- LPFcan be performed at thesame time. In thiscase, data memory for the sertions,deletions, and/or substitutions,alignment is a nontrivial FIRF isdrastically reduced because the input of theFIRF is thesame for problem.This paperdescribes development of a sequencecomparator everyband. With thenew SBC architecture, the 16-to 12-kbpssub-band that can be usedto obtainalignments automatically for phonemically coder/decoderwas implemented on a singleDSP. Bandselection and transcribedsentences. The comparatoremploys a weightsmatrix that suitable bit allocation are discussed. reflectspresumed visual distances between all possiblesegmental stimu- lus-responsepairs to findthe alignment that minimizesoverall stimulus- responsedistance. Initially, the comparator used weights based on viseme groupings,but these weights resulted in multiple,equal-distance, alterna- tive alignments.More effectiveweights were obtained empirically via multidimensionalscaling of phonemicconfusions. Vowel data were ob- tainedfrom Montgomeryand Jackson[J. Acoust.Soc. Am. 73, 2134- U49. Usingdynamic time warpingto formulateduration rules for speech 2144 (1983) ] and consonantdata from a nonsensesyllable identification synthesis.Marion J. Macchi,Murray F. Spiegel,and Karen L. Wallace task, whichemployed 22 consonantsspoken by the sametalkers who (Bell Communications Research, Morristown, NJ 07960-1910) producedthe sentencestimuli for thisstudy [Bernstein et el., J. Acoust. Dynamictime warping(DTW), a speechrecognition technique, was Soc.Am. 85, 397-405 (1989)]. [Work supportedby NIH. ] usedto time align long-durationsyllables with shorter-durationrendi- tionsof thosesyllables. A malespeaker of Englishproduced stressed sylla- bleswith long duration, like "ibe," and the samesyllables with shorter durationsin nonsensewords like "libous,""libegous," "libegass," and "libotous."Syllables were formant tracked and a frame-by-frameEuclid- can bark-formantdistance between each long syllableand eachof its U52. Speechreadingsentences II: Applicationof a sequencecomparator shortercounterparts was computed. DTW was appliedto the resulting to data on CID sentences.Marilyn E. Demorest (Department of distancematrix. The DTW path,referenced to the longsyllable, indicates Psychology,University of Maryland--Baltimore County, Catonsville, whichportions of the longsyllable are shortened(and by how much) to MD 21228) and L. E. Bernstein(Center for Auditoryand Speech matcha shorterversion of thesyllable. The DTW pathsshowed regions of Sciences,Gallaudet University, Washington, DC 20002) maximaland minimal shortening.These reactions were approximately alignedacross syllable durations. The DTW pathsfor syllablesof different When subjectsspeechread sentences, their performanceis typically durationswere distinguishedfrom one anotherprimarily in regionsof evaluatedin termsof the numberof wordsor keywordscorrect. A com- maximalshortening. The regionsof maximal shorteningwere aligned paratorthat alignsstimulus and responsesequences is beingused as a with regionsin thesyllable with little formantmovement. Consequently, a heuristicfor studyingrelationships between the lexical and the phonetalc spectral-movementtime functionderived from the templatesin an inven- levelof speechreading.Toward this end,a corpusof responsesequences, tory could serveas the basisfor duration rules for demisyllablespeech previouslyanalyzed in termsof wordscorrect, was reanalyzed with the synthesis.Further, this techniqueprovides a methodfor makingduration comparator.Stimuli were 50 CID sentencesspoken by a maleand a fe- measurementsautomatically. maletalker and recordedon videolaserdisc. Subjects were normal-hear- ing collegestudents. One resultshowed that whensentences are short, computedvisual stimulus-responsesimilarity is well-correlatedwith numberof wordscorrect. But with few exceptions,when sentences are long,the correlation is reduced,suggesting that thetwo measuresprovide complementaryinformation. The sequencecomparator appears to be a US0. Mixed spectral representation--Formants and LPC coefficients. usefultool for elucidatingpatterns of speechreadingperformance. [Work JosephP. Olive (AT&T Bell Laboratories,Murray Hill, NJ 07974) supportedby NIH. ] A cascadeformant model is well suitedto describecertain speech segments,such as vowelsand vowel-like sounds.The formant model is alsouseful because the relationshipbetween formants and the vocaltract configurationsare well understood;however, this model is not adequate for otherspeech sounds, such as stops, fricatives, nasals, etc. On theother hand,LPC analysis,of sufficiently high order, can adequately describe the U53, Investigatingrandomness in foot timing patterns in English. spectrumof anyspeech sound, but the relationshipbetween the LPC Briony Williams and SteveHiller (Centre for SpeechTechnology parametersand the spectrumor vocaltract configurationis not obvious. Research,80 SouthBridge, Edinburgh EH1 IHN, Scotland) This paperdescribes a speechanalysis/synthesis scheme that usesboth formantsand LPC parametersfor differentsections of a speechsignal. Isochronyhas beenconsidered only in terms of stressedsyllables. Thus, in someregions, the benefitof the formant modelcan be utilized, However,it mayalso be a randomproperty of unstressedsyllables, and a while,in otherregions, the LPC representationcan be usedto obtaina controlexperiment was deemed necessary. A hand-transcribeddatabase gooddescription of the speechspectrum. The analysisalgorithm resolves of 98 sentences,each produced by threespeakers, formed the inputto an theproblem of discontinuities that arise from using the two different spec- algorithmcalculating durations of feet,number of syllablesper foot, and tral representations.The methodof speechanalysis described in thispa- meansyllable duration within each foot. In eachoutput dataset, feet were per producesresynthesized speech of the qualityof multipulseLPC. basedon one of the following:stressed, tense, unreduced, random, or arbitrarysyllables (the latter basedon ordinalnumbers of syllableswithin the utterance). Calculations were made of the correlations between foot durationand numberof syllablesper foot, and between foot duration and meansyllable duration. The firstcorrelation was significant for all foot types;the second was significant (and negative)for all exceptthe random US1.Speechreading sentences I: Development of a sequencecomparator. andarbitrary types. The conclusionwas that, althoughthe mechanismof L. E. Bernstein(Center for Auditoryand SpeechSciences, Gallaudet the tendencytoward isochrony had by no meansbeen discovered, it had University, Washington, DC 20002), Marilyn E. Demorest beenshown that the tendencywas nonrandom and wasdue to linguistic (Departmentof Psychology,University of Maryland--Baltimore rather than arbitrary factors.

S59 J.Acoust. Soc. Am. Suppl. 1, Vol. 85, Spring 1989 117thMeeting: Acoustical Society of America S59 WEDNESDAY MORNING, 24 MAY 1989 COMSTOCK A, 8:25 A.M. TO 12:00 NOON

SessionV. Engineering AcousticsIV: New Transducer Materials

James M. Powers, Chairman Naval UnderwaterSystems Center, New London, Connecticut06320

Chairman's Introduction-•8:2$

Invited Papers

8:30

V1. Recent developmentsin piezoelectric compositesfor transducer applications. Robert Y. Ting (Underwater SoundReference Detachment, U.S. Naval ResearchLaboratory, Orlando, FL 32856-8337)

The designtrend for futuresonar transducers is to emphasizethe utilizationof hydrostatic-modesensing, asopposed to theclassical 31 - or 33-modeconfiguration in a Tonpiltz transducer.The conventionalPZT-type ceramicscannot meet this need because they have very low hydrostaticpiezoelectric coefficients. Piezoelectric PVdF polymersare attractivefor thistype of applicationsbecause of their high sensitivity,but they are limited by their poortemperature stability, low dielectricconstant, and planaranisotropy. Piezoelectric composites havetherefore been considered as alternatetransduction materials that can be usedfor hydrostatic-mode sensing.Recent developments in ceramic/polymercomposites having 1-3 and0-3 connectivitypatterns and nonferroelectricglass/ceramic composites will bediscussed. Some test results on the acoustical performance of prototypehydrophones will alsobe presentedto demonstratethe potentialof thesenew materials for under- water acousticalapplications. [Work supportedby ONR.]

8:55

V2. Ceramlc-alrcompositesforhydrostatlcsenslng.Manfred Kahn (NavalResearchLaboratory,Code6374, Washington,DC 20375-5000) The hydrostaticresponse (dj,) of conventionalPZT ceramicis only about 10% to 30% of itsbiaxial (d•3) response.This is expressedin dj, = d• ( 1-2 •,), where 7, is Poisson'sratio. Higher dj, valuescan then be obtainedby loweringthe Poisson'sratio of the ceramic.This can be accomplished,without lowering the d• valuesignificantly, by introducinginto the ceramicarrays of voids,ordered in sucha mannerthat void-free columnsof ceramicare maintainedbetween the voids.The depositionof fugitiveink throughphotolitho- graphicallyprepared screens onto unfired ceramic tapes, together with stacking,laminating, and subsequent firing, providea methodfor the controllablepreparation of PZT sensors.These not only exhibit d•, valuesof •200 pC/N, but the voids also control the capacitance,so that g•, valuesof •>0.03 Vm/N are obtained. Capacitancevalues above 400 pfin a 0.5X 0.5X 0. l-in. sensorchip permit some cable capacitance and the use of bipolarrather than ofFET preamplifiers.Hydrostatic tests of suchdevices have shown these to bealso rugged, easyto connectand use,and capableof withstandingsignificant hydrostatic pressures.

9:20

V3. Monolithic piezoelectrictransducers. W. B. Harrison (Honeywell CeramicsCenter, 5121 Winnetaka Avenue North, New Hope, MN 55428)

This paperwill reviewnew piezoelectric transducers concepts where layers of leadzirconate titanite (PZT) havebeen electrodeal and thencoilred into a monolithicstructure that wasready for polingand usein various typesof transducers.These techniques were initially developedfor underwatermilitary applications,but are nowready to beapplied to commercialtransducers. Several methods for constructingthese transducers will be reviewedwhere either tape processed or moreconventionally pressed PZT shapeswere used. Typical applica- tionsand advantagesfor this technologyin severalacoustic transducers will alsobe described.Relationships between the thermal expansioncharacteristics of thicknessand transversemode transducerswill also be presentedalong with data on a new,more temperature stable PZT composition.[ Work supported, in part,by Office of Naval Research.]

S60 J. Acoust.Soc. Am. Suppl.1, Vol. 85, Spring1989 117th Meeting:Acoustical Society of America S60 9:45 V4.Electrostrictive •naterials. Robert E.Newnham andQichang Xu(Materials Research Laboratory, PennsylvaniaState University, University Park, PA 16802) Two typesof clcctrostrictivematerials will be described:(l) relaxorferroelectrics with diffusephase transitions,and (2) antiferroelectricceramics with a field-inducedferroelectric phase. Transducers rhade from relaxorferroelectries such as lead magnesium niobate (PMN) andlead zinc niobate (PZN) areoperated above Tc in a broadtransition range characterized by thepresence of nanometer-sizemicrodomains that impart large electromechanicalcoupling coefficients to the ceramic. These relaxor materials show no piezoelectriceffect underac drivebecause of the absenceof any net spontaneouspolarization, but microdomainfluctuations give riscto large ½leetrostrictive strains ( -- 10 s) withno hysteresis. Under dc bias, PMN ceramicsshow piezoelec- tric d_•_•coefficients as largeas 1500pC/N, threetimes those of PZT. The secondtype of electrostrictive transduceris basedon a field-inducedphase change from an antiferroelectricstructure to a fcrrneleetricphase. Ceramicsin the PbZrO•-PbTiO•-PbSnO_•ternary systemare usedas bistabletransducers for digital motions whereshape-memory hysteresis can be an advantage.Other uses for electrostrictivetransducers include adap- tiveoptic systems, micropositioners, and smart transducers in whichthe size of thepiezoelectric coefficient can beadjusted with adc biasfield.

10:10

V$. Rare earthmagnetostrictive materials. Arthur E. Clark (White Oak Laboratory,Naval SurfaceWarfare Center,Silver Spring, MD 20903-5000} The rareearth elements Tb andDy possessthe largest known magnetostrictions by far (nearly1% }. While thesegiant magnetostrictions arecurrently available only at cryogenictemperatures, magnetostrictive strains ashigh as 0.3% havebeen obtained at roomtemperature in compoundsofthe rareearths. In thispresentation, focuswill be on the recentlydeveloped TcrfenoI-D compounds prepared by freestanding zone (FSZ) and modifiedBridgman (MB) techniques.Because near balance of the magneticanisotropy can be achievedin thesecompounds, huge magnetostriction"jumps" can occur.During thesejumps, energyis transformed betweenan internalmagnetic state to an externalmechanical state causing large spontaneous magnetostric- tions.Special emphasis in thepresentation will beon: ( I } magnetostrictiveproperties at lowand high tempera- tures,{2) dependenceof the magnetizationand magnetostrictionon externalstress, (3) preparationtech- niquesand growthmorphology of the highlymagnetostrictive compounds, (4) Delta E effect,and (5) theoreticalmodels. Recent designs of low-losstransducer modules using high-strain rare earth alloys will be presented.[ Work supported by the NSWC Internal Research Program and the Office of NavalTechnology. ]

10:35

V6. Silicontransducer technology. W. S. Henrion(Triton Technologies, Inc., 1301Capital of Texas Highway South, Austin, TX 78746) '

The useof integratedcircuit technology to buildmechanical structures by the useof siliconmicromachin- ing hasgained wide acceptance for somesensor types over the past 10 years.The principalapplication for siliconmicromachining has been for pressuretransducers used in the automotiveand medical markets. The use ofsiliconmicromachining technology in acousticalsensors has been somewhat limited, although some micro- phonesand aceelerometershave been built usingthis technology. This paperwill reviewthe micromachining technologieswith specificapplication to the acousticsand acceleration sensors. Examples will be givenfor microphones,accelernmeters, and pressuretransducers with the materialprocess technology used for their manufacture.Projections are madeof futuretrends in siliconmicromachining technology for acoustictrans- ducers.The electronicinterface to theseacoustic and accelerationtransducers are explored.

Contributed Papers

11:oo intrinsicproperly of thematerial but depends on the distance of thesound sourcefrom the material.In thispaper, an expressionfor the spherical V7. The sphericalwave absorptioncoefficient of a patch of material. waveabsorption coefficient of a finite-sizepatch is derived(in thecylin- Matthew A. Noblie '(IBM AcousticsLaboratory, Department C18, dricalcoordinate system considered, the patchis either a circularor annu- Building704, P.O. Box 950, Poughkeepsie,NY 12602) lar disk). As will beshown, this quantity can be approximated experimen- tally from measurementsof the reflectioncoefficient at severaloblique Kecently,the concept of a sphericalwaoe absorption coefficient, anglesover the surface of thesample using the two-microphone transfer wasintroduced [M. A. Noblie, Proc. NOISE-CON 88, 567-572 (1988) ] functionmethod in a hemianechoicenvironment [an extensionof M. A. to accountfor the fact that whenspherical waves are incidentupon an Noblie, Proc. NOISE-CON 87, 611-616 (1987) ]. This can be the basis acousticalmaterial, the absorptioncoefficient is not the sameas it would for a simplifiedmethod of comparingthe absorptiveproperties of two be under(less realistic) plane-wave incidence. In fact, ct,oh•r is not an materials.

S61 J. Acoust.Soc. Am. Suppl. 1, Vol.85, Spring1989 117thMeeting: Acoustical Society of America S61 11:15 velocitydecreases with increasingBMA contentin MMA-BMA. The temperaturedependences of ultrasonic attenuation in MMA-BMA show VS. Smart acoustically active surfaces. F. Douglas Shields, James that the glasstransition temperature T• wasdecreased with increasing E. Hendrix, and L. Dwynn Lafieur (National Center for Physical BMA content,and T• couldbe easily determined with ultrasonicmethod. Acoustics, University, MS 38677) The resultshave been explained by thermoelasticmechanism and scatter- Bilayeredtransducing surfaces have been constructedand used to ing mechanism. control the reflectionof soundin both liquidsand gases.The acoustic signalgenerated in oneof thelayers is amplified, passed through a digital filter, and usedto drive the secondlayer with the properphase and ampli- tudeso as to eliminatethe reflectionsof single-frequencytone bursts. The toneburst frequencies were between 20 and 40 kHz in liquid and between 11:45 5 and 20 kHz in air. Feedbackis controllcdby the digital filtcr so as to eliminateinstabilities. A theoreticalanalysis predicts the performanceof VI0. Ultrasonicinvestigation of a BiSrCaCuO high T,. superconductor. suchsmart surfaces, but asyet thereare discrepancies between theory and Jiankai Hu, Qianlin Zhang, Deng Tingzhang, and Weili Cai experiment.[Work supportedby ONR. ] (Departmentof Electronics,University of Scicnccand Technologyof China, Hefci, Anhui, People'sRepublic of China) The temperaturedependences of ultrasonicattenuation and velocity in a high T,. superconductorBiSrCaCuO were measured by theultrasonic pulseecho method, in the temperaturerange 77-300 K. Ultrasonicat- 11:30 tenuationanomalies were foundat 95, 135,and 250 K; the slopeof ultra- V9. Ultrasonic investigationon different structure and composition sonicvelocity was changed at thesetemperatures rcspondingly. There are cogolymers.Jiankai Hu, Zhou Jing,and Xu Wenying (Departmentof two superconductivephases in BiSrCaCuOsamples at 87 and 120 K Electronics,University of Scienceand Technology of China, Hefei, foundfrom x-ray examining.The ultrasonicanomalies at 95 and 135 K Anhui, People'sRepublic of China) are related to the superconductivetransition at 87 and 120 K resulting from microstructureinstability. The samephenomenon has also been Ultrasonic attenuation and velocities have been measured for three foundby internalfriction experiments [ H. Shenet al., Proc.of 2ndInter- kindsof copolymers:MMA-BMA, MMA-MAA, and ST-MAA con- nal Friction and Ultrasonic Attenuation Conference of China, C63 tainingdifferent kinds of cross-linkers.Experimental results indicate that (1988) ]. An ultrasonicanomaly at 250 K is a relaxationprocess, similar ultrasonicattenuation increases with increasingBMA contentin MMA- to the mechanismin YBCuO [M-F. Xu et al., Phy. Rev. B 37, 3675 BMA, with addingcross-linkers EGD or BA in MMA and in ST-MAA; (1988)1.

WEDNESDAY MORNING, 24 MAY 1989 NEWHOUSE II, ROOM 254, 8:30 A.M. TO 12:30 P.M.

SessionW. Bioresponseto Vibration II, PsychologicalAcoustics IV, and PhysiologicalAcoustics IV: VibrotactionMPhysiological,Psychophysical, and Applied Aspects

Ronald T. Verrillo, Chairman Institutefor SensoryResearch, Syracuse University, Syracuse, New York 13244

Chairman's IntroductionmS:30

Invited Papers

8:35

W1. Four channelsmediate vibrotaction: Facts, models, and implications. S. J. Bolanowski,Jr. (Institutefor SensoryResearch, Syracuse University, Syracuse, NY 13244)

Four separatepathways or channelsapparently mediate tactile ( i.e., mechanical) stimuli. Each channel,as definedpsychophysically by its frequencycharacteristics in responseto vibratorystimuli and physiologically by additionalconsiderations such as receptive field sizes and adaptation rates to ramp-and-holdstimuli, oper- atesover a wide rangeof frequenciesand intensities.The psychophysicalchannels are: Pacinian or P; non- PacinianI or NPI; non-PacinianII or NPII; and non-PacinianIII or NPIII. As definedphysiologically and anatomically,the channelsare hypothesizedto be, respectively:Pacinian (Pacinian corpuscles) or P; rapidly adaptingI (Meissnercorpuscles) or RA I; slowlyadapting II (Ruffiniendings) or SAII; andslowly adapting l (Merkel-cellneurite complexes) or SA I. Becausethe channelsare overlappingin their operatingranges, it is proposedthat undercertain conditions (e.g., low stimulusintensities) a singlechannel may mediatetaction, while other conditionsrequire that more than one channelcontributes to tactile sensationsand to overall perceptualimpressions. From thestandpoint of appliedaspects such as the development of tactileaids for the deaf,it shouldbe of interestto determineif thechannels can be used independently and to determinethe types of interactionsthat may occurfor the purposeof enhancinginformation transfer via this sensorysystem. S62 d.Acoust. Soc. Am. Suppl. 1,VoL 85, Spring 1989 117thMeeting: Acoustical Society ofAmerica S62 9:05

W2. VibrotaetJlemeasurement procedure for assessingperipheral neuropathies. A. J. Brammerand J. F. Piercy(Division of Physics,National Research Council, Ottawa, Ontario K IA 0R6, Canada) it hasbeen suggested that someperipheral neoropathies may be detectedearlier by vibrotactionthan by moretraditional methods (viz., nerve conduction). Most commercial apparatus for this purpose isdesigned primarilyfor useon any flesh surface, and only records the sensitivity of onemechanoreceptor type. Recent laboratorystudies have identified a techniquefor establishing,independent]y, the sensitivityof eachof the threereceptor popo]ations essential for thesense of touchat thefingertip, with minimaleffect from confound- ingvariables. A portablemeasurement system using this technique has now been developed for clinicaluse or field surveys,which enables the thresholdsof untrainedsubjects to be determinedrapidly, by employing audiometric]ikeprocedures. The data are convenientlysummarized by "tactograms,"or "tactilograms,"in whichthe change in vibrotactilethreshold from the mean value recordccl in normalhands, at eachfrequency, is expressedgraphical]y, in a mannersimilar to an audiogram.Results from persons with diagnosedor suspected neuropathieshave revealed three patterns of thresholdshift, at leastone of whichis receptorspecific.

9:35

W3. Clinicalsspeets of vibrotaetiledevices with deafchildren. Mary Joe Osbergerand Amy IVl. Robbins (Departmentof Otolaryngology,Indiana University School of Medicine,Indianapolis, IN 46223) Longitudinaldata will be presentedon the speechperception and production abilities of 15deaf children whouse a vibrotactileaid (TactaidIlL Theirperformance isbeing compared to thatof deafchildren who use eithera single-or multichannelimplant. Initial findingsindicate that the performanceof the subjectswith implants,even those with single-channeldevices, is superior to thatof thesubjects who use the tactile aid. The subjectswho achievedthe highestscores with the tactileaid tendeelto havemore sophisticated cognitive and linguisticskills that permitted them to developstrategies to decodethe vibratory patterns. The importance of priorknowledge of the languagein decodinginformation perceived via the skinis also supported by the data collectedfrom postlinguallydeaf adultsusing the sametactile aid. The implicationsof generalizingdata collectedon adultsto prelinguallydeaf children will bediscussed. [Work supportedby NIH.]

10:05-10:15 Break

ContributedPapers

10:15 10:30

W4. Independenceofspatial and temporal tuning in theNP I cutaneous WS. Identifyingpossible neural codes for vibrotactionusing the theoryof mechanoreceptorsystem. Clayton L. Van Doren (Department of temporal summation.C. M. Checkoskyand S. J. Bolanowski,.Jr. BiomedicalEnginecling, Case Western Reserve University, Cleveland, (Department Surgery, University of Rochester Medical School, OH 44106) Rochester,NY 14642 and Institute for SensoryResearch, Syracuse University,Syracuse, NY 13244} Resultsfrom a previousstudy that measuredtactile detection thresh- olds for spatiotemporalsinusolds suggest that the spatialand temporal The theoryof temporalsummation refers to the psychophysicalphe- tuningof the P andNP I cutaneousmechanoreceptor systems are inde- nomenonin whichthreshold decreases with increasingstimulus duration. pendent.In otherwords, provided that thespatial configuration of a vi- The effect is found in audition and is central. Vibrotactile thresholds me- bratorystimulus is i•dependentof temporalfrequency, changing the spa- diatedby the Pacinian-corpuscle (PC) population( the "P" channel)also tial configurationshould not changethe shapeof the temporaltuning exhibittemporal summation. Assuming that the tactilesummatot is also curveof eithersystem. To testthis hypothesis for the NP I system,vibro- central,it maybe possible to determinethe neuralcode for thresholdused tactilethresholds were measured as a functionof temporalfrequency ( 10, by the P channel.Theoretically, temporal summation predicts a decrease 12, 15, 20, 25, 30, 40, 55, 80, 100, 175,and 250 Hz) for 200-msstimuli in thresholdat a rate of -- 3 dB/doublingof durationfrom 10 to 100ms. deliveredto the thenareminence via a 0.75-cm2 circularcontactor, with Thus by integratingthe responsefrom singlefibers for variousresponse and withouta rigid surround.At frequencieswhere the thresholdwas criteria, thosenot havingthe potentialfor temporalsummation can be mediatedexclusively by the NP I system,the presenceof a rigidsurround rejectedas possible coding schemes. PCs isolated from cat mesenterywere did not significantlyalter the shapeof the temporaltuning curve, but did stimulatedwith bursts of vibrations(300 Hz) havingdurations from 10to changethe overallsensitivity. That is, NP I thresholdswere uniformly 1000ms, the intensityof the stimuliadjusted for fixedcriterion responses higherwithout the surround than with thesurround. Similar results were of 1, 2, and 4 impulses/burstand ! impulse/cycle.Data were sampled obtainedwhen the experimentwas repeated on the forearm.The observed over the entire 0urst duration, in effect analyzing the responsewith an invariancein the shapeof the low-frequencytuning curve is consistent idealsummator. The decreasesin intensityfor increasesin durationfrom with thespatiotemporal independence hypothesis, but is consistentwith 10 to 100ms were -- 0.9, -- 1.2, -- 2.3, and -- 0.2 dB/doubling,respec- conclusionsfrom prior studies.The apparentdiscrepancy will be dis- tively, with neitherthe i impulse/burstnor the impulse/cyclecriteria cussed. showingsignificant summation. The othertwo criteriashow modest sum-

S63 J. Acoust.Soc. Am. Suppl.1, Vol. 85, Spring1989 117th Meeting:Acoustical Society of America S63 mation,indicating that they havethe potentialfor beingthe neuralcode (CTS, n = 2). Thresholdswere measuredwith a two-interval, forced- for thresholdin the P channel.[Work supportedby NS23933.] choicetracking procedure. The vibratorystimuli consisted of 700-mssin- usoidalbursts with rise-fall times of 37 ms. The frequencyof the test stimuliranged from 3-300 Hz. Threeof the RSD patientsdemonstrated a 20- to 30-dBloss of sensitivityat all frequenciesfor their affectedhands. Thesepatients had normal sensitivityin their unimpairedhands. The 10:45 other four RSD patientsdemonstrated no lossin sensitivityin neither their affectednor normalhands. The two patientstested with CTS also W6. Vibrotactile forward masking in young and old subjects. G. had normal threshold functions for both their affected and unaffected A. Oescheiderand A. Valetutti, Jr. (Hamilton College, Clinton, NY hands.The resultssuggest that the clinicaldiagnosis of RSD subsumes 13323) severalpathological conditions one of whichmay or maynot be a decrease Thresholds for the detection of a 50-ms test stimulus were measured as in thresholdsensitivity. The fact that CTS patientsmay not experience a function of the time interval betweenthe offsetof a 500-ms masking impaired thresholdsuggests that this neuropathymay not affect nerve stimulusand the onsetof the test stimulus (At). The frequencyof the fibersmediating low-threshold tactile sensitivity. maskerand the test stimuluswas the sameduring a particular testing sessionand waseither 20 or 250 Hz. The stimuliwere presented through a 2.9-cm-'circular contactor applied to the thenareminence. Thresholds were measuredby a two interval-forcedchoice tracking procedure. A groupof sevenyoung subjects (average age 21 years)and a groupof older 11:15 subjects(average age of 67 years) were tested.The amountof forward maskingexpressed as thresholdshift decreased as •xtincreased. At all WS. A comparisonbetween the growthsof loudnessof vibrotactilepulse valuesof •.t, the older subjectsexhibited significantly more maskingthan and sinusoidalstimuli. Amy A. Collins and Roger W. Cholewiak did the youngsubjects. The forwardmasking functions and the effectsof (Department of Psychology--Green Hall, Princeton University, agewere essentially the same for stimulithat primarilyaffect the Pacinian Princeton, NJ 08544-1010) system(250 Hz) and thosethat primarily affect non-Paciniansystems The growthsof loudnessof pulsatileand sinusoidal stimuli were exam- (20 Hz). inedby the methodof absolutemagnitude estimation. Fourteen observers judged32-pps pulse and 250-Hz sinestimuli on two siteson the palm:the thenar and hypothenareminences. Estimates revealed that pulsestimuli wereperceived as being louder than the sinestimuli on bothsites. Power functionsfit to the sinedata had exponents of 0.84, whilethose fit to the 11:00 upperlimbs of the pulsedata had slopesof 0.82. Cross-qualitymatches W7. Vihrotactile threshold for subjectswith peripheral neuropathies.L. betweenthe two typesof stimuliwere made by nineof theseobservers. The H. Novick, R. T. Verrillo, S. J. Bolanowski, Jr., A. Ecker, and G. A. groupmatches were not foundto be internallyconsistent. That is, those made when the sine was the standardwere not equivalentto matches Gescheider (Institute for Sensory Research, SyracuseUniversity, Syracuse,NY 13244) madewhen the pulsewas the standard.Such consistency was apparent, however,in someindividual observer's data. In addition,slopes of match- Thresholdsfor detectingvibrotactile stimuli applied to the thenaremi- ing functionswere often well predictedby magnitudeestimates using a nencethrough a 2.9-cm-• contactor were measured for patientshaving procedurebased upon the absolutescaling hypothesis. Intercepts were reflexsympathetic dystrophy (RSD, n = 7) and carpal tunnelsyndrome alsopredicted in someindividual cases. [ Work supportedby NANCDS. ]

11:30-12:30 DiscussionGroup

S64 d. Acoust.Soc. Am. Suppl.1, Vol. 85, Spring1989 117th Meeting:Acoustical Society of America $64 WEDNESDAY MORNING, 24 MAY 1989 COMSTOCK B, 8:30TO 11:35A.M.

Session X. Musical Acoustics II: Acoustics

William Y. Strong,Chairman Steinwayand Sons,Steinway Place, Long Island City, New York

Invited Papers

8:30

XL Plano bistory•cience and art, William Y. Strong(Steinway and Sons,Steinway Place, Long Island City, NY 11105)

The pianoenjoys a uniqueposition in boththe concerthall and the home.It hasbeen in existencefor well over200 yearsand was the subjectof muchdevelopment activity during the middle1800s. Competition was fierceat the timeand innovation was crucial to a company'ssurvival. Artists placed musical demands on the instruments,designers countered with their own ideasand capabilities,and reputationswere made on the resultinginstrument. Some of the greatminds of the day focusedon the pianoacoustics challenge, perhaps mostnotably Hermann Helmholtz, a namefamiliar to all acousticians.This talk will presenta few interesting historicaldetails of the liaisonbetween science and art in the designof the piano.

8:50

X2. Vibrationcharacteristics of rectangulartest soundboards. Hideo Suzuki(Ono SokkiCompany, Limited, 2-4-1 Nishishinjuku,Shinjuku-ku, Tokyo, 163Japan)

Sincea pianosoundboard has a very complexstructure, it is difficultto separatelystudy the effectof each parameter(such as the board thickness, rib dimensions,bridge dimensions) on thevibration characteristics of the wholesoundboard. To moreeffectively study the effectof theseparameters, four testsoundboards were built. A much simplerstructure was usedto study the vibrationcharacteristics of a sprucepanel reinforced with severalspruce ribs. Driving point inertaneefunctions at differentpoints were compared among the four soundboards.Mode numbersand modalpatterns were also compared. It is interestingthat the vibrationat a pointon (or near) a rib is quitedifferent from that on a pointaway from ribs in thefrequency range above the coincidencefrequency. [ This studywas performed while the author was at CBSTechnology Center, Stamford, CT and supportedpartially by Steinwayand Sons,Long Island City, NY. ]

9:20

X3. Woodfor pianosoundboards. Daniel W. Haines(School of Engineering,Manhattan College, Riverdale, NY 10471)

The wood soundboardof the piano is amongthe most importantcomponents of the instrument.It is essentialfor projectingthe desiredvolume of sound,and the soundboardmaterial stronglyinfluences the quality of the sound.As it is for the soundradiating elements of many string instruments,spruce is the unanimouschoice of woodfor pianosoundboards. The reasonsfor the useof spruceand selection criteria for superiorperformance will bediscussed.

9:50

X4. The mathematicsof pianotuning. Albert E. Sanderson(Inventtonics, 171 Lincoln Street,Lowell, MA 01852)

It is a well-knownfact that piano stringsvibrate inharmonically--thepartials actually run sharp by amountsthat vary from piano to piano and from note to note on any one piano.This affectsthe tuning significantly,and it is correctto saythat no two pianosshould be tunedexactly alike. This paperpresents a mathematicalsolution to the problemof tuningsuch instruments for typicalclasses of inharmonicityversus note-numbercurves, the most important case being a straight-linelogarithmic increase of about3:1 per octave. Equal temperamentis literally impossiblein this case,and if one forcesit with an electronictuning, the instrumentsounds very unmusical.The octaveis no longerexactly 2:1, and must be redefinedto allow for differenttypes of octavepartial matching.More generaldefinitions of equal temperatureand octaveslead to a tuningsolution in the form of a differenceequation. Although no two octavesor evensemitones are exactlythe samewidth, they are consistently wide by an amountthat growswider as the inharmonicityrises. Comparison with pianostuned auraflyshows that fine pianotuners have beensolving this equationsubconsciously for centuries.

S65 d. Acoust.Soc. Am. Suppl. 1, Vol.85, Spring1989 117thMeeting: Acoustical Society of America S65 10:20

XS. Nonlinearmodeling of piano hammer-stringinteraction. Donald E. Hall (PhysicsDepartment, California StateUniversity, 6000 J Street,Sacramento, CA 95819) Measurementsof complianceon realpiano hammers show that they are not well represented by Hooke's law,and it hasbeen found that theoretical models with linear compliance have only modest success in account- ingfor measured spectra. Two new computer programs now perform numerical integrations of theinteraction process for hammerswith nonlinear compliance. One treats the string as a pairof digitaldelay lines,and is limitedto perfectlyflexible strings. The otherrepresents the string by itsnormal modes, and can includestring stiffness. Results from these two programs agree well with each other, and provide improved agreementwith laboratorymeasurements.

ContributedPapers

10:50 Composers'pulses are patterns of expressivemicrostructure ( i.e., tim- ing andamplitude modulations) said to conveyindividual composers' x6. Timingin skilledpiano performance. Caroline Palmer ( Psychology personalitieswhen implemented in computerperformances of their music Department,Ohio StateUniversity, Columbus, OH 43210) [seeM. Clynes,in Studiesof MusicPerformance, edited by J. Sundberg Skilledmusic performance is characterizedby expressivevariations (1983), pp.76-181 ]. The presentresearch continued the perceptual eval- thatcommunicate the performer's interpretations of structuralcontent to uationof suchpulses, which so far hasyielded inconclusive results [B. H. a listener.Four experimentsare describedthat addressthe procedures Repp,Music Perception (in press)]. Theinitial bars of five piano pieces by thatpianists use to governthe assignment of structuralinterpretation to eachof fourcomposers ( Beethoven, Haydn, Mozart, and Schubert)were timingvariations. Six piano performances of thesame music were record- playedon a computer-controlledelectronic piano with eachof the four ed on a computer-monitoredacoustic piano. Three timingmethods were composers'pulses ( following Clynes' specifications asclosely as possible) measuredin eachperformance; chord asynchronies, rubato patterns, and andalso in a deadpanversion. Listeners judged to whatextent each com- overlaps(legato/staccato patterns). Each pattern corresponded to the puterperformance conveyed the cornposer'scharacteristic expression, pianists'notated interpretations ofmusical structure. Experiment 2 inves- relativeto thedeadpan version. Pilot resultsprovide occasional positive tigatedthe developmentof the timingmethods during learning. Each supportfor the Beethovenand Haydn pulses,but noneat all for the Mo- pianist'ssuccessive performances of an unfamiliarmusical excerpt dem- zartand Schubert pulses. Additional'data willbe reported from musically onstratedthe methods:Students' performances showed an increasein trainedsubjects who also listened to computer performances in which the eachmethod, while experts' performances stayed constant (with moreof timingand amplitude components of thepulses were applied separately. eachmethod). In experiment3, eachpianist performed different interpre- [Work supportedby NIH-BRSG. ] tationsof the same music.The same methods(applied in different amounts)were usedin eachperformance, and increasedin exaggerated performancesof the same structural interpretation. These results support a mappingof musicalintentions to performancetiming through a setof proceduresshared by manypianists. [Supported by NSF, MIT Media 11:20 Laboratoryand Psychology Department, Cornell University.] XS. Propertiesof pianohammers. Anders Askenfelt (Department of SpeechCommunication and Musical Acoustics,Royal Institute of Technology,Stockholm, Sweden)

11:05 Measurementsof thecompliance and loss factors for raw hammerfelt and completedhammers have been recorded. The resultsof thesemea- X7. Further testsof "composers'pulses" in computerperformances of surementswill bepresented and their implications discussed. The poten- piano music from the classicalperiod. Bruno H. Repp (Haskins tial for newmaterials for usein pianohammers is suggested and possible Laboratories,270 Crown Street,New Haven, CT 06511-6695) candidates for these new materials will be discussed.

$66 J. Acoust.Soc. Am. Suppl. 1, Vol.85, Spring1989 117thMeeting: Acoustical Society of America S66 WEDNESDAY MORNING, 24 MAY 1989 NEWHOUSE I, ROOM A1, 8:30TO 11:45A.M.

SessionY. PhysiologicalAcoustics V: From the Ear Canal to the Cortex

Robert V. Shannon, Chairman Boys Town National Institute, 555 North 30 Street, Omaha, Nebraska 68131

ContributedPapers

8:30 The directionaldependence of the transferfunction from free-field planewaves to a point near the tympanicmembrane was measuredin YI. On ear canal measurementtechniques applied to hearing anesthetizeddomestic cats. A probetube microphone was placed from a development.Douglas H. Keefe and Robert Ling (Systematic ventralapproach, which minimally affects the headand pinae. Acoustic Musicology Program, School of Music, DN-10, University of measurementswere taken using a quasianechoicmethod in whichan im- Washington,Seattle, WA 98195) pulsivestimulus was presented and room reflections were rejected using a Few data existon the functionaldevelopment of the humanexternal Kaiserwindow. The transferfunctions are similarto thosereported ear- and middleear, yet constraintsimposed by thesestructures limit the lier [A.D. Musicantet al., 12thICA, Toronto(July 1986)]. Theycan be soundpower transmitted to thecochlea. One measure of hearingdevelop- brokeninto threedistinct frequency ranges: A low-frequencyrange ( < 5 mentis the middleear reflectance,the fractionof incidentsound power kHz), whereinteraural level differences vary smoothlywith azimuth;a reflectedat theeardrum. Single and double microphone techniques mea- midfrequencyrange (5-18 kHz), wherea prominentspectral notch is surethe impedanceat the tip of an assemblysnugly inserted into the ear observed;and a high-frequencyrange ( > 18 kHz), wherethe spectrum canal.This impedance is of limitedusefulness, since it dependsnot only variesgreatly with sourcelocation. The frequencyof the midfrequency uponthe middleear reflectance,but alsoupon insertion depth, variations notch is a robustcue for soundsource direction; it varieswith both azi- in cross-sectionalear canal area, and ear canal curvature. A method has muth and elevation in a monotonic fashion in the frontal field. Source beenconstructed to assessthe joint influenceof theear canal area function directionis uniquelydetermined by combiningthe midfrequencynotch andcurvature with a spatialresolution along the ear canal of 4 mm (cT/2, cue from both ears. These resultssuggest that simpleconsideration of for phasevelocity c andsample period T). The reflectanceat theassembly interaural level differencesmay not be sufficientfor the studyof sound tip istransformed to that at an earcanal location just outsidethe eardrum. localizationat highfrequencies. [Work supportedby Grant No. NS 12524 The methodis alsorelevant for constructingthe outputimpedance of the from NINCDS/NIDCD. ] ear, as seenby a sourceon the eardrum.This techniquemakes no useof invasiveprobe microphones, has a frequencyresolution of 40 Hz, andis wellsuited for usewith infants.Preliminary data on tubes of knowngeom- etry will be discussed.[Work supportedby NIH.] 9:15

Y4. Ear canal cross-sectional acoustic modes. M. T. Friedrich and R. D. Rabbitt (Department of Mechanical Engineering, Washington University,St. Louis, MO 63130)

8:45 The cross-sectionalacoustic modes for real ear canalgeometries are determinedusing a WKB methodin combinationwith a Rayleigh-Ritz Y2. Revisionof a two-pistoneardum model to accountfor real ear canal procedure.This model, which appliesthe usual assumptionsof linear geometries.R. Michael Stinson(Division of Physics,National Research acoustics,can be used to analyze the three-dimensionalsound-pressure Council, Ottawa, Ontario K IA 0R6, Canada) distributionin any long,slender, rigid-walled waveguide. The methodis The acousticalbehavior of the middleear canbe convenientlysum- particularlywell suitedto obtainthe highermodes, which are trapped marizedusing acoustical network representations, analogous to electrical nearboth ends of theear canal. The analysiswas confirmed by comparing circuits.Previous middle ear networks, though, have been derived assum- computedresults with the exact solutionsfor fundamentalwaveguides. ing that the ear canal could be treated as uniform in crosssection and Resultswere alsoobtained for geometriesmeasured from real ear canals. terminatedperpendicularly by theeardrum. At frequenciesabove about 5 [ Work supported,in part, by the Whitaker Foundation.] kHz, it isnecessary to accountfor theactual ear canal geometry (varying cross-sectionalarea alongcanal length). In this paper,the two-piston representationofShaw [J. Acoust.Soc. Am. Suppl.1 62, S12 (1977) ] is incorporatedinto a horn equationdescription of the soundfield in ear canals.Several of Shaw'snetwork parameters must be revisedso that 9:30 eardumimpedances and ear canal standingwave ratioswill be correctly predictedwhen this network is usedin conjunctionwith realisticcanal YS. An approach to finite-element modeling of the middle ear. Susan geometries.The analysismakes use of recentmeasurements of humanear M. Funnelland W. RobertJ. Funnell (BioMedicalEngineering Unit, canal geometry. McGill University, 3775 University Street, Montr6al, Qu6becH3A 2B4, Canada)

It is becomingincreasingly clear that the mechanicalbehavior of the middleear is morecomplex than first thought.In particular,recent ex- perimentalevidence indicates that the ossicularaxis of rotation is not 9:00 fixed.Finite-element analysis is a methodwell suitedto the detailedanaly- sisof complicatedmechanical systems. A finite-elementmodel of the ear- Y3. Directionaldependence of free-field-to-eardumtransformations in dumhas previously been developed. This paper presents work on a system cats,J. Jeremy Rice, Brad May, GeorgeA. Spirou,and Eric D. Young developedto modelthe middleear ossiclesand importantsoft tissues. (Center for Hearing Sciences and Department of Biomedical Anatomicalinformation is input to computerby digitizingoutlines of Engineering,Johns Hopkins University, Baltimore, MD 21205) structuresof interestfrom serial section slides. The resultingthree-dimen-

S67 J. Acoust.Soc. Am. Suppl.1, Vol. 85, Spring1989 117thMeeting: Acoustical Society of America S67 sionalvolume is discretizedinto tetrahedralelements using an automatic indicativeof a placeon the basilarmembrane, the data are consistentwith mesh generatordeveloped to mesh irregularly shapedobjects. Prelimi- a model in which otoacousticemissions are generatedat more than one nary resultsof analysison middle-earstructures will be presentedand placein the cochlea. modelingof themiddle ear as a wholewill bediscussed. [Work supported by MRC Canada.]

10:00

Y7. Effect of contralateral acousticstimulation on 2f•-f2 acoustic distortionin humanears. KennethR. ToughandH. Kunov (Instituteof BiomedicalEngineering, University of Toronto, Toronto,Ontario M5S 9:45 IA4, Canada)

Y6. Stimulusfrequency otoacoustie emissions: Evidence for multiple The normal human cochleais known to exhibit acousticnonlinearity, sourcesin the cochlea.Beth A. Prieveand PaulJ. Abbas(Department observedmost easily as a 2f•-f2 distortionproduct tone in responseto two of SpeechPathology and Audiology,University of Iowa, Iowa City, IA tonal stimuli. This distortionproduct is physiologicallyvulnerable, and 52242 ) canbe influenced in animalsby electricalstimulation of thecochlear effer- ent nerves.The function of the efferentcochlear innerration is poorly Stimulusfrequency otoacoustic emissions (SFE) were measuredin understoodbut currentlyrevived theory suggestsa feedbacksystem may humansby recordingthe totalsound-pressure level in theear canal upon existbetween the oppositecochlea, influencing cochlear micromechanics stimulationwith continuouspure-tone stimuli across a widefrequency throughthe outer hair cells [ D. O. Kim, Hear.Res. 22, 105-114(1986) ]. range.SFE are typically not equal in magnitudeas a functionof frequen- The influence of a contralateral acoustic stimulus on cochlear nonlinear- cy.There are frequencies at which large magnitude emissions exist bound- ity was studiedin human subjectsthrough the changesobserved in the edby frequenciesat whichsmaller magnitude emissions exist. SFE can be 2f•-f,. distortionproduct. The influenceof interaural acoustictransmis- maskedby simultaneouspresentation of a secondpure tone and the mask- sion of the stimuluswas controlledby usingconstant SPL stimuli on ing functionsdemonstrate strong frequency dependence. These tuning subjectswith varyingdegrees ofsensorineural hearing loss in thestimulat- propertieswere measured with probes at frequenciesevoking large magni- ed (contralateral) ear. Resultsindicate a slightsuppression in distortion tudeand those evoking the surrounding smaller magnitude emissions. For product'withno significantfrequency tuning. Strong correlation with eachtuning curve, the trip ishigher in frequencythan that of theprobe. As middle ear reflex threholds and lack of correlation with sensation level probefrequency is increased,the tip frequencyalso increases, although indicate the suppressionis not causedby a cochlea-to-cochleaneural not alwaysproportionally. Assuming that the tip of the tuningcurve is mechanism,and is likely causedby the middleear reflex.

10:15-10:30 Break

10:30 modulationfrequency. The resultingtemporal modulation transfer func- tions(TMTFs) aresimilar to thoseof normallyhearing listeners IN. F. YS. Characteristicsof the 2fl-f2 differencetone in humansubjects and in Viemeister,J. Acoust.Soc. Am. 66, 1364-1380(1979) ]. Modulationde- a hardware eoefilear uonlinear preprocessing model with active tectionfunctions are basicallylow pass,with bestsensitivity to modula- feedback. Frances P. Harris and Eberhard Zwicker (Institute of tion frequenciesof 20-100 Hz anddecreasing sensitivity for modulation Electroacoustics,Technical University of Mfinchen, Arcisstrasse21, frequenciesabove 100 Hz. Modulationdetection performance is similar 8000 Miinchen 2, Federal Republicof Germany) whetherthe carrieris an analogsinusoidal stimulus or a biphasicpulse Level and phaseof the 2f•-f• combinationtone were measuredin five train.These results suggest that envelope detection mechanisms are intact humansubjects using two methods:Psychoacoustic cancellation and di- in theseimplanted patients, even though their cochleae are not function- rect cancellationof the distortion-productemission (DPE) measuredin ingand the pattern of activationin theirauditory nerves are quite different theear canal. A probeassembly, composed of twoearphones and a micro- fromany normal acoustic pattern of activity.[Work supportedby NIH phone,was placedin the subject'sear canal for the deliveryof stimulus NS24754. ] tones,f•and f2, andthe 2f•-2f2 cancellationtone and for measurementof DPEs. Frequencyoff• was 1620Hz with.f, either 1800, 1851, 1944,or 2052 Hz. Leveloff• or.f_,was varied in 5-dBsteps from 70-30 dB SPL for eachfrequency pair. Data fromthese subjects were compared with similar data measuredusing the hardwaremodel. DPE cancellationlevels were 11:00 40-50 dB belowcomparable psychoacoustical cancellation levels for both Y10. A negative correlation between endocochlearpotential and data sets,however absolute differences varied by frequencyseparation endolymphpotassium concentration. Alec N. Salt,Ruediger Thaimann, and levelof the primariesand by method.Dependencies of the leveland and John DeMott (Department of Otolaryngology. Washington phaseof 2f•-f2 on the frequencyseparation and levelof the primarieswere University, St. Louis, MO 63110) similar for all three methods. It iswidely accepted that theendocochlear potential (EP) arisesfrom a secretionof K + intoendolymph by striavascularis, although, as yet, thereis no consensus concerning that cellular basis of thisprocess. Studies in whichchanges in EP and endolymphpotassium (K,,) wererecorded 10:45 duringanoxia or treatmentwith transportinhibitors (e.g., ouabain) have Y9. Detection of modulationin pulse trains by patients and cochlear shownthat a declineof K•, is associatedwith the suppressionof EP. On implants.Robert V. Shannon(Boys Town National Institute, 555 North thebasis of suchexperiments, it would be presumed that K,, wouldtend to 30th Street, Omaha, NE 68131 ) be positivelycorrelated with the magnitudeof EP. On the contrary,a numberof procedureshave been found in which a decreaseof K• is asso- Detectionof amplitudeand pulse-widthmodulation was measured in ciatedwith an increaseof EP. Perilymphaticperfusion of solutioncon- patientswith the Symbionand Nucleuscochlear implants as a functionof taining20 mM K + causeda transientincrease of EP (by up to 10 mV)

$$8 J. Acoust.Soc. Am. Suppl.1, Vol. 85, Spring1989 117th Meeting: AcousticalSociety of America S68 followedby a decline.During this period, K• recordedby ion-selective topicorganization of thecochlear nucleus leads to theinteresting possibil- microelectrodestypically showed a decrease,followed by an increase. ity that the spatialdistribution of voidscorresponds to the low-intensity Similarly,iontophoretic injection of Ca+ + intoendolymph produced an portion of the tonotopicregions of the cochlearnucleus and the void EP decreasethat was mirrored by a K,. increase.These findings cannot be distributionreflects an anatomicalsubstrate for intensitycoding. explainedby changesin K + transportand/or K + permeabilityalone, but are more likely accountedfor by changesin anionpermeability. [Work supportedby NIH ProgramGrant No. P01 NS24372.]

11:30

11:15 Y12. Global brain asymmetriesin regionalcerebral blood flow (rCBF} observedduring restingconditions with posltronemission tomography Yll. Voids in the gerbil cochlear nucleus: Is there an anatomical (PET): Establishinga baselinefor experimentson brain asymmetries and substrate for intensity coding? K. D. Statler, S.C. Chamberlain, R. complexsounds in the CNS Project. Judith L. Lauter and Elena Plante L. Smith, and N. B. Slepecky(Institute for SensoryResearch and (Speechand Hearing Sciences,University of Arizona, Tucson, AZ Departmentof Bioengineering,Syracuse Univerity, Syracuse, NY 13244) 85721)

The presenceof voidsin the gerbilcochlear nucleus has been reported During 1981-1985,the first author and colleagues at the Mallinckrodt by Morestet al. [IUPS SatelliteSymposium on HearingAbstract, p. 80 Instituteof Radiologyat WashingtonUniversity in St. Louiscollected a (1986) ] and relatedto someaspects of auditoryexperience by MeGinn seriesof 29 PET-scan studiesof the brains of 16 normal young adult and Faddis [Hear. Res. 31,235-244]. The number,volume density, and subjectsusing the PETT VI and intravenousoxygen-15 to testeach sub- void sizewere investigated in animalsof variousages from 18-485 days. ject in multiple40-s scans, comparing rCBF topographyduring session- Thesevariables were found to increaseas a functionof agewith a maxi- initial and session-finalcontrol scans,and under a variety of auditory mum volumedensity of about1% [Statleret al., ARO Abstracts,p. 209 stimulationconditions. Global hemispheric rCBF in all controlscans are (1988) ]. The spatialdistribution of the numberof voidsin the cochlear currentlybeing measured in this library. Resultswill be presentedfor nucleuswas computed as a functionof the incomingneural activity pro- work to date,detailing between- and within-subjectcomparisons, includ- ducedby ambientnoise over the life of the animal. In a three-dimensional ing patternsto within-and between-session replications. These measure- reconstruction,the voids form a contiguousarea in thegranular layer and mentswill providea baselinefor the CoordinatedNoninvasive Studies posteroventralcochlear nucleus. The anteroventralcochlear nucleus and (CNS) Project,in whichsubjects first examined behaviorally for process- dorsalcochlear nucleus are spared. The numberof voidswas found to be a ingasymmetries (e.g.. ear advantages), are then tested with PET to deter- monotonicallyincreasing, negatively accelerated function of the total mine the degreeof correlationbetween behavioral and physiological neural activity. The differencebetween the void distributionand tono- asymmetries.[Work supportedby AFOSR. ]

WEDNESDAY MORNING, 24 MAY 1989 REGENCY C, 8:40 A.M. TO 12:00 NOON

SessionZ. Underwater Acoustics IV: Propagation

Kenneth E. Gilbert, Chairman NationalCenter for PhysicalAcoustics, University of Mississippi,University, Mississippi 38677

Chairman's Introduction--8:40

ContributedPapers

8:45 startingfield can be obtained by computingthe - I/4 powerof thema- trix generatedfrom the FFT of the indexof refraction.This resultis Zl. Efficientcomputation ofideal •a•,i•rabolic equation derivedand some example starting fields are presented compared to start- models.E.Richard Robinson a•l David H. Woo•R2ode3122, New erscomputed or approximatedin otherways. Further, the effectson PE LondonLaboratory, Naval Under:water SYstemg Center, New London, modeloutputs using the variousstarters are demonstrated. CT 06320)

When the Helmholtz equationis replacedby the relatedparabolic equation,the resultinggain is the relativenumerical ease of solvingthe parabolicequation using a marchingtype algorithm.However. there is 9:00 still the problemof providingthe initial data-•or the startingfield for the PE model.Although it is well knownthat the normalmode starter is the Z2.A modifi/fi•edko•indee•e•..ntparabolic equation incorporating range correctinitial data,it is not widely usedbecause of the expenseinvolved in refraction/I•.•W.Schurman,•W. L. Siegmann, and M. J. Jacobson the computation.In the presentapproach, however, the idea is exploited (RensselaerPdlytechnic institute, Troy, NY 12180-3590) that it is not necessaryto computethe normalmodes individually to ob- tain the correctstarting field. If the functionrepresented by a weighted Parabolicequations currently in useto predictacoustic intensity re- sum of the normal modes is considered,then it is found that the correct quirea judicious choice of thereference wavenumber ko. A newparabolic

Sfi9 J. Acoust.Soc. Am. Suppl. 1, Vol. 85, Spring 1989 117th Meeting:Acoustical Society of America equation(PE) is presentedhere which is independentof ko and capable of the deviationin depthof th{ handlinglarge variations in theindex of refraction.This equation is simi- tionsare usedto represent lar to, andostensibly simpler than, an earlierrange refraction PE (RAR- lems. The mean and vari• EPE) reportedrecently by Tappert and Lee. The modifiedrefraction terms of statistics of the ra parabolicequation (MOREPE) is obtainedby a transformationap- nel is treated, and the rati• proach,and operatorand multiscaleformalisms are alsodescribed to is expressedin termsof • validatethe equation. Principal properties of MOREPE arediscussed. An randomprocesses repre• exactsolution with only rangevariation in soundspeed is presentedto behavior of this ratio is d illustratedifferences between standard PE and MOREPE. Propagation Further, the effect on ir examplesin range-independentenvironments demonstrate close agree- lotionsare compared.[ mentbetween MOREPE and standardPE, whileexamples with strong rangedependence exhibit significant differences between the two equa- tions in their predictionsof acousticintensity. [Work supportedby ONR.]

Z6. A self-consiste• weakly inhomoge Program in Ocean •'U•)i½ '• 9:15 Ocean Engineering,. ,,•"•'•-•3.•-J•ations ofhigher-order parabolicequations• MichaeF MA 02139) and GeorgeV. bn•. ,_ Do.•2ollin• (Naval Ocean Research andDevelopment Activity,stennis WoodsHole Oceanographic Institution• Woods :Spac•ff•enter,MS39529) A unifiedperturbation approach to wavepropagation and scattering Theparabolic equation (PE) model is very useful for many range- in weaklyinhomogeneous media is presented.By separatingthe total dependentacoustic calculations. However, the PE solution breaks down wavefield into an averaged coherent propagation part and a randomscat- forpropagation at large angles, out to longranges, and in domainsin teringpart, a setof coupledwave equations is found.The problemof a whichsound-speed variations are relatively large. This problem was re- wavepropagating in a randommedium is changed to a problemof a pair ducedwith the introductionof the wide-anglePE of Claerbout,which is of coupledwaves propagating in a deterministicmedium with randomly basedon a rationallinear Pad6 approximation. Generalizing this ap- distributedsources. This method not only improves upon the convention- proachto a sumof rationallinear terms [ BambergeretaL, SIAM J.Appl. al Bornapproximation for the scatteredfield, but alsogives the attenu- Math.48, 129-154(1988) ] leadsto a higher-orderPE thatis easy to solve ationbehavior of thecoherent propagating field related to the statistics of numerically.Calculations will bepresented to demonstrate that this high- therandom media. Examples of underwateracoustic waves in an inhomo- er-orderPE accuratelyhandles problems involving very wide anglesof geneouswater column and an inhomogeneousbottom are given. propagationand large differences in soundspeed including elastic wave propagationinvolving a superpositionof bothshear and compresisonal waves.

•'- 10:15

Z7. Exponential growth of multipaths under chaotic conditionsin a 9:30 simpledeterministic range-dependent waveguide. F. D. Tappert, M. G. Brown,andG. Goni (RosensteilSchoolofMarineandAtmospheric Z4. Spectral decompositionof parabolicequation fields. Kenneth Science,University of Miami,4600 Rickenbacker Causeway, Miami, FL E. Gilbert,Xiao Di, andDchua Huang(National Center for Physical 33149) Acoustics,University, MS 38677) Propagationis consideredin a simplerange-dependent waveguide Theparabolic equation (PE) methodhas an advantageover normal- consistingof a constantsound-speed gradient, g, overlyinga reflecting modeand fast-field program methods because it can easily handle a broad sinusoidalbottom. Let a andR denotethe amplitude and wavelength of classof range-dependentproblems. Normal-mode and fast field program thebottom sinusold. Previously it hasbeen shown [ F. D. Tappertand M. methods,however, do provideuseful information on the horizontal wave- G. Brown,J. Acoust. Soc. A•m. 83, 537 (1988) ] thatwhen y = 4•r:aco/Rg numberspectrum, while the PE methodgives only the total field. In some exceeds0.97 ray trajectories ex}i•B•t global chaos. Under such conditions, situations,such as upslope propagation, a spectral decomposition of the raytrajectories have an extreme sensitivity to initialconditions and envir- PE fieldinto horizontalwavenumber components is a valuabletool for onmentalparameters; they are freeto wanderwithout bound in angle- analyzingthe acoustic field. This papershows that for a PE fieldp(r,z), depthspace. Under suchconditions it is shownthat the numberofeigen- the spectraldecomposition •(r,r,z) canbe obtainedby solvinga one- raysconnecting a sourceand receiver on thebottom grows exponentially dimensionalelliptic equation. The derivation of thedecomposition equa- asthe separation between them increases. Meanwhile, the average intensi- tion is givenalong with a numericalmethod for solvingit. Numerical ty of the eigenraysdecays exponentially. The exponentialgrowth and examplesare given for severaltypical PE fields. decayrates are compared to the averageLyapunov exponent for the ray trajectories.These results vividly demonstrate that underchaotic condi- tionspredictability using ray theory is unattainable.

Z5. Effects of random-bottomtopography on the parnbolie- 10:30 approximationdetermination of acousticintensity. K. B. Mohrmann, M.J. Jacobson,and W. L. Siegmann(Rensselaer Polytechnic Institute, 7.8. Mode couplingcaused by a mesoscaleoceanic eddy. E. C. Shang Troy, NY 12180-3590) (C1RES, University of Colorado/NOAA/Wave Propagation Laboratory, Boulder, CO 80303) A modelis presentedfor stochasticvariations about a horizontal mean water-bottominterface below a shallowocean channel. A pressurerelease Fromthe full-wave theoretical point of view,there are two regimes for surfaceand a rigidbottom are taken as boundary conditions for solutions the interactionof acousticwaves with an oceanicmesoscale eddy: the of a parabolicapproximation to thewave equation, when sound speed is weakcoupling regime and the strong coupling regime. Understanding the depthdependent. A perturbation approach isused to generatea sequence limitsof thesetwo regimes is crucial for developing the new generation of of differentialproblems, the perturbation parameter being a measureof oceanacoustic tomography systems based on the full-wavetheoretical

S70 J.Acoust. Soc. Am. Suppl. 1, Vol. 85, Spring 1989 117thMeeting: Acoustical Society of America S70 frameworkinstead of raytheory. In thepresent paper, the mode coupling ceivermay lie acrossthe slopefrom eachother, rather than directlyup- causedby an oceanic mesoscale eddy is investigated by numerical simulat- slopeor downslope.Acoustic propagation in the 3-D wedgeis modeled ingon CYBER 205.The eddyis modeledas a Gaussianeddy with param- usingan extensionof the complexray methoddeveloped for the flat wave- eters:DR (horizontalscale), DZ ( verticalscale), ZE (centerdepth ), and guideand the 2-D wedge[E. K. Westwood,J. Acoust.Sec. Am. Suppl.1 DC (strength).By incorporatinga single-modestarting field into a 2-D 83, S79 (1988) and84, S90 (1988) ]. However,due to thephenomenon of PE (IFD) code,mode coupling coefficients are given by a modefiltering horizontalrefraction (the bendingof multiplyreflected rays when viewed processingafter passing through the eddy. Mode coupling coefficients are from above),each ray fieldin the 3-D wedgemust be expressed as a plane calculatedfor a frequencyrange of 10-100HZ, and a modenumber range waveintegral over two angular variables, rather than just one. Evaluation of 1-10. It hasbeen found that the modecoupling has a complex"reso- of the integralsinvolves finding complex saddle points, each of which nant feature"with eddy parametersand alsohas a dependenceon fre- consistsof a pair of anglesgiving the eigenraydirection. For raysthat are quencyas well ason modenumber. However, the limit of the weakcou- reflectednear the critical angle, numerical integration along the path of pling regime,within which the adiabaticmode theory is valid, can be steepestdescent must be performed; otherwise, a first-ordersaddle point drawnout but it is by no meansa simplecriterion. [Work supportedby approximationmay be used. The natureof the fieldin the 3-D wedgewill NOAA.] bediscussed, and possible benchmark problems will besuggested. [Work supportedby ONR contractN00014-87-K-0346. ]

10:45

Z9. Effect of subbottomroughness on VLF acoustic propagationfrom a seamount. Stanley A. Chin-Bing (Naval Ocean Research and DevelopmentActivity, NumericalModeling Division, StennisSpace 11:30 Center, MS 39529-5004) and JosephE. Murphy (Department of Physics,University of New Orleans,New Orleans,LA 70148) Z12. The useof multipathtime-delay estimation for sourcelocalization with passivebroadband sonar systems.Peter Bilazarian and David Recently,two range-dependentocean acoustic propagation and scat- J. Pistacchio(Raytheon Company, Submarine Signal Division, 1847 teringmodels based on the finite-element(FE) methodhave been devel- West Main Road, Portsmouth, RI 02871 ) oped:the Finite-element Full-wave Range-dependent Acoustic Marching Element (FFRAME) mode and the hybrid finite element/parabolic The employmentof multipathtime-delay estimation for acoustic equationPE-FFRAME model[J. E. Murphy and S. A. Chin-Bing,J. sourcelocalization with passiveautocorrelation and cross-correlation Acoust.See. Am. Suppl.1 84, S89-S90( 1988) ]. Thesemodels have been systemsis examined. Important differences in multipathtime-delay esti- appliedto simulatethe effectsof subbottomroughness on the very-low- mationwith widebandand narrower band systems are delineated. Several frequency(VLF) propagatedacoustic field at bothnear- and long-range algorithmsare presented that convert multipath time-delay estimates into distancesfrom a "seamount."The "seamount"is simulatedas an axisym- localizationquantities, such as source depth or range.Some algorithms metricfeature with gradualvarying slope. Examples are presentedthat presumean isospeedmedium, while another employs a procedureusing show the value of usingthese full-wave models(FFRAME and PE- thegeneric sonar model (GSM) andis applicable to a nonisospeedmedi- FRAME) overthe usualone-way parabolic equation model when exam- um.Examples from a varietyofmultipath environments are provided that ining such underwaterfeatures. [Work supportedby ONR and demonstrateconsistent improvement in localizationperformance with NORDA. ] the nonisospeedtechnique over the isospeed algorithms. Also, dramatic improvementsare reportedat rangesthat exhibita fairly complicated multipathstructure. A theoreticalcomparison of theperformance differ- encesas a functionof signal-to-noiseratio between a wavefrontcurvature rangingsystem and a multipathranging system is provided.Finally, ad- vantagesof combininglocalization information obtained from wavefront 11:00 curvaturesystems and systems which employ multipath time-delay esti- mation are discussed. Z10. A new split-step algorithm for solving acoustic propagation problems.David H. Bcrman,Evan B. Wright,and Ralph N. Baer(U.S. Naval ResearchLaboratory, Code 5160, Washington, DC 20375-5000) A newequation is proposed to mimic the one-way aspects oftbe Hclm- holtz equation.This new equationallows a split-stepsolution like the conventionalparab61ic equation (PE) does,and thus it canbe solved equallyfast. Moreover, unlike the PE, the raysassociated with high-fre- 11:45 quencysolutions of thisequation are exactlythe raysof the Helmholtz equation(even at high angles)for weakly range-dependentenviron- Z13. Coherent acousticfield computationsusing first-order multiple ments.For low-anglepropagation, the equation reduces the conventional scatteringand the genericsonar model. SusanM. Bates (MS 171, PE, andhence phases in thisregime are given correctly. For whatare now Raytheon Submarine Signal Division, 1847 West Main Road, standardtest cases, without severebottom interaction, this new split-step Portsmouth, RI 02871-1087) algorithmperforms as well or betterthan morecomplicated, and hence slower,one-way wave equation algorithms. [Work supportedby ONR. ] Thegeneric sonar model (GSM) ismodified to include,as an option, thecomputation of the coherentacoustic field in an oceanenvironment with internal waves.This modificationto GSM permitsestimation of coherentsignal processing performance. GSM computesthe acoustic pressurein a horizontallystratified ocean in theabsence of environmental inhomogeneitiesusing WKBJ solutionsto theHelmholtz equation. Using 11:lS the first-ordermultiple scattering approximation and the Garrett and Munk internal wave model, the coherentacoustic field is included in Zll. Propagation modeling in a three-dimensionalwedge using ray GSM forfrequencies from 100 to 10000 Hz. Resultsare presented using theory. Evan K. Westwood (Applied ResearchLaboratories, The University of Texas at Austin. Austin, TX 78713-8029) the modifiedGSM with internalwaves. Comparisons are madewith ear- lier results,which usedthe parabolicequation method [B. J. Batesand S. A usefulmodel for shallow-water,sand-bottom coastal regions is the M. Bates,J. Acoust.Soc. Am. 82, 2042-2050 (1987) ], and GSM without three-dimensional(3-D) wedge.Unlike the 2-D wedge,source and re- internal waves.

$71 J. Acoust.Sec. Am. Suppl. 1, Vol.85, Spring1989 117thMeeting: Acoustical Society of America S71 WEDNESDAY MORNING, 24 MAY 1989 ROOM 203, 9:00 A.M.

Meeting of AccreditedStandards Committee S2 on MechanicalShock and Vibration

to be held joinfly with the

TechnicalAdvisory Group (TAG) Meeting for ISO/TC 108Mechanical Vibration and Shock

S. I. Hayek, Chairman S2 AppliedResearch Laboratory, Penn State University, P.O. Box30, StateCollege, Pennsylvania 16801

D. F. Muster, Chairman,Technical Advisory Group for ISO/TC 108 4615 O'Meara Drive, Houston, Texas 77035

StandardsCommittee S2 onMechanical Sho•k and Vibration. Working group chairs will presentreports of theirrecent progress on writing and processing various shock and vibration standards. There will be a reporton theinterface of S2activities with those of ISO/TC 108(the Technical Advisory group for ISO/TC 108consists of membersof S2,S3, and other persons not necessarily members of thosecommittees) including plans for the nextmeeting of ISO/TC 108,to beheld in Milan, Italy in thespring of 1990.

WEDNESDAY MORNING, 24 MAY 1989 REGENCY B, 10:20 TO 11:55 A.M.

Session AA. Structural Acoustics and Vibration IV: Active Vibration Control

Gary H. Koopmann,Chairman Departmentof MechanicalEngineering, Pennsylvania State University, University Park, Pennsylvania 16802

Chairman's Introduction--10:20

Contributed Papers

10:•3 hasbeen studied. Real-time experimental results have been obtained from mountedvibrating structures, using a high-speeddigital signal-processing AA1. Adaptivevibration control for structuralmounting systems. Scott board to run the controlalgorithm. D. Sommerfeldtand Jiri Tichy (Graduate Programin Acoustics,The PennsylvaniaState University, Applied Science Building, Box 30, State College, PA 16804) It is often desired to isolate a sourceof structural vibration from sur- 10:40 roundingstructures. Typically, the vibratingstructure is attachedto the foundationvia someform of passive,flexible mount, asa meansof accom- AA2. A method for controlling radiation from compositeplates using plishing the desired objective.One weaknesscommon to all passive embeddedactive fibers.Koorosh Naghshinehand Gary H. Koopmann schemesis that they producerelatively little (or no) vibrationreduction (Noise Control Laboratory,157 Hammond Building, The Pennsylvania at thelower frequencies. Active control provides a meansof compensating StateUniversity, University Park, PAi 6802) for thisweakness to achievegood vibration isolation over a widefrequen- cy range.In thisstudy, adaptive closed-loop control has been combined A noveimethod ofactive control isproposed thatfocuses oncontrol- with passivecontrol to giveboth active reduction at thelower frequencies ling the acousticradiation of a compositeplate by directly altering its and passivereduction at the higherfrequencies. The adaptivenature of the material properties.By integratingactive clementswithin the plate, its controller allows the controller to convergeto the optimal solution,as materialproperties can be madeto be time dependentand thus,given a well asto trackany variations in thesystem parameters that mayoccur. A fluctuatingload, the materialproperties'can be activelyadjusted to pro- controllerhas been developed, based on the LMS algorithm,and investi- ducea minimumradiation condition. The controlmethod in this applica- gatedto determineits stabilityand convergenceproperties. As well, the tion can be best describedas being quasiactive.In this study, a finite mechanicalcoupling that occurswhen multiple control actuators are used elementmodel of a compositeplate madeof shapememory alloy fibers

S72 J. Acoust. Soc. Am. Suppl. 1, VoL 85, Spring 1989 117th Meeting:Acoustical Society of America S72 and epoxyis usedin conjunctionwith an acousticradiation model to aaismsof controlare discussed.The useof a flexuralpower-based cost predictthe effectiveness of using shape memory alloy fibers as a meansof functionis again demonstrated to be important in designingan efficient activenoise control. Initial resultsdemonstrate that the radiationcharac- controlstrategy. [ Work supported by NASA LangleyResearch Center. ] teristicsof a simplysupported plate comprising one side of anotherwise rigidrectangular box can be altered drastically by using the shape mem- ory alloy fibers.

11:25

10:55 AAS. Large area sensorsfor active acoustic control systems.Thomas AA3. Optimizationof placementof piezoelectricelements for the active R. Howarth, Xiaoqi Q. Bao, Vijay K. Vatarian, and Vasundra controlof platevibrations. Janice L Bayer,Vasundara V. Varadan,and V. Varadan(Department of EngineeringScience and Mechanics,The VijayK. Varadan(Department of EngineeringScience and Mechanics, PennsylvaniaState University, University Park, PA 16802) ResearchCenter for the Engineeringof Electronicand Acoustic The designand developmentof a compositepiezoelectric polymer Materials,The PennsylvaniaState University,University Park, PA (PVDF) sensorfor usein an activeacoustic control system are presented. 16802) Largearea PVDF platesare encapsulated in a polymermatrix to detect Activevibration control of structuresusing piezoelectric sensors and boththe incidentand reflectedsignals in an underwaterpulse tube at low frequencies.These signals are amplified,phase shifted, and thenused to actuatorsis explored.Finite element analysis providing theoretical pre- dictionsof theamplitudes of vibrationof each of a meshof nodesdistribut- drive an absorbingtransducer to negatereflections. The resultsof this ed over a plateis described.Statistical analysis of the predictednodal systemare compared with earlierdata [ X.-Q. Bao,V. K. Varadan,and V. amplitudesfurnishes an optimized scheme for theplacement of piezoelec- V. Varadan,J. Acoust.Soe. Am. Suppl. I 84, S49 (1988)] that utilized tric sensorsand actuators. Said scheme provides for theminimum number piezoceramicspherical hydrophones. [Work supportedby the Research of Sensorsand actuators needed to controlthe importantvibration. Gen- Center for the Engineeringof Electronicand AcousticMaterials. ] eralizationof thisalgorithm to the controlof othertypes of structuresis discussed.

11:40

11:10 AA6. Experiments on optimization of active control on a three- dimensional acoustic source. Jeffrey A. Giordano, Kenneth AA4. Furtherresearch on activecontrol of flexuralpower flow in elastic A. Cunefare,and Gary Koopmann (Noise Control Laboratory,The thin beams.Luc O. Gonidou and Chris R. Fuller (Departmentof PennsylvaniaState University, University Park, PA 16802) MechanicalEngineering, Virginia PolytechnicInstitute and State University,Blacksburg, VA 2406! ) in thisexperiment, a box-shaped,acoustic radiator has top andbot- tom platesIhat are arbitrarilydriven at their structuralmodes. The sides In a previouspaper, preliminary results on activecontrol of flexural of the boxconsist of six loudspeakersthat are usedas activesources. An powerflow in elasticthin beamswere presented [C. R. Fullerand L. O. acousticboundary element program is usedas the basisfor the active Gonidou,J. Acoust.Soc. Am. $uppi.i 84, S47 (1988)]. The workde- controlstrategy. The program,which allows active sources to bemodeled scribedhere will be concernedwith furtherexperimental and analytical at anyposition on the acoustic radiator, provides the magnitude and phase workon the same subject. In particular,the control of flexuralpower flow at whichto drive the activesources to minimizethe radiatedpower for a from finitebeams with variousterminating impedances and different prescribedfrequency and normalvelocity distribution on the plates.The lengthbeams is bothanalytically and experimentallystudied and direct platevelocity profiles were determined via experimentalmodal analysis. comparisonsare now made. Parameters such as discontinuity impedance, The radiatedpower measurements, which were performed in a calibrated bendingnearfield generation, and numberand locationof control actu- reverberationchamber, compared favorably to the theoreticalpredic- atorsand sensors are studied in lightof thenew test configurations. Mech- tions.

S73 J. Acoust.Soc. Am. Suppl.1, VoL85, Spring1989 117thMeeting: Acoustical Society of America $73 WEDNESDAY MORNING, 24 MAY 1989 REGENCY A, 10:45 A.M. TO 12:00 NOON

SessionBB. Physical AcousticsIV: General Topics

Michael R. Stinson, Chairman Divisionof Physics,National ResearchCouncil, Ottawa. Ontario KL4 OR6, Canada

Contributed Papers

10:45 20 Hz, a computationalaeroacoustics technique has been applied to the simulatedflow fieldofsuch an event.The theoreticaldevelopment reveals BBl. SHwavesin an inhomogeneouselastic solid. Hyun S. Kim and J. that the emitted infrasonicpressure is proportionalto the secondtime H. Ginsberg(School of MechanicalEngineering, Georgia Instituteof derivativeof the vorticitywithin the flow.Thus peakpressure levels occur Technology,Atlanta, GA 30332) duringthe rapiddeeeleration and radialoutflow developing as a micro- This paperconcerns the propagationof SH wavesin an inhomogen- bursttouches down upon the groundsurface. The frequencyspectrum eouselastic half-space subject to a distributedshear excitation on 'the free- failsat a rateof approximately6 dB perdecade. The computationalresults surface.The densityand second-orderelastic coefficient are assumedto are comparedto experimentalrecords of naturallyoccurring dcviateby smallamounts from thc average values, where such variations takenthroughout the year 1984,and supportthe point of view that in a are periodicfunctions of the coordinatenormal to the surface.Integral certainclass of theserecords the infrasound originated from atmospheric transformmethods arc usedto solvethe first-and second-orderequations microbursts. of motion,which are obtainedfrom striaghtforwardperturbation expan- sionof the displacement.Two casesof spatialdistribution of shearexcita- tion on the surfacearc considered;sinusoidal and Gaussiandistribution. When the shearexcitation is temporallyperiodic, it is shownthat the periodicinhomogeneity can cause secular solutions. In thesinusoidal dis- 11:30 tributioncase, either the first-or second-orderdisplacement becomes se- cularif thewavelength of thesignal and the periodicity of inhomogeneity BB4. Acousticwaves over a transpiringsurface. Yiping Ma, W. K. Van and of the spatialdistribution satisfy certain relations. In the caseof a Moorhem, and R. W. Shorthill (Department of Mechanical Gaussiandistribution, it is shownthat the second-orderdisplacement Engineering,University of Utah, Salt LakeCity, UT 84112) becomessecular when the wavelengthis twicethe periodicityof inhomo- geneity.[Work supportedby NSF.] An investigationof the effecton the acousticwaves due to wall mass injectionin a piston-drivenclosed-end test chamber has been conducted. Dry ice is usedas a sourceof massinjection. Acoustic pressure is mea- suredwith a pressuretransducer mounted at theclosed end. A compari- son with the resultswith no sidewall massaddition showsa significant 11:00 increasein the acousticpressure amplitude due to the interactionof the acousticwave and sidewall massinjection near resonance.A shift in the BB2. Amplificationof noisefrom liqald jets by entrainedgas bubbles. H. lowestresonant frequency between the two caseshas also been detected. S. Ribher (UTIAS, University of Toronto, Ontario M3H 5T6, Canada High-speedflow visualizationand hot wire anemometrymeasurements and NASA, Hampton,VA 23665) all suggestthat turbulencemay occur in the acousticboundary layer abovethe transpiringsurface. This, in turn, feedsmore energyinto the This studyreexamines turbulence-driven pulsations of gasbubbles in acousticwave. This increase in amplitudehas never been reported before submergedliquid jets. The expectationof largeamplifications--as much to the authors'best knowledge. [Work supportedby U.S. Air ForceAs- as !(P--of thejet noiseunder restricted conditions is confirmed. A macro- tronauticsLaboratory and Morton Thiokol, Inc. ] scopicview via the dilatationtheory of jet noiseand a microscopicview examiningindividual bubble pulsations both predict sound power ampli- ficationequals (liquid sound speed/mixture sound speed).4 This follows also from the classicaltreatment of Crighton and Ffowcs Williams (i 969). They relatedbubble monopole pulsations to Lighthill'sjet noise quadrupolesin terms of scalinglaws. Herein the bubblepulsations are 11:45 relatedto thoseof localliquid monopoles by a directamplification factor. BB5. At-seameasurements of underwatercavity resonanceusing a towed This factor is quantitativerather than order-of-magnitude:It provides catamaranplatform. S. A. Elder, L. G. Baker (U.S. Naval Academy, further insightinto the propertiesof the bubblyjet noise.Strong inward -Annapolis, MD 21402), and S. Yoshikawa (Sth Research Center, refractionis expected when the bubbles are confined to thejet, leadingto a TechnicalResearch and DevelopmentInstitute, Japan Defense Agency, focusedaxial lobe of enhancedemission. Both studiespostulate a stable Yokosuka,239 Japan} bubblepopulation, but, in real flows,bubble breakup and the violentcol- lapseof cavitationare prevalentand even noisier. Criteria for theiroccur- Earlierinvestigations in the USNA high-speedtow tank,using a 4.5-ft rence are discussed. towed model, had shown that large amplitude resonantoscillations can bc producedby flow over a wall cavity immersedin water. For this case,it wasfound that criticalspeed is predictablefrom a Strouhalnumber for- muladerived for resonantcavity oscillations in air. Currently,an attempt to measureradiation from an underwaterresonating cavity is beingmade, 11:15 usingthe sametowed model. Since "waveguide" cutoff of the tow tank is BB3. Infrasonicemissions from atmosphericmicrobursts: Theory versus aboveoscillation frequency, it hasbeen necessary to performthe measure- experiment. Allan J. Zuckerwar, Harlan K. Holmes, Jay C. Hardin mentsin deeperwater. For this purposea 17-ftcatamaran has been adapt- (NASA LangleyResearch Center, MS 238, Hampton, VA 23665), and ed for useas a towingplatform to makeit possibleto takemeasurements in D. Stuart Pope (PRC Kentron, Inc., Hampton, VA 23556) ChesapeakeBay. A YP classvessel, equipped for oceanographicresearch, isused for towing and for recording da,ta. For speeds up to 10kn,f• • and To demonstratethe existence ofinfrasonic emissions from atmospher- f•2 modeshave been detected at the expectedspeeds. Current results for ic microbursts,and to investigatetheir properties in thefrequency band 2- amplitudeand radiationwill be described.

S74 J. Acoust.Soc. Am. Suppl.1, Vol. 85, Spring1989 117th Meeting:Acoustical Society of America $?4 WEDNESDAY AFTERNOON, 24 MAY 1989 COMSTOCK A, 12:50TO 3:00P.M.

SessionCC. EngineeringAcoustics V: Materials' PropertiesEvaluation

Thomas R. Howarth, Chairman Departmentof EngineeringScience and Mechanics, Pennsylvania State University, University Park, Pennsylvania 16802

Chairman's Introduction•12:80

Invited Papers

12:58

CCI. Characterizationand developmentof transducerelastomers. Robert Y. Ting (Underwater Sound ReferenceDetachment, U.S. Naval ResearchLaboratory, Orlando, FL 32856-8337) The failureof underwatertransducers is oftenrelated to problemswith the materialsused, such as clas- tomers,ceramics, adhesives, coatings, and fill fluids.The general practice has been to select proprietary mated- als from differentcommercial sources, and usethem as they are availablefor the fabricationof a transducer. Suchpractices allow the designer very little controlof the qualityof the materials.The resultis the production of devicesthat aredoomed to fail becausethey are nonreproducible, or containmaterials incompatible to each other.In recentyears, improper choices of elastomcrhave been typical in causinglarge numbers of failurein sonartransducers. Research efforts at NRL-USRD havetherefore been focused on the developmentofcompo- sition-propertyrelationships for elastomersby usingwell-characterized samples. Instrumentational tech- niqueswere developed for the analysisof chcmicaland acousticalproperties. These techniques were subse- quentlyused for materialsevaluation and quality control. Based on theseresearch results, specialty elastomers were also successfullydeveloped for specifictransducer applications. [Work supportedby ONT and NAYSEA. ]

1:20

CC2. Characterizationof viscoelasticmateriais used to control underwatersound. Wayne T. Reader (Vector ResearchCompany, Inc., Suite 1200,690•3 Rockledge Drive, Bethesda,MD 20817) The controlof soundfields within confinedregions such as water-filledtanks may requirethe useof a combinationof threetypes of matedhals:one designed to absorbwaterborne sound, one designed to blockthe passageof waterbornesound, and one that dampsstructural vibrations. The mostfrequently used materials consistof viscoelasticpolymers containing voids or gasfilled inclusionsin volumefractions that are essentially zero for dampingmatedhals, are of the order 10% for absorbers,and that may approach90% for blocking materials.The empiricalcharacterization of thesevery different materials during their development or priorto theirinstallation is achieved with a varietyof apparatusand techniques. Typical forms of theseapparatus, the associatedprinciples of opera.tion, the physical properties that are measured, and limitations of thetechniques will be reviewed.Described will be proceduresfor obtainingthe mostfundamental property of underwater acousticalmaterials, viz., thecomplex modulus, the useof water-filledwaveguides to determinethe reflectivity and transmissivityof smallsamples at normal incidence,and measurementof the sameproperties on finite sizedpanels at obliqueangles. Finally, conlrary to commonwisdom, a procedureis proposedfor "scaling" acoustical materials.

1:45

CC3. Characterizationand analysisof vlscoelasticmaterials over wide frequencyand temperatureintervals. W.M. Madigosky(NSWC, 10901New HampshireAvenue, Silver Spring, MD 20903) Typically,the dynamicbehavior of matcrialsis a strongfunction of bothtemperature and frequency. An accurateknowledge of thedynamic properties over a wideinterval of temperatureand frequency is, therefore, essentialto theefficient design and engineering use of theviscoelastic phenomenon. Recently, both laboratory and commercialapparatus for making measurementsover the requiredlarge frequencyand temperature rangeshave become available. This paperreviews the current statusof the measurementtechniques. the useof theWLF timetemperature shift equation, and presentsdata on a numberof purematerials and polymer blends that illustratethe capabilitiescurrently available. Finally, the data maybe analyzedin termsof the fractional operatormodel that describesboth the storageand lossroodall with a singlecomplex equation. The adequacy of the model to fit the data will be discussed.

S75 J. Acoust.Soc. Am. Suppl. 1, Vol.05, Spring1989 117thMeeting: Acoustical Society o! America S75 2:10

CCA. Characterization of piezoelectric ceramics for high-power transducers. Paul Gonnard and Lueien Eyraud (Lab. de G6nie Electriqueel Ferro61ectricit•,Ins. Nat. desSciences Appliqu6es, 69621 Villeurbanne, France)

The choiceof piezoelectricmaterials for a high-powerelectromechanical conversion must take into ac- countvarious factors such as the figureof merit of the material(FOM), thestability of the electromechanical parameters,and thedielectric and mechanicallosses. Materials suitable for impact-typeigniters must present botha highFOM anda goodstability under repetitive shocks. For high-powerelectromechanical conversion, the FOM of a singlepiezoelectric bar andofa Langevin-typetransducer depends on the ratioof the piezoelec- triccoefficient d_•_• over the elastic compliance s•'• of thematerial. Without losses, the limiting factor would be the maximumdynamic stress at a vibrationmode. Methods for characterizingthe dielectricand mechanical lossesunder high driving level are given. The electromechanicalcharacteristics and losses of somenew compo- sitionsare compared with thoseof standard"hard" materials.An interpretationof the high-levelbehavior is giventaking into account a compensationof theoxidation state of manganeseduring cooling by a changein the valencyof thesubstitution ions. [Work supportedby DCAN.]

2:35

CC5. Evaluation of the property coefficientsof piezoelectric polymers. Donald Ricketts (Raytheon Company,Submarine Signal Division, Portsmouth, RI 02871-1087) Analyticalmodels are presentedfor evaluatingthe propertycoefficients of thick-filmpiezoelectric poly- mers. In particular,these models facilitate the evaluationof the complexelastic compliance coefficients svv,s•2, s:2, s•.•, and s• fromthe measured set of quantities{f,,,f•,f,,, •41,/1,},where f,, is theresonance frequencyof thetest specimenft

WEDNESDAY AFTERNOON, 24 MAY 1989 AMPHITHEATER, 1:00 TO 3:00 P.M.

SessionDD. ArchitecturalAcoustics II: Room Acoustics,Laboratory Measurements,Etc.

Angelo J. Campanella,Chairman CampanellaAssociates, 3201 RidgewoodDrive, Columbus,Ohio 43026

ContributedPapers

1:00 usuallyhad both (i) electronicsound masking and (ii) acousticallyhard screens,whereas the oppositewas usually found for the quieterworksta- DD1. Ambientnoise in openplan offices.J. B. Moreland (Westinghouse tions. Research and Development Center, 1310 Beulah Road, Pittsburgh, PA 15235)

This papersummarizes ambient noise data that werecollected in open 1:15 plan officesover the past2 years.The approachcentered on monitoring DD2. Propagationand reverberant phasein acousticalspaces. Lan Liu the noiselevel in emptyworkstations to establishsome statistics of the and Richard H. Lyon (Departmentof MechanicalEngineering, MIT, noisethat would be auditionedby a personsitting in that workstation Cambridge,MA 02139) duringa normalwork day. Offices both with andwithout electronic sound maskingwere investigated, as were offices with eitheracoustically hard or Systemswith low modaloverlap cannot support a "direct field" and acousticallysoft screens. It wasfound that the noiselevel in an individual havealso beenshown to have a phasetrend and correspondinggroup workstationincreases with the numberof peoplein this office.For the 25 delay that is far in excessof the expectedpropagation delay. The phase workstationsconsidered in thisinvestigation, the averagedaily noise level trend that is associated with this behavior has been termed "reverberant in a workstationranged from 42.2-58.6 dBA. The noisierworkstations phase."The reverberantphase also shows up in systemswith highmodal

S76 J. Acoust.Soc. Am. Suppl.1, VoL85, Spring1989 117th Meeting:Acoustical Society of America $76 overlap,but in such systems, the phase of the direct (or propagation)field Computersimulation can be used to generatethe spatial and temporal is expectedto alsobe present.If the effectsof reverberationcould some- data describingacoustical behavior. By usingcomputer graphics to dis- howbe subtracted from the data, one would expect to see the propagation playthe multidimensional data, substantially greater amounts of informa- phase.In thispaper, a procedurefor thedecomposition of propagation tion than conveyedby standardtechniques can be communicatedto the andreverberant phase components from a receivedsignal is presented, designer.A methodologyis presentedfor evaluatingan acousticalenvi- usingproperties of thecomplex eepstrum. These ideas are tested experi- ronmentusing a two phaseapproach. The firstphase entails simulating mentallyusing data from transferfunctions for smallacoustical cham- the time varyingspatial distribution of soundenergy, using techniques bers.Directions for futurework on this topicwill alsobe discussed. similarto thoseused in computergraphics to modelillumination. These [ Worksupported by NTT Researchand Development Center. ] techniques,specifically probabilistic geometric ray tracingand reflection modeling,have been highly refined.By modifyingthese methods to ac- countfor a fewbasic differences between light and sound, they can be well suitedto thesimulation of soundpropagation. The secondphase entails an investigationof techniquesof displayingmultidimensional data that are usefulto theuser. These techniques, which include the use of three-dimen- 1:30 sionalcolor imagegeneration, animation, and icon representation,are DD3. Measuring and using the impulse responseof a room. E. used to visualize acoustical measurements derived from the simulation Paul Palmer and David A. Berry (Department of Physics and data.Using these criteria, three variations in the designof a performance Astronomy,Brigham Young University, Provo, UT 84602) hall areevaluated and compared. [Work supportedby NSF.]

The point-to-pointimpulse response of a roomis a recordofthe impul- sivesound from a singlesource to a singlemicrophone. Different systems andsignal-processing methods may be usedin this measurementdepend- ing on the accuracyrequired. if only the time historyof major echoesis 2:15 desiredin ordarto trace(and correct) reflecting surfaces, the energy-time DD6. Standard measurementof soundtransmission through suspended curveof a time-delayspectrometer system is excellent.An m-sequence ceilings..LD. QuirtandR. E. Halliwell(AcousticsSection,lnstitutefor signal,with its speedof processing,is versatilefor a homebuiltPC-based Research in Construction, National Research Council of Canada, systemand comescloser to a true impulseresponse. For an impulsere- Ottawa, Ontario K 1A 0R6, Canada) spouseadequate for convolutionwith a signal,in orderto accuratelysim- ulate a room, more care is required.The poor frequencyresponse and Soundtransmission through the spaceabove the suspendedceiling directionalityof the loudspeakermust be nullifiedto reduceit to a "per- commonlylimits insulationbetween offices where intero•ice partitions feet"point source. A computer-basedsystem to approachthis ideal will be do not extendabove the suspendedceiling. This paperpresents a detailed described.Further, a real sourcemight be an orchestrarather than a comparisonof standardtest methodsfor evaluatingsuspended ceiling point,and the usual receiver has two ears.Research to graphicallydisplay performance.A laboratoryhas been constructed that can readilybe con- a binaurallyrecorded impulse response and to deconvolveearphone char- vertedto satisfyrequirements of ISO Standard140 Part 9, or a corre- acteristics(as wasdone with the loudspeaker)will be reported. spondingASTM draft standard,or the AcousticalManufacturers' Asso- ciation standard (AMA I-II) from which these descended. Characteristicsof the test environment have beenstudied, and a seriesof suspendedceiling systems have been tested using all threestandard meth- ods.Significant differences and their causeswill be discussed.

i:45

DD4. The role of the mieroi•honein parametrizJngthe acousticsof three rectangularconcert spaces. J. M. Mastracco(School of Engineering, 2:30 RensselaerPolytechnic Institute, Troy, NY 12181and WRPI-FM 91.5, Troy, NY 1218l) DD7. Sound transmissionmeasurements through concrete block walls with attacheddrywall layers. A. C. C. Waroock (Institute for Research The scientificmethod is a principlethat statesthat no theoryor model in Construction, National Research Council, M27 Montreal Road, of natureis tenable,unless the resultsit predictsare in accordwith experi- Ottawa, Ontario KIA 0R6, Canada} ment.The concerthall, as a physicalsystem, has long been misunderstood in termsof theeffects it hason acoustics. This paper discusses the applica- Soundtransmission through a seriesof concreteblock walls was mea- tionof thescientific method to themeasurement of acousticalparameters suredin a reverberationroom according to ASTM E90.The measurement in threerenowned spaces: Boston Symphony Hall, the Troy MusicHall, frequencyrange was extended down to 63 Hz. The effectsof themethod of and the Union CollegeMemorial Chapel. The resultsof the experiments attachingthe drywall and of addingsound absorbing material to the cav- stronglysuggest that no characterizationof a hall'sacoustics is possible ity wereinvestigated during the series.The seriesproduced a reasonably without the specificationof the microphoneused in the measurement. well-behavedset of data evenat the lower frequencies.As expected,in- Microphonesranging from a I/2-in. omnidirectionaltransducer to an creasingthe depth of the cavity and addingsound absorbing material acousticmanikin employinga l/2-in. omnidirectionaltransducer pro- moved the mass-air-massresonance to lower frequenciesand usually duceclearly identifiabledifferences in reverberationtimes and other wide- improvedthe soundtransmission class rating. The highestsound trans- ly usedparameters that are calculatedfrom the transientresponse of the missionclass measured was 73. Becauseof the extendedrange of the space.These results suggest, contrary to thebelief of many,that acoustical measurements,reductions in the low-frequencytransmission loss values scienceapplied to concerthalls is not an exact science, but pathological in werequite evident. A simplemethod of predictingthe resultsobtained character.It is concludedthat acousticalcomparisons between different will be presentedand its extensionto other casesdiscussed. spacesare not possibleunless the type of microphone,as well asits place- mentand orientation in thespace, are specified. [ Work supportedin part by the Audio EngineeringSociety Education Foundation. ]

2:45

DD8. Transferfunction method for measuringcharacteristic impedance 2:00 and propagation constant of porous material. Hideo Utsuno (Department of Mechanical Engineering, University of Kentucky, DD5. Computer graphics for acoustic simulation and visualization. Lexingtnn,KY 40506-0046and Applied MechanicsCenter, Kobe Steel, Adam Stettner (Program of ComputerGraphics, Cornell University, Ltd., Takatsukadai I-chome Nishi-ku, Kobe, 673-02, Japan}, Ithaca, NY 14853) ToshimitsuTanaka, TakeshiFujikawa (Applied MechanicsCenter,

S77 J. Acoust.Soc. Am. Suppl. 1, VoL85, Spring1989 117thMeeting: Acoustical Society of America S77 KobeSteel, Ltd., Takatsukadail-chome Nishi-ku, Kobe. 673-02,Japan), developedmethod of determination,called the transfer function method, and Andrew F. Seybert (Department of Mechanical Engineering, canbe applied.An appropriateset of air spacedepths is alsodiscussed. Universityof Kentucky, Lexington,KY 40506•046) Glasswooland porous aluminum were used to assessthe usefulness of the presentmethod. The normalacoustic impedance and normal absorption coefficientof the test materialswith arbitrary thicknessesor with an arbi- A methodfor measuringthe characteristicimpedance and propaga- trary air spacedepth were calculated from the obtainedcharacteristic tion constantof porousmaterials is described.Measurements were per- impedanceand propagationconstant, then they werecompared with the formedbased on a surfaceimpedance method that requireda setof dis- measuredvalues that were obtaineddirectly usingthe transferfunction tinct acoustic impedancesderived at the material surface. This method.The goodagreement achieved suggests that thepresent method is requirementis satisfied by arbitrarilychanging the air spacedepth behind reliableand effective enough to measurethe characteristic impedance and the material,and then a new formulationis derivedso that a recently propagationconstant over a broadbandfrequency range.

WEDNESDAY AFTERNOON, 24 MAY 1989 REGENCY B, 1:00 TO 3:00 P.M.

SessionEE. Musical AcousticsIII: General Topics

Donald E. Hall, Chairman PhysicsDepartment, California State Uniuersity,6000 J Street,Sacramento, California 95819

Contributed Papers

1:00 1:15

EEl. Efficient real-time musical spectrum analyzer using DSP chip. EE2. Computer simulation of the guitar, work in progress. Harold William F. McGee (Departmentof ElectricalEngineering, University of A. Zintel (AcousticsDepartment, Pennsylvania State University, State Ottawa, Ottawa, Ontario K I N 6N5, Canada) College,PA 16801)

A 72-notetranscriber for polyphonicmusic has been realized. A Texas The guitarwithout strings is modeledby the displacement response of InstrumentsTMS320C25 digital signalprocessor operating with a 40- the bridgeand the pressureresponse at an observerlocation due to an MHz clock( 100-nsinstruction times) has been programmed to providea impulseforcing function at thebridge. The modelthus entails nine unique musical spectrum analyzer. The analyzer is a bank of 72 filters, tuned to impulse responsefunctions, six for combinations of impulse directions the frequenciesof westernmusic. Each filter has a transferfunction of and displacementresponses and three for the observerlocation pressure unity at its centerfrequency and a zeroat the 71 other frequencies.Due to due to each di•ction of the impulse direction. These nine impulse re- the design,only 14 instructionsper filter per sampleare needed.Logarith- sponsesare obtainedexperimentally. A finitedifference approach is used mic responseof eachfilter is computedat a slowerrate, onceevery 72 to modela stringand its interactionwith the instrument.The observer samples.Response times appear adequate to permittranscription of poly- pressurelevels predicted by the programare plottedas a waterfall spec- phonicmusic. Postprocessing to removeweaker notes a semitoneaway is trum and alsosent to headphonesby way of a D/A conversion.By con- found to improve the transcriptioncapabilities, whereas removing par- ducting modal analysisof the guitar, the effect of modificationsto the tials doesnot appear to offer as much improvement.The transcriberis structureof the instrumentcan be estimated.Further, analyzingthe new testedby passingthe output to a MIDI synthesizer.Synthetic music is modal parametersusing an acousticboundary element method (CHI), reasonablyaccurate, other music is usuallyrecognizable; further postpro- the impulsepressure response can be estimated. The final result,when the cessingwill improve performance.[Work supportedby BNR and projectis complete,is a tool Ihat can be usedto predictthe soundof a NSERC. ] particularinstrument after structuralmodifications.

S78 J. Acoust.Soc. Am. Suppl. 1, Vol.85, Spring 1989 117thMeeting: Acoustical Society o! America $78 1:30 2:15

EE3. Statistical energy analysis modelingand testing of an acoustic EE6. Musical pitch trackingbased on a patternrecognition algorithm. guitar. Daniel J. Hosek and Glen E. Johnson (Department of JudithC. Brown (Media Laboratory,MIT, Cambridge,MA 02139 and MechanicalEngineering, Box 8-B, VanderbiltUniversity, Nashville, TN Departmentof Physics,Wellesley College, Wellesley, MA 02181) 37235) It canbe shown that, whenthe Fouriertransform is plottedagainst log Principalsof statisticalenergy analysis (SEA) wereapplied to devel- frequency,the patternobtained in the frequencydomain is the samefor opa mathematicalexpression for thetime-averaged, space-averaged ener- anysound with harmonic frequency components. A constant Q Fourier gyof vibrationin specifiedfrequency bands for thetop plate of an acoustic transformhas been calculated for frequenciescorresponding to a musical guitar.The modelpredicted energy in termsof stringparameters, guitar quartertone and plotted against log frequency. The resultingpattern can parameters,and plucking data. Primary assumptions were that thedamp- be "tracked"using cross correlation to givethe musicalpitch. Excellent ingof thestrings was negligible, that energy flowed from the strings to the resultshave been obtained for a varietyof instrumentsincluding the vio- resonancebox, and that energywas dissipated in theresonance box. Pow- lin, flute,and piano. [Work supportedby a BrachmanHoffman Fellow- er suppliedto the stringswas estimated from a classicalmodel of the shipfrom Wellesley College. ] vibratingstring. An experimentalplucking apparatus was designed and instrumentedwith Bruel& Kjaer vibrationanalysis equipment. The re- sultsof the SEA-basedcomputer program were compared to actualex- perimentaldata for •i YamahaFG335 acoustic guitar. The SEAmodel tendedto overpredictthe energy in the topplate in mostfrequency bands. Possible causes for the differences were identified and discussed. 2:30

EE7. Effectsof precedingscale on melodicpitch intervaljudgment. Minoru Tsuzaki (ATR Auditory and Visual PerceptionResearch Laboratories,lnuidani, Seika-cho,Kyoto 619-02, Japan) To investigateinteractive aspects of musicalscale systems and pitch intervalsin humanmusical cognition, the melodicpitch intervalwas 1:45 judgedin threepreceding scale contexts: (a) diatonic,(b) chromatic,and (c) noscale. Subjects compared standard and comparison pitch intervals EE4. Statistical data modelingapproach for determiningthe acoustic usingthree response categories: "small," "equal," and "large." Standard impedanceof musicalinstruments. Gerald J. Lemay (Electrical and intervalsbegan with noteB, or noteC, andascended by 100,150, or 200 Computer Engineering Department, SoutheasternMassachusetts cents.A "start noteeffect" is the mostprominent for the 200-centstan- University,North Dartmouth, MA 02747) dardin thediatonic context. When it beganwith noteB, i.e.,a leadingtone in a diatoniccontext, a peakin the "equal"response histogram disap- Recenttheoretical models [M. E. Mcintyre etal., J. Acoust.Soc. Am. peared,and the boundary between "small" and "large" response moved 74, 1325-1345(1983) ] for the oscillationmechanism of musicalinstru- far awayfrom its musically equal point. For the 100-centstandard, judg- mentshave utilizedan analyticclosed-form relationship between the mentswere rather more precise in theC startcondition than in theB start Green'sfunction g(t), the reflectionfunction r(t), and the acousticim- condition,irrespectively ofthe scale context. For the 150-centstandard, a pedanceZ o (whichmay also be time varying). Given two of thethree "startnote effect" was not observedclearly in anyscale context. Detailed quantities(g(t), r(t), Zo},the method used to findthe third function discussionisprovided on the role of thediatonic scale system as a referen- usuallyinvolves the discreteFourier transform. This paperpresents an tjulframe in viewof twoaspects of pitchinterval judgement, that is, size alternateapproach to theproblem of estimatingZ•, from measurements of andequality relationship. g(t) and r(t). Statisticaldata modelingin the contextof digitalfilter designprovides a solutionthat doesnot requirethe computationof a discreteFourier transform.It is shownthat the acousticimpedance is the impulseresponse of the cascadeof two digitalfilters whose coefficients minimizethe fitting error between an (M,N)th ordermodel and the ob- 2:45 servedsequences. EES. Adults' perceptionof Westernand Javanesemusical scales. Michael P. Lynch, RebeccaE. Eilers, and D. KimbroughOller (Departmentsof Psychologyand Pediatrics, University of Miami,P.O. Box 016820 (D-820), Miami, FL 33101) A cognitive/perceptualmodel of theprocessing of musical intervals wasinvestigated byassessing the role of experience with Western music in 2:00 perceptionofmistunings in both Western and non-Western scales. Musi- EE5. Model-basedtrumpet tone synthesis. Paul H. Dietz (Department callyinexperienced subjects, persons with limited background in music, andprofessional musicians heard seven-note major, minor, and Javanese of Electricaland ComputerEngineering, Carnegie Mellon University, pelogmelodies. Each of the melodies contained successively thefirst, sec- Pittsburgh,PA 15213) ond,third, fourth, fifth, third, and first pitches of eachscale, with thefirst [n an effortto producerealistic trumpet tones, a detailedmodel of the andlast pitches always D4 (293.66Hz). Thefrequency relationships of dynamicsof theinstrument and the player was created. The trumpetwas thepelog scale were maintained within this framework. Each melody was modeled as a collection of linear circuit elements to account for the effects alteredin twoways. First, the toppitch (A4, 440 Hz in majorand minor; of the mouthpiece,tubing, bell, and radiationimpedance. Testing was 461.3Hz in pelog)was raised along a continuumin ten0.4% steps. Sec- performedusing both impulseresponse and equivalentlength measure- ond,any pitch but the first was randomly selected for sharpening at each ments,verifying the accuracyof the model.The modelof the playerex- of ten0.5 % steps.PEST was used to estimatethe smallest degree of pitch tendsfrom the lungs through the lips and contains both linear and nonlin- raisingon thesecontinua that subjects could reliably perceive for each ear elements. The two nonlinearities are due to the inelastic collision of the scaletype. As predictedby the model, results indicate a strongrelation- lips,and the impedanceof the lip opening.These models were computer shipbetween musical training and perception of tuning alterations in the simulatedvarying three control parameters: the springconstant of the Javanesescale. Musically sophisticated subjects had equalperceptual upperlip, the forcekeeping the lipsclosed (which can also be thoughtof thresholdsacross the three scaletypes. Musically naive subjectshad a as an offsetinthe spring'szero position),and the pressurein the lung. perceptualadvantage for Western scales. Patterns of subjectresponding Listenersreport that the resultingsimulated tones are quire realistic. diff,:redslightly when pitches were randomly selected for sharpeningas Thesetones demonstrate many of the attributesof real trumpet tones, opposedto when only the top pitch was raised. [ Work supported by Am. includingthe tendency to lock onto the same notes in theharmonic series. Psychol.Assoc. ]

$79 J. Acoust.Soc. Am. Suppl. 1, Vol.85, Spring 1989 117thMeeting: Acoustical Society of America S79 WEDNESDAY AFTERNOON, 24 MAY 1989 GOLDSTEIN AUDITORIUM, 1:00 TO 3:00 P.M.

SessionFF. Noise V: Noise Control and Effects (PosterSession)

M. G. Prasad, Chairman Departmentof MechanicalEngineering, Stevens Institute of Technology,Castle Point, Hoboken, New Jersey07030

ContributedPapers All posterswill beon display from 1:00to 3:00p.m. (Viewinghours will alsobe extended into the evening andthrough noon on Thursday.)To allowcontributors an opportunityto seeother posters, contributors of odd-numberedpapers will beat theirposters from 1.'00to 2:00p.m. andcontributors of even-numberedpapers will beat their postersfrom 2:15to 3:00p.m. Contributorsare encouragedto leavetheir postersin placeuntil 12.00 noon on Thursday.A cashbar will be set up in the eveningto facilitateinformal discussion.The GoldsteinAuditorium will be closedat 10:00p.m. and reopenon Thursdaymorning.

FFI.Application ofan acoustic noise synthesis tec[•nique inthe design of vestigated.The lining is assumedto be anisotropic,bulk rescling,and a ductsystem. M. G. Prasad(Department of MechanicalEngineering, coveredby a thin imperviousmembrane. The effectof flowfor low Math StevensInstitute of Technology,Castle Point, Hoboken, NJ 07030) and numbersis alsotaken into account.Frequency averaging within octave T. V. Ananthapadmanabha(AT&T Bell Laboratories,600 Mountain bandsis usedto produceuseful design curves. Limited comparison Avenue,Murray Hill, NI 07974) betweenprediction and measurement will bereviewed and is encouraging. This paperdiscusses the applicationof acousticnoise synthesis (ANS) for the designof a duct system,specifically, a mufflersystem. ANS isbased on well-known principles of speech synthesis using a source- filtermodel. The designer can use an ANS techniqueto studythe influ- enceof designparameters of theduct system on the perceptual quality of noise.This approachis usefulin studiesrelating to perceptualloudness FF4. Physiologiceffects of environmentalnoise and talking in coronary criteriaand noisecontrol. The modelconsidered in thisstudy is a plane- care patients.Carol F. Baker (Collegeof Nursing,The Ohio State wave white Gaussiannoise source, a simpleexpansion chamber-type University,1585 Nell Avenue,Columbus, OH 43210) muffler,and an open-endtail pipe.The systemtransfer function is ob- tainedbased on the transmissioncoefficient expression derived from the The purposeof the studywas to describechanges in heart rate and chainmatrix. Impulse response ofthe system is obtained by the applica- bloodpressure in patientswith acutemyocardial disease when exposed to tionof an inverseFFT. The impulseresponse is convolved with the source noiseand talking in the environment.A conveniencesample of ten adult signalto obtainthe systemoutput in the timedomain. The outputfed patientsadmitted to an 18-beduniversity hospital CCU wereselected as througha digital-to-analogconvertor and a loudspeakeryields the simu- subjects.Private rooms separated patients from an opennurses' station. lated acousticnoise. This simulationprocedure can be appliedfor any Sound-pressurelevel and content of soundswere measured with a Bruel& givenmodel for source-mufflertermination. The advantageof acoustic Kjaertype 2230 sound level meter; the microphone was placed above the noisesynthesis is that the source-mufflerinteraction, muffler design head of the bed. Heart rate and ECG from the bedside monitor were changes,and the effects of boundary conditions can be simulated based on recordedsimultaneously with dBA and soundon a TEAC R-61 physio- theoretical models. logictape recorder and later printed onto a 2600SGould chart recorder. Bloodpressure was measured every 5 rain with a Dinamap.Data collec- tionoccurred during four 45-rain periods on twoconsecutive days. Mean sound-pressurelevel of noise sourceswere: toilet flush--76 dBA, alarms--66 dBA, talkinginside the room--65 dBA, and ambients49 dBA. Repeatedmeasures ANOVAs compared noise sources, content of FF2. Noise control in microelectronics clean rooms. Colin G. Gordon conversation,and rolesof peoplewith changesin deeibel,heart rate,and and Amir M. Yazdanniyaz (BBN Systems and Technologies bloodpressure. Short bursts of noiseshowed the greatest mean change in Corporation,21120 VanowenStreet, Canoga Park, CA 91303} maximumdBA, followedby talking of nursesor doctorsinside the room. Heartrate changes were greater when family talked. Mean arterial pres- Modem cleanrooms of the sort usedby the microelectronicsindustry surewas higher during talking and background noise. [Work supported may entail600 air changesper hour. They pose,therefore, unique noise by a UniversitySeed Grant. ] controlproblems. These problems are exacerbatedby the fact that con- ventionalacoustically absorbent materials cannot be used within the clean room.In this paper,some typical sound data that havebeen measured in cleanrooms are presented.Also discussedare the noisecriteria that are desirablefor personnelworking within the spaceand for sound-sensitive equipmentthat may occupythe space.Some practical ideas for noise controlare suggested. FF5. Efficiency of absorbentlayers on barrier. Andr6 L'Esprrance (Groupe d'Acoustiquede I'Universit6de Sherbrooke,Drpartement de Grnie M•canique,Universit6 de Sherbrooke,Sherbrooke, Qurbec JIK 2RI, Canada) Thispaper presents a reelhod for calculatingthe insertion loss of bar- FF3. Duct attenuationwith bulk reactinglining. David A. Biesand Colin riershaving the sourceside, the receiverside, or both sidescovered with H. Hansen (Departmentof MechanicalEngineering, University of an absorbentmaterial. In this method,the approximatesolutions for dif- Adelaide, GPO Box 498, S.A. 5001, Australia) fractionover an absorbentwedge proposed by Koersis combinedwith a classicalmodel of soundpropagation over an impedanceground. Theo- Attenuationof lowest-ordermodes in linedstraight ducts of bothrec- reticaland experimentalresults are comparedfor variousgeometrical tangularand circular cross section is analyticallyand experimentally in- configurations.andbarrier surface conditions and confirm the accuracy of

S80 J. Acoust.Soc. Am. Suppl. 1, VoL 85, Spdng 1989 117thMeeting: Acoustical Society of America $80 the methodproposed. This studyhas enabled one to •liscoverthat it is sidesof the barrier,an absorbentcovering will reducethe diffractedfield, moreefficient to placethe absorbentcovering on thesurface of the barrier no matter if it is placedon the sonteeside or on the receiverside. These associatedwith the most important angles of diffraction(source top edge resultsexplained various conclusions found in literatureabout the useful- and/or receivertop edges). When these angles are about the same on both nessof absorbentbarriers compared to hard barriers.

WEDNESDAY AFTERNOON, 24 MAY 1989 REGENCY A, 1:00 TO 3:00 P.M.

SessionGG. Physical AcousticsV: Relaxation, Sonic Booms,and Propagation

Richard Raspet, Chairman Departmentof Physicsand Astronomy,University of Mississippi,University, Mississippi 38677

ContributedPapers

1:00 1:30

GG1. Propagationof soundin vibrationallyexcited N2/CO and CO/H_, GG3. Propagationof nonlineartransients, such as sonicbooms, through mixtures.Timothy H. Ruppeland F. DouglasShields (Department of an absorbingand relaxing atmosphere.1ongmin Kang and Allan Physicsand Astronomy,The Universityof Mississippi,and the National D. Pierce (Noise Control Laboratory and Graduate Program in Centerfor PhysicalAcoustics, University, MS 38677) Acoustics,Pennsylvania State University, 157 Hammond Building,State College, PA 16804) Measurements of the resonant reverberation of sound in a tube con- taining N2/H 2, N_,/He, N2/CH 4, and N2/H_•O mixtureshave shownan Recentresurgence of interestin sonicboom propagation through the amplificationof the soundfollowing a rapid excitationof the gasby an atmospherenecessitates detailed understanding of how absorption,relax- electricdischarge [F. D. Shieldsand L. D. Lafleur,J. Acoust.Soc. Am. ation, ray focusingand defoeusing,and nonlinearsteepening interact. 83, 2186 (1988) ]. This effecthas been named SACER (sound amplifica- Previouslyused techniques, such as by Bassel al. (1983) for simulta- tion from controlledexcitation reactions). This paper reportssimilar neouslytreating molecularrelaxation and nonlinearpropagation, al- measurementsin N2/CO mixtures,and alsoreports preliminary results thoughyielding important insights, have required extensive computation from measurementsin CO/H,mixtures. It hasbeen possible in thepast to time and havebeen limited to simplesource models. The presentpaper determine vibrational relaxation times and relaxation times for the con- givesthe extensionof Burger'sequation, with relaxationincluded, to ductionof translationaland vibrationalenergy to the tubewall from the propagationthrough inhomogeneous atmospheres using the weddingof changesin the translationaltemperature in the gasfollowing the electric nonlinearpropagation and ray acousticssuggested by Hayes.It isargued discharge.In the work reportedhere, these rates have been confirmed by that, in the absenceof shockformation, and for loweramplitude wave- direct measurementof the decay times of the CO infrared emission. forms,relatively large step sizes may be usedwith nonlinearsteepening, [Work supportedby ONR.] dispersion,and absorptiontreated as additiveeffects, the former being easilyhandled using the implicit exact solutionof the inviscidBurger's equationthat incorporates the concept of an agevariable. After something that resemblesa shockappears, nonlinear effects, relaxation, and absorp- tion mustall be simultaneouslyconsidered in the computationof wave- form detailsover the narrow risetimeof the shock,but a perturbation techniquebased on the methodof multiplescales .shows promise of cut- 1:15 ting down the computationtime. [Work supportedby NASA-LRC and by the William E. Leonhardendowment to PennsylvaniaState Universi- GG2. Acoustic absorption in high-temperature gas mixtures of ty.l atmosphericconstituents. Wallace George(Noise Control Laboratory, PennsylvaniaState University, University Park, PA 16802)

Experimentaldata on acousticabsorption at high temperatures(up to 1000 K) due to vibrational molecularrelaxation are presentedfor gas mixturesprO2, N2, CO2,and H,_O. These absorption tests represent some of the first acousticalmeasurements in gas mixtures at theseelevated 1:45 temperatures.These data are compared with the predictedresults of the GG4. Extended Huygens-Kirchhoff method for predicting transient matrixformalism for soundabsorption in multicomponentgas mixtures, sound propagation through inhomogeneous moving media. due to molecular relaxation. This formalism, which is based on irrevers- Spiro Kouzoupisand Allan D. Pierce(Graduate Program in Acoustics, ible thermodynamics,was utilized by Bauer,Bass, and others. The litera- PennsylvaniaState University, 157 HammondBuilding, State College, ture was examinedto determinethe temperaturedependence of the var- PA 16804) ious empirically derived energy transfer rates requiredby this model. Someof therates were adjusted to correspondwith thecurrent data. This The linear acousticsequations for when the ambientmedium has in- meansthat the empiricalrate constantsare adjustedbased on high-tem- homogeneousflow yield an integralcorollary analogous to that originally peratureacoustical tests, rather than on lessreliable shock tube data. derivedby Helmholtzfor the reducedwave equation and by Kirchhofffor

$81 J. Acoust.Soc. Am. Suppl. 1, Vol.85, Spring1989 117thMeeting: Acoustical Society of America S81 the waveequation. Such a corollaryinvolves a Green'sfunction for the measurements.Tile measurements aredifficult because high atmospheric ambientmedium that is here approximated using the eikonal approxima- sound-pressurelevels (80-90 dB) arenecessary for goodsignal-to-noise tion followingthe techniqueof Sommerfeldand Runge.The corollary in the acoustic-to-seismiccoupling ratio measurements;the LDV also enablesone to predicttransient waveforms at distantpoints from informa- coupleswith the soundfield. Good agreement has been reported among tion prescribedover a surfaceand improvesupon ordinary geometrical geophoneand LDV measurementsof verticalground velocity for an im- acousticsin that it canaccount for the presenceof causticsin the interven- pulsiveatmospheric sound source and adequate agreement for a cw sound ingspace. Huygens' principle is realized by this corollary and geometrical sourcein thefrequency range 100-500 Hz. Useof theLDV for ground- acousticsand parabolic equation approximations arise as limiting cases. geophonecoupling measurements, also pertinent in seismology,will be Numericalexamples are givenfor somesimple cases of flowsand the use discussed.[Work supportedby ONR.] of the overalltechnique to exploresonic boom propagation in the turbu- lent atmosphereis outlined.Although the Green'sfunction is approxi- mate, the relationis a goodapproximate technique for advancingthe overallfield over moderate distances, without having to explicitlyconsid- er the fieldat intermediatepoints. [Work supportedby NASA-LRC and by the William E. Leonhardendowment to PennsylvaniaState Universi- 2:30 ty.] GG7. Surfacewaves above porous ground surfaces. G. A. Daigle (Divisionof Physics,National Research Council, Ottawa, Ontario K IA 0R6, Canada)

2:00 In atmosphericacoustics, the subject of surfacewaves has been an area of discussionfor manyyears. Theory for sphericalwave propagation GG5. Anomalies in backscatteringon large-scale inhomogeneities. abovean impedanceplane describes the reflectedfield as a branchline YevgenyG. Schhemelev(Department of Radiophysics,Gorky State integral(ground wave) with the possibility of a contributionfrom a pole. University, Gorky, USSR and Sibley School of Mechanical and The contributionfrom the polepossesses the standardproperties for a AerospaceEngineering, Cornell University, Ithaca, NY 14853) surface wave. Ground waves exist becausecurved wave fronts strike dif- ferentparts of thesurface at differentangles of incidenceand because the The backscatteredfield is investigatedunder conditions such that the reflectioncoefficient is also a functionof angleof incidence.Surface waves planemonochromatic wave falls on a layerof chaoticstatistically isotrop- existwhen the surface is sufficiently porous, relative to itsacoustical resis- ic inhomogeneities.It is shownthat the mainpart of the receivedsignal tance,that it can influencethe airborneparticle velocity near the surface comesfrom a specificdirection a (determinedby geometryand scale), if and reducethe phasevelocity of soundwaves in air at the surface.This the backscatteringsignal is receivedby a directedantenna and the condi- trapssome of the soundenergy in the air, regardlessof the shapeof the tiond < I isrealized (d isthe receiving signal aperture, I isthe characteris- incidentsound field, to remainnear the surface as it propagates.Above tic scaleof the inhomogeneities).This effectmay be of usefor determina- porousgrounds, the existence of surfacewaves has eluded direct experi- tionof charactersiticscales of large-scaleinhomogeneities from analysis mentalconfirmation and indirect evidence for itsexistence has appeared of the back-scatteringsignal. contradictory.Experiments made here several years ago, but unreported, will be describedand discussedin the light of somerecent theoretical work. Furtherexperiments are also planned.

2:15

GG6. Laser-Doppler vibrometry measurementsof acoustic-to-seismic 2:45 couplingand geophone-groundcoupling ratios. W. Pat Arnott and .lamesM. Sabatier(National Centerfor PhysicalAcoustics, P.O. Box GGS. The relfeetionof acousticpulses from arrays of tubes.Heui- 847, University,MS 38677) Seol Rob, JamesM. Sabotlet,and Richard Raspet(Department of Physicsand Astronomyand National Centerfor PhysicalAcoustics, The surfaceof the groundis an air-filledporous material because of University,MS 38677) weatheringand vegetation. Typically, soils are porous to a depthof sever- al feet.An airbornesound wave can couple into the ground as a porefluid The theoryof soundpropagation in and the reflectionof soundfrom wave.The porefluid wave is attenuatedthrough viscous drag at thepore rigidporous media is well established [K. Attenborough,J. SoundVib. walls;hence, energy can be coupled into the soilmatrix as seismic motion 99, 521-544(1985)]. This theoryhas been applied to regulararrays of [J. M. Sabatieret al., J. Acoust.Soc. Am. 79, 1345-1352(1986)]. This straighttube to developa low-reflectivitysurface. Low reflectivitiesre- mechanismgives a couplingten timesthat whichwould be expected for quire high porositiesin order to minimize the surfaceadmittance. A momentumtransfer from the fluid air to thesolid soil. In thepast, ground 15.25-era-i.d.tube terminatedby arraysof rectangulartubes has been velocitywas measuredusing geophones. A modifiedoff-the-shelf laser- constructedto verifythe theoryin the limit of highporosity. Work is in Doppler vibrometer(LDV) is presentlybeing used for groundvelocity progressto examinethe effectof varyingpore radius with depth.

$82 J. Acoust.Soc. Am. Suppl. 1, Vol.85, Spring 1989 117thMeeting: Acoustical Society of America $82 WEDNESDAY AFTERNOON, 24 MAY 1989 NEWHOUSEI, ROOM A1, 1:00TO 2:45P.M.

SessionHH. PsychologicalAcoustics V: BinauralHearing and the PrecedenceEffect

Edward M. Burns, Chairman Departmentof Speechand Hearing Sciences, University of Washington,JG-15, Seattle, Washington 98195

ContributedPapers

1:00 1:30

HH 1. The effectof numberof componentsand component spacing on the HH3. Buildup and breakdown of the precedenceeffect. Richard ability to detecta delayedcomponent embedded in a dipticcomplex. M. L. Freyman, Rachel K. Clifton, Ruth Y. Litovsky, and A. Stellmack, R. H. Dye, and S. V. Jakubczak (Parrely Hearing Urea Balakrishnan(UniversityofMassachusetts, Amherst, MA01003) Institute,Loyola University, 6525 N. SheridanRoad, Chicago, IL 60626) Dynamicvariations in the strengthof echosuppression were investi- The purposeof thisstudy was to understandthe processesthat pro- gatedthrough earphone simulation of the free-fieldprecedence effect. duceinterference when observers attempt to latera]izca targetcomponent Each test stimulusconsisted of two click pairs,with the interauraltime in the presenceof other components.To this end, thresholdinteraural parametersof the leadingand laggingpairs reflecting stimuli originating differencesof time (AIDTs) weremeasured for 753-Hztones presented from oppositesides of the head.Echo thresholds, the minimumlagging againsta dipticbackground consisting of 2, 4, 6, or 8 additionalcompo- click delay requiredfor subjectsto reporthearing an echoclick, were nents.The frequency spacing ( Af ) of thecomponents was I 0, 25, 50, 100, obtainedin two basicconditions: (a) testclick presented in isolation,and or 200 Hz. A modifiedsame-different task was employed in whicha diptic (b) testclick precededby a train of clicksidentical to the testclick. The 753-Hztone was presented followed by eithera dipticn-component com- moststriking finding was that the presenceof the precedingclick train plex or a complexcontaining a delayed(to the right channel) 753-Hz usually elevated the echo threshold of the test stimulus relative to its component.Stimuli were 200 msin durationwith 10-msrise/decay times, thresholdwhen presented in isolation,suggesting that echosuppression witheach component presented at 55 dB SPL.The largestthresholds were builds up during the click train. The magnitudeof the effectwas in- obtainedwhen Af's were25 or 50Hz andthe number of components in the fluencedby the numberof clicksin the train and the periodof silence backgroundwas large. Interestingly, thresholds fell as the frequency spac- betweenthe end of the train and the testclick. The effectis surprisingly ing was narrowedfrom 50 or 25 Hz to 10 Hz. In all cases,the obtained persistent,lasting through several seconds of silence.Partial releasefrom thresholdsare larger than those obtained with a 753-Hz tonepresented in the built-upsuppression occurred when the leadand lag locationsof the isolation.The resultsare explained in termsof binauralprocessing that is test click were reversedfrom the dicks in the precedingtrain. [Work spectrallysynthetic for moderateto widefrequency separations and spec- supportedby NSF. ] trallyanalytic at smallfrequency separations.

1:15

HH2. The effectof envelopepower on the ability to !ateralizethree-tone 1:45 complexeson the basis of interaural envelopedelays. R. H. Dye, M. A. Stellmack,and A. J. Niemiec (Parmly Hearing Institute, Loyola HH4. Cross-frequency interactions in the precedence effect. R. University,6525 N. SheridanRoad, Chicago, IL 60626) K. Clifton (PsychologyDepartment, University of Massachusetts, Amherst,MA 01003), P.M. Zurek, B. G. Shinn-Cunningham,and N. In the presentexperiment, envelope power was varied by settingthe I. Durlach (Research Laboratory of Electronics, Massachusetts startingphases of thethree components of a complex0ø•3ø•0 ø(high), 0ø- Instituteof Technology,Cambrige, MA 02139) 45ø•3ø (medium), or 0ø-90ø•3ø (low). Thresholdinteraural envelope de- layswere measured in a 2-AFC taskas a functionof frequencyspacing The extentto whichthe precedenceeffect is observedwhen leading ( Af= 25, 50, 100,and 200 Hz) with thecarrier frequency • ) setto 4000 and laggingsounds occupy different spectral regions has been measured. Hz. Thelevel of eachcomponent was 50 dB SPL,and the signal duration Subjects,listening under headphones,were askedto match the lateral was200 mswith 10-mslinear rise/decay times. For comparison,thresh- positionof an acousticpointer to that of a teststimulus composed of two oldswere also measured for SAM 4000-Hz toneswith reduceddepths of binaural noise bursts with asynchronousonsets, parametrically varied modulationso that the effectsof decreasingmodulation depth and frequencycontent, and different interaural delays. The precedenceeffect creasingenvelope power could be directly compared. Reducing envelope wasmeasured by thedegree to whichthe interauraldelay of the matching powerhad only a negligibleeffect on thresholdinteraural envelope delays pointer was independentof the interauraldelay of the noiseburst in the for Af's of 200and 100Hz buta largeand systematic effect at 50 Hz and teststimulus. These results show an asymmetricfrequency effect in which especiallyat 25 Hz. For threeof thefive observers, the 0ø-90ø•0 ø, Af- 25- low frequenciesdominate. For example,a stimuluscomposed of a high- Hz condition was so difficult that 75% correct could not be reached with frequency( 1.25kHz) leadingburst and a low-frequency(0.45 kHz) lag- delaysas largeas 2000 #s. While reductionsin the depthof modulation gingburst produces no precedenceeffect, whereas the reverseproduces a also elevatedthresholds, the agreementwas not particularly good be- strong precedenceeffect. These resultsare in qualitative agreement with tweenthe data obtainedwith SAM tonesand equal-amplitudecompo- thoseof Blauertand Divenyi [Acustica66, 267-274 (1988)], despite nentsof the sameAfand comparableenvelope power. In general,the numerousdifferences in stimuliand methods,including the restrictionof results obtained here are consistent with binaural cross correlation of the this stimulito the phase-sensitive( f< 1.4kHz) region.[ Work supported outputsof envelopedetectors. by NIH. ]

$83 J. Acoust.Soc. Am. Suppl. 1, Vol.85, Spring1989 117thMeeting: Acoustical Society of America S83 2:00 Measurementsof NoS•rthresholds and interauraltime and intensity jnd's with and without a 10-dB roving level for both normal-hearing HHS. Confirmation and rejection of the "precedence effect." (4000 Hz) and hearing-impaired(500 and 4000 Hz) subjectshave been Kourosh Saberi and David R. Perrott (PsychoacousticsLaboratory, obtained.This extendsprevious measurements of the effectsof roving California State University, Los Angeles,CA 90032) level on binaural detection and interaural discrimination at 500 Hz for A seriesof experimentsdesigned to investigatethe "precedence effect" normal-hearinglisteners [J. Koehnkeand H. S. Colburn,J. Acoust.Soc. in lateralizationspace were conductedusing a two-alternative,forced- Am. Suppl.I 82, Sl0g (1987)]. All measurementswere made using an choiceparadigm. Stimuli consisted of 40-pstransients separated by inter- adaptive, four-interval, two-alternative,forced-choice procedure and clickintervals (ICIs) of 0.38-30 ms.In a two clickparadigm (experiment 1/3-octnoise bands. For detection,the targetwas a toneburst centered in 1) interaural differencesof time (IDT) thresholds were determined inde- the noise band. Binaural detection and interaural time discrimination pendentlyat click positionsI and 2. Thresholdsmeasured at click 2 showno effectof rovinglevel at 500 Hz. However,interaural intensity rangedfrom 12ps at extended(over 5 ms) andshort duration (less ttlan 1 jnd's at 500 Hz for the hearingimpaired listeners are consistentlylarger ms) ICIs to a peakof 250 ps at ICls of 1.75-2.35 ms. Thresholdsmea- with the rovinglevel. In contrastto the data obtainedat 500 Hz, at 4000- suredat click I were uniformacross ICIs, constantat approximately15- Hz performanceof all the subjectsfor interauralintensity discrimination 25 ps. Experiment2 consistedof a three click paradigmwhere the ICI and NOS,' detectionis worsewith the rovinglevel. For interauraltime betweenclicks 2 and 3 was held constantat a value where subjectsin discrimination,there is no apparenteffect of the rovinglevel at 4000 Hz. experiment1 had peaked( 1.75-2.35 ms), while the ICI betweenclicks 1 [Work supportedby NIH. ] and 2 was varied from 0.38 to 10 ms. IDT thresholds were measured for click 3. Resultsshow a U-shapedfunction for which thresholdsdrop below30 ps for click3 at ICIs between2-8 ms,with theeffect returning at longand shortduration ICIs. Experiment3 consistedof click trains of 2:30 n = 2, 3, 4, 5, 6, and 12 whereICI was held constantat subjects'peak valuein experiment1 and IDT thresholdswere measuredat the lastclick HH?. Detection and Internlizntion thresholds for repeated random in the train. Resultsshow a negativelydecelerating function as n in- waveforms in noise. Irwin Pollack (Mental Health Research Institute, creases,wtih IDT thresholdsfalling from 250 down to 20/.rs.The most Universityof Michigan, Ann Arbor, MI 48109-0720) dramaticfind in theseseries of experiments,however, was the surprising yet compellingdissipation of "suppression"in the temporalwindow of Interauralphase effects are reportedfor the lateralizationand for the interest( 1- to 5-msICls) over multipleruns. Thresholds fell by 5 to 10 detectionof repeatedrandom waveforms in white noise.For lateraliza- folds,matching values reported by Perrottet al. (in press)in thefree field. tion,the primary component of interaural phase effects is theinteraural Acrossvariations of stimulusduration, form, intensity,or frequency, phaseof time-delayedsignal and isrelatively independent of the interaural highly trained subjectsshowed no recoveryof the precedenceeffect. phaseof a nondelayednoise. In-phase signals yield substantiallylower [Work supportedby NSF and NIH. ] lateralizationthresholds, at leastfor interauraldelays up to 0.5-1.0 ms. This resultis obtainedwith the followinginteraural noise relations: in phase,out of phase,random phase, and monaural noise. The importance of signalphase may relateto the searchfor moment-by-momentcorrela- tion by a binauralsystem with differentialprocessing of waveformcon- densationsand rarefactions.For detection,the primarycomponent of 2:15 interauralphase effects is relatedto the homophasic-antiphasiccombina- tion of signaland noise.The magnitudeof the interauralphase effects is HH6. Effectsof rovinglevel on binauralperformance in normal-hearing substantiallysmaller for widebandrepeated random waveforms than re- and hearing-impaired listeners at 500 and 4000 Hz. P. Curliss, portedfor puretones. The smallerinteraural phase effects may relateto J. Koehnke,H. S. Colburn,and G. A. Owen (BostonUniversity, 48 thedifficulty of establishinglateralization cues for widebandsignals in the CummingtonStreet, Boston, MA 02215) absenceof a time delay.

WEDNESDAY AFTERNOON, 24 MAY 1989 NEWHOUSE II, ROOM 254, 1:00 TO 2:48 P.M.

SessionII. SpeechCommunication VI: Perceptionand Analysis of Vowels

JamesE. Flcgc, Chairman Departmentof Biocommunication,University of Alabama, UniversityAvenue, Birmingham, Alabama 35294

ContributedPapers

1:00 nativeGerman speakers differing in English-languageexperience. In ex- II1. The establishmentof a new phoneticcategory by German learners periment 1, German and Englishmonolinguals read listsof Englishb Vt of English. O. -S. Bohn and J. E. Flege (Department of Bio- words.Similar reco•'dings were made of German front vowels by the Ger- communication,University of Alabama, Birmingham,AL 35294) mansubjects. On thewhole, duration and spectral measurements indicate that the distancebetween/i/and/•/in an F,/F 2space is aboutthe same This paperreports experiments examining the productionof English in German,English, and nativeGermans' English. The vowels/i/and/•/ vowels(/i, •, •, ze/) and Germanvowels (/i/i, r, r:,a/) by two groupsof of Englishand German differedacoustically. Both experiencedand inex-

S84 J. Acoust.Soc. Am. Suppl. 1, Vol.85, Spring1989 117thMeeting: Acoustical Society of America $84 perleneedGermans approximated but did not reach the English monolin- 1:36 guals'values for/i/and/•/. Experiencedbut not inexperiencednative Germansdifferentiated English/•e/and/e/acoustically, probably be- II4. The effects of relative formant intensity on vowel perception causeGerman lacks an/a•/category. The acoustic results of experiment 1 revisited.Kam-Cheong Tsoi (Departmentof Psychology,SUNY at Buffalo, Amherst, NY 14260) wereconsistent with experiment 2, whichexamined monolingual English listeners'categorization of theGerman speakers' English b Vt words.The The effectsof relativeformant intensity on the phoneticidentity of resultssupport Flege's [J. Phonetics15, 47-65 (1987)] model of L2 vowelswere investigatedin the presentstudy. Ambiguous stimuli which learningwhich predicts that extendedforeign language experience will were near the phonetic category boundary of /a/-/•/, /u/- leadto the establishmentof phoneticcategories for new (e.g.,/•e/) /u/, and/t-/a:/series wereused to constructexperimental stimuli by soundsin L2. [Work supportedby NIH Grant 20963.] varyingthe intensity ratio between F 1and F2. The resultsshowed that the perceivedidentity of thesethree sets of stimulishifted towards/a/,/u/, and/a•/when the intensityofF2 wasincreased, and shiftedtowards/•/, /u/, and/e/when the intensityofF2 wasdecreased. The magnitudeof effectwas largest in stimuliof the/a/-/•/series, andsmallest in stimuliof the/e/-/ae/series. The resultssuggest that ( 1) the relativeintensity of formantsdoes affect the phoneticidentity of the stimuli, and (2) the 1:12 frequencyrange within whichspectral integration between adjacent for- mantscan take place is not limited to 3 Barks, but followsa continuous II2. The perceptionof English vowelsby native speakersof Spanish.J. probabilityfunction. [Work supportedby NIH.] E. Flege and O. -S. Bohn (Department of Biocommunication, Universityof Alabama, UniversityStation, Birmingham, AL 35294)

This studyexamined native Spanish speakers' perception of four Eng- lish vowels (/i, i, œ, •/). In experiment 1, subjectsused letters ((i,e,a,o,u)) to identifythe vowelsin beat, bit, bet, bat or responded "none"if theydid nothear a Spanishvowel. The patternof responseswas unsurprising:mostly (i) for the Englishvowels/i/and/•/, (e) for the 1:48 English/e/s,and (a) for/a•/. Subjectswho could speak English respond- ed "none"significantly more often than Spanish monolinguals for all four II5. Tonguepositioning and dynamicsduring productionof tenseand lax words,suggesting they had begun to differentiatethe English vowels from vowels in CVC contexts. P. A. Dagenais (Department of theirnearest phonemic counterpart in Spanish.In experiment2, subjects Biocommunication,University of Alabama,P.O. Box 503, UAB Station, identifiedthe membersof continuawhich varied spectralquality ( 11 Birmingham,AL 35294) steps)and vowel duration (3 steps).Like nativespeakers, most Spanish A comparisonbetween tense and lax vowel pairs was undertakenus- subjectsshowed clear crossoverswhen identifyingstimuli rangingfrom ing simultaneousrecordings of tonguemovements via glossometryand /bet/to/ba-•t/, probablybecause the contiuumendpoints were identified audio signals.A normal speakerrecorded five repetitionseach of three with differentSpanish vowels (viz., /e/ and/a/). Only six (30%) of the pairsof tense-laxvowels (i-l, •e-t, u-o) in pipsirecontext (•pvp, •tvt, Spanishsubjects, however, showed clear crossovers for a/bit/-to-/bxt/ •kvk). Measuresfor maximumtongue displacement, durations and ve- continuum,probably because the endpoints were identified with reference locitiesof physiologicalonglide, and targetand offglidemovements rela- to a singleSpanish vowel (/i/). The patternof identificationresponses tive to the acousticrelease of the initial pipsirewere taken.Greater maxi- did not changesystematically when stimulidiffering in spectralquality mal displacementfrom a centralposition was noted for all tensevowels. In wereblocked on vowelduration in experiment3. The resultswere inter- pvpcontexts, consistent preplosive anticipatory positioning was found for pretedto meanthat even experienced Spanish speakers of Englishmay not all vowels, and maximal tongue positioningfor the lax vowels was establishphonetic categories for "new" Englishvowels such as/•/and achieved50 ms prior to the tensevowels. For both lingual pipsire con- /a:/. [Work supportedby NIH Grant 20963.] texts, tensevowel movementshad longer total durationsbut slower on- glideand offglide velocities than theirlax counterparts.These results will bediscussed in termsofbiomechanical restrictions for productionand the effectsof perceptualsaliancy and coarticulation.[Work supportedby NIH Grant NS24697. ]

1:24

113.S'pose a vowelis lost.Joann Fokes(School of Hearingand Speech Sciences,Ohio University, Athens, OH 45701) and Z. S. Bond (Departmentof Linguistics,Ohio University,Athens, OH 45701) Varioustypes of reductioncan be observed in casualspeech, one being vowelloss in unstressedsyllables as in "s' pose."The question,how is the 2:00 phoneticdetail of thisspecific reduction implemented, is the focusof the II6. Relationshipbetween vowel height and speakingrate in American study.Three typesof testwords were selected for investigation,initial English. H. S. Oopal, Joyce Manzella, and Lillian Stuman /sp/and/sk/clusters, two and threesyllable words beginning with an (Departmentof Speechand HearingSciences, University of Californiaat unstressed/a/+ V followedby/p/or/k/in the stressedsyllable, and a Santa Barbara, Santa Barbara, CA 93106) word with a clustercreated by the lossof the vowel,such as sport, support, and sport. Male subjectsread each test word in contextfive times.Mea- The phoneticdimension of vowelheight seems to be representedreli- surementsincluded (1) durationof the/s/, (2) durationof the stop ably and robustlyby the differencebeween Bark-transformed F 1 and F0 closure,(3) voiceonset times, and (4) total time from the beginningof [A. K. Syrdaland H. S. Oopal, J. Acoust.Soc. Am. 79, 1086-1100 the/s/to the onset of the stressed vowel. Results indicated two different (1986) ]. This studyexamined the relationshipbetween speaking rate and speakerpatterns but consistencywithin eachsubject. Differences between two acoustic-auditorycorrelates of vowel height. Measurementswere the subjectsoccurred in the lengthof the/s/in all typesof testwords, madeofF0, F 1,vowel duration, and sentence durations of/pVC/target voiceonset time, and the total time. For oneof the speakers,voice onset syllablescontaining one of four pairsof high-low vowelsand voicedor time was relatively short regardlessof the cluster or word types.For an- voicelessstops or fricatives.Target syllableswere producedin sentence other speaker,VOT was short for the/sp/clusters while valuesfor the context at three different speakingrates by two male and two female /sk/cluster, for the createdclusters, and for the two and threesyllable nativeAmerican English speakers. Results will bereported and discussed wordsbecame increasingly longer. This speakerdifferentiated between for twocorrelates of vowelheight: changes in F 1and changes in thediffer- real clustersand createdclusters by meansof voicetiming. encebetween Bark-transformed F l and F0 asa functionof speakingrate.

S85 d.Acoust. Soc. Am. Suppl. 1, Vol. 85, Spring 1989 117th Meeting:Acoustical Society of America S85 2:12 thedistance between a real spectralpeak and its targetwhich is a spectral peakmean computed for voweluttered in isolation.The interaetionfunc- I17. Minimalist synthesisof /bVb/ stimuli. Jean E. Andruski and tion thusdetermined suggests that: (1) therecan be a time-frequency TerraneeM. Nearey(Department of Linguistics,University of Alberta, lateralinhibition intbe auditorysystem like that on theretina in thevisual Edmonton, Alberta T6G 2E7, Canada} system,(2} the interactionfunction is consistentwilh the resultsof pay- Vowelsboth in isolationand in/bVb/syllables canbe well identified chaocoustieexperiments concerning the assimilationand/or contrastef- from brief (30 ms) windowedportions taken from the beginning(head) fect usingpaired single formant stimuli, and (3) the contextualeffect andend (tail) of thesyllable IT. Neareyand J. Andruski,1. Acoust.Sac. betweenadjacent phoneroes can be represented as the sum of theassimila- Am. $uppl. I 83, S83 (1988) ]. Despitesimilar confusion matrices, for- tionand/or contrasteffects between each spectral peak pair. Applying the mant measurements of windowed/bVb/data show substantial under- determinedinteraction function to •al speechdata to copewith coartieu- shootcompared to initial and final targetsof isolatedvowels. It is of ladonproblem, spectral peak Irajectories overshoot, spectral peaks at the interestto constructstimuli that are minimallyspecified but are nonethe- vowelcenter approach their own targets,and the distancebetween each lesscategorized like morecomplex natural stimuli. Vowels were synthe- vowelcategory pair increases. sizedwith lineartransitions based on fundamentaland formant frequency measurements from four brief sections of the windowed/bVb/stimuli. (Thesesections correspond roughly to transitiononset, initial voweltar- get, finalvowel target, and transitionoffset.) Preliminary listening tests 2'.36 indicatethat these simple stimuli are well identified.Results from experi- mentscomparing listeners' error patternsfor suchminimalist synthetic 119. Experimental evidence for the unit of bird song production. syllableswith thosefor windowednaturally producedsyllables will be JeffreyCynx (Rockefeller University Field Center, Millbrook, NY presented. 12545)

An experimentalprocedure was developed to determinethe real-time natureof birdsongproduction. In a giventrial, a burstof strobedlight, directedat a malezebra finch (Poephila guttata), was triggered at a ran- dompoint in hiscourtship song. Repeated trials allowed the formulation 118.Modeling of contextal •e½ lined on sl•tral Iw.ak interaction. of threerules governing song production: ( 1 ) A zebrafinch can stop song MasatoAkagi (ATR Auditory and Visual PerceptionResearch productionin themidst of song,(2) themotor unit for songproduction is Laboratories,Inuidani, Seikacho, Kyoto, 619-02 lapan) quantal,and (3 } thequantal unit of songproduction is largely identical to a syllable,as read offs soundspectrogram. The comparativegenerality of This paperpresents a modelof a lower levelcontextual effect that can the ruleswas tested by replicatingresults with anothertwo otheroscine copewith coartieulationproblems. especially vowel neutralization. The species,the songsparrow (Meiospiza meiodia ) and the canary($erinus modelis constructedto overshootspectral peak trajectoriesbased on canarius).The resultsplace constraints on neuralmodels of songproduc- spectralpeak interaction, assuming that the lowerlevel contextual effect tion, and suggestinvarianee between the unitsof songperception and is representedas the sumof interactionbetween each spectral peak pair. production.[Research supported by NIH and the Cary Charitable The interactionfunction is determinedexperimentally in orderto reduce Trust. ]

WEDNESDAY AFTERNOON, 24 MAY 1989 REGENCY C, 1:00 TO 3:00 P.M.

SessionJJ. Underwater AcousticsV: Acoustic Bottom/Interface Properties

Ronald Dicus, Chairman Naoal ResearchLaboratory, Washington,DC 20375

Chairman's Introduetionml:00

Inuited Paper

1:05

JJl. Geoacousticpruperties of the seabedsediment critical to acousticreverberation at 50 to 500 Hz: A preliminarydata set. Tokuo Yamamoto,Morris $chulkin (Geo-AcousticsLaboratory, Applied Marine PhysicsDivision, Universityof Miami, Miami, FL 33149-1098},and Richard Bennett(NORDA Code 360, StennisSpace Center, MS 39529} As muchas 80% of acousticreverberation is producedthrough bottom interactions. Deep-sea sediment havehigh porosity (or lowveincities), therefore, a waveguideis often formed from strongbottom interactions. In additionto the bottomroughness, the randomvariation in the geoacousticproperties (the compressional wavevelocity in particular}of the sedimentis responsiblefor generationof the incoherentpropagation/ acousticreverberation. Our existingdata [e.g.,Bennett et al., Handbookof GeophysicalExpro. (1983) ] indi- cate that very strongspatial variations (vertical and horizontal}usually exist in the deep-seasediments. A

S86 J. Acoust.Soc. Am. Suppl. 1, Vol.85, Spring 1989 117thMeeting: Acoustical Society of America S86 preliminaryanalysis of thesegeological data by the Biot-Yamamototheory [Yamamoto and Turgut,J. Acoust.Soc. Am. 83, 1744-1751(1988) ] revealsthat strong velocity variations, as much as 20% in velocity magnitude,usually exist in the deep-seamuds at horizontaland verticalscales of 0.3 to 30 m, whichis very criticalto acousticreverberation at 50 to 500Hz. [Worksupported by ONR Code11250 A. ]

ContributedPapers

1:30 2:00

,I3'2. High-resolutioninvestigations of seismoacoustic0ropagation in J J4. Bottom shear modulus profiler (BSMP) measurementsof the shallow-waterareas. George H. Sutton,Noir Barstow,Jerry A. Carter shallow-waterseabed geoacoustics properties in Japan. Mobsen Badicy (RondoutAssociates, Incorporated, P.O. Box 224, StoneRidge, NY (University of Miami, Miami, FL 33149 and Nakajima Institute of 12484),John I. Ewing(Woods Hole Oceanographic Institution, Woods Geophysics, Nakajima City, Ishikawa Prefecture, Japan), Hole, MA 02543), and David Harris (Hawaii Instituteof Geophysics, Tokuo Yamamoto (University of Miami, GeoacousticsLaboratory, Universityof Hawaii, 2525 Correa Road, Honolulu, HI 96822) 4600 RickenbackerCauseway, Miami FL 33149-1098), Hideo Suzuki (Ono SokkiCo. Ltd., Tokyo 163,Japan), and Hiroshi Kanai (Tohoku Data froma newlydeveloped 30-element accelerometer/hydrophone University,Sendai, Japan) arrayare used to studyseismoacoustic propagation in shallow-waterloca- tionsoff New Jerseyand Martha's Vineyard.The elementsof the array The methodof bottomshear modulus profiler (BSMP) wasused to have l-m spacing;each consistingof three orthogonalaccelerometers measurethe seabedproperties of severallocations in Japan.In this meth- (flat from 2 to 500 Hz), a hydrophone,and a vertical directionsensor. od, the seabed admittance, which is defined as the ratio of the wave- The 120accelerometer/hydrophone signals and 30 verticaldirection sig- inducedparticle motion to the wavepressure on the seaflooris measured nalsare digitized and transmitted via I km of fiberoptic cable to a PC-type IT. Yamamotoand T. Torii, Geophys.J. K. Astron.Soc. 85, 413-431 recordingsystem. The A/D convertersdigitize all hydrophonesat 2048 (1986) ]. Thesedata are then used as input to a linearinversion scheme for samples/sand all accelerometersat 512 samples/s.Good coupling to the calculationof the shearmodulus profile. The collecteddata are presented bottomis obtainedsince sensor symmetry has been maximized; coupling in a completeform of shearand compressional wave velocity profiles. An to the waterhas been minimized; and densityis matchedto the sediments. attempthas been made to improvethe numericalanalysis of the inverse There are 10-m extensions between the 30-m sensor section and the A/D methodused in the BSMP software.By applyinga taperingHamming converterhousing at eitherend of the array. Units containingport-star- windowin the truncationof the order employedin the singularvalue board paired, shotgun-shellsources were mountedwithin the array in decomposition(SVD) technique,the truncatedexpansion equation was theseextensions and fired through the arraycircuitry, providing precise modifiedand the higher-ordereigenvalues were used stably. A numerical timeand distance control and reverseprofile capability. Differenced shot testas well asthe analysisof the data usingthis methodis presented. pairsemphasize transverse horizontal shear (SH) andLove wave signals; summedpairs emphasize P, SV, and Rayleigh/Stoneley/Scholtewaves. Shearboundary wave energy is observed with frequenciesgreater than 60 Hz and velocitiesand wavelengthsas low as20 m/s and 1 m, respectively. Considerableenergy appears to resultfrom lateralheterogeneity and/or 2:15 anisotropy.[Research supported by ONR. ] &JS. Resultsfrom two shallow-waterexperiments utilizing synthetic bandwidth("step•d FM"I signalsto estimate compressional wave speed in the seabottom. Neil J. Williams and Harry A. DeFerrari (Departmentof AppliedMarine Physics, RSMAS, University of Miami, Miami, FL 33149) Twoexperiments were performed to investigatethe utility of synthetic 1:45 bandwidthor "steppedFM" signals[ H. A. DeFerrariand H. B. Nguyen, J. Acoust.Soc. Am. Suppl. I 82,S74 ( 1987) ] foracoustic remote sensing JJ3. Low-frequency measurementsof bottom reflectivity at a thin of geoacousticproperties of theseabottom. In eachexperiment, pseudo- sediment site in the North Pacific. Patricia L. Grubcr (AT&T Bell randomcodes with carrierfrequencies ranging from 100to 1600Hz were Laboratories,1201 S. Hayes Street, Arlington, VA 22202) and Ronald transmittedconsecutively at a fixedrange to a mooredvertical array. L. Dicus (Naval ResearchLaboratory, Washington, DC 20375) Afterevery other complete sweep of theentire bandwidth, the range was Bottom reflectivitymeasurements were made in the North Pacific, increasedand the transmission was repeated. The experimental sites were during PacificEcho I, usinga low-frequency,towed source. A MK VI 42 nauticalmiles SE of CorpusChristi, TX and75 nauticalmiles E of sourcetransmitted 50-s FM sweepsignals ( 5 to 15Hz) to a verticalarray Lewes,DE. Thewater depth in eachcase was about 60 m andthe range from sourceto receivervaried from 300 m to 2 kin. The data have been of 16hydrophones. The FM rampswere deconvolved and beamformed to separatedirect and bottom arrivals in time and angle. In addition, ray reducedto pulse responses with a resolutionof6 ms.This, combined with theorypredictions of the arrivalstructure, scaled by spreadingloss, wcrc theangular resolution of thearray, aids in theidentification of eigenrays beamformed.A comparisonbetween the time integratedenergy in the andinversion of the data to yield estimates of compressionalwave speed in measured and theoretical bottom arrivals, led to a measure of the bottom the seabottom.[Work supportedby ONR.] reflectivity.FM rampswere processed along the sourceship track to vary the bottomgrazing angle from 10 to 75 deg. Reflectivityas a functionof bottom grazing angle, smoothedover angle to reduc• variance, will be presented.Theoretical computations of reflectivityfrom a simulatedbot- 2:30 tom that includes a sediment layer with sound-speedgradient and an elasticbasement, with shearand compressionalspeed gradients and at- JJ6. Gaussianbeam algorithm for bottom reflection and head wavesdue tenuations,will bepresented. Theory and measurementsare compared to to extendedaperture sources. X. J. Gao and L. B. Felsen(Department infer the sedimentthickness and the wavespeed profiles in the upper200 of ElectricalEngineering/Computer Science, Weber ResearchInstitute, m of the oceanic crust. PolytechnicUniversity, Farmingdale, NY 11735)

S87 d. Acoust.Soc. Am. Suppl. 1, Vol.85, Spring1989 117thMeeting: Acoustical Society of America S87 Gaussianbeams furnish a usefulalgorithm for high-frequencysound P.O. Box 153, WellesleyHills, MA 02181-5339)and Gary H. Brooke propagationin complexenvironments but in their paraxialimplements. (Defence Research Establishment Pacific, FMO Victoria, British tion, they arc flawedby spectraldefects that obscurecertain wave phe- Columbia V0S lB0, Canada) nomena.Critical reflection and head wave generation due to a fastbottom belongin thiscategory. In a separatestudy, methods for "fieshing out" the A surprisinglylarge leaky Rayleighwave componenthas beenob- deficientspectrum for the prototypestructure of a homogeneousocean servedpropagating along the edgeof a laboratorynonsaline-ice quarter- anda homogeneousfluid bottom, have been explored with excitationdue spacein water with both sourceand receiverpositioned along the edgeof to a line sourceIX. J. Gan et aL, 2rid [MACS Symposium,Princeton oneof the two surfacesof the quarter-space.Studies on differentsolids University(March 1989)]. In the presentationhere, thesemethods of (aluminum,Plexiglas, limestone) indicate that all surfaceand interface excitationfrom a continuouslydistributed extended aperture source and edgewaves travel slower than theircorresponding waves on a solidhalf- from an arrayof linesources have been applied. in the Gaussianbeam space.The measuredratio of theedge Rayleigh wave velocity to the half- modeling,not onlyare the ad hocdiscrctization that involvesarbitrary spaceRayleigh wave velocityis 0.9617 for aluminum6061, 0.9665 for parametersemployed but the self-consistent Gabor phase space stacking plexiglas,and 0.9954 for limestone.Ultrasonic experimental results are are alsoemployed. It is foundthat distributedsources decmphasize the presentedon edgeRayleigh waves, and on edgeleaky Rayleigh waves and above-notedspectral defects but do not removethem entirely. [Work Scholtewaves for the liquid/solid case. The edge wave has no geometrical supportedby ONR. ] spreadingand dominatesthe receivedsignal when the receiveris moved slightlyaway from the water loaded edge of thequarter space. The Ray- leighwaves along the horizontal and vertical faces at theedge are out of phaseinfluencing the radiationof theleaky Rayleigh wave for the water- loadedcase. Near the edgeit is observedthat a decreasein the Scholte 2;4S wavesignal is accompaniedby an increasein the leakyRayleigh wave signal.The leaky Rayleighwave velocity for the water/ice is slightly JJ?. Propagstionof Rayleighand SohoIre waves along edge of quarter- smallerthan the shearwave velocity at the onsetof the signal.[Work space.Jacques R. Chamuel(Sohoquest Advanced Ultrasonics Research, supportedby DREP and ONR. ]

WEDNESDAY AFTERNOON, 24 MAY 1989 COMSTOCK B, 1:45 TO 3:00 P.M.

SessionKK. Binresponseto Vibration III and PhysicalAcoustics Vl: BiomedicalAcoustics

WesleyL. Nyborg, Chairman PhysicsDepartment, University of Vermont,Burlington, Vermont 05405

ContributedPapers

1:45 above90 mW/cm-',which increased to 50% at 500mW/cm:, for 30-rain exposureat 37 'C in isotonicphosphate buffered saline. Hemolysis in- KKI. A comparisonbetween !ow-frequeacy sound absorption in seawater creasedwith exposureduration (4-64 min) but did not greatlychange and high-frequeacy sound absorption in serum albumen. David with exposuretemperature (25, 37, 48 'C), or prior heattreatment (48 øC G. Browning (Code 3131, Naval Underwater SystemsCenter, New for 30 min). Thetemperature results were especially interesting because London,CT 06320) and RobertH. Mellen (Kildare Corporation,95 increasedtemperatures might have been expected to increasethe sensitiv- Trumbull Street, New London, CT 06320) ity of the cellsto the shearstress generated in acousticmicrostreaming Althoughlarge scale ( > 1000 km), low-frequency( <20000 Hz) flownear the ultrasonicallyactivated gas bodies. Increasing the viscosity soundabsorption measurements in seawater[Me!len et al., J. Acoust. ( !, 2, 4 cP) of the mediumdecreased the effect,while variationsin osmo- Soc.Am. 74, 987-993 (1983) ] might appearto havenothing in common larity ( ! 80,290, or 580ransin) or density( 1.03or !. ! 2 g/cm• } hadlittle with high-frequencysound absorption in serumalbumen [ Barneset ai., J. influenceon the results. Increasing the density of themedium might have Acoust.Soc. Am. 83, 2393-2404(1988) ], the resultsshow some intrigu- beenexpected to reducethe effectivenessof the exposures,since the radi- ingsimilarities that may be due to a commonchemistry. Specifically, both ationforce, which theoretically gathers cells to thegas bodies, vanishes for showa pH dependence,a buffered reaction involving a carboxylgroup, isopycnicconditions. [ Work supportedby PHS GrantCA42947 awarded andthe needof calciumto promotethe principal reaction. However, boric by the National Institutesof Health.] acid,which is essentialfor seawaterabsorption, is apparentlynot a factor in serumabsorption. A comparisonispresented in thehope of stimulating 2:15 a dialoguewith the binacousticscommunity to explorea possiblelinkage. KK$. Measuremeatofln riro lungacoustic impedance for animalsusing randomnoise and the two microphonetechnique. J. E. Sneckenberger and Cheryl Chandler (Departmentof Mechanicaland Aerospace Engineering,West VirginiaUniversity, Morgantown, WV 26506) KK2. The influence of biophysicolconditions on hemolysisnear ultrasonicallyactivated gas-filled micropores. Douglas L. Miller and The in viooacoustic impedance of rats' lungswas measured using Ronald M. Thomas (Battelle Pacific Northwest Laboratories,P.O. Box randomnoise and the two microphonetransfer function method for cal- 999, Richland, WA 99352) culatingimpedance. This methodeliminates the needfor the sensitive pressuretransducers used in theconventional measurement of respiratory Hemolysisin 0.5% suspensionsof canine erythrocytes exposed to 1.9- impedance.Measurements were performed on controlrats and ratsthat MHz ultrasoundin thepresence of 3.7-pm-diamgas bodies in filtermicro- had, 5 monthsprior to the experiments,been exposed to coaldust for 2 pores(Nucleopore") was investigated asa functionof spatial peak inten- weeks.Random noise, fiat to 6.4 kHz, waspropogated down a threesec- sityfor variedbinphysical conditions. Significant hemolysis was observed tion impedancetube. The experimentsbegan with the insertionnfa tra-

S88 J. Acoust.Sec. Am. Suppl. 1, Vol.85, Spring1989 117thMeeting: Acoustical Society of America S88 chealtube through the rat's mouth to a depthof approximately3/4 in. Encagedaggregations of Euphausiasuperba have been ensonified at intothe trachea. Sound traveling through the impedance tube and trache- 38 and 120 kHz and the echoenergy measured. Derived estimatesof al tubeand reflecting from the lungwas measured with the two micro- targetstrength are considerablylower than previouslymeasured values. phonesand recorded by a twochannel FFT analyzer.The analyzer calcu- latedthe transferfunction between the microphonesand, from this transferfunction, the complex lung acoustic impedance was calculated. Theimpulse response was also computed from the transfer function, and 2:45 wasfurther processed, by theWare-Aki area inversion algorithm, to pro4 ducethe effective airway cross-sectional area as a functionof depthinto KKS. Study of intensityin the focal lobe for a focusedultrasonic stone the lungfrom the trachea. removaldevice. V. R. Singhand RavinderAgarwal (Instrumentation, NationalPhysical Laboratory, New Delhi- 110012,India)

2:30 In modernsurgical practice, the operativeprocedures for stonere- movalare still findingdifficulty in theiracceptance by thepatients. Thus it KK4, Target strengthsof Antarctic krill. K. G. Foote (Institute of givesmotivation for findinga newand alternative, noninvasive technique Marine Research,5024 Bergen,Norway), I. Everson,D. G. Bone,and forthe removal of kidney stones. Focused ultrasound isused in thedisrup- J. L. Watkins(British Antarctic Survey, High Cross,Madingley Road, tion of suchstones. Intensity pattern pratmetersin the focal lobe are CambridgeCB3 0ET, United Kingdom) studiedfor a transducerused for removalof kidneystones.

WEDNESDAY AFTERNOON, 24 MAY 1989 CROUSE AUDITORIUM, 3:30 P.M.

Plenary Session

W. Dixon Ward, Chairman President,Acoustical Society of America

Presentation of Awards

R. Bruce Lindsay Award to Mark F. Hamilton Gold Medal to Lothar W. Cremer

Musical Demonstration and Lecture

ProfessorWilliam Headlee will givea recitalon theSyracuse University Holtkamp Organ, preceded by a short lectureon its history.

S89 J. Acoust.Soc. Am. Suppl. 1, Vol. 85, Spring 1989 117th Meeting:Acoustical Society of America $89 THURSDAY MORNING, 25 MAY 1989 COMSTOCK A, 8:00A.M. TO 12:00NOON

SessionLL. EngineeringAcoustics VI: Transducersand Arrays

SungH. Ko, Cochairman Naval UnderwaterSystems Center, New London,Connecticut 06320 Howard H. Schloemer,Cochairman Naval UnderwaterSystems Center, New London,Connecticut 06320

ContributedPapers

8:00 shownthat a verycompact transducer can be constructed with an energy densityone order of magnitudehigher than that of a magnetostrictive LL1. Historyof the flextensionaltransducer. Kenneth D. Rolt'• device.A detaileddesign and analysis has been completed for a transducer ( Departmentof OceanEngineering, MIT, Cambridge,MA 02139) with a ratingof 250 kW andan operatingfrequency of 50 kHz. Althoughthe inventionof the flextensionalacoustic transducer is usuallyattributed to William J. Toulis, it wasactually invented at theU.S. Naval ResearchLaboratories, Washington DC, in 1929by Harvey C. Hayes.It wasintended as a foghornfor theLighthouse Service. This paper will review Hayes' flextensionalfrom inventionto disappearance(c. 1936), and discussits reinventionand developmentby Toulisand Frank R. Abbottin the 1950s.•'• Presently on educationalleave from, and work 8:45 supportedby AcousticEngineering, Raytheon Company, Submarine Sig- LL4. Analysis of magnetostrictivetransducers by the ATILA finite nal Division, Portsmouth,RI 02871-1087. elementcode. F. Claeyssen,D. Boucher(GERDSM, DCAN Toulon, DCN, Le Brusc, 83 140 Six-Fours-Les-Plages,France), K. Anifrani (SINAPTEC, 121 Rue Chanzy, 59620 Hellemmes,France), R. Bossut, andJ. N. Decarpigny(ISEN, 41 BoulevardVauban, 59 046 Lille Cedex, France) 8:15 New magnetostrictiverare-earth-iron alloys offer an attractiveop- LL2. A theoretical model for an array of flextensionaltransducers. portunityfor the designof high-powerlow-frequency transducers [F. RichardJ. Brind (Admiralty ResearchEstablishment, Portland, Dorset Claeyssen,J. Acoust.Soc. Am. Suppl. I 81, S89 (1987)]. In order to DT5 2JS,England) optimizethe designof thisparticular class of transducers,a model based on a newvariational principle has been derived following a classicalfinite Acousticinteraction effects can seriously degrade the performance of elementmethod approach. This modeldescribes the three-dimensional arraysof sonartransducers if the efficiency of theelements is high and the dynamicbehavior of heterogeneouselectrochemically coupled structures. interelementspacing is small. An experimentalarray of four300-Hz flex- Due to thereduced-scalar-potential formulation of themagnetic field, the tensionaltransducers was deployed in LochGoil in Scotlandto investi- modelhas beenrelatively easily implemented within the ATILA finite gatethese effects. Here, an equivalentcircuit model for the transducersis elementcode. In thispaper, a generalview of themethod is given and first developedand a theoryfor theinteraction effects presented. The modelis computationresults on teststructures are presented. validatedagainst the arraymeasurements taken in LochGoil. The theory wasused to predictadmittance loops and farfieldbeam patterns for un- steeredand steeredarrays with half-wavelengthand quarter-wavelength elementspacings. An interactiveprogram has been written to perform thesecalculations on an HP45 computer.Farfield beam patternswere obtaineddirectly with a hydrophonelowered from the surface,and were calculatedfrom nearfieldmeasurements. The agreementbetween the pre- 9:00 dictionsand the measurementswas very good.The interactioneffects in an array with half-wavelengthspacing were small. With quarter-wave- LLS.Improvement of a magnetostrletivelength-expander transducer by lengthspacing, interaction effects were severe,giving rise to a 2.5-dB use of a grain-orientedmaterial. F. Claeyssen,D. Boucher,and reductionin transmittingvoltage response and narrowfrequency bands S. Faure (GERDSM, DCAN Toulon, DCN, Le Brusc, 83 140 Six- wherethe conductanceof one of the elementswas dangerously low. Fours-Les-Plages,France) In orderto provethe ability of newmagnetostrictive rare-earth-iron alloysfor high-power low-frequency transmitting transducers, a first pro- totypeof a length-expanderprojector had been realized in 1987.Although the active material was a random-orientedalloy (R), high-power mea- 8:30 surementresults were quite satisfactory IF. Claeyssen,J. Acoust.Soc. LL3. Ultra-high-power superconducting transducers. Osman Am. Suppi.I 81, S89 (1987)]. On the otherhand, an activematerial K. Mawardi (Collaborative Planners, Inc., Cleveland, OH 44106) characterizationwork [F. Claeyssen,J. Acoust.Soc. Am. Suppl.1 83, S20 (1•18)] hasled to theoreticalpredictions showing the advantages of Recentdevelopments in high-temperature superconducting materials grain-orientedalloys (G.O.) comparedto therandom-oriented alloy. In makeit practicalto investigatethe feasibilityof very high-powersuper- additionto theincrease of acousticalpower, a lowerresonance frequency conductingacoustic transducers capable of generatingseveral hundreds anda bettereffective coupling factor are expected. In thispaper, the theo- of acoustickilowatts. A proposedscheme for sucha transducerthat con- reticalimprovement ofa transducerdue to the use of G.O. alloy is checked sistsof a variationof a linear motor is describedin this paper.Borrowing with the in-air and in-water measurementsof the prototypetransducer fromthe highlydeveloped technology of linearelectrical machinery, it is mounted with a G.O. material.

S90 J. Acoust.Soc. Am. Suppl. 1, Vol.85, Spring 1989 117thMeeting: Acoustical Society of America S90 9:15 10:00

LL6. Finiteelement modeling of piezoelectrictransducers including LL9. Finiteelement modeling of the ARE low-frequencyflextenslonal internallosses. B. Dubus,J. C. Debus,J. N. Decarpigny(lnstitut transducer.Richard J. Brind (Admiralty ResearchEstablishment, Suprrieurd'Eleetroniquc du Nord, 41 BoulevardVauban, 59046 Lille Portland,Dorset DT5 2JS,England) Cedex,France), and D. Boucher(Groupe d'Etude et de Recherchede DrtectionSous-Marine, Le Brusc,83140 Six Fours les plages, France) A requirementfor underwateracoustic sources with highersource leveland wider bandwidth at lowerfrequencies has, in thepast 5 years, Anactual radiating sonar transducer isalways generating heat, due to leadto interestin flextensionaltransducers. A low-frequency prototype, internallosses and to thefriction between the different parts of thestruc- whichconsists of a GRP shelland conventionceramic stacks, has been ture.Thus its ef•eiency is lower than I anda temperaturerise can occur. developed,manufactured, and tested at ARE(Portland); the technology Todescribe these phenomena, thefinite element code ATI LA [ Deearpigny is thesubject of a licenseagreement with industry.In thispaper, finite etal.,I. Acoust.Soc. Am. 78, 1499(1985) ] hasbeen improved by includ- element(FE) analysesperformed in supportof theprototype develop- ingthe effects of internallosses, using a complexYoung's modulus for mentusing PAFEC software are described. PAFEC isa commerciallyavail- isotropicmaterials and complex tensors for piezoelectric ceramics. Then, ableFE packagewith thefacility to modelpiezoelectric materials, and electricaland thermal measurements have been performed on various exteriorfluid loading by the doubly asymptotic approximation. In-air and sandwichtransducers, at differentdrive levels,to determinethe ceramics in-waterresonant frequencies are well predicted, as is the effect of hydro- lossangles. Finally, the electrical impedance, transmitting voltage re- staticpressure on stackprestress. The shellis subjected to largeinterla- sponse,and mechanical displacement field have been computed for a mul- minorshear stresses during stack insertion, and predictions for thesehave tifrequencyTonpilz transducer[Boucher et al., J. Acoust.Soc. Am. alsobeen obtained. Work is in handat PAFECto addthe capability to Suppl.I 80,S27 (1986) ] anda ringtransducer [Bossut etal., J. Acoust. couplea Helmholtzintegral equation representation for the exterior fluid Soc.Am. Suppl. 1 74, S23 (1983) ] radiatingin water,and the theoretical to the existingfinite element package for the structure.This will enable resultshave been compared to experimentalvalues, showing a reasonable sourcelevel and bandwidth calculations to bemade, which, at present, agreementwhich will be carefullydiscussed. cannotbe accuratelypredicted.

9:30 10:15

LL7. A Poisson-coupledplastic projector. G. W. McMahon and J. LL10. Minimaxshadingofarbitraryarrays. ThomasE. Bordley(Naval B. Franklin (Defence ResearchEstablishment Atlantic, Box 1012, ResearchLaboratory, Code 5123, Washington,DC 20375-5000) Dartmouth, Nova ScotiaB2Y 3Z7, Canada) An iterativealgorithm for minimizingthe maximum sidelobe level of An underwaterelectroacoustic projector is describedin which a hol- an arbitrarilyshaped array over bandsof frequenciesand directionsis low tubeof plasticis drivenaxially in orderto exciteits radialresonance presented.The approachis novelboth in providingan optimalTcheby- by Poissoncoupling. The driveris a piezoceramicstack that connectsto shevsolution for nonuniformlyspaced, multidimensional arrays and in theplastic tube via stiff metal end plates. The projector was desgined using providinga solutionover frequencybands. At eachiteration, the algo- thefinite-element program MAVART to predictperformance and enable a rithmgenerates a descent direction minimizing the response at thehighest suitableselection ofdimensions for an experimental model. The projector sidelobes.The method is applicable both to plane-wavebeamforming and is 18cm long, 11.4 cm in diameter,and weighs 0.7 kg. Although no well- to matchedfield processing. In this present,ation, thetrade-offs between definedresonance isexhibited, ef•cient operation is predicted from 2200 beamwidth, bandwidth, and sidelobelevel are consideredfor the conven- to 3300Hz, witha sourcelevel up to 191dB re:1 •zPa @ 1 m. Themeasured tionalbeamformer for a varietyof nonuniformlyspaced arrays. performanceof theexperimental unit is compared with MAVART predic- tions.

10:30

9:45 LLll. Randomlinear projectorarrays with reducedacoustic interaction. P.M. Joseph,P.R. SaseendranPillai, and C.S. Sridhar(Department of LLS. Finiteelement modeling and array interactionmodeling of the ARE Electronics,Cochin University of Scienceand Technology,Cochin 682 low-frequencyflextensional transducer. Richard J. Brind (Admiralty 022, India) ResearchEstablishment, Portland, Dorset DT5 2JS,England) Acousticinteraction effects among the elementsof closelypacked so- A requirementfor underwateracoustic sources with highersource nar projectorarrays should be minimizedconsiderably, as it reducesthe leveland wider bandwidth at lowerfrequencies has, in thepast 5 years, acousticpower output and deteriorates the beam characteristics, at higher lead to interestin flextensionaltransducers. A low-frequencyprototype drivelevels. This effect can be minimizedby restructuringthe array for- has beendeveloped, manufactured, and testedat ARE(Portland); the matwith appropriatelychosen interelement spacing [ P.M. Josephand P. technologyis the subjectof a licenseagreement with industry.In this R. SaseendranPillai, in Proceedingsof the1EEE InternationalConference paper,finite element (FE) analysesperformed insupport of theprototype onAcoustics, Speech, and Signal Processing (IEEE, New York, 1988),pp. developmentusing PAFEC software are described. PAFEC iS a commercial- 2697-2700]and further reduction in interactioneffect can be achieved by ly availableFE packagewith thefacility to modelpiezoelectric materials, incorporatingthe nonuniformarray concept.The appropriateinterele- andexterior fluid loading by the doubly asymptotic approximation. In-air mentspacing for thisnonuniform array can be determined by usingtotal and in-waterresonant frequencies are well predicted,as is the effectof enumerationmethod. But thismethod cannot be recommended for arrays hydrostaticpressure on stackprestress. The transduceris subjectedto comprisedof largenumber of elements,as it is a time consumingand large stressesduring assembly,and predictionsfor thesehave alsobeen tediousprocess. In the approachpresented in thispaper, the suitableinter- obtained.Problems remaining in theFE modeling,and improvements in elementspacings that reducethe interactionare determinedby using thecapabilities of I'Ar:ECunder development to overcomethem, are dis- Gaussiandistributed random numbers with the elementspacing of the cussed.An equivalentcircuit model for an arrayof th•aeflextensional. restructuredarray as meanand by retainingthe array dimensionsame as transducersis described,and a comparisonof admittadcesand farfield thatof therestructured array. Beam pattern and array gain are found to be predictionswith measurementspresented. little affectedin the randomlydistributed element configuration.

S91 J.Acoust. Soc. Am. Suppl. 1, Vol. 85, Spring 1989 117thMeeting: Acoustical Society of America S91 10:45 radiators.Sensitivity analysis of a body vibratingat a singlefrequency with a known normal velocitydistribution indicates those areas of the LLI2. Active dampingof a piezoelectriccrystal designedfor airborne surfacethat havethe greatestinfluence upon the radiatedpower at that acoustic rangefinding.Christopher L. Kenney and Ilene J. Busch- frequency.Regions of high sensitivitywould be likely candidatesfor the Vishniac (Department of Mechanical Engineering,The University of applicationof damping materialsor as locationsfor active control Texas at Austin, Austin, TX 78712) sources.Optimization analysis provides the optimum magnitudeand Piezoelectriccrystal ultrasonic transducersare ideal for airborne phaseat whichto driveactive cancellation sources in orderto minimize acousticrangefinding because they are low-damping(high Q) devices the radiatedpower. Both techniques are based upon a discretizedexpres- capableof producingrelatively high sound intensities at a singlefrequen- sionfor radiatedpower, where surface pressure has been replaced by an cy. However, the low internal dampingof the crystalresults in substantial expressionthat relates pressure to surfacevelocity through a transferma- ringing,which can interferewith the reflectedacoustic signal if left un- trix. The transfer matrix is derived from a numerical discretization of the treated.The conventionalmeans of dealingwith theringing is to passively Helmholtzintegral equation. dampthe crystal,but thiscauses a reductionin efficiency,increases the risetime, and addssubstantially to the massand costof the transducer. An alternative approach,demonstrated here, is to actively damp the transducerusing feedback control. In this system,the piezoelectricdisk elementis subdividedinto two pieces:one largeand one small.The small portionis used to sensemotions resulting from driving the larger segment. 11:30 The signalfrom thesensor is fed through a triggeredclassical proportion- al-derivativecontroller. The controlleris triggeredso that it is only active LL15. A new type of Gaussianultrasonic transducer. Gonghuan Du, when it is desiredto quenchthe crystalmotions. Results show that using DeshengDing, and ChangmingGan (Instituteof Acoustics,Nanjing this controllerit is possibleto dramaticallyincrease the dampingof both University,Nanjing, People's Republic of China) the radial modeand the longitudinalmode of the crystalwithout adding massto the system,decreasing the transduceroperating efficiency, or A Gaussianultrasonic field is knownto havesome advantages [ G. Du increasingthe risetime. [Work supportedby GeneralMotors Research and M. A. Breazeale,J. Acoust. Soc. Am. 78, 2083-2086 (1985) ]. In this Laboratories.] article,a newtype of Gaussianultrasonic transducer is presentedwith a curvedback electrode instead of a usualplane electrode. The mathematics of designis basedon an inverseapproach. The theoreticalresult shows that the shapeof the curvedback electrode is dependenton the thickness of the transducerand on the Gaussiancoefficient of vibration displace- ment on the surface of the transducer as well as on the ratio of dielectric 11:00 constants of the transducer to the material of the back electrode. The inspectionof displacementdistribution is carriedout on thesurface of the LL13. Large area sensorsfor active aeoustlecontrol systems.Thomas transducerby usinga laserinterference technique. The measuredresults R. Howarth, Xiaoqi Q. Bao, Vijay K. Vatarian, and Vasundara indicategood agreement with the predictionof the theory. V. Varadan (Department of Engineering Science and Mechanics, Research Center for the Engineering of Electronic and Acoustic Materials, The PennsylvaniaState University, University Park, PA 16802) Thedesign and development ofa composite piezoelectric polymer (PVDF) sensorfor usein an activeacoustic control system is presented. 11:45 Large area PVDF platesare encapsulatedin a polymermatrix to detect both the incidentand reflectedsignals in an underwaterpulse tube at low LL16. Characteristics of variable-reluctance transducers as underwater frequencies.These signals are amplified,phase shifted, and then usedto acoustic projectors. Elizabeth A. McLaughlin and Mark B. Moffett drive an absorbingtransducer to negatereflections. The resultsof this (Code 3111, Naval Underwater Systems Center, New London, CT systemare comparedwith earlierdata [X.-Q. Bao et al., J. Acoust.Soc. 06320) Am. Suppl.l 84, S49 ( 1988) ] that utilizedpiezoceramic spherical hydro- Variable-reluctanceprojectors, because they can deliverhigher forces phones. thanmoving-coil projectors, have long been proposed for underwateruse. Singleelements are nonlinear, however, and push-pull configurations of elementpairs [W. T. Harris, U.S. Pat No. 2,713,127;J. Chervenak,U.S. Pat. No. 3,725,856;G. Pida, U. S. Pat. No. 3,691,515;F. Massa,Jr., U.S. Pat. No. 3,319,220] have beenused to eliminatesecond-order nonlineari- ties. Such push-pull arrangementsare usuallydipole radiators in nature 11:15 and needto be baffed for monopoleradiation. The displacementis nor- LL14. A theoretical basis for acoustic sensitivity and optimization mally limited by the gap thickness,but transversevariable reluctance devices [F. R. Abbott, U.S. Pat. Nos. 3,126,520, 3,353,040, and analyses of three-dimensional radiators. Kenneth A. Cunefare and 3,605,080;J. Chervenak,U.S. Pat. No. 3,517,279] are not subjectto this Gary Koopmann (Noise Control Laboratory, 157 Hammond, The limitation and hencecan producegreater displacements, albeit smaller PennsylvaniaState University, University Park, PA 16802) forces, than can direct variable-reluctancetransducers. The characteris- Numericaltechniques have been developed that enableacoustic sensi- tics of these transverse variable-reluctance devices turn out to be similar to tivity and optimization analyses to be performed on three-dimensional moving-coil projectors in many respects.

S92 J. Acoust.Soc. Am. Suppl. 1, Vol. 85, Spring 1989 117th Meeting:Acoustical Society of America $92 THURSDAY MORNING, 25 MAY 1989 REGENCY A, 8:00 A.M. TO 12:00 NOON

SessionMM. PhysicalAcoustics VII: Reflection,Transmission, Dispersion, and Scattering

Anthony A. Atchley, Chairman PhysicsDepartment, Naval PostgraduateSchool, Monterey, California 93943

ContributedPapers

8:00 ChristenSalvesen (Department of Mathematics,The Universityof Bergen,5007 Bergen,Norway), and Sigve Tj•tta (Applied Research MMI. Reflection of focused sound from curved, rigid surfaces. Laboratories,The Universityof Texasat Austin, Austin,TX 787i 3-8029, Michalakis A. Averkiou and Mark F. Hamilton (Department of and Departmentof Mathematics,The Universityof Bergen,5007 Bergen, MechanicalEngineering, The Universityof Texasat Austin,Austin, TX Norway } 78712-1063) The analyticalsolution of manyproblems of acousticsis expressed in Targetgeometry and orientation significantly affect the current accu- termsof a Fourier integral.In this paper,general asymptotic expressions racy of ultrasonicsensors used for gaugingand proximitysensing [R. thatappxoximate both the location and the value of themaximum ampli- Hickling and S. P. Marin, J. Acoust. Soc. Am. 79, 1151 (1986)]. The tude of a one- or two-dimensionalFourier integralare presented.These reflectionof focusedsound from curved,rigid surfacesusing Gaussian expressionsare generallyeasier to computethan evaluationsusing a fast beamsolutions obtained from the parabolicapproximation of the wave Fouriertransform algorithm. The methodis usedto studythe reflection equationhas been investigated. Both the focusingof the sourceand the and transmission of a real sound beam at the interface between two homo- curvatureof the targetare modeledby quadraticphase factors. A simple geneousand dissipativefluid layers.Simplified analytical formulas that closed-form solution is thus derived for the sound reflected from concave explainthe beamdisplacement and otherbehavior near the interfaceare andconvex targets in eitheraxisymmetric or nonaxisymmetricconfigura- obtained.Numerical results are comparedwilh thoseof an earlierwork tions.The validityof thesolution is restrictedto easesin whichthe focus- [see Sagen,Naze Tjrtta, and Tj6tta, J. Acoust.Soc. Am. 85, 24-38 ing gainof the source,and the curvatureof nonperpendieularityof the (1989) ]. The influenceof variousparameters on the directionand shape target,are not too large.Propagation curves, beam patterns, and scatter- of the reflectedand transmitted sound beams is investigated.[Work sup- ing trajectoriesare usedto illustratethe combinedeffects of diffraction portedby theIR&D programof ARL:UT, The RoyalNorwegian Council and targetcurvature on the reflectedsound field. Transfer functions are for Scientific and Industrial Research (NTNF), and VISTA/ obtainedby comparing the received to thetransmitted acoustic power for STATOIL, Norway.[ the caseofa monostaticacoustic sensor. [Work supportedby GM and NSF.]

8:4•,

MM4. Reflection and transmissionof elastic wavesfrom a fluid/porous 8:!5 solidinterface.Kunyu Wu, Qiang Xue,andLaszlo Adler(Department MM2. Echo identification using phase information. Nurgun Erdol of WeldingEngineering, The Ohio StateUniversity, Columbus, OH {Department of Electrical Engineering,Florida Atlantic University, 43210) Boca Raton, FL 33431), Louis Roemer, Nathan Ida, and Ke- In thispaper, Biot's theory of wavepropagation in a poroussolid has Sheng Huo (Departmentof ElectricalEngineering, The Universityof Akron, Akron, OH 44325) beenapplied to a theoreticalstudy of energy reflection and transmission of elasticwaves at obliqueincidence on an interface between fluid and fluid- The signalwaveforms chosen for reflectomerryoften result in overlap- saturatedporous solid. For this purpose, the necessary formalism of ener- pingecho waveforms. The waveformschosen are constrainedby trans- gy equation,Poynting energy flux vector, and sound intensity of elastic ducerlimitations, attenuation, and resolution properties of the testmedi- wavein fluid-saturatedporous solid are presented. Two generalcases of um. The extractionof echo locationinformation can be achievedusing modeconversion have been investigated: (i) The initialwave is incident phaseinformation, via the maximum entropy method. The phaseestimate fromthe fluid to theinterface and generates three transmitted bulk waves is constructedfrom the powerspectrum of theeven components (S,.,.) of in the fluid-saturatedporous solid, and (ii) the initialwave is incident the signaland the powerspectrum of the odd components(S,,,) of the from the fluid-saturatedporous solid to the interfaceand generates three signal.The cosineof the phaseis reflected bulk waves in the same media. The calculated results are in agreementwith the law of conservation ofenergy. Furthermore, the trans- S,,.(e •'•) -- $,.(e •'•) cos[ 2a ] = missionof sound through a fluid-saturatedporous solid plate immersed in So,(e•") + S,•(e'")' fluidis calculatedto specifythe optional condition supporting a strong By computingthe spectrum of theabove relation, the echo delay t,• canbe slowcompressional wave and to interpretPIona's experimental results. computedusing cos[20(co)[ = cos[2a•(td) ]in the frequencydomain. [This work wassupported by the U.S. Departmentof Energy,Basic The methodof analysisis presented, along with experimentalverification EnergyScience Grant ED-FG02-84ER45057.A0005.] that overlappedechoes are easilyidentified for a simplereflecting struc- ture usingultrasound.

9:00

8:30 N4_NIS.Dispersive guldgd waves in interface ia:/ers. Pctcr [J. Nag:/and Laszlo Adler (Departmentof WeldingEngineering, The Ohio State MM3. Transmission and reflection of a real sound beam at a two-fluid University, Columbus,OH 43210) interface.Jacqueline Naze Tj•tta (Applied ResearchLaboratories, The Universityof Texasat Austin,Austin, TX 78713-8029,and Department It wasrecently suggested by theauthors [J. Acoust.Soc. Am. Suppl.I of Mathematics,The Universityof Bergen,5007 Bergen, Norway), Hans- 83, S78 (1988)] that guidedwaves in an interfacelayer can be usedto

$93 J. Acoust.Soc. Am. Suppl. 1, VoL 85, Spdng 1989 117th Meeting:Acoustical Society of America $g3 characterizebond quality in adhesivejoints. Experimental results clearly Identificationof Resonances"(MIIR) [G. Maze andJ. Ripoche,Phys. indicatethat leakyguided modes of the interfacelayer itself are much Lett. A 84, 309-312 ( 1981); J. Acoust.Soc. Am. 73, 41-43 (1983) ] and moresensitive to mosttypes of bonddefects than the corresponding Lamb derivedpulse methods. The firstinterest is the isolationof resonancesin modesof the multilayeredjoint asa whole.Quantitative evaluation of the quasilinespectra, which are obtained for passiveor activetargets when the experimentalresults requires the development of an analyticaltechnique excitationis externalor internal.The secondinterest is the experimental to calculatethe dispersioncurves of guidedwaves in a solid(adhesive) identificationof eachresonance by thedetermination of the n modenum- layer betweentwo solid (adherent) half-spaces.Special emphasis was ber, which allows a classificationof resonances.The resultscorroborate placedon complex modes that are substantially attenuated by leakinginto the"Resonance Scattering Theory" [H. 0berall,L. R. Dragonette,and the substratesbecause of the relativeeasiness of generatingand detecting L. Flax, J. Acoust.Soc. Am. 61, 711-715 (1977) ]. QuasiharmonicMIIR themby simpleexperimental techniques. Differences between free and and short-pulseMIIR can be appliedto cylinders,air- or liquid-filled forcedvibrations of the interfacelayer are considered,too. Experimental shells,and multilayeredstructures (or other targets)immersed in water resultsare shownto be in goodagreement with the calculatedtheoretical by meansof an externalor internalexcitation. Experiments give reso- dispersioncurves. nancespectra of liquidcylindrical inclusions in elasticmaterials. [Work supportedby D.R.E.T., D.G.A., Contract 86/045. ]

9:15

MM6. Studyof thedispersion of the$cholte-Stoneley waves propagating 10:00 at a planeinterface. M. de Billy,G. Quentin(Groupe de Physiquedes Solidesde I'ENS, University Paris 7, Paris, France), H. Franklin, MM9. Scattering from elastic shells in time domain at coincident M. Rousseau,and Ph. Gatignol (UniversityParis 6, Paris,France) frequencies.M. F. Werby and H. Ali (NORDA NumericalModeling, SCC, MS 39529) Theoreticalresults [Osborne and Hart, J. Acoust.Soc. Am. 17, 100 (1945)] pointedout that for low valuesof the productFd (frequency Scatteringfrom the submergedelastic spherical shells at the frequency timesthe thickness of theplate), there exists a dispersionof theScholte- at which the phasevelocity of the flexural (Ao) modeis approximately Stoneleywave as it propagatesalong the interfacebetween a liquidand a equal to the speedof soundin the ambientfluid is considered.This is plate.Measurements of thevelocity on different materials and for various referredto as the coincidentfrequency for plates,and it producesstrong thicknessof theplate reveal a verysmall dispersion for valuesof Fd that flexuralvibrations in both platesand sphericalshells. The resonancesthat rangesfrom 0.5-3 MHz ram.The experimental results will becompared arise for boundedobjects are observedto have a fairly constantgroup with the theoreticalcalculations. [Work supportedby DRET. ] velocityand resonancewidth over a broad ka region.It is shownthat this is sufficientto producea large backscatteredreturn of a characteristic shapein the time domain.This is demonstratedfor severalexamples.

9:30

MM7. Acousticscattering from an air-filled prolatecylinder. G. Maze, F. Lecroq,J. L. Izbicki,J. Ripoche(Laboratoire d'Electronique et d'Automatique,Ultrasons, Universit6 du Havre,Place Robert Schuman, 76610 Le Havre, France), and $. Numrich (Code 5133, U.S. Naval 10:15 ResearchLaboratory, Washington DC 20375-5000) MM10. The Rayleigh and flexural resonancesfor elastic solids and The ultrasonicscattering from circular cylinders is describedin nu- shells.M. F. Werby (NORDA, NumericalModeling, SSC, MS 39529) merouspapers. If theinsonification isperpendicular to thecylinder axis, and G. C. Gaunaurd (NSWC, White Oak, Silver Spring, MD 20910) thescattering isstrongly influenced by the propagation ofcircumferential In a comparativestudy, the Rayleigh (leaky Rayleigh-type) reso- waves.These circumferential waves propagate either in the elasticshell, nance and the flexural resonances for the solid and shells of thicknesses of wherethey are the Whispering Gallery waves, or at theinterface water/ 1% to 95% of the outer radii are calculated. It is shown that, as the shell elasticshell, where they are the Scholte--Stoneley waves. These waves, for thicknessincreases, the flexuralresonance goes into the Rayleighreso- somefrequencies called resonances, form standing waves around the cyl- nanceat about a thicknessof 60%. Further, theseresonances are observed inder.Previously, it has been shown that the resonance frequencies are out to a ka of 500. It is also shownthat thin shell theoriespredict the functionsof thecylinder diameter, the shell thickness, and the targetcom- resonanceshapes or the flexuralmodes for the thin cases,including the position.In thispresentation, the influenceof thecurvature radius on the well-knowneffect of an upturn at the lower end of the frequencyrange. positionand the amplitude of resonancesisstudied. The method of isola- tion and identificationof resonances(MIIR) is usedto plot resonance spectraof air-filledprolate cylinders. The incidentultrasonic beam per- pendicularto the cylinderaxis insonifies the crosssection at different positions.The resonancespectra of an air-filledprolate cylinder are com- paredto thoseobtained with a circularcylinder that has the same thick- ness and the same circumference.

10:30

MMll. A suitablebackground for elasticshells. M. F. Werby (NORDA NumericalModeling, SCC, MS 39529)

9:45 It has been known for some time that a usefulbackground in the MMS. Acoustic signaturesof passiveand active targets by the MIIR. descriptionof scatteringfrom elasticsolids is the rigid scatterer.When Jean Ripoche, G6rard Maze, Jean-Louis lzbicki, and Pascal Pareige resonancesare not too stronglyoverlapping, then, by subtractinga rigid (Laboratoired'Electronique et d'Automatique,Ultrasons, Universit6 du background,it is possibleto isolatethe resonanceresponse from the elas- Havre, Place Robert Schuman, 76610, Le Havre, France) tic solid. Previously,it was reportedthat, for very thin shellsat low fre- quency,a softbackground was suitable and that, at veryhigh frequencies The acousticsignatures of elastictargets immersed in wateror inclu- for thickershells, a rigidbackground was suitable. A suitablebackground sionsin materialsare more easilyobtained and interpretedsince the dis- for the elasticshell for all frequenciesand for shellsto moderatethickness coveryand implementation, in the 1980s,of the "Methodof Isolationand is derived,and its utility is demonstratedwith severalexamples.

S94 J. Acoust.Soc. Am. Suppl. 1, Vol.85, Spring1989 117thMeeting: Acoustical Society of America S94 10:45 cy range7 < ka < 100.The partial-waveseries (PWS) for f(O,ka} does not facilitatea directunderstanding of the physicalmechanisms causing MMI2. The acousticscattering by a submerged,elastic spherical shell: thisstructure. Hence, a modelfor f(O, ka) is developedfrom an elastic High-frequencylimit. Roger H. Hackman and Gary S. Sammelmann generalizationof the geometricaltheory of diffraction(GTD) [P. L. ( NavalCoastal Systems Center, Physical Acoustics Branch ( Code2120 ), Marston,1. Aooust.Soc. Am. 83, 25-37 (1988) ]. The generalizedGTD is Naval CoastalSystems Center, PanamaCity, FL 32407-5000) based on the Watson transformation of the PWS. The GTD model in- Thispresentation represents the third in a seriesdevoted to theanaly- eludesexplicit contributions from ordinary forward diffraction and from sisof the analyticstructure of the acousticscattering amplitude of an individualLamb waves excited on the shell.Calculations of o',(ka) with elasticspherical shell. In previousmeetings [J. Acoust. Soe. Am. Sulppl. I ff'ws(o,ka) and fc;rD(O,ka) showgood agreement between the exact 83, S94( 1988);84, S185(1988) ], a fundamentallyoriented analysis of PWS resultand the GTD modelfor the ka rangeinvestigated. The agree- thepole structure of thescattering amplitude in thelow- to mid-frequency ment confirms the GTD model and demonstrates the relevance of Lamb regionwas presented. The mostsurprising result of thisinvestigation was wavesguided by the shell and forwardglory scattering.Finally, these the demonstrationthat the fluid-loadedantisymmetric Lamb wavebifur- calculationsverify the correctnessof the numericalmethods by which the catednear the frequencythat the vacuumdispersion curve transitioned Lambwave parameters were obtained [S. G. Kargi andP. L. Marston,J. from a subsonicto a supersonicphase velocity. In this presentation,the Acoust.Soc. Am. 85, 1014-1028{ 1989)]. The numericalcomputations previousanalysis of boththe behavior of theacoustic scattering amplitude presentedare for a stainlesssteel shell with an inner-to-outerradius ratio of a thin sphericalshell and the polestructure of the $ matrixis extended b/a = 0.838. [Work supportedby ONR.] to the high-frequencyregion (100

11:45

MM!6. Acousticsampling volume. K. G. Foote (Institute of Marine Research,5024 Bergen,Norway) 11:15 Knowledgeof thesampling volume is necessary in manyquantitative MM14. Total scattering cross section of an elastic spherical shell: applicationsof acoustics.In general,the sampling volume is not merely a characteristicof thetransmitting and receiving transducer or transducers, Comlmrisonof exactcomputations with a GTD modelthat includes Lamb waveresonances. Steven G. Kargl and Philip L. Marston (Department but alsodepends on theconcentration and scattering properties of the target,the kind of signalprocessing performed on the echo, and the detec- of Physics,Washington State University, Pullman, WA 99164-2814} tionthreshold. Thesc dependences arestated explicitly in formulasfor the Theoptical theorem, relating the total scattering cross section o', (ka) samplingvolume and a differentialmeasure, the effective equivalent beam to the forwardscattering function f( 0 = O,ka), is usedto studythe rich angle.Numerical examples are given for dispersedand dense concentra- structurecontained in o',(ks} foran elasticspherical shell in thefrequen- tionsof bothpoint scatterers and directional fish scatterers.

S95 J. Acoust.Soc. Am. Suppl. 1, Vol.85, Spring1989 117thMeeting: Acoustical Society of Amedca S95 THURSDAY MORNING, 25 MAY 1989 NEWHOUSE II, ROOM 254, 8:00 TO 11:56A.M.

SessionNN. SpeechCommunication VII: FundamentalFrequency, Timing, and Stress in Wordsand Sentences

Robert F. Port, Chairman Departmentof Linguistics,Indiana University,Bloomington, Indiana 47405

ContributedPapers

8:00 8:24

NN1. Artieulatorycorrelates of stressdash rhythms.Mary E. Beckman NN3. Effects of the more and segmentalfeatures on word duration in (Ohio State University, Department of Linguistics,204 Cunz Hall, Jalmnese.Robert Port and Jane Hardy (Department of Linguistics, Columbus, OH 43210-1229) Indiana University, Bloomington,IN 47405)

Linguisticcharacterizations of Englishstress patterns typically claim Word duration in Japaneseis determinedby numberof moreswhen that whenone stressedsyllable is followedimmediately by anotherand wordsare pronouncedat a normalspeaking tempo in focusposition in the rhythmic clash is not correctedby retracting the first stressto an carrier sentences[Port etal., J. Acoust.Soc. Am. 81, 1547-1585 (1987) ]. earlier position,then the first vowel will be protracted,increasing the Still, variationin segmentalmakeup has some effect on work duration.It phoneticseparation between the adjacentbeats and thereby regularizing wasexpected that, whenout of focusposition or whenspoken at faster the rhythm. Acousticstudies, however, consistently show that the mean tempo,durations for wordswith a givennumber of moreswould show durationfor thefirst vowel in sucha stressclash is notsubstantially longer more variation.A set of Japanesewords of two, three,and four mores than that of its counterpartin an alternatingstress pattern. Examination havingvarious syllabic templates (e.g., tokki, tooki,etc.) was chosen. of articulatory correlatessuggests an explanationfor this discrepancy: They were producedin both focusposition and nonfocusposition (by Syllablesin a stressclash may undergoa rhythmicreorganization of seg- changinga nontargetword from sentenceto sentence)at two tempos. mental gesturesthat can distancethe first syllable'sprosodic peak from Words with samemore length exhibitedless word-to-word variation at the followingstress without lengthening the vowel'smeasured duration. slowtempo than fast,and lessvariation in the focusposition than when Displacements,durations, and peakvelocities of jaw openingand closing nonfocused.To factorout segmentaleffects, subjects were asked to pro- gestureswere measured for four speakers'productions of stressclash se- duceeach sentence reiterantly by replacingeach more of the targetword quencesPop posed and alternatingstress sequences Pop opposed. In gen- with ta. As expected,reiterant results showed almost no variationdue to eral,the jaw openinggesture was relatively shorter and the closing gesture original segmentsand much lesseffect of sentenceposition and tempo. relativelylonger in the stressclash context. If the degreeof jaw openingis The resultssuggest that competingconstraints affect Japanese timing: a takenas an approximationto thesonority contour within the syllable, this moreconstraint ("make all morasequal") plusintrinsic segmental con- resultmeans that the prosodicpeak occurred relatively earlier within the straints (differentfor each segmenttype). More timing dominatesat initial [pap] in Popposed. [Work supportedby the National Science slower temposand in focus position,but can be overpoweredby con- Foundation under grants IRI-8617852 to Mary Beckmanand IRI- straintsof intrinsicsegmental duration elsewhere. [Work supportedby 8617873 to Jan Edwards.] NSF, DCR-85-18725.]

8:36

NN4. A cross linguistic contrast in the temporal compensationeffect. Takashi Otake (Departmentof GeneralEducation, International Bado 8:12 University, 841 Shinkan,Katsuura, Chiba 299-52 Japan)

NN2. Stress clash in isolated phrasesand sentencecontexts. Michael The purposeof this investigationis to evaluatewhether the temporal S. Cluff and Keith Johnson (Department of Psychology,Indiana compensationeffect in Japanesecan be attributable to moratiming. It has University,Bloomington, IN 47405) beenasserted that the temporalcompensation effect has an importantrole in regulatinga CV syllableduration in Japanese[ Port etal., Phonetica37, The experimentreported in thispaper investigates the possibilitythat 235-252 (1980)]. In an earlier study IT. Otake, J. Acoust.Soc. Am. stressclash should be called"accent clash." Stress clash in the phonologi- Suppl. I 84, S97 (1988) ], Arabic and Japanesewere investigated under cal literaturehas been defined in termsoflexically specified stresses, while the sameconditions with respectto the compensationeffect, and it was experimentalinvestigation of suchstress clash candidates has given a foundthat both languagesshowed the samecompensation effect, which mixedpicture as regardsany phoneticeffect of adjacentlexical stresses. may suggestthat it is a universalphenomenon [Beckman, Phonetica 39, The hypothesiswas that lexical stressdefines the candidatesfor a clash 113-135 ( 1982) ], The experimentreported here used the methodof Port and that the placementof accentsduring production determines whether et al. (1980) to test the hypothesisfurther by investigating other lan- a clash will actually occur. Io test this, subjects' productions of pairs of guagesthat belongto stresstiming (English and German) and syllable adjectivenoun phrases that contrastedstress clash versus no stressclash timing (Spanishand French). In addition, Chinese,which doesnot be- environments(big dinosaur/big dimension) were analyzed. These long to any of thesetimings, was investigated. Pilot resultsshow that the phraseswere recorded both in isolationand withinsyntactically identical temporalcompensation effect reported by Port etal. (1980) can beequal- sentenceenvironments. This manipulationwas used to elicit two typesof ly observablein the abovelanguages. accentpatterns; in isolation,both the adjectiveand noun receivedintona- tionalaccent, while in context,only the nounwas accented. The resultsof a pilot experimenthave suggested that, for phrasesof this type, thereis a differencein the durational effect of stressclash (duration of the adjec- 8:48 tive) whenitems are producedin isolationversus when they are produced in sentencecontexts. Ihe relevanceof thesedata for currentphonological NN$. On the temporalalignment of F0 with segmentalstructure. Kim E. theorywill be discussed.[Work supportedby NIH ResearchGrant NS- A. Silverman (Room 2C-440, AT&T Bell Laboratories,600 Mountain 12179 to Indiana University.] Avenue, Murray Hill, NJ 07974)

S96 J. Acoust.Soc. Am. Suppl. 1, Vol.85, Spring1989 117thMeeting: Acoustical Society of America S96 Timingand F0 tendto be correlated inspeech. For example, a syllable A majorassumption of thesyllable-timing/stress-timing distinction is nearthe endof a phrasewill be lengthened,and if it bearsa localF0 that interstressinterval length in a languagelike Frenchis a directaddi- maximum(a highpitch accent), then the peak will occur earlier in that tivefunction of the numberof syllablesit contains.In stress-timedlan- syllable.The more the lengthening, the earlier the accent peak. However, guageslike English, by contrast, interstress interval length is supposed to thecurrent experiment shows acase where F0 peaks are aligned earlier in showa relationshipofnegative acceleration with increasing syllable num- theirsyllables without the expected concomitant lengthening. Two speak- berdue to an underlyingtendency towards the isochronous spacing of ersrecorded My .... livesin Memphis,where the second word was Ma, stresses.Nakatani et aL ( 1981), however,showed that interstressinter- More,Mama, Pa, Pop, or Papa,both with and without a lowF0 target valsare not only positively correlaled with intervening number of sylla- (correspondingtoan utterance-internal prosodic boundary ) after the sec- bles,there is also no relationship ofnegative acceleration between foot size ondword. Acoustic measurements, combined with perceptual judgments, in syllablesand foot duration. Acoustic timing data for French concur showthat the low tonepushes the precedingpitch accent about 50% withNakatani et al.'s findings for English. Accentual phrase duration was earlieri• its syllable,with little or no lengtheningof that syllable.Thus highlycorrelated with the numberof syllablesthat unit contained.Al- peakalignment depends on upcomingtonal events, as well as those utter- thoughdisyllabic units were not twiceas longas monosyllabicunits in ance features that determine durational structure. theseFrench data, this could reflect the fact that rhythmic units in French includea long final syllable due to a rightboundary accent. The similarity ofthese results and those for American English would suggest that appar- entcompression effects are not a strongargument in favor of one typologi- 9:00 cal descriptionas opposedto another.A furtherexperiment revealed lengtheningpatterns associated with phrasingthat are hierarchical in na- NN6. Prosod•caspects of French speechrhythm. Janet Fletcher tureand are compatible with recentmodels of intonationalphrasing pro- (Departmentof Linguistics,Ohio State University,204 Cunz Hall, posedfor French(e.g., Martin, 1987)and highlight the relevanceof ac- Columbus,OH 43210-1:229) centualgrouping in descriptionsof Frenchtiming.

9:12-9:22 Break

9:22 The aim of thisstudy is to investigatewhether the durationof a word in speechproduction is relatedwith the informationvalue (carrying NN7. Evidence for levels of prosodic hierarchies in Swedish. J. "new" or "old" information) and with the accentedness( + or - ac- M. Rauschenberg(Department of Linguistics,Ohio StateUniversity, 204 Cunz Hall, 1841 Millikin Road, Columbus,OH 43210) Mem. Lang. 26, 489-504 (1987)] found that speakerstend to shorten Pierrehumbertand her colleagues have proposed a modelof prosodic wordsconveying old information.It hasalso been found, by others,that organizationthat utilizes not only types of constituentsand their accentedwords have a longerduration than wordsthat do not carry ac- marker(s),but alsowell-defined edges. Beckman and Pierrehumbert cent.Because the features new/accented and old/unaccented appear to be (1986) havesuggested that, in English,the phrasetone followingthe closelyrelated, it is unclearwhich of the two featurescauses the differ- nuclearaccent marks the right edge of an intermediatephrase (ip), giving encesin durationas found by Fowlerand Housum. In thepresent study, it evidenceof phrasinginternal to the intonationalphrase (IP). Beckman is attemptedto sortout the effectsof accentednessand informationvalue. andEdwards (1987) accountfor a finallengthening effect in Englishas cent)Data willofthe beword.presented Fowlershowing and Housumhow both [C.factors A.Fowlerseparately andandJ. Housum,combined J. one markerof the edgeof the IP. Swedishdiffers from Englishin that affect word durations. sentenceaccent does not occurat a phraseedge. Thus, if thereis a levelat whichthere is oneand only onesentence accent, utterances with single terminaljunctures and multiple phrase tones must be analyzed as having oneIP with multipleip's. But thereis no tonalmarker for theedges of the ip's.An experimenthas been constructed (in progress)to testthe hypoth- 9:46 esisthat lengthening will occurat theend of the IP and,to a lesserextent, the ip, and that this might allow a determinationof edgesof Swedish NN9. Lexical neighborhoodsin speechproduction: A first report. phrasalunits. Thus words at theends of phrasesshould be longer than in Stephen D. Goldinger and W. Van Summers (Speech Research medialposition. The corpusconsists of sentences,each having five accent Laboratory, Department of Psychology, Indiana University, 2 words,in sixdifferent constructions. The predictionsare, specifically, Bloomington,IN 47405) (1) that the testword will be longerin sentencefinal position, and (2) that in tokensthat show internal phrasing(as indicatedby multiple Investigationsof speechproduction have shown that talkerswill sys- phrase/sentencetones), the word will be longerwhere it occursat the tematicallyalter the acoustic-phoneticproperties of their utterancesin edgeof an internalconstituent than wheremedial to a singlephrase con- responseto changesin the contextin whichthe wordsare spoken.Well- stituent. knownexamples of suchcontexts are thepresence of a loudbackground noise[e.g., Lombard ( 1911) ], or the linguisticcontext surrounding the target word in a sentence[e.g., Lieberman,Lang. Speech6, 172-188 (1963) ]. Recentwork by Balotaand Shields[Psychonomic Soc. Conf. (1988) ] suggeststhat factorsintrinsic to words,such as their frequencies, mayalso affect the durationsof spokenwords. The presentpaper reports 9:34 the resultsof a preliminaryinvestigation of the effectsof similarityneigh- borhoodstructure on speechproduction. Global, as well as segmental, NNS. Relationbetween the features"givenness" and "accentedness"and comparisonsof subjects'productions of words from denseand sparse the durationof Dutch words.Wieke Eftting (Institute of Phonetics, lexicalneighborhoods will be presented.[Research supported by NIH Universityof Utrecht, Trans 10, 3512 JK Utrecht, The Netherlands) researchgrant NS-12179-11.]

$97 d.Acoust. Soc. Am. Suppl. 1, Vol. 85, Spring 1989 117thMeeting: Acoustical Society of America S97 9:58 ablyto maximizearticulatory displacement (and perhapsderivatives or resultsof displacement,such as articulatoryvelocity or contract). Like NN10. An articulatory characterization of contrastire emphasis in many manipulationsused in speechtherapy, there are no data indicating correctinganswers. John R. Westbury(Weisman Center, Universityof theefficacy of the techniqueand, at a morebasic level, little data that bear Wisconsin,Madison, WI 53705-2280) and Osamu Fujimute (Speech on the phenomenaresulting from applicationof the technique.The pur- andHearing Science, Ohio State University, Columbus, OH 43210-1372) poseof this paperis to describehow vocalicformant trajectories and New recordingsof articulatorymovements of the tongue,lips, and segmentaldurations vary as a functionof contrastivestress in fourgroups mandiblehave been obtained using the Universityof Wisconsinx-ray of speakers.The groupsinclude normal geriatric persons, persons with microbeamsystem, from eightnormal adult speakers of AmericanEng- apraxiaof speech,ataxic dysarthria, and conduction aphasia. Results will lish who utteredthree-number sequences in question-answerpairs such bediscussed relative to the underlyingarticulatory behavior that isaffect- as"Is it 995 PineStreet? No, it's 955 PineStreet." Analysis of thesedata is ed by the stressmanipulation. intendedto providea detailedcharacterization of the implementationof contrastlyeemphasis observed in this context.Preliminary comparisons of maximumdisplacements and peak velocitiesfor the tongueblade and lower lip, during the words "nine" and "five," respectively,show that both movementparameters increase during a syllableunder the influence 10:22 of contrastiveemphasis, but that the relativechange in articulatordis- NN12. Effects of cognitive workload on speech production. W. Van placementis alwaysgreater. This observationis at leastpartly consistent Summers,David B. Pisoni, and Michael A. Stokes (SpeechResearch with resultsof previousresearch [ Fujiinureand Spencer,J. Acoust.Soc. Laboratory, Department of Psychology, Indiana University, Am. Suppl.I 74, S117(1983) ], whichshowed that maximumarticulator Bloomington,IN 47405) displacementsduring emphasizedand unemphasizedvowels differed more than did certainportions of the movementstoward and away from Previousresearch on the acousticproperties of speechhas generally thosevowels. [Research supported by USPHS Grant NS-16373.] focusedon "normal" speechproduced under benign conditions. Typical- ly, subjectsproduce utterances in a quietlaboratory setting with no com- petingor distractingstimuli present. Almost no basicresearch has exam- inedspeech in moredemanding environments. For example,pilots may oftenbe required to producespeech while simultaneously performing sev- eral other attention-demandingtasks. The information-processingre- 10:10 quirementsof thesesimultaneous tasks may affect the acoustic properties NNll. Acoustic characteristicsof contrasfive stress production in of speechin a widevariety of ways.The presentresearch examined speech normal geriatric, apraxle, conductionaphasie, and dysarthriespeakers. producedunder benign conditions and while simultaneouslyperforming Julie M. Liss and Gary Weismet (Department of Communicative an attention-demandingperceptual-motor task. Speech produced while Disorders and Weisman Center, University of Wisconsin-Madison, carryingout the perceptual-motortask showed reliable increases in am- Madison, WI 53705) plitude and fundamentalfrequency and reductionsin segmentaldura- tionsand spectral tilt. The resultshave implications for automaticspeech Contrastirestress drills are oftenused in speechtherapy for persons recognitionin demandingenvironments. [ Work supportedby Armstrong with neurogenicspeech disorders. These drills are designedto havethe AerospaceResearch Laboratory, Wright-Patterson AFB, ContractNo. patientproduce heavy stress on a word embeddedin a sentence,presum- AF-F-33625-86-C-0549. ]

10:34.-10:44 Break

10:44 10:56

NN13. Initial I•rominenee and accent in Seoul Korean prosody. NN14. The accentualpattern and prosodyof the Chonnamdialect of Kenneth de Jong (Department of Linguistics, Ohio State University, Korean.Sun-Ah Jun (Departmentof Linguistics,Ohio StateUniversity, Columbus, OH 43210) 204 Cunz Hall, 1841 Millikin Road, Columbus, OH 43210) Thispaper investigates two questions about the pros •odic system of This paperexamines the pitchaccent and intonationpatterns of the SeoulKorean--whether there is a word-initialprominence, and whether Chonnamdialect of Korean,spoken in theSouth Cholla province. The F0 a concurrentF0 peak is best seenas an optional pitch accentor as a contoursshow that the Chonnamdialect has two kindsof accentualpat- boundarytone associatedwith someprosodic level. It analyzesthe utter- terns, low-high-low and high-high-low, the choiceof which is deter- ancesof two speakersof the Seouldialect. The durationsof syllablesand mined by the first segmentof a phrase.If the segmenthas a laryngeal vowelsplaced in variouspositions within a sentenceare compared.The featureof either [ + spread]or [ + constricted],a phrase beginning with two intonational analyses are testedby noting the positionof the F0 peak, the segmentgets a h-h-I pattern. Otherwise,it getsa l-h-I pattern. Cross determininghow consistentlythe peakappears, and notingthe effectsof linguistically,it is wellknown that aspiratedor glottalizedsegments cause pitch rangevariation. Resultssuggest: ( 1) that initial syllablesof a word higherF0 at the onsetof the followingvowel. However, these phonetic are consistentlylonger than medialsyllables; (2) the positionof the initial factsdo not meanthat the h-h-1 patternis a low-levelproduct of the F0 peakis closelybound to the initial syllableof the utterance,but not of physiologicaleffect. Rather, the occurrence of thisaccent pattern defines the word;and (3) the initial F0 peakappears in all tokens,except relative- a phonologicalphrase. The F0 contoursalso suggest that the Chonnam ly short or fast tokens.This lack is shownto be due to tonal undershootof dialecthas two more unitsof prosodicstructure above the phonological a followinglow tone,as is apparentfrom strongand continuousrelation- phrasewithin an utterance,namely the intermediatephrase and the into- shipsbetween height of pitch fall and riseand the temporaldistance be- nationalphrase. An intermediatephrase in Chonnamis characterizedas tween the F0 peaks.These results suggest there is a word initial promi- the domainof downstepbetween phonological phrases. An into.national nencein Seoul prosody,distinct from initial tones.The tones are best phraseis characterizedby a high or high-low boundarytone. The data analyzedas boundarymarkers for somelarger prosodiclevel, which be- usedin thispaper are from thedialect spoken in Kwangju,the maincity in comeassociated with initial syllables. the Chonnamprovince.

S98 J. Acoust.Soc. Am. Suppl. 1, Vol.85, Spring1989 117thMeeting: Acoustical Society of America $98 11.'08 11:32

NNI$. Intonational domains of the Seoul dialect of Korean. Sook- NNI7. Phonetic implementation rules for tones in Yor•b•i. hyangLee (Ohio State University, Department of Linguistics,204 Cunz Yetunde Laniran (DMLL, Morrill Hall, CornellUniversity, Ithaca, NY Hall, Columbus,OH 43210) 14853)

Pitch trackswere analyzed to determinethe prosadiedomains needed This paperreports on someaspects of the phoneticimplementation to describedintonation palterns in the Seouldialect of Korean.Three rules for tones in Yorfibfi declarative sentences. Some of the current litera- differentdomains are observed:lhe intonationphrase, the accenlual ture on intonationsuggests that declinationis not sensitiveto the phono- phrase,and thephonological word. The intonationphrase consists of one logicalcomposition of thetones of an utterance.In Yorfibfi,tonal compo- or moreaccentual phrases, and iscued by the occurrenceof a final falling sition is relevant,since the rate at which pitch drops in identical tone or risingboundary tone configuration. The accentualphrase consists of sequencesdepends on the tonetype. H and M sequencesboth begin at the oneor morephonological words and is cuedby an F0 peakat the begin- samepitch level and are onlydistinguished subsequently by thedegree of ningand a low-highaccent on thelast syllable. Since the initial peak is not declinationin theM sequence.The rateof declinationin a sequenceof L associatedwith every word-initialsyllable, it belongsto the accentual tonesis fastestof all. The largestdrop in pitchof L sequencesis between phraseand is not a correlateof word-initiallexical stress. Undershoot of the final and penultimateL tone for two of the three speakerswe have the initial peak occurswhen the accentualphrase is very short.There is considered so far. Another feature of the F0 contour in Yorhbfi is the also downstepbetween each accentualphrase within the intonational phenomenonof high-raisingby whicha H tone is raisedby a following phrase:the pitch range is reset at thebeginning of a newintonation phrase. and/or a precedingL tone.High-raising seems to bea cumulativeeffect of surroundingL tones,Ihe pitch valueof the H tonesdecreases in the fol- lowingrepresentation: LHL > LHM • MHL > MHM.

11:20

NN16. Prosodicstructure in languageunderstanding: Evidence from tone andhi in Mandarin. Shaft R. Speer(Department of Psychology,P.O. Box I1A Yale Station, New Haven, CT 06520) and Chi Lin Shi ( Departmentof ModernLanguages and Linguistics,Cornell University, Ithaca, NY 14853) 11:44

Two experimentsshow that listenerscan usephrase-level prosodic NN18. Normafiveand functionallong-term acoustical asl•ets of English informationto disambiguatelocal lexicalambiguilies that occurdue to and French men'sand women'scontinuous speech produced normally or the operationof the tonesandhi rule in StandardMandarin Chinese.In with masking noise. William Weiss (University of Ottawa, Ottawa, Chinese,each word is associated with a tone;changes in a word'stone that Ontario K IN 6N5, Canada) occurin relationto the tonesof wordsnearby in phrasalcontext are re- ferredto as "tonesandhi," e.g., ( ILl • [LH]/_ ILl ). In experiment1, An acousticmeasure of voicequality was proposed by Frokjaer-Jen- listenersidentified lexical tones for ambiguous,unambiguous, and non- senand Prytz [Tech. Rev. (1976) ] asa = intensityabove I kHz/intensi- sensewords in phrasalcontexts where the tonesandhi rule might have ty belowI kHz.Sundberg and Gnuflirt, [Q.P.S.R. 2-3, { 1978)] seemedto applied.Comparable results in the lexicalversus nonsense conditions in- suggestthat judging higher spectra as a measureof qualityis misleading dicatethat judgments did notrely simply on lexicallystored tonal infor- becauseit couldbe obtained with an increasedvocal effort. They proposed mation,but alsomade reference to prosodicstructure. In experiment2, thata measureof good quality is a higherincrease of energy in theF0 area subjectschose the correct written English translationfor auditory sen- relativeto theF I area( "flow"phonation). The objectiveof theinvestiga- teneesof Mandarin. Global prosodicinformation was manipulatedto tionwas to find out how tension, •dce quality, and spectra levels are affect- createdifferent levels of "prosodiccloseness" between two criticalitems ed underdifferential masked (that is, functional) conditionsfor ( I ) men in a tone sandhienvironment, but the syntacticrelation between these andwomen, (2} anglophonesand Francophones. It was found that men itemswas held constant. Results show that listenersrelied on the prosodic havesignificantly higher F I/F0 thanwomen and that Anglophones have structureof the phrasesto determinewhether or not the tonesandhi rule significantlyhigher a than Francophonesunder masked conditions. had applied,and consequentlyto identifyindividual lexical items. The However,in spiteof the normatiredifferences, the spectral changes were evidenceis takento supportthe notionthat prosodicstructure influences notsignificantly different between the groups. These results shall be dis- auditory languagecomprehension processes. [Work supportedby cussedin viewof existing theories of acoustic measurements of voice qual- NICHD.] ity.

S99 J. Acoust.Soc. Am. Suppl. 1, Vol.85, Spring1989 117thMeeting: Acoustical Society of America sgg THURSDAY MORNING, 25 MAY 1989 AMPHITHEATER, 8:30 TO 11:45 A.M.

Session OO. Architectural Acoustics III and Musical Acoustics IV: Music Education Facilities Since 1975

Richard H. Talaske, Chairman The Talaske-JoinerGroup, Inc., 137 North Oak Park Avenue,Oak Park, Illinois 60301

Chairman's Introduction-•8:30

Invited Papers

8:35

OO1. The dynamicsof a musiceducation facility designteam--The role of acousticalconsultant. Dennis A. Paoletti (Paoletti/Lewitz/Associates, Inc., 40 Gold Street, San Francisco,CA 94133)

The designof facilitiesfor musicperformance, rehearsal, and educationis a complextask• Some of the major aspectsof realizingsuch facilities include: Teaming, marketing, negotiating contracts, establishing criteria,client/user interface, technical acoustical analysis and design,aesthetics, consulting, compromise, budgeting,construction/installation, contractor interface, acoustical measurements, acceptance, and evalua- tionof userand audience satisfaction. This paper will discussthe prominent role of theacoustical consultant in the processof designingfacilities for musicperformance, rehearsal, and education.

9:00

002. Planningschool and college music facilities. Harold P. Geerdes(Geerdes Consulting Services, 2210 WoodlawnAvenue, S. E., Grand Rapids,MI 49506) Educationalmusic facility planning has become a specialtywithin the broadfield of acoustics.While teaching,rehearsal, and performancespaces for schooland collegemusic departments share many of the requirementsfor downtownconcert hails and opera houses, they are in manyways unique. A schoolor college musicfacility planner ideally combines a practicing background as a teacherand conductor with knowledge andexperience in roomacoustics, noise control, and electronic systems. As a memberof thedesign team, he representsthe musicstaff of the educationalinstitution and articulatestheir needsto the otherplanners. Throughoutthe design development process he provides a levelof expertise beyond that of themusic educator. A closerelationship with the 55 000 memberMusic EducatorsNational Conferenceis very beneficial.The educationalmusic facility planner can work under contract with theclient or withthe architect, depending on the particularcircumstances, or he may work for a firm of establishedacoustical consultants who wish to use hisspecial experience and expertise to supplementtheir own.

9:25

003. The acousticsof smal!rooms for musicpractice and teaching. David L. Klepper(Klepper Marshall King Associates,Ltd., White Plains, NY 10603)

At best,the small roomstypical for musicteaching and practiceare unnaturalenvironments for music production.Given the usual constraints of budgetand practicality, a smallroom cannot be made to approxi- matethe acousticsof a fineconcert hall. If all normalmodes are suppressedcompletely by sound-absorbing treatment,the roomwill heunnaturally dead or anecboic,and will bedisliked by studentsand instructors.Yet, if normal modesare not controlledand the small room left "live," it wil! not soundlike a normal concerthall but he "hoxy," with a very unevenfrequency response, and will be equallydisliked. Compromise solutions involvingfixed treatment on onewall or two adjacentwalls, or adjustabletreatment, with varyingdegrees of roomirregularity and splaying, which have provided satisfaction in musicteaching buildings, will bediscussed. Organpractice rooms pose a separateproblem, and solutions involving no applied sound-absorbing treatment, but considerahlesplaying or irregularitiesin ceilingand wall surfacesappear best. Some discussion of sound isolationwill be presented.

S100 J. Acoust.Soc. Am. Suppl. 1, Vol. 85, Spring 1989 117thMeeting: Acoustical Society of America S100 9:50

004. Theacoustic design nf recitalhalls fur educational facilities. J. ChristopherJaffe (Jaffe Acoustics, Inc., 114A WashingtonStreet, Norwalk, CT 06854) A recitalhall for an educationalfacility requires a closeappraisal of anticipatedteaching, rehearsal, and performanceuse. In mostcases, a modifiedset of acousticcriteria is requiredfor thesespaces in contrastto thoseassociated with the designof professionalrecital halls such as Weill Hall, Town Hall, or the 92ridStreet YMHA. This paperdiscusses the specialrequirements of recitalhalls in educationalfacilities, recognizes the workof ReinPirn in thisarea, and develops a revised scale for volume-to-seatingarea ratios for theserooms. Qualitativesubjective judgments related to the ratioof direct-to-reverberantenergy are reviewed and measure- mentstaken in somerepresentative recital hallsare analyzed.

10:15

005. Schnitgermeets Sabine: Designing for organs.Robert F. Mahoney(Kirkegaard & Associates,954 Pearl Street, Boulder, CO 80302)

In the planningof musiceducation facilities there are few areas that affordthe possibilityof collaboration betweenthe acoustician and the instrument builder; the design of spacesfor organ practice and performance is oneof these.The organbuilder has within the traditionsof hisor her craftconsiderable latitude in regardto tonal design,pipe scaling, and the dispositionof variousdivisions. The acoustician,on the other hand,must servean organistwho is likely to relisha highlydiffuse and reverberantsound, but who is oftenconfined to practicerooms of limitedvolume and is seatedclose to a powerfulinstrument of considerablephysical extent. In additionto thecustomary concerns of adequateisolation and suitable background sound levels, the designer mustmarry the room acoustical design to thecharacteristics of theinstrument to beinstalled there, recognizing the distinctionbetween practice and performanceenvironments.

10:40-10:45

Break

ContributedPapers

10:45 Light reflectionscan provide an easily understandableanalogy to someacoustical featbres of architecturalspaces. The interiorsurfaces of a 006. Acousticalconsiderations for two musicinstruction buildings. Roy 30-x 60-ft lecture/conferenceroom were coveredwith reflectiveplastic. L. Richards (Towne, Richards & Chaudiere, Inc., 105 N. E. 56th Street, Reflectionsfrom variouslight sourceswere observed and photographed. Seattle, WA 98105) Soundblasts were generated in the sameroom and the resultingreflec- The acousticaldesign features and performancedata for musicin- tionswere recorded and analyzed.Results from the two experimentswere structionand performancefacilities at George Fox College iu Newburg, comparedin order to determinethe natureand extentof the correspon- Oregon (completed in 1982) and Whitman College in Walla Walla, dence. Washington(completed in 1985) will be discussed.Since these facilities househigh levelactivities that demandvirtually no intrusionof sound from adjacentspaces, methods for achievinga high degreeof soundisola- tion will beemphasized. At GeorgeFox, the rehearsalrooms were located in a formergymnasium, thereby imposing design restrictions in addition to thosedictated by a limitedconstruction budget. 11:15

008. Optimizing home listening rooms. Peter D'Antonio (RPG DiffusorSystems, Inc., 12003Wimbleton Street, Largo, MD 20772)

Variousaspects of the listener,the loudspeaker,and the listeningroom will be discussed.The psychoacousticmechanisms used by the auditory 11:00 systemare briefly reviewedto understandhow the listeningroom can corrupt spatialand spectraltextures. Experimental polar patterns,mea- 007. Sound reflectionsand their optical counterparts.Julian L. Hook sured at the ear drum, for a human ear, a dynamic speaker,a dipole (Schoolof Architecture,University of Illinois at Urbana-Champaign, speaker,and an omnidirectionalspeaker, will bepresented. TEF measure- 608 E. Lotado Taft Drive, Champaign,IL 61820), Arne S. Guilefurl mentswill be usedto demonstratehow the loudspeakerpolar response (University of Illinois, Urbana-Champaign, IL 61820), Paul dictatesthe typeof acousticaltreatment necessary. After a discussionof D. Schomer (U. S. Army Construction Engineering Research the principles behind the designswhich comprise the RPG Home Concert Laboratory and University of Illinois Department of Electrical and Hall, a detailedoutline of three listeningroom designsfor dynamicspeak- ComputerEngineering, Champaign, IL 61820), and Ingvar Schousboe ers (Opus I), dipolespeakers (Opus II), and spatiallyoriented or omni- (Schoolof Architecture,University of Illinois at Urbana-Champaign, directionalspeakers (Opus III) will be presented.Experimental before 608 E. LoradoTaft Drive, Champaign,IL 61820) and after TEF ETC measurementsare presentedand discussed.

S101 d. Acoust.Soc. Am. Suppl. 1, Vol.85, Spring1989 117thMeeting: Acoustical Society of America S101 11:30 offices.Too oftenin the designof multifamilystructures little systematic attentionis given to thebackground sound levels that will actuallyexist in 009. The significanceof backgroundsound in acousticalprivacy for thecompleted dwelling spaces and therefore the ultimate acoustical pri- multifamily dwellings. Timothy J. Foulkes (Cavanaugh Tocci vacythat will beexperienced by theoccupants. A numberof recentcase Associates,Inc., 327 F BostonPost Road, Sudbury, MA 01776) historieshave been examined in termsof thesound isolation rating (NIC or STC) and backgroundsound level (dBA) versussatisfaction. This Backgroundsound is generally recognized as an importantconsidera- effortsuggests criteria in t•rmsof bothSTC andbackground sound levels tion in achievingacoustical privacy for open plan as well as enclosed are necessaryto adequatelypredict occupant satisfaction.

THURSDAY MORNING, 25 MAY 1989 REGENCY B, 8:30 A.M. TO 12:10 P.M.

SessionPP. Structural Acousticsand Vibration V: Experimental Techniquesin Structural Acoustics

JosephM. Cuschieri,Chairman Departmentof OceanEngineering, Florida .4tlantic University,Boca Raton, Florida 33431

Chairman's Introductions8:30

Invited Papers

8:35

PPI. Scanninglaser vibrometersystem for structuralintensity measurements. Alan D. Stuart, Martin J. Pechersky,Sahib I. HayeLand B.C. T. Suen(Graduate Program in Acousticsand the Department of EngineeringScience and Mechanics, The Pennsylvania State University, University Park, PA 16802) The steady-statereal-time velocity response at successivelocations on a beamare measuredwith a laser vibrometerand stored in a computer.The scanning system associated with the vibrometer consists ofprecision lineartranslation stages tocontrol alens•mirror combination. The laser beam is scanned along the length of the beamand the flexural vibration of a sinusoidallydriven beam is measured at severallocations. The amplitude andphase data are recorded at eachlocation as well as a signalproportional to and in phasewith the driving force.Knowing the distance between measurement locations, the recorded data are used to compute any of the following:spatial derivatives, transfer functions, and intensity.

9:00

PP2. Measurement of structural intensity in submerged plates and shells using nearfield acoustical holography.Earl G. Williams and Anthony J. Romano (Naval Research Laboratory, Code 5137, Washington,DC 20375-5000) Nearfieldacoustical holography provides a completemapping of the normalsurface velocity distribution on the surfaceof a plateor cylindricalshell. For platesthis measurementcompletely determines the full structuralintensity (SI) in the plateand no assumptionsneed to be madeabout the wavefield on the plate.In shellsthis normal velocity is not sufficient to determinethe SI accurately( belowthe ring resonance) because of the couplingbetween in-plane velocity and out-of-plane velocity. Several techniques are presentedto predict thein-plane velocities from a knowledgeof the normal (radial } velocitytaken from measured holographic data andthe corresponding SI iscalculated and compared. In addition,the instantaneous energy exchange between theshell and the nearfield in thefluid (the couplingbetween structural and acoustic intensity) is obtained from measureddata and presented.

S102 J. Acoust.Soc. Am. Suppl. 1, Vol.85, Spring 1989 117thMeeting: Acoustical Society of America S102 9:25

PP3. The use of optical techniquesfor monitoring fluid--structureinteractions. Yves H. Berthelot, Dowon Lee, and Jacek Jarzynski(School of MechanicalEngineering, Georgia Institute of Technology, Atlanta, (3A 30332)

The useof coherentlight from laser sources has revolutionized the capabilities of measurementtechniques in experimentalfluid mechanics.In particular,laser Doppler velocimetry has become a standardtool for measuringnonintrusively the small-scalestructure of turbulencein fluids.Similarly, laser vibrometers are becomingcommon instruments for detecting vibrations on solid surfaces. Intcrferometric measurements (ho- modyneor hetcrodync)can provide very accuratesurface vibration measurements, with resolutionof a frac- tionof an Angstrom;subsequently, they are a powerfultool for monitoringfluid-structure interactions, espe- ciallyfor smallscale phenomena. At largerscales, another powerful tool is the laserspeckle and holographic interferometrywhich, when combined with opticalFourier transform techniques, can yield a directvisualiza- tionof wavepropagation of thew-k space ( wavevector filtering). A recenteffort has also been made to designa simpleand rugged fiber optic laser probe that wouldbe used to measurenoninvasivcly the vector displacement of a vibratingstructure. Such a probeallows the identification of bothin-plane (short wavelength, acoustically inefficient)and out-of-plane(long wavelength,acoustically efficient) modes of vibration,and the conversion between these modes at discontinuities such as ribs on the surface. The relation between such vector measure- mentswith acousticalholography and structuralintensity will be discussedtogether with the useof scanning techniques.[Work supportedby ONR. ]

9:50

PP4. Structural intensity measurementtechniques for single and multiple sources.Peter R. Wagstaft, BoudjemaBouizem, and Jean-Claude Henrio (Department G6nie M6caniquc, Universit6 de Compi•gnc, B. P. 649,60206 Compi•gne, France) The informationavailable for powerflow measurements may be used to determinethe transmissionpaths of vibrationsources. In multiplesource situations, direct measurements of structuralintensity do not give informationon the contributionof eachsource. Reference signals associated with eachsource may be usedto conditionthe spectra obtained at themeasurement point to providean estimateof thepower flow due to each input.This technique has already been successfully applied to acousticmeasurements. Results are presented usingthe direct method and these "selective techniques" for measurementsusing two, three, and four acceler- omctcrs,and for singleand multiple inputs. The structure used for theseexperiments was a lightlydamped bar andthe results,using different types of referencesignal and various cstimators for the sourcecontributions, illustratethe problemsand the advantagesof suchmethods in structuralintensity measurements.

10:15

PP5. Experimentalmeasurementofstructuralpowerfiowonan aircraft fuselage. J. M. Cuschieri(Centerfor Acousticsand Vibrations, Department of OceanEngineering, Florida Atlantic University, Boca Raton, FL 33431)

An experimentaltechnique is used to measurethe structural power flow through an aircraftfuselage with the excitationnear the wingattachment location. Because of the largenumber of measurementsrequired to analyzethe whole of an aircraftfuselage, it is necessarythat a balanceis achievedbetween the number of measurementtransducers, the mounting of thesetransducers, and the accuracy of the measurements.Using four transducersmounted on a bakeliteplatform, the structuralintensity vectors at locationsdistributed throughoutthe fuselageare measured.To minimizethe errorsassociated with usinga four-transducertech- niquethe measurementpositions are selectedaway from bulkheadsand stiflenets.Because four separate transducersare used,with eachtransducer having its owndrive amplifier, phase errors arc introduced in the measurementsthat can be muchgreater than the phasedifferences associated with the measurements.To mimimizethese phase errors two sets of measurementsare taken for eachposition with theorientation of the transducersrotated by 180ø and an averagetaken between the two sets.In thispaper results of the measure- mentswill bepresented and discussed. [Work supportedby NASA Langley.]

Contdbuted Pape•

10:40 The Wignerdistribution (W.D) maybe usedto examinethe time- frequencystructure of a time history:e.g., to givean indicationof signal PP6. The useof the Wigher distributionto identify structure-bornenoise arrivaltime versus frequency. The W.D. hasrecently found application in componen•ts.J.S. Bolton and T. J. Wahl( RayW. Herrick Laboratories, thestudy of wave scattering and in speechanalysis. In thispaper the use of Schoolof MechanicalEngineering, Purdue University, West Lafayette, theW.D. in structuralacoustic problems will be illustrated.In a typical IN 47907 ) structure,vibrational energy is conveyedby severalwave types simulta-

S103 J. Acoust.Soc. Am. Suppl. 1, Vol.85, Spring1989 117thMeeting: Acoustical Society of America S103 neously:e.g., flexural, torsional, longitudinal. Each wave type is charac- 11:25 terizedby a dispersionrelation that may be interpretedin termsof phase speedas a functionof frequency.In thispaper it will be shownthat the PP9.Resonant excitation of interfacewaves on a compliant cuatln.g. inthe presenceof a fluidflow. Maryline Talmant,Xiao-Ling Bao,H. Uberall W.D. maybe applied to structuralimpulse responses to revealthe disper- (Departmentof Physics,Catholic University of America,Washington, sion relationsof the wave typescarrying significant energy between two DC 20064),and W. Madigosky(Naval SurfaceWarfare Center, White pointson a structure.Insofar as the dispersion relations may be associated withparticular wave types, the W.D. maybe used as the basis of anexperi- Oak, SilverSpring, MD 20903) mental procedureto identify the wave types presentin a structure. Thestability of interfacewaves on a compliantcoa. ting, attached to a Knowledgeof thistype is usuallyrequired to designoptimum noise con- rigid substrateand exposedto a laminaror turbulentfluid flow,has been trol treatments.Example calculations based on wavepropagation in fluid- thesubject of severaltheoretical studies, and of experimentalinvestiga- loadedplates and beams will be usedto illustratethe proposedprocedure. tionsin which the onsetand growth of instabilitywaves was determined. Solutionsof the characteristicequation of the problemhave beenob- tained,which furnish dispersion curves and stabilityinformation for the Interfacewaves, assuming a compressiblefluid in orderto attain the cor- rect static limit. It has been shown that the excitation of these interface wavescan occurin a resonantfashion; using this approach,an accurate 10:55 experimentaldetermination of thedispersion curves, the onsetof instabil- PP7, Acoustic characteristics of confined jets. Part 1: Theory and ity, andthe growthproperties of interfacewaves will be possible. numerical calculations.Karo W. Ng (Naval Underwater Systems Center, Newport, RI 02841-5047) and Peter R. Stepanishen (Department of Ocean Engineering,University of Rhode Island, Kingston,RI 02881) A theoreticalmodel was developedto study the wall pressureand vibratorymotion of an elasticpipe whichis excitedby a confinedturbu- 11:40 lentjet flowresulting from fluid flow through orifices in thepipe. Based on flow fieldmeasurements, the blockedsurface pressure was calculated us- PPI0. Modeling of transientvibration envelopes using statistical energy ingLighthill's method, and then used to drivethe fluid-filled shell. The analysisteChniques. Ming-Lai Lai and AndresSoom (Department of wall pressureand pipewall accelerationwere determined by solvingthe Mechanicaland AerospaceEngineering, University at Buffalo,Buffalo, coupledfluid-solid interaction problem. The wall pressurewas obained NY 14260) by summingthe blockedsurface pressure and the pressuredue to thewall The modeling,by the statisticalenergy analysis (SEA) method,of vibration.An amplitude-modulatedconveering wave field was usedto transientvibration envelopes of coupledsystems is investigated.The rela- simulatethe movingacoustic sources of thejet. The randomnature of the tion betweenthe time-varyingenergy transferred between two coupled turbulentjet wasincorporated into the analyticalmodel. Specifically, the subsystemsand time-varying energies of the individualsubsystem is stud- acousticpressure was assumedto resultfrom hydrodynamicpressure led numericallyand experimentally.These studiesindicate that time- fluctuationswhich are uncorrelated in the radial direction, but correlated varyingenergy transmitted between two subsystemscan be relatedto the in the axial directionnear the jet exit. The uncorrelatedpressure fluctu- subsystemenergies by an appparenttime-varying coupling loss facior. It ations in the radial direction reflect the random motion of the turbulent isshown that the apparent coupling loss factor approaches the asymptotic jet, whereasthe correlatedpressure fluctuations in the axial direction ( or steady-state) coupling loss factor as response energies and transferred reflectthe motion ofthe large-scalecoherent structures near the jet exit.It energiesare integrated over progressively larger times. Both the apparent hasbeen demonstrated that the noisemodel is capable of relatingthe flow time-varyingcoupling loss factor and the asymptotic coupling loss factor, field and the acousticfield of confinedjet flows.[Work supportedby determinedexperimentally, are usedin energybalance equations to pre- ONT and ONR. ] dictthe time-varying vibration envelopes of a systemof twopoint-coupled platesand the resultsare compared.Although overall response predic- tionsare similar, considerable differences are notedin individualfrequen- cy bands.

11:10

PPS. Acousticcharacteristics of confinedjets. Part 2: Measurements. Karo W. Ng (Naval UnderwaterSystems Center, Newport, RI 02841- 5047) and Peter R. Stepanishen(Department of Ocean Engineering, Universityof Rhode Island, Kingston,RI 02881) 11:55

The flow and acousticcharacteristics of confinedjets were measured PPII. A nonlinear theory for high-frequencyvibrations of piezoelectric by a laserDoppler velocimeter, flush-mounted hydrophones, and acceler- crystal rods. M. Cengiz Dokmeci (Faculty of Aeronautics and ometers.Unrestricted pipe flow and flowsrestricted by variousorifices Astronautics,Istanbul Technical University, P.K. 9, Istanbul 80191, were testedfor,a wide rangeof velocitiesto simulatethe flow in piping Turkey) systems.Wall pressuredata showedthat the noiselevels vary with the pipe'saxial locationand the peak noise is locatedin the vicinityof the end This paperis addressedto a systematicderivation of a hierarchyof of thejet potentialcore. Correlations of wallpressure fluctuations with jet one-dimensionaltheories for themotions of crystalrods in viewof the velocity showed a velocity to the 3.7th to 5.0th power relationship. A author's review article l ShockVib. Dig. 20 (2), 3-20 (1988) ]. The non- nondimensionalwall p•ssure spectrumwas established for the various linear theoriesare derivedusing a unifiedvariational principle [IEEE confinedjets by the Strouhalrelationship, where the lengthscale is thejet UFFC, 35(6) (November1988) ] togetherwith the trigonometricseries hydraulicdiameter. This jet pressurespectrum agrees well with the wall expansionsof thefield quantities [of. Int. J. SolidsStructures 10{4), 401- pressurespectrum of a turbulentboundary layer above a rigid plane.Cor- 409 (1974)]. All the mechanicaland electricaleffects and the material relationsof wall pressurefluctuations and pipewall accelerationsignals nonlinearityare taken into account.The resultingequations govern all the showedthat jet flowsgenerate more deterministic features than pipe flow. extensional,thickness, flexural, torsional, and coupled motions of crystal The coherencefunctions of the wall pressureand pipe wall acceleration rods.By a propertruncation of the seriesexpansions, special motions and signalsare relativelyhigh near the exit of the jet. The high coherenceis materialof crystalrods are considered.Also, the fully linearizedequa- probablydue to the large-scalecoherent structures. Experimental results tions of crystal rods are examined.The sufficientboundary and initial for wall pressureand accelerationcompared reasonably well with the conditionsare enumeratedso as to ensurethe uniquenessin solutionsof theoreticalmodel for a widerange of parametersof interest.[Work sup- the linearizedrod equations.[Work supportedby U.S. Army throughits ported by ONT and ONR. ] EuropeanResearch Office. ]

S104 J. Acoust.Soc. Am. Suppl. 1, VoL85, Spdng1989 117thMeeting: Acoustical Society of America $104 THURSDAY MORNING, 25 MAY 1989 ROOM 202, 9:30 A.M.

Meeting of AccreditedStandards Committee S12 on Noise

to be heldjointly •vith the

TechnicalAdvisory Group for ISO/TC 43/SC1 Noise and ISO/TC 94/SC12 Hearing Protectors

W. Melnick, Chairman S12 OhioState University,University Hospital Clinic, 456 W. loth Avenue,Columbus, Ohio 43210

H. E. von Gierke,Chairman, Technical Advisory Group for ISO/TC 43/SC 1 1325 Meadow Lane, YellowSprings, Ohio 45387

StandardsCommittee S12 on Noise. Working group chairs will reporton their progress under the plan for the productionof noise standards. The interaction with ISO/TC 43/SCI andISO/TC 94/SC12activities will also bediscussed, with referenceto theinternational standards under preparation. The Chairof therespective U.S. TechnicalAdvisory Groups (H. E. vonGierke) will reporton currentactivities of thesecommittees.

THURSDAY MORNING, 25 MAY 1989 REGENCY C, 8:45 A.M. TO 12:05 P.M.

SessionQQ. UnderwaterAcoustics VI: Spatialand Temporal Variability of AmbientNoise I

Frederick H. Fisher, Chairman MarinePhysical Laboratory, P-001, Scripps Institution of Oceanography,University of California,San Diego, La Jolla, California 92093

Chairman's Introduction---8:45

Invited Papers

8:50

QQI. Remotesensing of theocean bottom using the vertical directionality of theambient noise in thewater column.Michael J. Buckingham(Mission Management Department, Royal Aerospace Establishment, Farnborough,Hampshire GU 14 6TD, England) Thevertical directionality ofambient noise inthe shallow ocean overlying afast, fluid sediment 'isa stable featureof the noise field. It iscontrolled by the reflection properties ofthe bottom, most notably the fact that the water/sedimentinterface shows a criticalgrazing angle at. Noiserays that are incident on thebottom at grazingangles greater than at penetratethe interface and are lost to thewater column, whereas rays with shallowergrazing angles are totally internally reflected. The latter remain trapped in the channel, and contrib- uteto thenoise field. Thus, the noise field shows a symmetricalpeak in thehorizontal whose angular width is 2ac. Measurementsof the vertical directionality of the ambient noise have been made at sixsites around the U.K. coastusing air-deployed vertical line arrays. From these data, estimates of thecritical grazing angle have beenobtained. Since the sound speed in thewater column was also known from AXBT data,it waspossible to inferfrom the measuredvalues of a,. thesound speed in thesediment. A comparisonof thesediment sound speedobtained from the new noise technique with the results obtained by an independent survey using conven- tionalseismic methods shows excellent agreement.

S105 J.Acoust. Soc. Am. Suppl. 1, Vol. 85, Spring 1989 117thMeeting: Acoustical Society of America S105 9:20

QQ2. Simulation of array processingin three-dimensionalnoise fields: Suggestedexperiments. John S. Perkins,Bruce H. Pasewark,and W. A. Kuperman(U.S. Naval ResearchLaboratory, Washington, DC 20375-5000)

The growingcapability to modelthree-dimeosionai noise fields in complexocean environments taken togetherwith concurrentrecent developments in matched-fieldprocessing (MFP) suggestsnoise experiments thatwill shedlight onto the physicalprocesses generating and propagating the noise fields. These experiments shouldespecially yield information concerning the noisefield as it impactson signaland/or array processing. Someof theexpected (modeled) characteristics of low-frequencyambient noise in a deepocean basin with realisticcomplexity and its subsequentimpact on MFP are reviewed.For example,the effectson MFP of down-slopeconversion from discrete sources {surface ships) and distributed sources (storms), and theeffec- tivenessof variousrejection techniques are demonstrated. These results suggest experiments to investigatethe mostimportant processes.

9:50

QQ3. Low-frequency ocean ambient noise variability: Measurements. David G. Browning. William M. Carey, and William A. Von Winkle {Naval UnderwaterSystems Center, New London,CT 06320)

The interactionof the wind with the oceansurface is recognizedas a major sourceof ambientnoise, however,at low frequencies{ < 200 Hz) it isoften difficult to isolatewind-generated noise from shipping noise. Thisis furthercomplicated by a relativelylow transmissionloss at thesefrequencies which allows possible noise contributionsfrom long distances and various propagation paths. An analysisis made of historicambient noise data basedon recentdevelopments in noisegeneration and soundpropagation theory to sortout the ship- generatednoise component. The resultsappear to supporttwo distinctwind-generated noise mechanisms which may be delineated,as suggestedby Kerman, by a critical surfacevelocity.

10:20

QQ4. lee edge noise "hot spots." Orest Diachok, Patricia Gruber, Peter Mitchell (Naval Research Laboratory,Code 5120, Washington, DC 20375), and George Vermillion( U.S. Naval Station,Rots, Spain) Previouslyreported and newmeasurements of the noisefield at the peripheryof the ArcticOcean will be reviewed.Previous measurements with sonobuoysreveal that ambientnoise levels are usuallyhigh at the ice edge,and that levels increase with windspeed, ice concentration, and fetch. Subsequent measurements of the noisewith a towedarray (by Yanget aL ) indicatethat the edge noise is concentrated at spaticilylocalized ( < 5 kin), widely separated(nominally 30 km) "hot spots."To shedmore light on this noisesource and its predictability,an experiment was conducted with a towedarray to probethe hot spots acoustically with a ship- towedarray, and electromagneticallywith an aircraft-mountedpassive microwave imager, a ship-mounted radar,and satellitesensors. Results of thesemeasurements and their implicationsfor the predictabilityof hot spotlocations, effective source levels, and long-range effects will be presented.

ContributedPapers 10:50 concentrationand floe size distribution. These parameters provided infor- mationabout how ice caninfluence the ambientnoise level and frequency QQS. Ice edge ambient noise. Ola M. Johannessen,Hanne Sagen distribution.Procedures to enhancewave signaturein the SAR images (NansenRemote Sensing Center, Edv. Griegsv. 3A, N-5037Solheimsvik, were usedto analyzethe wave pattern.Correlation between SAR and Norway), KennethV. Starke(Naval OceanSystem Center, San Diego, ambientnoise data supportthe hypothesisthat eddiesand jets represent CA 92152), Ingjald Engeisen(Norwegian Defence Res. Establishment, noiselevel anomaliesalong the ice edge. Horton, Norway), and Susan Payne (Applied Research Laboratory, University of Texas, Austin, TX 78712) Ambient noisedata alongwith oceanographic,meteorological, and remotesensing data were collected during the MarginalIce ZoneExperi- mentin March andApril 1987in the GreenlandSea. The experimentwas designedto studyhow ambientnoise was generated by ice kinematics,ice 11:05 edge eddies,and wave propagationinto the ice pack. Sohobuoyswere deployedin the wateroff the ice edgeand in the adjacentice-field where QQ6. Measurementsof ambientnoise "hot spots"along the ice edgein eddies,jets, and surfacewaves were present.SAR imagesof the area were the Greenland Sea Marginal lee Zone. Kristian P. Biggs (Naval obtainedduring the ambientnoise recordings and providedimportant PostgraduateSchool, Monterey, CA 93943), PatriciaL Gruber (AT&T informationsuch as positionof the ice edgerelative to the SohObUoys. Bell Laboratories, 1201 S. Hayes Street, Arlington, VA 22202), and Advancedimage processing enabled ice classification, and estimates of ice RobertH. Bourke(Naval PostgraduateSchool, Monterey, CA 93943)

8106 J. Acoust.Soc. Am. Suppl.1, Vol. 85, Spring1989 117th Meeting:Acoustical Society of America S106 During July 1987,an experimentwas conducted to measureambient 11:35 noisealong the iceedge in theGreenland Sea. Ambient noise "hot spots," concentratedareas of relativelyhigh noiselevels, were located along the QQg. A switched-sourcemodel for simulating Arctic underseanoise. ice edgeusing a towedarray. Ambient noiselevels were then recorded SamuelM. Nagle (Honeywell Marine SystemsDivision, M/S 3D02, usingSOhObUOyS deployed from P3 aircraft.The SOhObUOy data were aver- 6500 Harbour HeightsParkway, Everett, WA 98204-8899) agedin time to obtainthe noisespectra below 2 kHz. The temperature A switched-sourcemodel is developedfor simulatingthe impulsive structureof the areawas determined by XBT and AXBT buoysand the characterof Arctic underseanoise. The modelis basedon one proposed iceedge location was determined from coincident satellite photos, 90-Ghz by S.V. Czarnecki["Nearly optimal detection of signals in non-Gaussian microwaveimagery, and P3 radar ice edge maps. The relationship noise,"Ph.D. thesis,Dept. of'EECS, PrincetonUniv. (October 1983)] betweenthe environmentaland acousticdata suggeststhe existenceof hot whereimpulsive and normal backgroundnoise regions are treatedas com- spotswhich are ( 1) primarilyrelated to windand sea state and (2) pri- ingfrom two independentGaussian sources with differingvariance. P. K. marily relatedto ice edgecompaction by eddy flow. Willet and J. B. Thomas [IEEE J. Ocean. Eng. OE-12, 29-37 (1987) l havesuggested that the dual modenoise sequence can be treatedas sta- tionaryand dependentif the stateof the sourceselection switch is gov- ernedby a two-stateMarkov process.In this papera statisticalanalysis is conductedon a I 0-rain time seriesof Fram 2 noisedata in order to provide a completestochastic description of realnoise data within the framework of sucha model.An earlierpoint process analysis is extendedby examin- ing theduration and amplitude of burstevents. Results of the analysisare 11:20 usedto specifythe dual source characteristics, and the terms of thetransi- tion matrix for the Markov process. QQ7. Updateon an evolvingmodel for predictingthermally induced noise from Arctic packice. Peter J. Stein(Atlantic AppliedResearch Corp., 4 "A" Street, Burlington, MA 01803), James K. Lewis (Science ApplicationsInternational Corporation, 1304 Deacon, College Station, 11:50 TX 77840), and Warren W. Denher (ScienceApplications International Corporation,205 MontecitoAvenue, Monterey, CA 93940) QQ9. Simulatingand processing the Arctic acousticsdue to ice dynamics. C. A. Pomalaza-Raez,S.S. Shahart(Department of Electrical and ComputerEngineering, Clarkson University, Potsdam, NY 13676), and Fracturingof Attic packice due to thermalstresses is knownto be a H. H. Shen (Departmentof Civil and EnvironmentalEngineering, sourceof higherfrequency ( > 300-Hz) Arctic ambientnoise. Recently, ClarksonUniversity, Potsdam, NY 13676) Lewisand Denner [J. Acoust.Soc. Am. 84, 1444 (1988) ] reportedon a numericalmodel for predictingtemperature profiles through the ice. Under sea-icenoise, in particularthat producedby ice floesin the They showedthat ice temperatures,and thus the stressesthat lead to Arcticregion, is studied by meansof a modelsimulation and the develop- fracturing,are a functionof sensibleheat flux, solar radiation, and long mentof signalprocessing techniques for itsmeasurement and estimation. waveradiational heat flux. This impliesa dependenceon snowand cloud This noiseis due to the interactiouamong ice floesthat producesnon- coverand explains some of thevariations in higherfrequency noise. Here Gaussiannoise in timeand frequency. Based on previousstudies, a Gaus- an extensionof the model to include estimation of stressesin the ice via a sian shapeacoustic wave pressuregenerated by a singlecollision is stress-strainrheology that includescreep is reported.These calculations assumed.The randomoccurrence of theice collision process is modeled as canbe used to predictfailure of the iceat a givendepth in the ice.The ice a Poissonsequence of impulses.Different sonar array spectrum estima- wasfound to fail notonly nearthe surface, where the maximumtempera- tion techniques[Fourier, autoregressive (AR), and minimumvariance turevariations occur, but alsodeep within the ice.Acoustic data show (MV) ] areanalyzed for theprocessing of theresulting acoustic signal. It that the radiationfrom the surfacefracturing is strongerthan the radi- is foundthat the minimumvariance spectral estimation technique is the ationfrom the deep fracturing. Variations in acousticsource strength for a overallbest for this type of signalfor a wide rangeof the modelparam- crackin the ice as a functionof depthwithin the ice may explainthis eters.Previously reported studies have often used the periodogramtech- feature.[Work supportedby ONR. ] niquethat asshown here usually gives poor results.

THURSDAY MORNING, 25 MAY 1989 NEWHOUSE I, ROOM A1, 9:45 TO 11:30 A.M.

SessionRR. PsychologicalAcoustics VI: General Psychoacoustics

Richard Freyman, Chairman Departmentof CommunicationDisorders, University of Massachusetts,Amherst, Massachusetts 01003

Contributed Papers

9:45 The psychometricfunction of an experimentalsubject is almostcer- tainlynot fixed, but varies in responseto nonsensoryfactors such as atten- RRI. Computer simulationsof mutable psychometricfunctions. Marjorie tion and learning. This is particularly true when the subjectis inexper- R. Leek (Army Audiology & SpeechCenter, Walter Reed Army ienced,or the complexityof the taskrequires a substantialallocation of MedicalCenter, Washington, DC 20307-5001), ThomasE. Hanna,and attentionalresources by the subject.With commonlyused psychometric Lynne Marshall (NSMRL, Box 900, SUBASENLON, Groton, CT proceduresit is impossible to knowwhether a shallowpsychometric func- 06349) tionslope is a truereflection of thesensory process, or isa resultof"aver-

S107 J. Acoust.Soc. Am. Suppl.1, Vol. 85, Spring1989 117thMeeting: Acoustical Society of America S107 aging"a highlyvariable underlying function. Computer simulations were 10:30 usedto assessthe ability of a 2IFC adaptiveprocedure with two inter- RR4. Perceived distance and loudness-softness functions. leavedtracks to monitor the stabilityof the underlyingpsychometric functionover the course of an experiment.Variability due to the slopeof Miguelinn Guirao (Auditory Perception Laboratory, Northeastern the underlyingfunction and the measurementprocedure will be reflected University, Boston, MA 02115 and Laboratorio de lnvestigaciones Sensoriales CONICET, Facultad de Medicina UBA, Buenos Aires, in the averagelevel difference between the two tracks(across-track mea- surement),while the additionalvariability due to a changingpsychomet- Argentina) ric function will be reflected in the within-track level differences. Simulat- Experimentswere designed to investigatethe relationbetween audi- ed psychometricfunctions were either fixed across all. trials, shifted along tory-perceiveddistance and sound intensity. A puretone at 1000Hz anda the"stimulus" axis according toeither a sinusoidalorsquare-wave move- wideband of noisewere heard through earphones in a soundproofroom. ment (to simulatedrifts or lapsesof attention,respectively), or shiftedby Soundswere presented at randomand at continuouslyincreasing or de- a negativeexponential function to simulatelearning effects. The across- creasinglevels over a stimulusrange from 20 to 80 dB SPL. Naive listeners track variability remainednearly constantacross all attentionalcondi- with normalhearing estimated distance by judging nearness (proximity) tions,and wasdependent almost entirely on the underlyingslope of the and farness(remoteness). They alsojudged loudness and softness. Judg- function.However, within-track variability was stronglyaffected by the ments were made by a conventionaland two modified versionsof the changesin psychometricfunction location. An estimateof underlying methodof magnitudeestimation. According to preliminaryresults, the slopemay be obtained from theacross-track variability, and an indication effectof stimuluslevel on the responsesdepends on whetherthe subjects of the relativestability of the underlyingfunction can be extractedfrom are instructedto judge the soundin termsof its nearnessto or distance within-trackvariability. [ Work supportedby the VA. 1 from them.The nearnessand farnessfunctions are similarin shapeto the loudnessand softnessfunctions, respectively. Results are discussedin relationto theauditory attributes of densityand volume.[ Work support- ed by NIH. ]

10:00

RR2. Effect of thresholdon the growth of loudnessat low frequencies. Wait Jesteadt (Boys Town National Institute, 555 N. 30th Street, 10:45 Omaha, NE 68131) and Larry E. Humes (Departmentof Speechand HearingSciences, Indiana University, Bloomington, IN 47405) RRS. Pure-toneintensity dlserimination in hearing-impairedand normal- hearinglisteners. Anna C. Sehroder,David A. Nelson(Department of Loudnessis generally thought to increaseas a functionof intensityat a Otolaryngoiogy,University of Minnesota,Minneapolis, MN 55455), and morerapid rate at frequenciesbelow 500 Hz thanat higherfrequencies. It Neal E. Viemeister (Department of Psychology, University of is well establishedthat loudnessincreases at a morerapid ratenear thresh- Minnesota,Minneatmlis, MN 55455) old for all frequencies.To whatextent can the patternof loudnessgrowth at low frequenciesbe accountedfor by a combinationof the threshold Intensityjnd's for 500-mstones were obtainedfrom five cochlear- effect and the marked increase in threshold below 500 Hz? To answer this impaired and three normal-hearingsubjects. The jnd-level functions, question,equations incorporating the thresholdeffect were fitted to sever- from thresholdto 97 dB SPL, weremeasured at five testfrequencies, in al setsof data in the literaturedescribing growth of loudnessat low fre- quiet and in high-passnoise. The "near-miss"to Weber'slaw was ob- quencies.Two suchequations are generallyused: •b = k(• - •b,,)t• or servedfrom normalsin quiet,from two subjectswith fiat losses,and from •b= k(• - • ), where•b represents the psychological magnitude, • rep- regionsof normalthreshold in threesubjects with high-frequency loss. In resentsthe stimulusintensity, and 4•orepresents stimulus intensity at thesame three ears, at frequenciesjust belowand within the region of loss, threshold.With the exponent/• held constantacross frequencies and k jnd's conformedto Weber'slaw, as did thejnd's obtainedin the presence allowedto vary,either equation can account for very highpercentages of of thenoise for all subjects.These results are consistent with explanations variancein the data and the residualerror varianceis not systematicas a of the near-missthat involveexcitation at frequencyregions well above functionof frequency.This analysissuggests that the exponentof the the testfrequency. At equalSPLs, jnd's in quiet from impairedsubjects loudnessfunction does not changewith frequency.[ Work supportedby wereequal to, or largerthan, jnd's from normals.At equalSLs, jnd's in NIH. l quietfrom hearing-loss subjects were sometimes smaller than normal, but wereusually elevated by high-passnoise, thus implicating the near-miss. In someeases, however, jnd's at low SLs werestill smallerin the noise, which may reflectthe steeperrate-level functions seen in the auditory nervein regionsof cochlearloss [ M. C. Libermanand N. Y.-S. Kiang, 10:15 Hear. Res.16, 75-90]. [ Work supportedby NINCDS Grant NS 12125.I

RR3. The slol•eof the loudnessfunction for individualsand groulmwith normal and imlmired hearing. Rhona P. Hellman and Carol H. Meiselman (Auditory Perception Laboratory, Northeastern University,Boston, MA 02115) II:00

The slopeof the loudnessfunction for pure tonesis derivedat a fre- RR6. Auditory filter shapes at low frequencies.Robert W. Peters quencyin the regionof impairedhearing for more than 90 peoplewith (Speechand Hearing Sciences,Department of Medical Allied Health, bilateralmoderate-to-severe cochlear hearing losses. Calculations of the Universityof North Carolina, Chapel Hill, NC 27514) and Brian C. slopesare obtainedover the stimulusrange where cochlear impairment $. Moore (Department of Experimental Psychology,University of steepensthe loudnessfunction. Slope distributions for impaired hearing, Cambridge,Cambridge CB2 3EB, England) determinedfrom magnitudeestimation and productionand from cross- modalitymatching, are comparedto thoseobtained in a similarmanner Auditoryfilter shapes were measured in normallyhearing subjects for for 51 peoplewith normalhearing. Values of the slopesreveal two distinct centerfrequencies (J•,.) of 100,200, 400, and 800 Hz usingthe notched- populations.Most of the slopesin normalhearing vary from 0.4 to 0.7 noisemethod [ R. D. Pattersonand I. Nimmo-Smith,$. Acoust.Soc. Am. with a meanclose to 0.6; in cochlearimpairment they vary from I.I to 2.8 67, 229-245 (1980) ]. Two noisebands, each 0.4f, wide,were used; they with a meanclose to 2.0. In accordwith loudnessmatching, much of the wereplaced both symmetrically and asymmetricallyabout the signalfre- greatervariability of the impaireddistributions arises from the heterogen- quency,to allow the measurementof filter asymmetry.The overall noise city of thresholds.The resultsalso show that group loudnessfunctions level was always80 dB SPL Stimuli were deliveredmonaurally using generatedfrom cross-modalitymatching are consistentwith theoretical SennheiserHD424 earphones.Except for f,. = 100Hz, theauditory filters functionsdetermined from an equationfor loudnesssuggested by Zwis- wereasymmetric, the upperskirt beingsteeper than the lowerskirt. At Iocki [HandbookMath. Psychol.3, 3-97 (1965)]. [Work supportedby 100 Hz the filterswere more symmetric,or showedan asymmetryin the the RehabilitationResearch and DevelopmentService of the VA. ] oppositedirection. This can probablybe attributedto the reducedeffec-

S108 J. Acoust.Soc. Am. Suppl. 1, Vol.85, Spring1989 117thMeeting: Acoustical Society of America S108 tivenessof the lower noise band due to the transmissioncharacteristics of 200 Hz. In individualexperiments, numbers 1, 2, 3, 4, 5, 7, 9, theouter and middle ear. The equivalentrectangular bandwidths of the and 11 wereindividually mistuned, by 11 differentamounts ranging from filtershad averagevalues of approximately29, 42, 74, and 160 Hz for - 8% to + 8%. The experimentthus measured the shift in thepitch of a valuesoffc of 100,200, 400, and 800 Hz, respectively.The signal-to- sinecomponent caused by other componentsof the complextone. The maskerratio at the outputof the filter requiredto achievethreshold tend- experimentsshowed that for mistunedlow-order harmonicsa positive ed to increasewith decreasingf. mistuningproduces a positivepitch shift while a negativemistuning pro- ducesa negativepitch shift. For mistunedhigh-order harmonics the pat- tern is similarexcept that the pitchshifts caused by positivemistunings becomelarge. These data werecompared with a placetheory in which the peak in the excitation pattern for an individual harmonic is partially maskedby peaksdue to neighboringharmonics. Although the model 11:15 correctlypredicts the resultsfor positivemistunings, it failsdramatically RR7. On the pitch of mistunedharmonics in a complex tone. William for negative mistunings.The data are also compared with a theory Morris Hartmann and Sandra L. Smith (Department of Physics, wherebypitch is determinedby peaksin an interspike-intervalhistogram MichiganState University, East Lansing,MI 48824) per the M IT model.This theorycan account for all the data,except for the mistunedfundamental, though filter bandwidthsmust be considerably Four listenersmatched the pitchof a singlemistnned harmonic in an enlargedcompared to the MIT modelto obtainagreement. [Work sup- otherwiseperiodic complex tone, whose was near portedby the National Institutesof Health. ]

S109 J. Acoust.Soc. Am. Suppl. 1, Vol.85, Spring1989 117thMeeting: Acoustical Society of America S109 THURSDAY AFTERNOON, 25 MAY 1989 GOLDSTEIN AUDITORIUM, 1:00TO 5:00 P.M.

SessionSS. Architectural Acoustics IV and Musical Acoustics VI: Music Education Facilities Since 1975 (PosterSession)

Edward R. McCue, Chairman WengerCorporation, 555 Park Drive, Owatonna,Minnesota 55060

ContributedPapers

All posterswill be on display from 1:00 to 5:00 p.m. (Viewing hours will also be extended into the evening. ) To allowcontributors an opportunity to seeother posters, contributors of odd-numberedpapers will beat their postersfrom 1:00 to 3:00p.m. and contributors of even-numbered papers will be at theirposters from 3:00 to 5:00p.m. Contributors areencouraged toleave their posters inplace until 9:45 p.m. A cashbar will be set up in theevening to facilitateinformal discussion. The Goldstein Auditorium will be closed at 10:00p.m.

Posterswill bepresented by thefollowing persons and organizations:

David L. AdamsAssociates, Inc. KlepperMarshall King Associates,Ltd.

Artec Consultants Marshall Long Associates

Bolt Beranek and Newman Inc. NHK EngineeringServices, Inc. (Japan)

CampanellaAssociates MinoruNagata Acoustic Engineer & AssociatesCo., Ltd. (Japan}

CavanaughTocci Associates, Inc. Paoletti/Lewitz/Associates,Inc.

CoffeenFricke & Associates,Inc. AdviesbureauPeutz & AssociesB. V. (TheNetherlands)

Officeof M. David Egan,Consultants in Acoustics GeraldA. B. Riley (Australia)

Harold GeerdesConsulting Services TNO Instituteof AppliedPhysics (The Netherlands)

Peter GeorgeAssociates, Inc. PeterTerroux, Consultant in Acoustics(Canada)

Jaffe Acoustics,Inc. Towne, Richards & Chaudiere,Inc.

AdrianW. D. Jorigens(South Africa) Wilson,lhrig & Associates,Inc.

R. Lawrence Kirkegaard and Associates

Sl 10 J. Acoust.Soc. Am. Suppl. 1, Vol.85, Spring1989 117thMeeting: Acoustical Society of America S110 THURSDAY AFTERNOON, 25 MAY 1989 AMPHITHEATER, 1:00TO 5:30 P.M.

SessionTr. Educationin AcousticsI: Demonstrationsof Experimentsin Acousticsand Undergraduate Posters(Lecture and PosterSession)

Mark F. Hamilton, Cochairman Departmentof MechanicalEngineering, University of Texasat Austin,Austin, Texas 78712

Murray $. Korman, Cochairman Departmentof Physics,U.S. Naval Academy,Annapolis, Maryland 21402

Chairman's Introduction•l:00

In vitedPapers

1:05

TFI. Demonstrationsof underwaternoise generationby bubbles.Lawrence A. Crum and Hugh C. Pumphrey(National Center for PhysicalAcoustics, University of Mississippi,University, MS 38677) In 1933,Minnaert demonstrated that the soundof a babblingbrook was due to the oscillationsof gas bubblesentrained in the water [M. Minnaert, Philos.Mag. 16, 235 (1933) ]. In 1959,Franz discoveredthat raindrops could produce relatively large amounts of underwaternoise through the entrainment of gasbubbles duringdrop impact [G. J. Franz,J. Acoust.Soc. Am. 31, 1080(1959) ]. In 1988,Prosperetti suggested that a majorcontribution to oceanambient noise was due to bubbles[A. Prosperetti,J. Acoust.Soc. Am. 84, 1042 (1988) ]. A seriesofdemonstration experiments will bepresented that arenot difficult to assembleand that will showthat gasbubbles are a majorsource of underwaternoise for a varietyof hydrodynamicsituations. [The researchleading to the understandingof theseeffects has been supported by the ONR. ]

1:30

TT2. Demonstrationsof nonlinearosei!lators, l•arametrieexeitation, andsolitons. Robert Keolian(Applied and EngineeringPhysics, Cornell University, Ithaca, NY 14853)

The peculiarbehavior of nonlinearoscillations will be demonstratedwith a seriesof experimentsselected from thoseshown previously in Austin [J. Acoust.Soc. Am. Suppl.1 77, S35 (1985) ]: ( I ) A stretchedrubber band,driven by a loudspeaker,exhibits hysteresis due to its bentresonance curve. (2) A doublybent resonance curveand hysteresisare exhibited by a paramelricallydriven pendulum bouncing against stops. ( 3 } A hanging chainundergoes quasiperiodically modulated vibrations, where the modulations have a frequencyindependent of that of the drive. (4) A parametricallydriven rigid pendulumwill defy gravityby standingon end and oscillatingupside down. (5) Standingwaves on a troughof water will be parametricallydriven, as seenby MichaelFaraday. (6) A nonpropagatingsolitoh [ Phys.Rev. Lett. 52, 1421(1984) ] will beshown in a trough of water, and two of these solitons will oscillate about each other.

1:55

TF3. Education, research, and acoustic levity: Miscellaneous demonstrations.J. D. Maynard (The PennsylvaniaState University, 104 Davey Lab, UniversityPark, PA 16802) Duringthe course of teachingand conducting research in acoustics,a number of demonstrationshave been developed.Some have beenfor classroomeducation, some have beenfor our own education,some have beenfor entertainment,and some have led to seriousresearch projects. These demonstrations include the sonicmotor, acousticlevitation, the projectedChladni plale, shockinception, noise riding sound,following a massand springto chaos,acoustic Anderson localization, and tuning up a quasicrystal.The demonstrationswill be presentedas permittedby time and transportationlimitations.

Slll d. Acoust.Soc. Am. Suppl. 1, VoL85, Spring1989 117thMeeting: Acoustical Society of America Slll 2:20

'I'r4. A simpleapparatas for the acousticlevitation of a dropin a liquid.Robert E. Apfel (Departmentof MechanicalEngineering, Yale University,P.O. Box 2159, New Haven,CT 06520) A simpleapparatus consisting of a piezoelectricdisc, beaker, function generator, audio amplifier, current probe,and oscilloscope issufficient. todemonstrate the acoustic levitation of a liquiddrop in animmiscible host liquid.Applications of acousticlevitation, which include measuring the tensilestrength of liquids,sound velocity,interfacial tension, and other properties, will bediscussed. [This was has been supported by the Office of Naval Research.]

2:55

TT5. Simpledemonstration of a thermoacousticsound source. Thomas J. Hofler,Anthony A. Atchley,and StevenL. Garrett(Physics Department, Code 61, NavalPostgraduate School, Monterey, CA 93943) A simplethermoacoustic prime mover, known as the "Hoflertube," consisting of an open-closedtube containingmany G- 10fiberglass plates will be demonstrated. Sound of sufficientlylarge amplitude to produce streamingisgenerated when a temperaturegradient is imposed across the thermally insulating plates. The use of heliumgas rather than air asthe thermodynamic working fluid provides a dramaticdemonstration of the effectsthat sound speed and other thermal properties, such as the polytropic coefficient, have on the efficiency ofacoustic power generation from the thermoacoustic process. A simple model will be provided to explain the enginebehavior to a nonscientificaudience.

3:20

TF6. Demonstrationof computer-basedSOhograph display. Alan D. Stuartand Glenn Frey (Graduate Programin Acoustics,The PennsylvaniaState University, University Park, PA 16802) A computer-basedsonograph display has been developed that shows the amplitude of thefrequency spec- trum as a functionof time.Depending on the speedand processingcapabilities of the computer,real-time displayscan be obtained. The data acquisition procedure developed along with the display provides a means for conductingboth detailed statistical analysis of thedata as well as subjecting the data to otherpost processing analysis.

ContributedPapers

3:45 Thesing-around velocimeter [M. Greenspanand C. Tschiegg,Rev. Sci.Instrum. 28, 897-901 (1957) ] iscapable of greatprecision and is an TI'7. Demonstrationson the scatteringof ultrasoundby turbulencein elegantmeasurement technique. It is alsorelatively easy to implement water. Edward C. Zurey and Murray S. Korman (Departmentof withlow-cost electronics. Besides the obvious experiments on the depend- Physics,United States Naval Academy,Annapolis, MD 21402) enceof soundspeed in gaseson temperatureand molecular weight, it is A beamof monochromaticsound incident on a turbulentvelocity field alsopossible to measuregas diffusion rates or demonstratethe adiabatic (producedby a submergedwater jet) is scatteredby thevelocity fluctu- natureof acousticoscillations. Absolute measurement of soundspeed ationsin theflow. Angular measurements of the Doppler shift and spec- within 1% is easilydone. These demonstrations were developed for a tralbroadening in thereceived frequency spectrum of thescattered sound graduate-levelthermodynamics course given at the PennsylvaniaState intensityhelp to characterizethe mean flow and rms velocitiesof the UniversityGreat Valley GraduateCenter. turbulentfield, respectively. Scattered spectra are displayed for compari- sonin thecases where the incident beam is generated by a pointsource. a planecircular array, and a focusedspherical array transducer. Results are shownin an arrangementwhere the focusedbeam scans across the width of thejet. Scatteringtheories are brieflymentioned in light of spectral broadeningresults.

4:15

TY9. Videotapedemonstrations of auditoriumdesign principles using acousticscale models. Gary W. Sicbein(Department ofArchitecture, 4:00 231 ARCH, Universityof Florida, Gainesville,FL 32611) TTS. Measurementof the soundspeed in air by sing-aroundveloclmetry. A videotapedemonstration was developed to illustrateacoustical de- ThomasB. Gabrielson( 1216Barness Drive, Warminster,PA 18974) signprinciples for auditoria to undergraduatearchitecture students. An

S112 J. Acoust.Soc. Am. Suppl. 1, Vol.85, Spring1989 117thMeetir•g: Acoustical Society of America Sl 12 acoustical scale model of an auditorium was constructed with removable 4:30 walls,floor, and ceiling.Starting with a microphonein freespace, an enclosureisbuilt in stepsaround the source and receiver. An echogramis TT10. Sources for demonstrationexperiments in acoustics.Thomas recordedat eachstep so students can seethe effectof increasedenclosure D. Rossing(Department of Physics,Northern Illinois University, on the soundthat arrives at the listener'sposition. Theater seating, var- DeKalb, IL 60115) iousquantities of absorbentmaterial, acoustically shaped ceiling panels, Many teachers,since the time ofChladni, Helmholtz,and Rayleigh, and diffusingelements are addedto the enclosureas the demonstration haveused demonstration experiments to enhancetheir students'under- progresses.Echoes, excessive loudness, flutter, and other basic acoustical standingof acousticalphenomena. Some sources for descriptionsof suit- problemsand their solutionsare presented.The demonstrationsshow able experimentsfor lecturedemonstrations, corridor demonstrations, changesin the impulseresponse of the roomas changes are madein the and laboratoryuse are discussed,as well as the author'sexperience with shapeand volumeof the room.It servesas an introductionto acoustical usingdemonstrations experiments in acousticscourses at variouslevels of modelingand auditoriumdesign for the students. instruction.

PosterPapers

Contributorswill be at their postersfrom 4:30 to 5:30p.m.

TTI1. SimultaneousSLAM imagingand tensileloading of copperfilms. WayneM. Wright (AppliedResearch Laboratories, The Universityof WendyC. Crone(Department of Theoreticaland AppliedMechanics, Texas at Austin, P.O. Box 8029, Austin, TX 78713-8029and Mechanical Universityof Illinois,216 Talbot Lab, 104S. WrightStreet, Urbana, IL EngineeringDepartment, The Universityof Texasat Austin,Austin, TX 61801} 78713-1063)

Preliminaryexperiments on imagingthe mechanicalproperties of copperfilms (I and 5 mil thick) havebeen performed with the scanning laseracoustic microscope (SLAM). Assessmentof materialproperties An airborneexperiment to modelthe intense pulse field developed by can be obtainedthrough attenuation and speedmeasurements with the a iithotripteris in progress.The reflectoris half an ellipsoid,machined SLAM. Transmissioncurves for a copperfilm wereobtained at 24 and 30 froman aluminumblock and having the following dimensions: major axis MHz to assessthe effects of thickness and stiffness of the film. Predictions 280 ram, minor axis 140 ram, eccentricity0.866, distancefrom aperture ofoptimum insonifieation angle were then determined for 100MHz. Real planeto eitherfocus i 21 min.An electricspark at theinterior focal point time imagesof a copperfilm with a small crack were obtainedwhile generatesan N wavepulse. The reflectedwave in the exteriorregion is stretchingwas induced. Results are encouragingand the imagesdisplay observedwith the aid of a condensermicrophone having a very wide changesin the attenuationand speedin the regionof the cracktip as the bandwidth.Of particularinterest is the sequenceof axial measurements filmis loaded.It is suspectedthat thesechanges are caused by the plastic fromthe aperture to theexterior focus and beyond. Expectations based on deformationnear the cracktip. Furtherexperiments are beingconducted lineartheory were that the pulsewould start out N-shapednear the aper- to verifythis and to measureother mechanical properties. [Advisor: John ture.become U-shaped in theneighborhood of thefocus (because of phase Harris. Work donein cooperationwith SONOSCAN, Inc. and the Bio- changescharacteristic of three-dimensionalfocusing), and take on the acousticsResearch Laboratory of the Universityof Illinois.! shapeof an invertedN beyondthe focus. Measurements confirm expecta- tionsfor theprefocal and focal regions. Beyond the focal region, however, theshape is not an invertedN. Insteadit moreclosely resembles the U- Till2. Focusingof an N waveby an ellipsoidalreflector: An experimentin shapedpulse recorded at thefocus. [Work supportedin partby Officeof air. StepbenT.W. Cheng,MattbewR. Jones,DavidT. Blackstock,and NavM Researchand Texas Advanced Research Program. ]

Sl 13 J. Acoust.Soc. Am. Suppl. 1, Vol.85, Spring1989 117thMeeting: Acoustical Society of America Sl 13 THURSDAY AFTERNOON, 25 MAY 1989 COMSTOCK A, 1:00 TO 5:00 P.M.

SessionUU. EngineeringAcoustics VII: Acoustic Measurementsand General Topics

Robert D. Finch, Cochairman Departmentof MechanicalEngineering, University of Houston,Houston, Texas 77204

Ilene J. Busch-Vishniac, Cochairman Departmentof MechanicalEngineering, University of Texas,Austin, Texas 78712

ContributedPapers

1.•o nipulationand to improvethe precision, the liquid is replaced by a calibra- ted plungerand an electronicpressure transducer. The volumedisplace- UUI. A method for measuring dynamic properties of soils. Jerry mentbeing kept small, the temperature rise is minimaland theisothermal E. Fatstad (Research Department, Columbia Gas System Service conditionis obtainedwithout the needto useany liquid-filledbath to Corporation, 1600Dublin Road, Columbus,OH 43216) stabilizethe temperature.A calibrationprocedure is requiredthough, to A methodis proposedfor measurementof the elasticand damping accountfor possiblemovement of the transducerdiaphragm. Preliminary propertiesof soilsin the 100-to 1000-Hzfrequency range. The soilsare experimentalresults and error analysissuggest that porositycan be mea- assumed to behave as linear viscoelastie materials. The measurement suredwith thisapproach with 1%-2% accuracy. techniqueinvolves exciting vibration of a soilsample through fixtures of knowndynamic characteristics. The mechanicalimpedance matrix of a systemcomposed of sampleand fixturesis measureddirectly. A modelof thiscombined system permits the mechanicalimpedance matrix of the 1:4• soilsample alone to beextracted. From thisthe dynamic properties of the soil materialmay becomputed. UU4. Surfacephenomena of finite amplitude,pure-tone sound on air- saturated porous materials. Jason D. Mcintosh (Department of ElectricalEngineering, University of Minnesota,Minneapolis, MN 55455)

l:lS It is well knownthat the flow resistance,as definedby Darcy'slaw, becomesa function of thefluid flow for largefluid velocities. For porous UIJ2. Comparisonof complex dielectric constant with dynamic elastic materialsin air, thereappears to betwo separate nonlinear flow regimes; moduliofseveralelastomers.J. Burns (FioridalnstituteofTechnology, for low velocities,the resistancecoefficient increases with the squareof Melbourne, FL 32901) and P.S. Dubbelday (Naval Research the fluid velocity;and for high velocities,the resistancecoefficient in- Laboratory, Underwater Sound ReferenceDetachment, P.O. Box creaseslinearly with themagnitude of thefluid velocity. In thispaper, the 568337, Orlando, FL 32856-8337) twononlinear flow regimes are paramortized for several porous materials. Nonlinearcorrections are made to linearwave theory and numerical solu- Complendielectric constants were measured for severaltypes of rub- tionsfor puretones are obtained that thenare usedto predictsurface beryelastomers over a temperaturerange from -- 10 to 30 øC.The sam- admittance,absorption, and internal pressure attenuation for infiniteand piesincluded a seriesof ncopreneswith the samecomposition except for finitelength samples. Among the phenomena predicted and also observed variable amounts of carbon black filler from 0% to 33%. These dielectric experimentallyisa peakingand then a rollingoff the surface absorption of data are comparedwith elasticmoduli measuredon similarmaterial to a finitelength sample as the surface pressure is increased.Also, a surface determinewhich elastic response is mostclosely correlated with dielectric pressurecriterion is put forth that gives an approximate maximum surface properties.The correlationis discussed in termsof physicalmodels of the pressurethat a porousmaterial could be exposed to beforethese nonlinear polymers.[Work supportedby ONR.] phenomenabecome important in describingthe material'scharacteris- tics. [This work wassupported in part by a grantfrom the DefenseSys- temsDivison of Honeywell,Incorporated. ]

1:30

UU3. Developmentof a "dry"systemfor the measurementof porosity. Yvan Champoux(Mechanical Engineering Department, Faculty of 2:00 Applied Science,Universit6 de Sherbrooke,Sherbrooke, Quebec .IlK 2RI, Canada), Michael R. $tinson, and Oilles A. Daigle (Physics UUS. Wave attenuation in 1-3 piezoceramic compositesdue to electric Division, National Research Council, Ottawa, Ontario KIA 0R6, conductivity.X.Q. Bao, Vijay K. Varadan, and VasudaraV. Varadan Canada) (Departmentof EngineeringScience and Mechanics, Research Center for the Engineeringof Electronicsand Acoustic Materials, The Pennsylvania In thispaper, an experimentalsystem that permitsrapid and conven- State University, University Park, PA 16802) ient measurementof the porosityof materialsis described.The useof liquid,either di•ctly in the techniqueor for temperaturestabilization, is Piezcceramiccomposites can be tailored to provide propagating avoided.In ;his sense,it is truly a dry porositymeasurement technique. waveswith high attenuationby introducingappropriate electrical con- Porosityis oneof severalphysical parameters required for varioustheo- ductivityinto the materials. Analysis of 1-3type piezoceramic composite reticalmodels, to characterizea porous material. The proposedtechnique materialsis presented.The optimumvalue of conductivityfor maximum is basedon the approachsuggested by Beranek[J. Acoust.Soc. Am. 13, attenuationof propagatingwaves along the PZT fiber directionis dis- 248 (1942) ]. The pressurechange in a closedvolume (with andwithout a cussed.Numerical resultsfor 1-3 PZT/epoxy compositeswith various sample)is monitoredfor a givenchange in volume.To simplifythe ms- volume fractions are shown.

Sl 14 J. Acoust.Soc. Am. Suppl.1, Vol. 85, Spdng1989 117thMeeting: Acoustical Society of America S114 2:15 3:00

UU6. Acousticsource strength measurements of cavitation noise in a UU9. Acoustic source power evaluation based on finite-difference watertunnel. Gerald C. Lauehle(Applied ResearchLaboratory, Penn intensity. Ruey-ChangWei and Anna L. Pate (Department of StateUniversity, Box 30, StateCollege, PA 16804)and Silvio Bistafa EngineeringScience and Mechanics,Iowa StateUniversity, Ames, 1A (GuaratinguetJEngineering School, State Universityof SJo Paulo, 50011 ) Guaratinguet•i,12500-SJo Paulo, Brazil) Radiatedpower of a baffledpiston was investigated by numericalsim- An experimentalinvestigation of the noisegenerated by cavitationin ulationand also by measurementsin an anechoiechamber with the useof turbulentshear flow is ycported. The cavitation is producedby theflow thefinite-difference intensity. Several parameters involved in theacoustic througha sharp-edgedorifice plate mounted in the testsection ofa 15.25- powerevaluation were investigated. These include: the typeof the scan- cm-diamwater tunnel. The unique features of thisexperiment include the ning surface(hemisphere and half-cube),the locationof the scanning directmeasurement of acousticsource strength using a reciprocitytech- surface,source directivity (ka = I and ka = 10), microphonespacing, niqueand the developmentof semi-empiricalscaling laws for the noise and the numberand density of the measurementpoints. As an indepen- produced.The sourcestrength measurement method is usefulfor waler dent experimentalcheck, a pressure-based,farfield method was usedto tunnelcavitation noise studies because it is nonintrusive;the noiseis mea- evaluatethe sourcepower. The sourcepower estimated from the finite- suredby a reciprocaltransducer located outside of the testsection, in air. differenceintensity was within i-dB agreementwith the resultsfrom the The scalinglaws for orificeplate cavitation noise are developed to include farfieldpressure based method. As a resultof thisstudy the effects of each theeffects of pressuredrop across the plate, the mean velocity through the parameteron the accuracycan be estimated, and consequentlythe choice plate,the cavitationnumber, and theair contentlevel of the water.These of theseparameters can be made. [ Worksupported by NSF.] scalingformulas were verified by runninga similartest in a 30.5-cmwater tunneland comparing the measured source strength spectra to thosepre- dictedfrom the smallertunnel results. [Work supportedby the Applied ResearchLaboratory. ]

3:15 2:30 UUI0. Shifts in transverse vibration modes of elastic beams resulting UU7. Scatter in ultrasonicwave attenuationmeasurements caused by from a discontinuityin beam stiffness. Lawrence M. McClure and transducers.Mary A. Paul and Anna L. Pate (Department of RobertD. Finch(Department ofMechanicalEngineering, Universityof EngineeringScience and Mechanics,Iowa StateUniversity, Ames, IA Houston, Houston, TX 77204-4792) 50011 ) Vibration characteristicsof elasticbeams are modifiedby a changein The scatter in attenuation of ultrasonic waves in aluminum was inves- stiffnessdue to a discontinuity.This effectwas first investigated by W. T. tigated with five broadband, nonfocused,immersion transducerswith Thompson[J. Appl. Mech.,Trans. ASME 16, 203-207 (1949) ]. In this centerfrequencies of 10and 15 MHz. Threedifferent experimental tech- paperthere is a reporton a studyof the frequencyshifts due to variations niqueswere used: two typesof multipleecho techniques and a multiple in individualparameters of a crack in a beam.A quantitytermed the thicknesstechnique. The objective was to investigatethe repeatability of signaturesum is definedin termsof deviationfrom the modalfrequencies the measurement for the same transducer and same method, the bias of an uricrackedbeam and is proposed as an indexto identifythe presence towardsa particular method,and the consistencyof the measurements of a discontinuityin a beamunder investigation.[Work supportedby acrosstransducers. No bias toward a particular methodwas found and NSF.] repeatabilitywas good. However, the resultswere found to be transducer dependent.Efforts have currently begun to imagethe transducers in order to performtheir individual characterization. This characterization will be usedinstead of modelingtransducers as rigid pistons.The effectof trans- ducer characterizationon the consistencyin attenuationmeasurement will be discussed.[Work supportedby Centerfor NDE, Ames,IA.[

3:30

UU!I. An omni-directional, ultrasonic acoustical source for three- 2:45 dimensionalposition monitoring in air. Jack Leifer and Ilene J. Busch- Vishniae(Department of MechanicalEngineering, The Universityof UUS. Use of gating techniquefor calibrating soundintensity probes. Texas at Austin, Austin, TX 78712) G. Krishnappaand V. J. Chiu (EngineLaboratory, National Research Council Canada, Ottawa, Ontario KI A 0R6, Canada) An acousticallybased means of trackingthe positionof the endeffec- tor of a movingindustrial robot arm hasbeen proposed. The systemcon- Soundintensity probe calibration in largelaboratory spaces using the sistsof an omni-directional acoustical source fixed to the robot arm, and techniqueof"time gattrig"was investigated. In thisstudy, both the sound severalstationary sensors positioned throughout the robot'sworkspace. sourceand the probeswere mounted 2.45 m abovethe room floorand the Basedupon the time-of-flightof a 500-kHz signaltraveling from the nearestreflecting surface was 4.87 m from the measurementpoint. The sourceto eachsensor, the positionof the end effectorcan be determined. sourceand thc probewere separated by 1.8 m. The lengthof the sound This schemeis potentiallyan effective,yet economicalalternative to the pulse(chirp) and triggerdday were adjustedon an FIT analyzerto morecomplex optical tracking systems currently in use.The acoustical preventthe probesfrom sensingthe reflectedsignal. The performanceof sourceincorporates an exponentiallytapered solid Webster's horn that is the soundintensity probes was compared with soundintensity derived drivenin resonanceby a commercialpiezoelectric transducer mounted on from soundpressurc level measurementsby a singlecalibrated micro- itswide end. A high-amplitudevibration is produced at thenarrow end of phone.Both the two-microphoneprobe and the probe incorporating di- the horn, wherethe resultingsound field can be describedby the piston rect measurementof particlevelocity were examined at severalangles of equations.The pressureand omni-directional characteristics ofthe acous- incideneeboth in II•e horizontal and verlical planes.The results demon- tical field producedarc enhancedbeyond tho•c that could b• generatedby stratethat the calibrationofsound intensity probes can be carried out with a simplefiat piezoelectricsource alone. Results obtained with thissource reasonablecertainty in the 300- to 6000-Hz frequencyrange and that the confirmthe feasibilityof usingultrasound in air asa meansof accurately "timegating" technique has the advantage of not requiringany expensive determiningpositions in threedimensions. [Work supportedby General specialfacilities. Motors ResearchLaboratories. ]

Sl15 J. Acoust.Soc. Am. Suppl. 1, VoL85, Spring1989 117thMeeting: Acoustical Society of America $115 3:45 The forward projectionof transientpressure fields from ultrasonic transducershas been investigated both experimentally and theoretically. UU12. Generationof acousticpulses of short durutlonfrom laser pulses The transientpressure field of a planein front of a transduceris projected on metal foils. Peng Jiang and Robert E. Apfel (Department of to anotherplane further from thetransducer using wave-vector and time- MechanicalEngineering, Yale University,New Haven,CT 06520) domainmethods that are implementedusing FFT's. We havepreviously To calibratetransducers in water,a laserwas used as a meansto gener- shownthat this projection algorithm gives good results when applied to ate acousticpulses of shortduration. In the experiments,samples were thefield of a pistonthat iscalculated using impulse-response methods. In chosenfrom the available metal foils (stainlesssteel and aluminum ) with thecurrent work, experimentally determined transient pressure fields in a differentthicknesses. Several conclusions can be drawnfrom the experi- planein front of typicalmedical or NDE transducershave been obtained ments.( 1) The energydensity of the incidentlaser pulse has a strong usingoptical tomographic methods to measurea two-dimensionalslice of effect,depending on the properties of sample, on the duration of thegener- the fieldas a functionof time.The forwardprojection of the space-and ated acousticpulses. (2) Thermalexpansion/3 and thermaldiffusivity time-dependentfield via our projection algorithm yields results that are in lengthL art two importantparameters that affectthe generated acoustic goodagreement with the opticallymeasured field at the new plane.A waveforms,where L = (2Dtp)•/: andD = K/cop,K isthe thermal con- comparisonof analyticaland experimental results will bediscussed along ductivity,co isthe specific heat, p isthe density, and tp is the duration of a with potentialapplications of the methodfor transducercalibration and laserpulse. (3) If the thicknessof a sampleis comparableto the thermal characterization.• Present address: Naval Underwater Systems Center, diffusivitylength L, it will affectthe generated waveform. (4) Lasergen- Newport,RI. erationof acousticpulses from metalfoils may be ableto be usedto cali- bratereceiving transducers in a liquid,at leastin a relativesense. [Work supported,in part, by U.S. NationalInstitute of Health throughGrant IR01CA39374.]

4:30

'UUI$. Unidirectionalmagnetostrictive/piezoelectric hybridtransducer. 4:00 JohnL. Butler (Image Acoustics,Inc., P.O. Box 6, North Marshfield, UU13.Acoustical activity in structurallychiral composites. S.K. Yang, MA 02059), StephenC. Butler (Massa ProductsCorporation, 280 V.V. Varadan,and V. K. Varadan(Department of EngineeringScience Lincoln Street, Hingham, MA 02043), and Arthur E. Clark (Naval and Mechanics,Research Center for the Engineeringof Electronicand SurfaceWeapons Center, Silver Spring, MD 20910) AcousticMaterials, The Pennsylvania State University, University Park, The objectof thehybrid transducer is to produceenhanced motion at PA 16802) oneend and canceledmotion at the otherend. In the simplestform the "Opticalactivity" exhibited through electromagnetic wave propaga- transducerconsists of a quarterwavelength section of piezoelectricmate- tion and scatteringhas been well-studied in recentyears even at GHz rialjoined to a quarterwavelength section of Terfenol-Drare-earth mag- frequencies.Acoustical activity, on theother hand, was first experimen- netostrictivematerial. A 3-kHz experimentalhybrid transducerwith a tallyobserved in 1968by Portigaland Burstein [Phys. Rev. 170, 673-678 total lengthof 18 in. wasconstructed with a smallcentral mass and two (1968)]. Lakhtakiaet al. [papersubmitted for publication]argued that smallequal end pistonmasses. Measurements on this deviceshowed an sinceelectromagnetic waves can discriminate the chirality or handedness averagefront-to-back ratio of approximately17 dB. The operating theory, of themicrostructure, there is no reasonwhy other transverse waves can- equivalentcircuit analysis, and measuredresults will be presented.The not do so also. In general,the fields in an elasticsolid consistof both resultsconfirm the original 1984 theoreticalprediction [U.S. Patent transverseand longitudinalcomponents. Therefore, an elasticsolid can 4,443,731]. [Modelingeffort supported by SB1R.] exhibita phenomenonsimilar to opticalactivity that hasbeen referred to asacoustic activity by someauthors. To verifythis hypothesis, structural chiralityinduced by intrinsicallyanisotropic materials was studied. Four laminatedcomposite samples were prepared. In two of thesamples, the fiberdirection wa? rotated from one layer tO the next so that the resulting samplewas either left or right handed.In the third sample,the fiber directionswere random from layerto layer,whereas in the fourththey remainedaligned resulting in a samplewith orthotropicsymmetry. These 4:45 sampleswere then tested by usingshear wave transducers in an ultrasonic throughtransmission experiment. Our resultsindicate that shearwave UUI6. Improvement of reflection and transmission coefficient transducersare able to sensethe handednessof the samplesand detect measurementson test panels.C. Audoly and C. Giangreco(Groupe additional shear modes. d'Etudesct de Recherchesde D•tection Sous-Marine,Le Brusc, 83140 Six-Fours, France) Theefficiency of acousticmaterials is oftenevaluated by measuring the reflectionand transmission coefficients on testpanels in tanks.The aimis to obtain the intrinsic characteristics of the material, as if thepanel 4:15 wereinfinite. However, when the size of thepanel is not large compared to thewavelength in water,the measurements aredisturbed by scattering UU14. Forward projection of a transient tomographically reconstructed phenomena.Different techniques (use of surfacehydrophones and trans- pressurefield. ll. MichaelJ. Forbes,'1StepbenV. Letchef(Department mitters,intensity receivers, double-layer transducers) are studied experi- of Physics,University of RhodeIsland, Kingston, RI 02881), andPeter mentallyand theoretically and theiruse to improvethe measurementsis R. Stepanishen(DepartmentofOceanEngineering, UniversityofRhode examined.For normalincidence measurements, good results are obtained Island,Kingston, RI 02881) .witha surfacehydrophone placed in thenearfield of thetest panel.

S116 J.Acoust. Soc. Am. Suppl. 1, Vol. 85, Spring 1989 117thMeeting: Acoustical Society of America $116 THURSDAY AFTERNOON, 25 MAY 1989 REGENCY B, 1:00 TO 2:50 P.M.

SessionVV. Structural Acousticsand Vibration VI: Wave Propagation in Structures

Martin J. Pechersky,Chairman Departmentof EngineeringScience and Mechanics,Applied Research Laboratory, Pennsylvania State University, UniversityPark, Pennsylvania16802

Chairman's Introduction--l:00

ContributedPapers

1:05 1:35

VV1. Energy flow associatedwith fundamental elastic wave types on VV3. Analysisof kineticenergy repartition for in-planebeam structures. inhomogeneouscylindrical shells.Allen D. Pierce (Graduate Program 1. B. Piaud, T. Loyau, and I. Nicolas (Groupe d'Acoustiquede in Acoustics,Pennsylvania State University, 157 Hammond Building, I'Universit6 de Sherbrooke,Dgpartement de G6nie Mfcanique, StateCollege, PA 16804) Universit6de Sherbrooke,Sherbrooke, Qu6bec 11K 2R I, Canada)

The basicshell dynamic equations for an inhomogeneouscylindrical In thispaper, kinetic energy repartition for in-plane beam structures is shell (slowly varyingradius, thickness, and materialproperties) result analyzedusing three different methods: the statistical energy analysis, the from Hamilton'sprinciple. The versionadopted here is onewhich yields energyinfluence coefficient method (based on themodal approach ), and the Donnellequations in the limiting caseof a homogeneousthin shell, the exactmethod (based on the waveapproach). The two last methods althoughthe sametechnique applies for moresophisticated shell theories. allow the definitionof a linearrelation between the averagekinetic energy There are threewave types that resultfrom the theorythat can be identi- of eachbeam and the excitations applied to all thestructure. Therefore the fiedin thehigh-frequency limit ascompressional (longitudinal), in-plane contributionof eachexcitation to the kineticenergy of eachbeam can be shear,and flexural. The propagationof thesewaves is directionally depen- shown.In thestructure, the beam angle at ajunction can take any value. A dent,frequency dependent, and dispersive. The generalray acoustics for- junctionmodel with three degrees of freedomis developed toaccount for mulationdeveloped in previouspapers by the author,by Felsenand Lu, longitudinaland flexural motions. A comparisonbetween the three meth- andby Norrisis extended to includethe proper invariants for propagation odsis performed.The analysis results are presented for differentangles, alongray tubes. The energydensity and energy flux vectors for eachof the differenttypes of junctions,and supports. threewave types are derived with theaid of Hamilton'sprinciple and a Poynting'stheorem expressing conservation of waveenergy is obtained for eachwave type. This identificationallows the discussionof theenergy transferwhen waves are partiallyreflected and convertedto otherwave typesat ribsor at abrupttransitions of shellradius. [Work supportedby ONR and by the William E. Leonhardendowment to PennsylvaniaState University.]

1:50

1:20 VV4. Critical frequenciesof ribbedplates. G. Maidanik,$. Dickey (David Taylor ResearchCenter, Annapolis, MD 21402-5067),and VV2. Surface wavesin layered structureswith applicationto vocal-fold J. Ertel (Physics Department, United States Naval Academy, vibration. Richard S. McGowan (Haskins Laboratories, 270 Crown Annapolis,MD 21402-5026) Street, New Haven, CT 06511 ) The vibrationaland radiative properties of panelsare often cast in The initiationof surfacewaves over a layeredstructure, including an termsof therelationship between the two sets of properties.The relation- air channel,a thin elasticlayer, an inviscidwaterlike fluid, and an imped- shipis expressedin termsof the radiationefficiencies of thesepanels. anceboundary, is discussed. This structureis a rudimentarypicture of the Ofteninterest lies in thedependence of the radiation efficiency on frequen- vocalfolds near the edges. The initiationofsurface waves at the interface cy;the radiation efficiency is, therefore, usually displayed as a functionof betweenthe air and elasticlayer is similarto the problemsof initiationof frequency.If thepanel is basically a plateresponding in flexure it is cus- wind wavesover water and the flutterof panels.Early linearanalyses of tomaryto ascertain the radiation efficiency as a functionof the normalized surfacewave initiationconsidered Kelvin-Helmholtz instability,a static frequency(m/to,.), where to is the frequency variable and to,. is defined as instability,and the useof Jeffreys'sheltering coefficient as a destabilizing thefrequency at whichthe phase velocity of thefree waves, in a specified mechanismfor a dynamicinstability. Both static and dynamic instabilities direction,on the unloadeduniform plate matches the speed of soundin are possiblein vocal-foldvibration. However, the dynamictype of insta- the irradiatedfluid. The criticalfrequency may havedirectional proper- bility is the mechanismthat usually is operablein a layeredstructure ties.However, if the uniformplate is isotropic,the criticalfrequency is model of vocal-foldvibration, although Jeffreys' sheltering coefficient independentof direction. When the plate is nonuniform; e.g., because the doesnot providethe correctterm for negativedamping. This is confirmed plateis ribbedand/or finite, the "free waves and their phase velocity" on by the lumpedelement two-mass model, a verysuccessful model for simu- the unloadednonuniform plate may not correspond to thoseon the un- latingsome aspects of vocal-foldvibration [ K. lshizaka and J. L. Flana- loadeduniform plate. Even if thesefree waves admit to thedefinition of gan,Bell Syst.Tech. J. 51, 1233 (1968) ]. The two-massmodel also illus- thecritical frequency to• this critical frequency may not be equal to to,.. If trateshow to incorporatedynamic pressure loss into the layeredstructure thereis meritin displayingthe radiationefficiency as a functionof the approachto accountfor the negativestiffness. The layeredstructure ap- normalizedfrequency, which critical frequency need be used in the nor- proachhas the advantage of allowingfor testingof theeffects of changing malization?The paperis a briefattempt to answerthis question. The themechanical properties of varioushistological layers on theinitiation of definitionof the criticalfrequencies and their usein normalizingthe fre- the surfacewave. [Work supportedby NIH grantsHD- 1994,NS-13870, quencyfor displayingthe radiation efficiencies of regularly ribbed plates and NS- 13617 to Haskins Laboratories.] are cited as examples.

Sl 17 J. Acoust.Soc. Am. Suppl. 1, Vol.85, Spring1989 117thMeeting: Acoustical Society of America Sl 17 The nearfieldresponses of a thickviseoelastic plate are computed for epicenter,off-epicenter receiver locations to a pointstep load acting nor- WS. Prol•gation of e!•tie waveson thin-walledcircular eylindem. mal to the surface.Analysis of theseresponses shows that the ray arrival Hyun-GwonKil (Schoolof MechanicalEngineering, Georgia Institute behaviorof a transientultrasonic signal propagated through a thickvis- of Technology,Atlanta, GA 30332),Allan D. Pierce(Department of coelasticplate can be analyzed to recoverthe plate material's dispersion MechanicalEngineering, Pennsylvania State University,University and attenuation.Such measurements form the basisof thepoint-source/ Park, PA 16802), and Jerry H. Ginsberg (school of Mechanical point-receioermeasurement technique. Signal processing algorithms are Engineering,Georgia Institute of Technology,Atlanta, GA 30332) demonstratedwith syntheticand real signals obtained via thistechnique Thispaper examines the nature of elasticwaves propagating in a thin- in elastic and viscoelastic materials. walledcircular cylinder from the viewpoint that the cylinder's geometry is a sourceof anisotropy.A point-excitedcircular cylinder is regardedas a two-dimensionalanisotropic medium extending over an infinitedomain formedfrom the stretchedangular coordinate. Correspondingly, the dis- placementfield is represented asa superpositionof waves propagating out 2:35 from localized sources into an unbounded medium. The excitation of VV7. Forced vibrations of stiflened cylindrical elastic panels. wavesby varioustypes of pointforce is analyzed using Lighthill's theory. Zahit Mecitogluand M. C. I•kmeci (Faculty of Aeronauticsand This leadsto an expressionfor the farfieldresponse of the point-excited Astronautics,Istanbul TechnicalUniversity, Maslak, Istanbul 80626, unboundedmedium, which can be expressed in a simpleasymptotic form Turkey) at frequenciessomewhat higher than the ring frequency.Thus, in this frequencyrange, the fadieid response of a point-excitedcircular cylinder The objectiveof thispaper is to investigatethe forcedresponse of a can be easilyobtained using the correspondingasymptotic farfield re- stiflenedcircular cylindrical panel within the frameof Love'sfirst approx- sponseof an unboundedmedium. Using these results, it isshown that the imation theory of elasticshells. The effectsof stiflehersare taken into wavemotion in a thin-walledcircular cylinder at moderatefrequencies accountby theorthotropic material approach, including the eccentricity may be interpretedin termsof the wavemotion in a thin plate. [Work of stiffeners.The variationalequation of motionfor the forcedvibrations supportedby ONR. [ of thinelastic shells with clampededges is derived from Hamilton's prin- ciple.The stiflenedelastic panel is diseretizedby the Semiloofelements. Then, with the help of the variationalequation, the matrix equationis obtainedto determinethe frequenciesand modeshapes of the stiflened circularcylindrical elastic panel. Two typesof stiflenedshell panels are consideredfor forced-responseanalysis: the stiflenedmodels by the stiff- VV6. Theory and measurementsof transient ultrasonic waves in a enerswith rectangularcross section and with profileshape cross section. viseoelastieplate. RichardL. Weaver (Departmentof Theoreticaland The influenceof the spacingsand dimensions of stiffenerson the forced Applied Mechanics, University of 111inois•Champaign-Urbana, responseof the stiflenedcircular cylindrical panel is examined.The nu- Urbana, IL 61801), WolfgangSachse, and Lin Niu (Departmentof mericalresults are plottedwith respectto the parameters,and they are Theoreticaland Applied Mechanics,Cornell University,Ithaca, NY comparedwith certainearlier results. Further needs of researchare point- 14853) ed out.

THURSDAY AFTERNOON, 25 MAY 1989 REGENCY A, 1:25 TO 5:00 P.M.

SessionWW. PhysicalAcoustics VIII and Animal BioacousticsI: Applieationof PhysicalAcoustics to Agriculture

Lawrence A. Crum, Chairman National Centerfor PhysicalAcoustics, University of Mississippi,University, Mississippi 38677

Chairman's Introduction--l:25

Invited Papers

WW1. Acousticaldetection of insectlarvae in post-harvestcommodities. •I. C. Webb (USDA, ARS, Insect Attractants,Behavior, and BasicBiology Research Laboratory, Gainesville, FL 32604) An acousticalsystem to detect insect larvae in fruit, nuts,and grain will bedescribed. The systemcan detect !-day-oldfruit fly larva in grapefruit,mangos, or other similar fruit and lepidopterous and coleopteran larva in individualkernels of grain as well as bulk grain. Two types of detectors have been developed for this work. One typeis based on the closed organ pipe principle that works well with both fruit and grain and a piezoelectric sensorthat works primarily with grain. The signal of thefeeding larvae is detected, amplified approximately

Sl 18 J. Acoust.Soc. Am. Suppl.1, Vol. 85, Spring1989 117thMeeting: Acoustical Society of America $118 100dB, filtered through the appropriate bandpass filters, and then stored on computer. The computer and softwareare capable of monitoringthe larva 100% of thetime through its life cycle. The system has applica- tionsboth in basicresearch and quarantine inspection ofinsects in importand export commodities.

2:00

WW2. Acousticcommunication in pestmole crickets. T. G. Forrest(National Center for PhysicalAcoustics, P.O. Box 847 FraternityRow, Universityof Mississippi,University, MS 38677) Mole cricketsare commonpests of turfgrassand pasturesin the southeasternUnited States. The males producespecies-specific calling songs that functionto attract mates.Males begin calling after sunsetfrom a burrowconstructed prior to calling.The burrow'sopening expands exponentially and the burrows are "tuned" duringtheir construction. Output increases 20 dB duringthe tuningprocess. Sound fields are hemispherical. Poweroutput ranges from 4 to 20/•W andis dependentupon the sizeof the maleand the moistureof the soil surroundingthe burrow. Flying females respond to thecalling song and land near calling males. Males calling in an outdoorarena were highly variable in thenumber of individualsattracted to theircalling songs. Intensity differencesamong the maleswas the majordeterminant in the responseof femalesto malesin the arena.The differentialresponse tocalling males can be explained using a simplemodel of pressure fields surrounding two sources.

2:30

WW3. Soundand the mothsthat infestbee hives. Hayward G. Spangler(USDA, ARS, Carl HaydenBee ResearchCenter, 2000 E. Allen Road, Tucson, AZ 85719)

Two mothsthat infestbee hives, the lesserwax moth,,4chroia grisella, and the greaterwax moth, Galleria mellonella,generate ultrasonic pulses by bucklingtymbals. Lesser wax moth males call continuously, produc- ing 100-kHz soundpulses by whichfemales orient and find them.Greater wax moth malesgenerate a short seriesof 75-kHz soundpulses, but femalesfind themby orientingto malepheromone. Females wing fan in responseto male soundand may Signalmales to releasemore pheromoneto guidethem. In contrast,each tymbalof the relatedrice moth, Corcyra cephMonica, has nine striae that buckleand recoverin sequenceto produce125-kHz sound in an irregulartrain of pulses.Female moths may not distinguish 7.5-ms pulse trains from7.5-ms bursts of continuous sound. Both lesser wax moths and rice moths can be located and identified by detectingthe sound of callingmales. Acoustical traps may prove useful for monitoringor controllingpopula- tions.

3:00

WW4. Acousticalpeak identification system (APIS): An acousticaltechnique for distinguishingbetween Europeanand Africanizedhoneybees. Howard T. Kerr and M. E. Buchanan(B-Tec, Inc., Route 11, Box 7, Maryville, TN 37801) A simplemethod has been developed to distinguishbetween European and Africanized honeybees on the basisof differencesin the spectral content of soundsmade by worker bees in flight.The spectral content of the flightsounds for eachsubspecies may generally be correlated to characteristictaxonomial features (i.e., wing size,body weight, thorax dimensions, etc.) and physicalbehavior (i.e., foraging,stinging, etc.). Acoustic signalsfrom over 800 individual flying European and Africanized ,honeybees were collected. A time-averaged signalwas generated for eachspecimen, and standard Fourier analysis methods were used to generatepower spectraldensity plots. Examination of the PSD's revealedthat distinguishingdifferences exist between the acousticalsignatures of flyingEuropean honeybees and flying Africanized honeybees. Specifically, the flying Europeanhoneybee signature has a fundamentalpower peak in the210- to 230-Hzfrequency range whereas the flyingAfricanized honeybee signature has a fundamentalpower peak in the 260- to 280-Hz frequency range.This substantialdifference is easilyembodied in a varietyof simpleidentification algorithms. A patent applicationwas submitted for the acousticalpeak identification system (APIS), and a simple,inexpensive, field-portableinstrument based on acoustical signature techniques has been developed for screening identifica- tionof the Africanized subspecies ofhoneybees. This instrument is called "Buzz Buster" and is being marketed by B-Tec.

$119 J. Acoust.Soc. Am. Suppl. 1, Vol.85, Spring1989 117thMeeting: Acoustical Society of America S119 3:30

WWS. AudiospectraandrelatedbehaviorofMonocham,,stiti!!ntorF.larvae. R. T. Walden (NationalCenter for PhysicalAcoustics, University, MS 386??) and T. E. Nebeker(Department of Entomology,Mississippi StateUniversity, Mississippi State, MS 39762) The behaviorand audiospectra of Monochamustitillator F. larvae,the southernpine sawyer, were ob- servedand measured in its naturalenvironment. The sawyeris being utilized to assistin locatingsouthern pine beetleinfestations. The sawyer's audio emission is primarily in the 1000-to 2800-Hzrange with intensitypeaks at approximately1300 and 2300 Hz. Theanalysis was obtained using both a sweep-frequencyanalyzer and an FFT spectrumanalyzer. The oscilloscopedisplay gave surprising information in that a singlesound output seemsto first intensifywith time and then rapidlydecay. A closeranalysis reveals that a singlesound is composedof several•ime decaying but ever intensifying components. The sound repetition rate varies from 30 to 120pulses per minute depending on environmental condition s. Thebehavior of thesawyer during its sound productionis beingstudied with regardto seasonof the year,time of day, ambienttemperature, and sound productionmechanism.

4:00

WW6. Ultrasonic acousticemissions from drought-stressedtrees: Do bark beetles hear them? Robert A. Haack(USDA ForestService, 1407 South Harrison Road, East Lansing, MI 48823) Barkbeetles preferentially infest drought-stressed trees for reasonsnot completely understood. One possi- bilityis that bark beetles are attracted to theultrasonic acoustic emissions (AEs) thatresult from breakage of watercolumns in drought-stressedtrees. AEs were measured from 20 to 300kHz oncut trunk samples and on small,potted trees of severalconiferous and hardwood species, using ceramic piezoelectric transducers and a four-channelAE analyzer.Mean rate of emissionas well as mean signal duration, rise time, amplitude, and energywere determined at weeklyintervals during periods of drying.Some of theseresults have recently been publishedJR. A. Haacket al., FloridaEntomol. 71, 427-440(1988) ]. Usingthe mean emission rates and signalparameters to adjustthe settingsof an ultrasonicpulsing instrument, natural and artificialsubstrates were pulsedwith ultrasoundto simulatevarying degrees of droughtin the presenceof bark beetles.The influenceof pulsedAEs on the colonization behavior of bark beetles will be discussed. [Work suppot.ted by USDA. ]

4:30-5:00

Bull Session

THURSDAY AFTERNOON, 25 MAY 1989 ROOM 202, 1:30 P.M.

Meeting of Accredited Standards Committee S3 on Bioacoustics

to be held jointly with the

TechnicalAdvisory Group (TAG) Meeting for ISO/TC 43 Acoustics,IEC/TC 29 Electroacoustics,and ISO/TC 108/SC4 Human Exposureto Mechanical Vibration and Shock

L. A. Wilber, Chairman S3 422 Skokie Boulevard, Wilmette, Illinois 60091

StandardsCommittee S3 onBioacoustics. The currentstatus of standardsunder preparation will bediscussed. In additionto thosetopics of interest,including hearing conservation, noise, dosimeters, hearing aids, etc., considerationwill begiven to newstandards which might be needed over the next few years. Open discussion of committeereports is encouraged.

The internationalactivities in ISO/TC 43 Acoustics,IEC/TC 29 Electroacoustics,and ISO/TC 108/SC4 Human Exposureto MechanicalVibration and Shock,will bediscussed. The Chairsof the TAGs for ISO/TC 43 (H. E. vonGierke), IEC/TC 29 (V. Nedzelnitsky),and ISO/TC 108/SC4(H. E. yonOierke), will report on current activities of these Technical Committees and Subcommittees.

S120 J. Acoust.Soc. Am. Suppl. 1, Vol.85, Spdng 1989 117thMeeting: Acoustical Society of America S120 THURSDAY AFTERNOON, 25 MAY 1989 NEWHOUSE I, ROOM A 1, 1:30TO 4:15P.M.

SessionXX. PsychologicalAcoustics VII: Comodulationand Modulation

William M. Hartmann, Chairman Departmentof Physicsand ,4stronomy, Michigan State University, East Lansing, Michigan 48824

ContributedPapers

1:30 interval; a random-standard,forced-choice discrimination task with an 8- s interstimulusinterval; and an identificationtask. Thresholdswere ob- XXI. PhaSesensitivity to amplitude.modulatedstimuli as a functionof tainedfor modulation rates from 14-224 Hz usingnoise carriers bandpass componentspucifs. $avithriSivaramakrishnan, Glenis R. Long filtered from 500-4C00 Hz, 500-1600 Hz, 1700-2800 Hz, and 2900-4000 (Departmentof Audiologyand SpeechSciences, Purdue University, Hz. The four bandsyielded similar results except for modulationrates WestLafayette, IN 47907), andArnold Tubis(Department of Physies, above100 Hz, wherethe 500- to 1600-Hzthresholds were higher. Fixed- PurdueUniversity, West Lafayette,IN 47907) standard discrimination thresholds were about 3 Hz for modulation rates The relationbetween phase sensitivity of a three-componentampli- up to 66 Hz. Increasedthresholds for modulationrates above 66 Hz are tude-modulated(modulation index--- 1) stimulus,presented at 40 dB presumablydue to temporalresolution limits. For modulation rates above SL,as a functionof thefrequency spacing of theindividual components 100 Hz, modulation rate resolution with the 500- to 1600-Hz carrier is wasexamined. Five sets of stimuliwith carrier frequency of 2000Hz and probablylimited by critical band filteringrather than temporalresolu- modulationfrequencies of 50, 100,200, 300, and 400 Hz weregenerated. tion. Resolution in the random-standard discrimination task was similar Thephase of the center component was varied from 0-90 degin stepsof 10 to that for the identification task. Thresholds were elevated relative to deg to givea total of 50 stimuli.Subjects were asked to discriminatethe fixed-standardthresholds except at the extremesof thestimulus range. In zerophase stimulus from the other stimuli containing the same compo- the random-standarddiscrimination task, a pronouncedcriterion bias nentsin a 31-2AFCparadigm. The relativepitch, and pitchstrength, of wasalso present for stimulinear the extremesof the range.Durlach and stimulicontaining the samecomponents at differentrelative phase was Braida's [J. Acoust.Soc. Am. 46, 372-383 (1969) ] modeldescribes the determinedusing a paired-comparisonparadigm. Measurements of each datawell and provides quantitative measures for modulation-ratepercep- subject'sauditory filter characteristics at 2000Hz (basedon the notched- tionin goodagreement with those for intensity perception. [Work sup- noiseparadigm) will beused to interpretthe data. [Work supported by a portedby ONR. ] David RossFellowship at PurdueUniversity.]

2:15 1:45 XX4. Detecting FM of coherently and incoherently modulated XX2. DetectiOnand recognitionof amplitude modulationwith tonal componentsof complex sounds.Robert P. Carlyon (Laboratory of carriers.Stanley Sheri and William A. Yost(Parrely Hearing Institute, ExperimentalPsychology, University of Sussex,Brighton BNI 9QG, LoyolaUniversity, 6525 North SheridanRoad, Chicago, IL 60626} England) The abilityof listenersto processmultiple sources of sinusoidalampli- Thresholdswere measured for the detectionof FM offour-component tudemodulation (AM) wasevaluated using both detection and recogni- carriers,where each carrier comportera was modulated by the sameper- tion procedures.For all conditions,the stimuluswas a two-tone(909 and centageof itsstarting frequency ("F0 modulation").The frequencyspac- 4186 Hz} complex.Test-AM frequencieswere 4 and 17 Hz. In the detec- ing betweencomponents was such that they were resolvableby the peri- tion paradigm,d-primes obtained with simultaneousmodulation of both pheralauditory system. Each component was modulated by a singlecycle toneswere compared to thed-primes obtained with modulationof just one ofa 12.5-Hzsinusold, whose phase was either the same for all components of the tonal components.When both toneswere modulatedat the same {"coherentmodulation"), or differedbetween components ("incoherent frequency,a phasedisparity between the envelopesreduced AM detect- modulation"). Preliminary experimentsrevealed little or no effect of ability.With theenvelopes in phase,results showed a linearsummation of modulatorcoherence on thresholds,for stimulipresented either in quiet thed-primes for the individualcomponents. With modulationof the two or in burstsof pink noise.This noisewill be comparedto the outcomeof tonesat differentAM frequencies,performance approximated optimal further experiments,in whichthe coherentand incoherentsignals were processingof two sourcesof uncorrelatedinformation. A similar result presentedwith competingfrequency-modulatedsounds. The results of all wasobtained in the recognitionparadigm when the taskwas to discrimi- the reportedexperiments will be discussedin relationto the mechanisms natebetween the two modulationfrequencies. When the AM frequency by whichlisteners separate out concurrentcomplex sounds. wasfixed and the taskwas to identifywhich carrier was modulated, per- formancewas near chance. Results are consistent with processing of near- thresholdAM through modulation-specificchannels that are broadly tunedto carrierfrequency. [ Work supportedby NINCDS. ]

2:30 2:00 :, XXS. The effect of envelope energy on the discrimination of cross- XX3. DiscriminatiOnand identLficaiton of modulationrate usinga noise spectral envelopephase disimrity. Brent W. Edwards and Gregory carrier. Thomas E. Hanna (Naval Submarine Medical Research H. Wakefield (Department of Electrical Engineering and Computer Laboratory,Box 900, Naval SubmarineBase--New London,Groton, CT Science,University of Michigan,Ann Arbor, MI 48109} 06349-5900) The envelopecross-correlation difference •o can be usedto predict Modulation-rateperception was measured with three tasks: a fixed- thresholdsfor the discriminationof cross-spectralenvelope phase dispar- standard, forced-choicediscrimination task with a 500-ms interstimulus ity for modulationfrequencies up to 64 Hz [ Wakefieldand Edwards,J.

S121 J. Acoust.Soc. Am. Suppl. 1, Vol.85, Spring1989 117thMeeting: Acoustical Society of America $121 Acoust.Soc. Am. Suppl.I g2, S41 (1987) l- For the caseof two SAM variedmodulation depths. It is foundthat Ap for a complexsinusoidal carriers,Ap is inverselyproportional to depthof modulationwhich sug- modulatoris equal to that for a singlesinusoidal modulator when the geststhat sensitivity to cross-spectraltemporal differences depends on the energiesof the two modulatorsare equal.This relationshipis alsoob- degreeto whichcarriers are modulated.Results are presentedthat sup- servedfor envelopesof narrow-bandnoises. In contrast,other measures of port the hypothesisthat sensitivityis inverselyproportional to envelope envelopefluctuation do not yieldconstant performance as measuredby energy.Thresholds are obtained and Ap's calculated for SAM carriersof Ap. [This researchwas supported by a grantfrom the AFOSR.]

2:45-3:00 Break

3:00 3:30

XX6. Cross-spectralenvelope phase discrimination for FM signals. XXg. Signal thresholdin frequency-modulated{FM) noisebands as a (}regory H. Wakefield and Brent W. Edwards (Department of function of the coherence of modulation. J. H. Grose and J. W. Hall, III ElectricalEngineering and ComputerScience, University of Michigan, (Division of Otolaryngology/Headand Neck Surgery,University of Ann Arbor, MI 48109) North Carolinaat ChapelHill, ChapelHill, NC 27599-7070) Previousmeasures of cross-spectralenvelope phase sensitivity have In a recentpaper reporting the absenceofa co-(frequency)-modula- usedamplitude-modulated sinusoidal carriers. To the extent that these tion maskingrelease for FM maskers,it wasnoted that thresholdswere measuresreflect the fidelityof the auditorysignal representation of com- lower in maskerscomprised of comodulatedFM tonesthan of nonco- plexsignals, it shouldbe possible to predictphase disparity thresholds for modulated FM tones [G. S. Schooneveldtand B. C..L Moore, J. Acoust. arbitrary classesof signals.Modulation phasediscrimination functions Soc.Am. 83, 2290-2292 (1988) ]. This wasinterpreted as being due to a wereobtained for sinusoidalFM carriersat 500and 2000 Hz. For a 0-deg within-channelbeating cue. The presentstudy also observed a noncomo- phasedisparity between the modulatorsof the standard,sensitivity to a dulated-eomodulateddifference but in conditionsdesigned to minimize disparityin the phaseof FM modulationis monotonicallyrelated to the sucha cue.In a baselinecondition, detection of a signalwas measured in productof modulationfrequency and modulation index over the rangeof thepresence of an on-signalFM noiseband. Two flankingFM bandswere modulationfrequencies studied (8-64 Hz). A simplemodel of thisdis- thenadded in fourconfigurations relative to the on-signalband: ( I ) co- criminationtask assumes that FM signalsare convertedinto AM signals modulatedin both FM and amplitudemodulation (AM); (2) comodu- throughbandpass filtering at Ihe auditory periphery.This model was lated in FM but noncomodulatedin AM; (3) noncomodulatedin FM but testedby alemodulatingthe FM signalsthrough auditory filters tuned to comodulated in AM; and (4) noncomodulatedin both FM and AM. The 500 and 2000 Hz. Thresholdsobtained for these"FM-equivalent" AM paradigmwas tested with sinusoidaland random modulation rates, differ- signalswere nearly an order of magnitudesmaller than the original ent depthsof modulationand bothpure-tone and FM noiseband signals. thresholdsand it was necessaryto "de-tune" the auditory filters ( 5- to 10- Thresholdsfor mostconditions were raised relative to therespective base- dB slopes)to fit the FM data. [This researchwas supported by a grant line. However, for both the comodulated and noncomodulated AM con- from the AFOSR. ] ditions, thresholdswere usuallyreduced by the transitionfrom nonco- modulatedto comodulatedFM. [ Researchsupported by AFOSR. ]

3:15 3:45

XX?. Effects of flanking band proximity, number,.and modulation XX9. Thresholdsfor the frequency discrimination of pulsedtones (DLFs) pattern on comodulationmasking release. J. W. Hall, Ill and John andfor the detectionof frequencymodulation (FMDLs): Effectsof noise H. (}rose (Division of Otolaryngology/Head and Neck Surgery, and randomvariations in level. Brian C.J. Moore and Brian R. Glasberg Universityof North Carolina at Chapel Hill, Chapel Hill, NC 27599- (Department of Experimental Psychology,University of Cambridge, 7070) CambridgeCB2 3EB, England) Comodulationmasking release for a 700-Hz pure-tonesignal was in- In experimentI, DLFs weremeasured in fourconditions: ( 1) in quiet vestigatedas a functionof the numberand spectralpositions of 20-Hz- with the levelfixed at 70 dB SPL; (2) in quietwith the levelof eachtone widecomodulated flanking bands. The numberof flankingbands ranged variedrandomly over a 6-dBrange around 70 dB SPL; (3) as I, but with a fromone to eight.The resultsindicated ( 1) an effectof proximity,where continuousbandpass noise designed to maskthe upperside of the excita- bandscloser to the signalresulted in largermasking release, and {2) an tion pattern;and (4) with bandpassnoise and with the levelof the signal effectof numberof bands,where more bandsgave rise to larger CMR. randomizedover a 6-dB range.Center frequencies from 0.5-6.5 kHz were Two furthersets ofconditions were examined, and compared to the condi- used.Except at 6.5 kHz, the resultswere not consistentwith the assump- tion whereall eightcomodulated flanking bands were present:In one set tion that the DLFs were basedon the detectionof changesin excitation ofcondilions,two of the eightflanking bands were removed; in theother level on the low-frequencyside of the excitationpattern. Experiment11 setof conditions,two of theeight flanking bands were replaced with bands was like experimentI, exceptthat FMDLs (4-Hz rate) were measured, that were not comodulatedwith respectto the other bands.There was and, in conditions2 and 4, a 4-Hz amplitude modulation (AM) with a very little effectof removingtwo of the bands,even when closeto the peak-to-valleyratio of 6 dB wasimposed on all signals;the phaseof the signalfrequency; however, CMR was substantiallyreduced when the AM relativeto the FM wasrandom. The resultswere generally not incon- noncomodulatedreplacement bands were introduced. These results indi- sistentwith the assumptionthat the FMDLs werebased on the detection cated that the auditory systemis not able to disregardmodulations on of changesin excitationlevel on the low-frequencyside of the excitation flankingbands that differfrom themodulation pattern on thesignal band, pattern.However, neither a single-bandnor a multiple-bandexcitation- particularlyif thesebands are close in frequency.[ Research supported by patternmodel was able to accountfor the effectof the bandpassnoise of AFOSR. ] the FMDLs. [Work supportedby MRC, U.K.]

S122 J. Acoust.Soc. Am. Suppl. 1, Vol.85, Spring1989 -117th Meeting: Acoustical Society of Amedca S122 4.-O0 on and off and the modulationoccurred over the full durationof the tone, XXI0. Temporal modulation transfer functions for pure tones. whilein the continuouscondition, lhe carriertone was on continuously, and it wasmodulated during the observationinterval. Thresholds for William A. Yost and StanleySheft (Parrely HearingInstitute, Loyola modulationdetection were lower in thecontinuous than in thegated con- University,6525 North SheridanRoad, Chicago, IL 60626} dition and the thresholds were lower for the 500-ms than for the ! 25-ms Temporalmodulation transfer functions (TMTFs) wereobtained for stimuli.The TMTFs displayeda bandpasscharacteristic in all conditions, sinusoidallyamplitude-modulated (SAM) puretones. TMTFs wereob- but the high-passsegment was steeper for the gatedthan for the contin- tainedby determiningthe depthof SAM requiredfor modulationdetec- uousconditions. The lossin sensitivityat low modulationfrequencies tionin a two-alternative,forced-choice adaptive procedure. TMTFs were meantthat the lowest thresholds were obtained for modulationfrequen- obtainedfor 500-, 1000-,and 4000-Hz carrier frequencies; for durationsof ciesof 4-8 Hz in the continuouscondition and above16 Hz in the gated 125and 500 ms (all stimuliwere shaped with a 20-msraised cosine); in condition. The data will be discussed in terms of other measures of modu- gatedand continuousbackground conditions; and for modulationrates lation processingand theoriesof temporalprocessing, especially those rangingfrom 2-128 Hz. In thegated condition, the carrier tone was gated involvingenvelope extraction. [ Work supportedby the NINeDS. ]

THURSDAY AFTERNOON, 25 MAY 1989 NEWHOUSE II, ROOM 254, 1:30 TO 4:46 P.M.

SessionYY. SpeechCommunication VIII: Word-Level Perceptionand Production

James R. $awusch, Chairman Departmentof Psychology,SUNY at Buffalo,Amherst, New York 14260

ContributedPapers

1:30 the MRC PsycholinguisticDatabase of BritishEnglish (RP) with 38-K tokensrevealed that six stresspatterns (out of 17 attested)account for YY1. Syllablestructure and units of analysisin speechperception. 96% of the tokensin thesubset of two- andthree-syllable words. Further, lenny De•root and Howard C. Nusbaum(Department of Behavioral threesyllabic nuclei (out of 23 attested)account for 50% of the tokens, Sciences,University of Chicago,5848 South University Avenue, Chicago, independentlyof stresspattern. The interactionsof stresspattern and IL 60637) nuclei show not only increaseddiscriminatory power (in information Syllablesor their constituents,such as onsetsand rhymes,may be theoreticterms) over either attributealone, but also revealsignificant basicunits in speechperception. If so,then recognition of a targetpho- gapsbetween expected and observedcases. The gaps,both accidentalor nememight be influencedmore by its syllabiccontext (i.e., other pho- principaled,further reduce the relevantsearch spaces and increasethe neroesin the samesyllable or constituent)than by otheraspects of pho- usefulnessof this type of partial informationover other candidates. nefie context. To investigatethe influence of syllable structure on [Work supportedby AlveyGrant MM1 069.l phonemeperception, subjects in three response-timeexperiments were instructedto identifya targetphoneme, ignoring variation in an adjacent phoneme.In onecondition, the adjacent phoneme was held constant; in a secondcondition, contextual variation was irrelevant to targetidentity. In twoexperiments, context varied either within the same syllabic onset or in 1:54 @ an adjacentsyllable. The third experimentinvolved varying an adjacent phonemeeither in the samesyllable as the targetor in a neighboring YY3. Malleable frequency effects in spoken word recognition.Paul syllable.If thesyllable or onsetis perceived as a unit,then varying context A. Lute (Department of Psychology,SUNY at Buffalo, Buffalo, NY withinthat unit should slow target recognition more than varying context 14260) outsidethe syllable.The resultshave implications for the roleof syllable Recent researchhas demonstratedthat word frequencyeffects in structurein speechperception. [Research supported by AFOSR and spokenword recognitionare primarilydue to processesresponsible for BRSG. l decidingamong multiple lexical items activatedin memoryand not to differencesin activation levelsor thresholdsof word units. The present studyfurther supportsthis claim by demonstratingthat frequencyeffects in the identificationof spokenwords are malleable and can be modified by varying the compositionof the experimentalstimuli. A set of high-fre- queocywords was presentedfor identificationmixed with either other 1:42 high-frequencywords or with low-frequencywords. A setof low-frequen- YY2. Contingenciesin stresspatterns and syllabic nuclei:•essons for cy wordswas alsopresented with high- or low-frequencywords. The searchinglexical databases.Mary R. Smith (82 South Pine Avenue, resultsdemonstrated that high-frequencywords were identifiedmore ac- Albany, NY 12208) curately when presentedwith other high-frequeocywords and that low- frequencywords were identifiedmore accuratelywhen presentedwith In automaticspeech recognition programs, attempts have been made other low-frequencywords. The implicationsof theseresults for current to usepartial information about the phonetic structure of signals to search modelsof spokenword recognition,in particularthe neighborhoodacti- largelexical databases. Little attention has been given to theinteraction of vationmodel, will be discussed.[Work supportedby NIH Grant NS- stresspatterns and syllabicnuclei in restrictingthe searches.A surveyof 12179to Indiana University.]

S123 J. Acoust.Soc. Am. Suppl. 1, VoL85, Spring1989 117thMeeting: Acoustical Society of America S123 2:06 2:30

YY4. Gaininginsight into the representationai unit for spokenwords with YY6. The Delta System,version 2: A tool for testingphonological nnd a naming task. Deborah A. Gagnon and James R. Sawusch phonetictheories. Susan R. Hertz (EloquentTechnology, Inc., P.O. Box (Departmentof Psychology,SUNY at Buffalo,Amherst, NY 14260) 4328, Ithaca, NY 14852-4328and PhoneticsLaboratory, DMLL, Cornell University,Ithaca, NY 14853) Theoreticalproposals for the representational unit used in recognizing spokenwords include the phoneme,allophone, and position-specific The Delta Systemis a softwaresystem that letslinguists test the rela- phoneme.The presentexperiment was devised to differentiateamong tionshipsof phonologicaland phonetic units through speech synthesis [J. theseproposals. Subjects heard natural CVC stimuliin prime-targetpairs Acoust.Soc. Am. Suppl. 1 75, S60 (1984)]. The Delta programming and namedthe seconditem (target) asquickly as possible.The phonetic languagenow hasan improvedsyntax with greaterappeal to linguists, overlapbetween prime and target was varied to createfive different intra- alongwith a varietyof newfeatures. For example,it hasnew constructs pairrelations such that the expected pattern of primingeffects across the for manipulatingand testing Delta's multilevel utterance representation, set of relationswas differentfor each of the three phoneticrepresenta- for preventinggroups of rulesfrom crossing particular linguistic boundar- tions.The obtainedpattern is inconsistentwith an abstractphonemic unit ies,and for specifyingthe timingof phoneticevents with respectto higher andpoints to eithera position-specificphonemic or allophonicunit. This levellinguistic units. The Deltadebugger now lets users step through their patternwas found for both word and nonword stimuli.Thus these priming programsstatement by statement,and interactivelymodify their utter- resultsappear to tap the recognitionprocess prior to lexicalactivation. ancerepresentation on thefly (for example,to hearthe effect of a longer Primingeffects were eliminated when stimuli within a prime-targetpair duration). A macroprocessorlets userstailor the syntaxof Delta pro- wereproduced by differentvoices. The implicationsof the findingsfor gramminglanguage statement and debugging commands to their liking. refiningmodels of spoken word recognition will bediscussed. [ Work sup- The systemcomplies Delta programsinto C programsand lets users inter- portedby NINCDS.] mingleDelta andC statements.The systemwill be availablefor demon- stration.

2:18

YY$. Interword coarticulation modeling for continuous speech r.ecognition.Mei-Yuh Hwang, Hsiao-Wuen Hon, and Kai-FuLee (Computer Science Department, Carnegie-Mellon University, 2:42 Pittsburgh,PA 15213) YY7. A new approachto English text-to-phonemeconversion using In large-vocabularycontinuous speech recognition, subword units Delta, version2. SusanMcCormick (EloquentTechnology, Inc., P.O. mustbe used for practicalreasons. Context-dependent phone models have Box 4328, Ithaca, NY 14852-4328) and Susan R. Hertz (Eloquent becomea verysuccessful class of subwordunits. These phone-sized mod- Technology,Inc., P.O. Box4328, Ithaca, NY 14852-4328and Phonetics elstake into accountthe neighboringphonetic contexts, which strongly Laboratory,DMLL, CornellUniversity, Ithaca, NY 14853) affectthe realization of a phone.However, previous approaches have only consideredintraword coarticulation, and haveignored interword coarti- The Delta System,version 2 isbeing used to developa newset of text- culation,which is very importantin continuousspeech, especially for to-speechrules for English.This paperfocuses on the text-to-phoneme short function words like "the" and "a." This study extendstriphone- portionof theserules. These text-to-phoneme rules are based on an earlier basedmodeling to interwordcoarticulation modeling. A simpleextension rule set developedby Hertz [J. Acoust.Soc. Am. Suppl. 1 69, S83 of triphonesis problematicdue to the sharplygrowing number of tri- (1981) ], but are muchmore elegantand complete,taking advantage of phones.In orderto contain this growth, a maximum-likelihoodclustering Delta'sflexible facilities for buildingmultilevel utterance representations procedurewas introduced to reduce7057 intraword and interword tri- andmatching patterns against them. The rulesconvert an inputtext into phonesto 1000generalized triphones. Interword generalized triphones an utterancerepresentation containing the lexical,morphological, and wereincorporated into a large-vocabulary,speaker-independent, contin- phonologicalstructure of theutterance. Sophisticated algorithms are used uousspeech recognizer, SPHINX [K. F. Lee and H. W. Hon, Large for identifyingprefixes (productive and nonproductiveones), suffixes, Vocabulary Speaker-lndependentContinuous Speech Recognition androots (including the roots of compoundwords), for predictinglexical (ICASSP, 1988)]. Thisimprovement reduced the number of errorsby as stress,for assigninggrammatical categories, and for predictingpronunci- much as 44% on the 1000-wordDARPA resourcemanagement task. ations.Portions of thesealgorithms will bedescribed, with a focuson how This demonstratesthe importanceof interwordcoarticulation modeling, theDelta programming language allows them to beexpressed succinctly and the effectiveness of the methods used. and clearly.The ruleswill be availablefor demonstration.

2:54-3:10 Break

3:10 wordsshortened relatively less. Thus talkersappear to treatcertain types of informationdifferentlately. To investigatethis idea further, the present YYS. Consequencesof new and old information on the productionof studyexamined four grammaticalcategories and a fifth topicnoun cate- grammatical categories. Jan Charles-Luce (Department of gorywhen these were produced as old and new information. To determine Communicative Disorders and Sciences,SUNY at Buffalo, Buffalo, NY talkers'sensitivity to newversus old information,two passagetypes were 14260) constructed:coherent (paragraph of relatedsentences) and noncoherent (paragraphof unrelatedsentences). The resultsshow that duration does A recentstudy [C. A. Fowlerand J. Housum,J. Mem. Lang.26, 489- not decreasefrom new to old productionsfor all grammaticalcategories. 504 (1987)] demonstratedthat talkers distinguishsecond (old) token However,this finding is not independentof passagetype. Implications of productionsfrom first (new) token productionsthrough shortening. theseresults for talkers'sensitivity to semanticinformation will be dis- Moreover, listenerscould use this information to identify old from new cussed.[Work supportedby NIH Grant NS-12179to IndianaUniversi- tokens.Of interestfor the presentinvestigation was the findingthat topic ty.]

S124 d. Acoust.Soc. Am. Suppl.1, Vol. 85, Spring1989 117th Meeting:Acoustical Society of America S124 3:22 maticspeech recognition of digitstrings, prosodic contours provide cues aboutword boundarylocations and serveas a sourceof informationfor YY9.On-li•e measures of comprehension of natural and synthetic errordetection and correction. When concatenating stored speech to pro- speech.James V. Ralston,John W. Mullennix, Beth G. Greene,and ducenatural sounding digit strings, these findings provide guidance as to Scott E. Lively (Speech Research Laboratory, Department of how manytemplates need to be created.Finally, for text-to-speechsyn- Psychology,Indiana University, Bloomington, IN 47405) thesis,these results suggest the numberof rulesnecessary to modelnatu- Accumulatedperceptual research comparing natural and synthetic ral-soundingdigit strings. speechindicates relatively large differences in tasksassessing acoustic- phoneticprocessing, and small differences in tasksassessing higher levels of processingrelated to comprehension.Studies comparing comprehen- sionof passagesof fluentnatural and syntheticspeech have generally examinedperformance on questions presented after subjects have listened 3:58 to a passage.Such postperceptual measures are known to be relatively insensitiveto differencesin "real-time" processingoperations. The pres- YYI2. Comparing a magnitude estimation technique and a pair entinvestigation employed an "on-line"measure of processing,i.e., word eomlmrisonstechnique for use in assessingquality of text-to-speech monitoring,to studycomprehension. Subjects in thesestudies were pre- synthesissystems. Chaslav Pavlovic(Department of SpeechPathology sentedwith three types of passages--(! ) naturalspeech, (2) high-quality and Audiology,University of Iowa, Iowa City, !own 52242 and Centre syntheticspeech, and (3) low-quality syntheticspeech--and were re- National d'Etudes des Telecommunications, BP 40, 22301 Lannion, quiredto monitorfor targetwords as well asverify postperceptual com- France), Christel Sorin, Jean Pierre Roumiguiere, and Jean prehensionquestions. Monitoring latencies and verification performance Pierre Lucas (Centre National d'Etudes des Telecommunications,BP will bediscussed in termsof differencesin perceptualprocessing and com- 40, 2230] Lannion, France) prehensionof naturaland synthetic speech. [ Work supportedby NSF.] This studywas designed to comparea magnitudeestimation proce- dureand pair comparisons procedure for usein scalingquality of text-to- speechsynthesis systems. To thisgoal, the psychophysiealscale values that resultfrom the magnitudeestimation procedure were compared to the valuesobtained from a pair comparisonsprocedure. Four different synthesissystems and three different prosody rules in all possiblecombi- 3:34 nationswere scaled using a magnitudeestimation technique. To obtain YYI0. The effects of perceptual learning on capacity demands for the paircomparisons scale values, the resultsreported by Lucaset al. [CNET reportNT/LAA/TCS/375, Tom I, Lannion,France (1988)] recognizing synthetic speech. Lisa Lee and Howard C. Nusbaum for the samesystems were used. They werereanalyzed for thispurpose. (Committeeon Cognitionand Communication,5848 SouthUniversity Thedata indicate a goodgeneral agreement between the results of thetwo Avenue,The Universityof Chicago,Chicago, IL 60637) experiments.Thus the two methodsseem to validateeach other. The Previousstudies have demonstratedthat recognitionof synthetic relativeefficiency of the magnitudeestimation technique is greaterthan speechimproves with moderateamounts of training.Three experiments that of the pair comparisonstechnique. wereperformed to determinewhether the effectsof trainingare due to changesin the attentionalcapacity required to processthe speech.Atten- riohalcapacity available for recognizingspeech was manipulated using a recalltask with different length lists of visuallypresented numbers. In two experiments,before and after training,the primary task required subjects eitherto recalllists of wordsor to performspeeded word recognitionfor 4:10 syntheticspeech. Whereas training improved performance with synthetic speech,decreasing available capacity impaired performance. In a third ¾Y13. Perceptual normalization of talker differences. Howard experiment,the intelligibilityof the speechwas manipulatedby using C. Nusbaumand Todd M. Morin (Departmentof BehavioralSciences, speechfrom differenttext-to-speech systems. The resultsof theseexperi- 5848University Avenue, The Universityof Chicago,Chicago, IL 60637) mentssuggest that neither training nor intelligibility affects the amount of Different talkersmay producethe same phonemewith different attentionalcapacity required to recognizesynthetic speech. Rather, as acousticpatterns and different phonemes with similaracoustic patterns. perceptuallearning occurs, listeners begin to allocatetheir attentional In orderto recognizespeech correctly, a listenermust use information resourcesmore efficiently to the processingof syntheticspeech. [Work aboutthe talker'svocal characteristics. A speededtarget-monitoring task supportedby AFOSR and BRSG.] wasused to investigatewhether each token of speechcontains sufficient informationfor normalizationor whethera sampleof a talker'sspeech mustbe heardto normalizesubsequent segments. Subjects listened to a sequenceof syllablesfor a particulartarget. In onetype of trial, targets anddistractors were produced by a singletalker; in othertrials, targets anddistractors were produced by a mixof talkers.If eachtoken of speech 3:46 is self-normalizing,there should be no differencebetween conditions. YYII. Prusodicinformation in telephonedigit strings.Sara H. Basson, Otherwise,performance should be worsein mixed-talkertrials. In an- Judith Spitz, and Charles R. Jankowski (NYNEX Science and otherexperiment, the available cognitive capacity for recognizingspeech Technology,Artificial IntelligenceSpeech Technology Group, 500 wasmanipulated and recognition of speechproduced by a singletalker Westchester Avenue, White Plains, NY 10604} comparedto a mixof talkerswas examined. The resultsof theseexperi- mentshave implications for thetype of mechanismsused in normalization Intonationof naturallyproduced telephone digit stringsappears to and for the attentionallimitations they imposeon listeners.[Work sup- conformto particularpatterns. Concatenating strings of digitsproduced ported'byAFOSR and BRSG.] with "default"intonation highlights the importanceof maintainingap- propriateintonation patteros for intelligible,natural-sounding speech. The purposeof thisexperiment was to quantifythe acoustic events result- ingin natural-soundingtelephone number digit strings. Acoustic features of approximately1000 digits produced in the contextof telephonedigit 4:22 stringswere measured.The data were gatheredat MIT by presenting volunteerspeakers with lists of seven-digitnumbers to read. Shifts in YY14. Detailing the nature of talker variability effects in speech fundamentalfrequency of thevowel, changes in overallenergy, and digit perception.John W. Mullennixand David B. Pisoni(Speech Research durationas a functionof positionin thedigit string were calculated. These Laboratory, Department of Psychology, Indiana University, resultscan prove useful for speechrecognition and generation. For auto- Bloomington,IN 47405)

S125 J. Acoust.Soc. Am. Suppl. 1, Vol.85, Spdng1989 117thMeeting: Acoustical Society of America S125 Previousstudies have shown that changesin a talker'svoice from 4:34 stimulusto stimulusaffect the perception and recall of spokenwords [ see Mullennixet al., J. Acoust.Soc. Am. 85, 365-378 ( 1989);Martin etal., J. YYI$.Some perceptual correlates of phase in RELPcoded speech. Exp.Psychol. Learn. Mem. Cog. (in press)]. In thepresent study, the Margot Peet,Ward R. Evans,and Joseph Creekmore (The MITRE perceptualconsequences of talker variability were investigated in further Corporation,7525 Colshire Drive, McLean,VA 22102) detail.In orderto assessthe relativemagnitude of intratrialversus inter- A seriesof experiments tested the contribution of phaseinformation to trialchanges in a talker'svoice, a same--differentreaction time judgment the naturalnessof residualexcited linear prediction (RELP) coded taskwas used. Performance was compared across three talker conditions: speech,that is, how close a speaker'svoice sounds under RELP codingto singletalker, multiple talker across trials, and multiple talker within tri- its unprocessedanalog. Listeners were presented with a corpusof sen- als. In addition,the effectsof talker variabilityover time were examined tencesuttered by eight speakers(four male and four female). Three byobserving performance across varying ISI delays.The results obtained classesof approximationsof theresidual phase spectra were employed on providefurther information about the nature of talker variability effects in thesesentences: quantized approximations for decreasingbit rates,noise- theperception of spokenwords and will bediscussed in termsof their corruptedapproximations forincreasing noise levels, and combinations of relationshipto perceptualnormalization processes in speechperception. theseover varying window sizes. Listeners classified these utterances on [Work supportedby NIH.] the basisof theirproximity to unprocessedspeech. Results indicate that residualphase spectrum provides information about voice timbre and qualityand acts as a cueto speakeridentity in codedspeech.

THURSDAY AFTERNOON, 25 MAY 1989 REGENCY C, 1:30 TO 5:00 P.M.

SessionZZ. Underwater AcousticsVII: Spatial and Temporal Variability of Ambient Noise II

Michael J. Buckingham,Chairman MissionManagement Department, Royal AerospaceEstablishment, Farnborough, Hampshire GU14 6TD, England

Chairman's Introduction--l:30

ContributedPapers

1:35 aredistributed throughout the basin.The PE canbe used to computethe fieldat the array due to eachof the sources.The responseof the array to ZZ1. Time-evolvingcharacteristics of midfrequencyambient noise. W. the superpositionof thesenoise sources is foundby beamforming.The S. Hodgkissand F. H. Fisher(Marine PhysicalLaboratory, Scripps numberof PE runscan be reducedby usingthe elementsin the array as Institution of Oceanography,San Diego, CA 92152) sourcesand relyingon reciprocity,but eventhis indirectapproach is im- Measurements have been made of the ambient noise field between 25 practical.An efficientand directapproach is to start at a distantnoise and300 Hz with verticalarrays at 32ø N ( 124ø W, 136ø W, and 150ø W). sourceand superimpose additional noise sources on the PE fieldas the Due to substantialdifferences in weather at the stations,these measure- fieldis marched toward the array. Only one PE run isneeded in a cylindri- mentsprovide an opportunityto ohsevethe effect of weatheron theverti- cally symmetricocean basin. The justificationfor this approachis dis- cal distribution of ambient noise and how this distribution evolves with cussed.An applicationdemonstrates that noiseat the horizontal can be time. Array time series3-4 h in lengthat eachstation have been analyzed. causedby slopeconversion of low-frequencynoise sources over the basin The time-evolvingcharacteristics of ambient noise vertical directionality boundaries.[Work sponsoredby NUSC. 1 at eachstation will be compared.Specifically, the fluctuationsof beam powerfor beams pointing near the horizontal will becompared with those pointingboth upward and downward. [Work supportedby ONR.]

2:05

ZZ3. Frequency-aVeraged,mean-squared coherence of simulated underwater explosive transients. Allen E. Leybourne (School of 1:50 Engineering Technology, University of Southern Mississippi, Hattiesburg,MS 39406) ZZ2. Kfficient simulation of the vertical structure of noise using the A methodhas beendeveloped for determinationof the frequency- parabolicequation. R. B. Evans(SYNTEK, 1 DenisonAvenue, Mystic, averaged,mean-squared coherence (FMSC) of broadbandtransient CT 06355), W. M. Carey, G. Botseas(Naval Underwater Systems acousticsignals, similar to underwaterexplosions. It has many of the Center, New London, CT 06320), and J. A. Davis (Planning Systems, propertiesof the moreconventional mean-squared coherence (MSC), Inc., New London, CT 06320) includinga systematicbias, dependent upon the number of spectral values The structureof noiseat a verticalarray in a range-dependentocean usedin theestimate. The methodhas been demonstrated using a modelof basincan be simulatedusing the parabolicequation (PE). Noisesources theunderwater explosive direct arrival transient signal. As FMSC isaver-

S126 J. Acoust.Soc. Am. Suppl. 1, Vol.85, Spring1989 117th Meeting:Acoustical Society of America S126 agedover severalfrequencies the methodcompromises the functional 2:50 knowledgeof frequencydependence to achievestable and relatively unbi- asedvalues. Results are compared to MSC, utilizinga calibrationmethod ZZ6. Underwater noise generatedby Columbia River hydroelectric developedduring the study. The relative level of coherence between sepa- dams.Robert T. Miyamoto, StevenO. McConnell (Applied Physics ratesimilar transient acoustic processes can be determined when the sig- Laboratory, College of Ocean and Fishery Sciences,Umversity of nalsare precisely time aligned. FMSC can be used as lhe means of making Washington,Seattle, WA 98105), James J. Anderson, and Blake thistime alignment, thus making the necessarycomputations internally E. Feist (FisheriesResearch Institute, College of Oceanand Fishery consistent.[Work supportedby U.S. Navy,NORDA, Code242, Arctic Sciences,University of Washington,Seattle, WA 98105) Acoustics.] Low-frequency( 10-1000Hz ) underwaternoise measurements have beenmade in waterwithin and upstreamfrom fourColumbia River hy- droelectricdams. The motivationfor thesemeasurements was to mapout the soundfield within and upstreamfrom the powerdams as a firststep in understandingthe effect of thisfield on thebehavior of migratingsalmon- idsthat mustchoose between the bypasssystem or intakesto the turbines. Eventuallysound may be usedto guide the juvenile fish safelypast the turbineintakes and into the bypasssystem. Thus far, singlehydrophone measurementshave been made in thebypass slots within the dam and at a 2:20 numberof locationsupstream from the dam.The noiselevel varies with ZZ4. Low-frequencyambient noise measurementsin the South Fiji location,decreasing as the hydrophone is movedupsteam from the dam Basin. R. Marrett and N. R. Chapman'} (Defence Scientific andas the hydrophoneis movedcloser to the watersurface immediately Establishment, Auckland, New Zealand) upstreamof thedam as well as in thebypass slot. The noisespectra below 200 Hz arehighly modulated, displaying one or moresharp peaks, which The effectof wind speedon low-frequencyambient noise has been indicatesresonances in the structuralgenerating mechanism or propaga- measuredin an experimentcarried out in the SouthFiji Basin.This site tionpath. The spectrum level and modulation vary significantly from one providesan ideallocation for studyingsea surface noise, owing to lhe low dam to anotherand sometimesfrom oneconfiguration to another(e.g., densityof shippingin thebasin. The datawere recorded using a towedline when one of the turbines is on or off). A final set of measurementswill be array over an 1l-day period in the winter storm season.The local wind madeat theBonneville Dam usingseveral hydrophones placed at a num- speedwas measured at the site,with an observedvariation between 0-35 ber of locationsin the vicinityof the intakechannel, and thesemay help kn. The noise measurementsin the frequencyband 15-250 Hz were identifysources and propagation paths to the hydrophone.[Work spon- stronglycorrelated with the variationsin the localwind speed.The rela- soredby U.S. Army Corpsof Engineers.] tionship betweenwind speed 0 and noise level N is expressedby N = B + 20 n log(o). The constantsB and n have beendetermined by fittingthis model to the data at frequenciesfrom 15-250 Hz. At 250 Hz, the valuesare 22 dB and 1.5 for B and n, respectively.This valuefor n is higherthan the resultsof similarexperiments carried out in the northern hemisphereoceans where the influenceof shippingis greater.• On ex- changefrom DefenceResearch Establishment Pacific, FMO Victoria B.C. V0S I B0, Canada. 3:05

ZZ7. VLF acoustic ambient ocean noise measurementsusing Swallow floats. G. L. D'Spain, W. S. Hodgkiss, R. L. Culver, and G. L. Edmonds (Marine Physical Laboratory, Scripps Institution of Oceanography,San Diego, CA 92152-6400) A setof independent,freely drifting, neutrally buoyant, VLF (1-20 Hz) acousticsensors have been under development at the Marine Phys- ical Laboratory.These Swallow floats each contain a three-component 2:35 geophonefor measuringVLF particlevelocity, a magneticcompass, an 8- kHz acousticlocalization system, and hardware to record24 h of digitized ZZS. Ambient noise measurements from 100 Hz to 80 kHz. Steven data. By modelingthe ambientnoise field as a sumof independent,ran- O. McConnell (Applied PhysicsLaboratory, College of Ocean and domly distributedplane waves, the particlevelocity power spectra esti- FisherySciences, University of Washington,Seattle, WA 98105) and mated from geophonedata can be convertedinto equivalentpressure Michael P. Schilt (David Taylor Research Center, Ship Silencing powerspectra. Derived pressure power spectra from four deep water (wa- Evaluation Division, Bremerton, WA 98314) ter depth > 3.5 kin) deploymentsare comparedto pressurespectra re- cordedby concurrentlydeployed SOhObuoys and bottom-mounted hydro- Measurementscovering a broadfrequency range from 100 Hz to 80 phonesand to previouslyreported pressure spectral levels. In a recent kHz havebeen made in BehmCanal, Alaska. This siterepresents a fairly deployment,four floatswere equipped with VLF hydrophonesas well as deepembayment (400 m) with a verysoft bottom (porosity of about0.8) geophones.Comparisons are madebetween the powerspectra estimated and,hence, the noisedetected at the hydrophonesis affected negligibly by fromgeophone and hydrophone data collected at thesame time and place multipathcontributions except possibly at the very lowestfrequencies. by thesefloats. [Work supportedby ONR.] Data weregathered over a wide rangeof wind speeds(0-15 m/s) and duringperiods of rain and snow.Several unique and noteworthyresults were obtained. Foremost was the observationthat the wind-generated noiselevel measuredduring the winter was 5 dB lower than during the summerfor the same wind speedsand air-sea temperaturedifferences (air temperatureabout the sameor colderthan the seasurface). The summerdata agreewell with the most recent publishedmeasurements and are approximately2 dB higher than the standardKnudsen/Wenz referencespectra. Most reportedwind noise measurements are restricted to frequenciesless than 20 kHz. Thosethat go beyondthis frequency display a noticeable hump above the usual -- 17 riB/decade power-law ZZS. Bispectrum of ship-radiated noise. Melvin J. Hinich (Applied slope,and the Behm Canal measurementsshow that this hump continues ResearchLaboratories, The Universityof Texasat Austin, Austin, TX to 80 kHz, wherethe spectrumrejoins the extensionof the canonical 78713), Davide Marandino(ELSAG S.p.A.,Genova-Sestri, Italy), and power-lawslope. [ Worksupported by Battelle Pacific Northwest Labora- Edmund J. Sullivan (Naval Underwater SystemsCenter, Code 0Iv, toriesand NORDA. ] Newport, RI 02841)

S127 J. Acoust.Soc. Am. Suppl. 1, Vol. 85, Spring1989 117th Meeting:Acoustical Society of America $127 The bispectrumof ship-radiatednoise is estimated.The noisewas ponentsin the noise-generatingmechanism, it is concludedthat the radi- receivedon a towedarray being towed by the sameship that servedas the ated noiseof the towingplatform contains such nonlinear mechanisms. noisesource. The array wasbeamformed such that the forwardend-fire Also,the b/spectrumhas the capabilityof indicatingthe presenceof tran- beampointed toward the towingplatform and the broadsidebeam sam- sientsin the data.This propertywill be brieflydiscussed, and it will be piedthe environmentwithout the radiatednoise of the ship.The results shownthat the data under analysiscontain transients. Based on these showthat thereexist frequency-dependent bispectral components in the results,it is concludedthat the bispectrumcould be usedto indicatethe ship's radiated noise,whereas the ambient noisedoes not contain any existenceof transientand nonlinearsources that wouldnormally be hid- significantbispectrai components. Since the existenceof a nonzerofre- den in the backgroundnoise when the usualspectral estimation proce- quency-dependentbispectrum indicates the existenceof nonlinearcorn- duresare applied.

3:35-5:00

OpenDiscussion

MODERATORS Frederick H. Fisher ScrippsInstitution of Oceanography,San Diego, California MichaelI. Buckingham RoyalAerospace Establishment, Farnborough, England

THURSDAY AFTERNOON, 25 MAY 1989 COMSTOCK B, 2:00 TO 4:00 P.M.

SessionAAA. Musical AcousticsVI and Sl•eechCommunication IX: Vocal Fold Functionin Singing

JohanSundberg, Chairman Departmentof SpeechCommunication and MusicalAcoustics, KTH {RIT}, Box 70014,S-10044 Stockholm, Sweden

Inoited Papers

2.O}

AAAI. Relevantfactors in modelinglaryngeally controlled vocal vlbrato.Thomas Shipp and E. Thomas Doherty(Speech Research Laboratory, VA MedicalCenter, San Francisco, CA 94121} Rhythmicfrequency oscillations that characterize vocal vibrato are produced by either of two mechanisms. Oneinvolves driving the system with respiratory pulses and the other by intrinsic laryngeal muscle activity. In thislatter mode, ribtaro is most readily produced when several iaryngeal aspects are in order:( I ) thesinger's neuromuscularsystem has matured beyond a childhoodlevel; (2) a criticalbalance of adductory-to-abductory forceis appliedto thevocal fold margins;and (3) thelarynx is positionedvertically in theairway so that excessivevertical stiffening of the mucosallining is avoided.When these conditions are met, the intrinsic laryngealmuscle activity to producea givenpitch changes from a relativelystable interference pattern to quasiperiodicmodulated muscle activity oscillating at about5.5 to 6.0Hz. Theaverage value of themodulated EMG patternequals the steady-stateEMG signalused to producethat frequencywithout vocalvibrato. Whetheronly the cricothyroid muscle or otherintrinsic and/or extrinsic muscle are involved in thistype of vibrato productionis unknownat this time.

2:30

AAA2. Wherehas all the powergone? Ingo R. Titze (Voice Acousticsand BiomeehanicsLaboratory, Departmentof SpeechPathology and Audiology,The Universityof Iowa, Iowa City, IA 52242and The Recordingand Research Center, The DenverCenter for thePerforming Arts, Denver,CO 80204) An upperlimit on aerodynamic(pulmonary) power produced in shoutingand singing is on theorder of 1 W. Theradiated acoustic power is less than 10% of thisaerodynamic power, and in conversationalspeech can beas little as 0. 1%. Majordissipative elements are the vocal folds, the lungs, the soft walls of thevocal tract, and turbulencein theairstream emerging from the glottis. Some analytical calculations and some computer simula- tionwill focuson thedistribution of lossesalong the vocal tract. In particular,difference between the singing modeand the speaking mode will behighlighted. Speculations will bemade on the techniques by which a singer can optimizethe systemfor maximumpower output. [Work supportedby NIH.!

S128 J. Acou•. Soc.Am. Suppl. 1,Vol. 85, Spring 1989 117thMeeting: Acoustlc'•l Society ofAmerica S128 3:00

AAA3. Acousticstudies of the voice sourcein male singers.Johan Sundberg (Department of Speech Communicationand Music Acoustics,KTH (RIT), Box 70014, S-10044 Stockholm,Sweden)

Thispaper reviews various recent investigations with variousco-workers of malesingers' vocal fold func- tionmainly studied by inversefiltering for derivingthe waveform of thetransglottal airflow during phonation. Theoreticaland experimental studies confirmed the dominatingacoustic importance of ( 1) the peakairflow •/sfor the amplitude ofthe voice source fundamental, and(2) the negative peakamplitude ofthe differentiated waveformdU/dt forthe SPL of the radi,.ated sound. Unlike nonsingers, some professional baritone and bass singershave been found to retaina highU s duringloud tones at highpitches. Different strategies are possible for increasingdU s/dr for loudnessvariation: increasing Ug, increasing the duration of theclosed phase, and skewingthe pulseshape. Different singers use different combinations of thesealternatives depending on pitch, I,,oudnessrange, and voice type. Some of the physiological correlates ofthese strategies can be postulated. Here, Us seemshighly dependent on the degree of glottaladduction and dUs/dt on subglottal pressure. However, influenceof the breathingstrategy has also been quantitatively demonstrated.

ContributedPapers

3:30

AAA4. Laryngealadduction related to characteristicsof the flow AAAS. Vedic chanting and vowel intrinsic pitch: Evidence from an giottogram.Ronald C. Scherer(The Recordingand ResearchCenter, ancientsource. T. V. Ananthapadmanabha,Kim Silverman(AT&T The Denver Center for the PerformingArts, 1245 Champa Street, Bell Laboratories,Murray Hill, NJ 07974), and M. G. Prasad Denver, CO 80204), lohan Sundberg (Department of Speech (Department'of Mechanical Engineering,Stevens Institute of Communication and Music Acoustics, KTH, Box 70014, S-100 44, Technology,Castle Point, Hoboken,NJ 07030} Stockholm,Sweden}, and Ingo R. Titze (Voice Acoustics and BiomeehaniesLaboratory, Department of Speeeh Pathology and The purposeof thispaper is to shedfurther light on theaetiology and Audiology,University of Iowa, Iowa Cry, IA 52240and The Recording speechspecific nature of vowel intrinsic fundamental frequency (IF0 }, by and ResearchCenter, The Denver Center for the PerformingArts, investigatingits presencein vedicchanting. This is one of the earliest Denver, CO 80204) formsof chanting(circa 5000 years old) whichis still prevalenttoday, predatingmuch of Indianclassical music. It isinteresting to studyvedic Laryngealadduction is a basicphonatory property related to voice chantingas it representsthe borderline between speech and singing. There qualityand vocalpathology. In thisstudy, simultaneous inverse filtered are threedistinct tone levels in thischanting referred to as: (a) udatta airflowand electrogiottographic recordings were made for two malesub- high, (b) anudattalow, and (c) soarita,in-between. Sanskrit grammar- jeersphonating at deliberatelyvaried pitches, loudness levels, and quali- iansclassify vowels according to theposition of thetongue body and use ties.The goal of thestudy was to relatetemporal characteristics associated thesame labels as above for markingthe tones. The interactionof vowel withadduction with flow characteristics of the flow giottogram. A•tria• heightand tone level in thisvocal mode is investigated.Several vedic gular modelof laryngea^lflow glottogra•mspredicts that Uco/U passagesfrom threechanters with differentvowels occurring with the = k 2•r(Qo- Q, }, whereUis thepeak flow, U'is the negative peak flow same tone level and different tone levels for the same vowel have been derivative,Qo is the openquotient (the durationthe flow is abovethe recorded.Initial measurementsof F0 suggestthat chanters can override baseline,divided by the period),Q, is the risequotient (the durationthe theeffect of iF0 toachieve the same relative pitch values. This implies that flowrises from baselineto peak,divided by the period),and k = I. Em- theeffect of IFO dependson vocalmode and an activecontrol of IFO is piricalresults suggest k--'0.5. Thesefindings will bediscussed, and a var- possible. iety of adductionmeasures applied to the datawill becompared.

S129 J. Acoust.Soc. Am. Suppl. 1, Vol.85, Spring1989 117thMeeting: Acoustical Society of America S129 THURSDAY AFTERNOON, 25 MAY 1989 ROOM 202, 3:00 P.M.

Meeting of AccreditedStandards Committee S1 on Acoustics

to be heldjointly with

TechnicalAdvisory Group Meeting for ISO/TC 43 Acoustics, and IEC/TC 29 Electroacoustics

D. L. Johnson, Chairman S 1 Larson-Davis Laboratories, 1681 West 820 North, Provo, Utah 84061

StandardsCommittee S1 onAcoustics. Working group chairs will reporton their progress in thepreparation of standardson methodsof measurementand testing,and terminology,in physicalacoustics, electroacoustics, sonics,ultrasonics, and underwatersound. Work in progressincludes measurement of noisesources, noise dosimeters,integrating sound-level meters, and revisionand extensionof sound-levelmeter specifications. Opendiscussion of committeereports is encouraged.

The international activities in ISO/TC 43 Acoustics,and IEC/TC 29 Electroacoustics,will also be discussed. The Chairsof the respectiveU.S. TechnicalAdvisory Groups for ISO/TC 43 (H.E. yonGierke), and IEC/TC 29 (V. Nedzelnitsky),will report on current activitiesof theseTechnical Committees.

THURSDAY AFTERNOON, 25 MAY 1989 REGENCY B, 3:00 TO 5:05 P.M.

Session BBB. Structural Acoustics and Vibration VII: Sound Radiation from Structures and Viscoelastic Materials

Allan D. Pierce,Chairman Departmentsof Acousticsand MechanicalEngineering, Pennsylvania State University,University Park, Pennsylvania16802

Chairman's Introduction--3:00

ContributedPapers

3:05 3:20

BBB1. Vibration transmission in and sound radiation from a BBB2. Acoustic radiation from fluid-loaded structures with scaled model of a ship's engine room. Alfred Levi and Richard discontinuities. Charles Thompson and Rahul Sen (Electrical H. Lyon (Departments of Ocean and Mechanical Engineering,MIT, Engineering,University of Lowell, Lowell, MA 01854) Cambridge,MA 02139) The vibration transmittedfrom a power plant foundationthrough The presenceof discontinuitiessuch as joints, in a fluid-loadedstruc- supportingstructure and fluid containingtanks into the hull structure, ture results in farfield acoustic radiation even when subsonic wavenum- and then into the surroundingfluid hasbeen studied for a scalemodel of a bersprevail in the main bodyof the structure.The objectof thisstudy is to frigateship. The scalemodel is approximately1:6 and the scalefrequency developa rationalmodel of thisphenomenon using singular perturbation rangeis from 315-10 000 Hz. Transfer functionsrelating structuralvibra- methods.When a flexural wave in a thin structure impingeson a joint, tion and radiatedsound power to input force (or injectedmechanical evanescentstructural displacement fields are setup in the vicinityof the power) have beenmeasured. These experimental results have also been joint. This paperproposes to showthat thesefields are associatedwith comparedwith SEA calculationsof vibrationtransmission and sound rotation-dominatedmodes that are supportedby shear-correctedplate radiation.Of specialinterest is the role of in-planevibrations on the ener- theoriesof the Timoshenko-Mindlintype flexural mode. The methodof gy transmissionwithin the structure,and into the soundfield. matchedasymptotic expansions will be usedto obtainmode-conversion

S130 d. Acoust.Soc. Am. Suppl.1, Vol. 85, Spring1989 117th Meeting:Acoustical Society of America S130 coefficients,and it willbe shown that the spatial wavenumber spectrum of The soundradiation from baffled, thin, rectangularplates has general- the localfield is instrumentalin settingup an acousticfarfield in the ly beenrestricted to thesimply supported plate analysis, for whichsimple surroundingfluid. An importantmathematical issue is the properde- relationshold. This paperinvestigates the influenceon the acousticradi- scriptionof evanescentfields; this analysiswill be basedon resultsob- ation,of a moregeneral type of boundaryconditions, namely, edges pre- tainedpreviously in connectionwith acoustic waveguides. sentingarbitrary translation and rotationstiffness. For suchstructures, thein vacuomodal basis is notknown apriori. Thus the in vacuovibration- al responseof thestructure is determined using a polynomialexpansion of thetransverse displacement. In thelimit of a lowfluid-structure coupling (air loading),the in vacuovibrational response may be usedto calculate the acousticalperturbation generated in the fluid. Resultsare shownin 3:35 termsof quadraticvelocity of the plate,farfield acoustic pressure, acoustic BBB3. Experimental facility for fluid/structure interaction power,and radiation efficiency of theplate. The influenceof theboundary research.Courtney B. Burroughs(Applied ResearchLaboratory, The conditionsis examined,and the limiting casesof simply supported, PennsylvaniaState University, P. O. Box30, StateCollege, PA 16804) clamped,and free plates are presented. Theboundary layer research facility (BLRF) at PennState is being modifiedso that experimentalresearch on the interactionbetween fluid boundarylayers and vibration response of underlyingstructures can be conducted.Because the BLRF is a closed-loopglycerine tunnel, the boundarylayer is thick, which provides space for detailedmeasurements 4:20 requiredfor researchin fluid/structureinteraction. In addition,laminar, transition,or turbulentflow can be generatedand maintained. Modifica- BBB6. A simpleapparatus for the measurementof the shearmodulus of tionsto the BLRF for fluid/structureinteraction research include: ( 1) viseoelastic materials over 4 decades of frequency. Fred Schloss theintroduction of an elasticand exchangeable structure in contactwith (Wilcoxon Research,2096 Gaither Road, Rockville, MD 20850) the flow, (2) the reductionof backgroundvibration to removeinterfer- Two identicaltest samples are sandwichedbetween the metalends of enceof structuralresponse measurements by backgroundvibrations, and two smallidentical piezoelectric stacks, one acting as a transmitterhaving (3) an increasein themeasurement accessibility to theboundary layer. A a displacementproportional to the applied voltage V, the other receiving a descriptionof themodified BLRF ispresented along with technical sup- chargeQ proportionalto theforce. Since the ends of thestacks are moving portfor severalof thekey design elements. Measurements to characterize out of phasewith zeromotion at the center,no externalfixtures are neces- and definethe capabilitiesof the modifiedBLRF are discussed.[Work sary.The modulus equals Qt(VS) - •(d33) -2, wheret andS arethe sam- supportedby M. Reischman,ONR Code432F. ] ple'sthickness and cross-sectionalarea and du is a piezoelectricparam- eter. The usefulfrequency range is 1-10 000 Hz, whichcan be extended usingsmaller parts and differentmaterials for the end plates,and the temperaturerange is 50-200 øC. The deviceis limited to low valuesof dynamic strain. 3:$0

BBB4. Vibratory responseof heavily fluid-loadedplates to eonveeting pressureexcitations via impulseresponse methods. D. D. Ebenezerand PeterR. Stcpanishcn(Department of OceanEngineering, University of RhodeIsland, Kingston, RI 02881-0814) 4:35

A generaltime domain approach is presented to evaluatethe vibratory BBB7. Acousticattenuation in syntacticfoam and heavysilicone rubber responseof fluid-loadedplates to one-dimensionalconvecting pressure composites.Raymond Lim and Roger H. Hackman (Naval Coastal excitations.The velocityof the plateis expressedas a modalsum of the SystemsCenter, Physical Acoustics Branch, Code 2120, Panama City, FL productof the in vacuocigenfunctions and time-dependentcoefficients. 32407-5000) Previouslydeveloped [ D. D. Ebenezerand P. R. Stcpanishen,J. Acoust. Soc.Am. 82, 659-666 (1987) ] setsof coupledconvolution integral equa- Recently, a particularly effectiveunderwater sound attenuator has tionsfor the time-dependentmodal velocity coefficients are rearrangedto beendescribed experimentally by workersat the Naval SurfaceWeapons facilitatethe numerical solution. In the previousapproach, FFT methods Centerusing an impedancetube to measureecho returns [W. M. Madi- were usedto evaluatethe uncoupledvelocity responses. In the present goskyet al., MuhipleScattering of Wavesin RandomMedia and Random approach,analytical expressions are obtained for theimpulse responses of RoughSurfaces, edited by V. V. Varadanand V. K. Varadan(Pennsylva- themodal admittances and the impulseresponses of the modalradiation nia StateUniversity, 1985), p. 615]. The attenuatorstudied was earn- impedanccsare obtained via a combinationof analyticaland wave-vector- posedof a rigid syntacticfoam matrix loadedto 40% by volumewith time domain techniques.The known terms in the coupledconvolution manylarge viscoelastic rubber inclusions. The presentpaper uncovers the integralequations are thus very easilyobtained and a large numberof fundamentalattenuation mechanisms operating in thiscomposite by ana- modescan bc included in theanalysis. Numerical results arc presented for lyzingthe scatteringbehavior of a singlespherical scatterer embedded in theuncoupled and coupled velocity responses to loadsmoving across the an elasticmatrix. Effectsdue to resonantscattering by elasticand visco- plate.They clearlyshow that couplingbetween modes is significantand elasticspheres are studiedvia the T-matrixformalism. The dynamicsof thatthe general characteristics of the vibratory response can be anticipat- thescattered field at the water-syntacticfoam interface are also analyzed ed basedon a knowledgeof the Mach numberand the fluid-loadedmodal via classicalelastic theory at a planeinterface. The resultsof theseanaly- resonantfrequencies. [ Work supportedby ONR. ] sespoint to resonantcompressional to shearmode conversion at the inclu- sionsites as ultimately responsible for the attenuationsobserved by Madi- goskyet al. Consequencesof the modeconversion leading to attenuation includethe trapping ofbackscattered shear waves and the enhancement of dissipationmechanisms within the inclusion.

4:05

BBBS. Soundradiation of a finite plate with severaltypes of boundary 4:50 conditions. A. C. Berry, J. Nicolas (Groupe d'Acoustique de l'Univcrsit6de Sherbrooke,D6partement de O•nic M•caniquc, BBBS. Boundary element analysis of viseoelasticstructures Universit(•de Sherbrooke, Sherbrooke, Quebec I1 K 2RI, Canada),and J. involvingfractional operators.Kc-jun Xic (Departmentof L. Ouyader(Laboratoirc dc Vibration-Acoustique,INSA Lyon, 69621 Mechanicaland AerospaceEngineering, North Carolina State Villeurbanne Cedex, France) University, Raleigh, NC 27695-7910), Robert D. Ciskowski

S131 J. Acoust.Soc. Am. Suppl. 1, Vol. 85, Spring t989 117thMeeting: Acoustical Society of America S131 (Numerically Intensive Computing Center, International Business ratelydescribe the mechanical behavior ofviscoelastic materials. In this MachineCorporation, Kingston, NY 1•2401), and Larry H. Royster paper,a directBEM formulation for the transient dynamic analysis of (Departmentof Mechanicaland AerospaceEngineering, North Carolina three-dimensionalviscoelastic structures modeled by the fractionaloper- StateUniversity, Raleigh, NC 27695-7910) atorconstitutive equations ispresented. The BEM formulationis devel- opedin theLaplace transformed domain. The transient problem isfirst Theboundary element method (BEM) isapplied to solve viscoelastic solvedin the Laplace transformed domain and the time domain solutions structuralproblems. The viseoelastic characteristic ofthe structure isrep- areobtained by using an FFT basednumerical inversion procedure. Ex- resentedusing the fractional integrodifferential operators. The fractional ampleproblems are solved using this BEM formulation and the results are operatorrepresentation of viscoelasticity provides a means to moreaccu- compared.

S132 J. Acoust.Soc. Am. Suppl. 1, Vol. 85, Spring 1989 117thMeeting: Acoustical Society of America S132 FRIDAY MORNING, 26 MAY 1989 REGENCY A, 8:00 A.M. TO 12:05 P.M.

SessionCCC. Physical AcousticsIX: Inverse Problemsin AcousticsI

Robert C. Waag, Chairman Departmentof ElectricalEngineering, University of Rochester,Rochester, New York 14627

Chairman's Introduction-8:00

Invited Papers

8:05

CCCl. Inversefiltering for theanalysis of vocalfunction. Martin Rothenberg(DcpartmentofElectricaland ComputerEngineering, Syracuse University, Syracuse, NY 13244) The waveformof the volumevelocity of theairflow through the larynx, as obtained by inversefiltering the volumevelocity of the airflowexiting the mouth and nose, is a potentialconvenient noninvasive measure of the vibratorypattern of the vocalfolds during voiced speech. Of specialinterest is a measurethat is sufficiently robustfor clinicaluse in the detection,monitoring, and treatmentof voicedisorders. The problemsin this applicationare of threetypes: ( 1) The parametersof theinverse filter must be set to matchthe acoustic transfer functionof the vocaltract; (2) glottalairflow is, in someway, not an accurateindicator of vocalfold motion; and ( 3 ) the analysismust be accurate under a widerange of normaland disorderedvoice qualities and possible nasalcoupling. Because of theseproblems, it hasbeen difficult to find a robustand accurateautomatic proce- dure,even if the analysisis restrictedto only the simplestcase of openvowels. However, there appears to be a ratherstraightforward, although unconventional, solution to thisinverse-filtering problem if ( 1) thevocal fold vibratoryparameters of most interestare properlydefined, (2) physiologicalrestrictions on the possible vibratorypatterns are takeninto account,and ( 3 ) the nonlinearinteraction between the glottalsource and the vocaltract acousticsis usedin the analysisprocedure.

8:35

CCC2. Inverseproblems in nondestructiveevaluation. R. B. Thompson( Departmentof EngineeringScience and Mechanicsand NDE Center, Iowa StateUniversity, Ames, IA 50011)

The goalof nondestructiveevaluation is to obtaininformation about the stateof a structuralor electronic componentthat will allow a quantitativeassessment of its future serviceability.Because of the ability to penetrateopaque media, ultrasound is oneof the mostwidely used forms of interrogatingenergy. This paper will considerseveral current problemareas, ranging from the measurementof materialproperties such as porosityor grainstructure through the characterization of thenature of discreteflaws and the determination of their sizeand shape.In eachcase, an interpretationof the measurementin termsof elasticwave scattering theorywill be followedby a discussionof the inversetheories used to interpretthe data, with emphasison assumptionsrequired to obtainunique solutions. The presentationwill concludewith a discussionof future directions of needed research.

9:05

CCC3. Multiparameter inversionfor acousticand elastic media. Robert Burridge and Gregory Beylkin ( Schlumberger-DollResearch, Old Quarry Road, Ridgefield,CT 06877-4108) Inversionand imagingof an acoustictwo-parameter medium and for a three-parameterisotropic elastic mediumfrom seismic data are discussed. The inverseproblem is linearized by considering the actual medium as a perturbationfrom a knownbackground model. By usingthe single-scattering approximation, integral equa- tionsrelating the singlyscattered field linearly to the unknownparameters are obtained.Asymptotic solutions of the linearized inverseproblem are derived usingthe generalizedRadon transform. This method is closely related to methodsof seismicmigration. Spatially varying backgroundparameters and an almostarbitrary source-receiverconfiguration are allowed.The computationis performedin the time domain. All available dataare used even if redundant.Combinations of theparameters which can be reconstructed best and worst are identified.The data may be readjust onceand in an arbitraryorder.

S133 J. Acoust.Soc. Am. Suppl.1, Vol. 85, Spring1989 117thMeeting: Acoustical Society of America S133 9:35

CCC4. Inverse acousticproblems in the resonancescattering regime. G. C. Gaunaurd (Naval Surface WarfareCenter, White Oak Laboratory,Research Department, Silver Spring, MD 2090340005 Solvingan inversescattering problem here means the extraction of physical(viz., compositionand shape) informationfrom the active echo returned to an underwaterelastic target. This is thegeneral area of target identification.In thissense, solving inverse scattering problems is relativelysimple (!) in thelow or high spectralregions because there a numberof simplifying approximations may apply. However, for the intermedi- ateor resonanceregion of all scatterers,the above approximations do nothold, and exact solutions or novel typesof approximationsare necessary, making the actual inversions of scatteredwaveforms extremely hard. A certainlevel of success has been achieved by exploiting the presence of certain resonance features that manifest themselvesin the resonance region of thescattering cross sections (SCS) of submergedelastic targets. Exam- piesof how and how well one can extract identifying sets of resonance features from an echo have been recently overviewed[ G. Gaunaurd,J. Acoust. Soc. Am. Suppl. 1 84, S 168 (1988) ]. Althoughthe main interest over the yearshas'been the isolation of theresonance features in theSCS either by theoretical(viz., thebackground subtraction) and/or experimental (viz., samplingsof echoesin theirtail portions)means, little has been said aboutwhat to dowith them, once isolated. This paper will show(idealized) examples illustrating how these resonancefeatures can be actuallyused for unambiguoustarget characterization.

10:05

CCC5. Three-dimensionalinverse scattering tomographyusing elastic waves. Steven A. Johnson (Departmentof BiomedicalEngineering, University of Utah, SaltLake City, UT 84112) A 3-D ultrasoundmethod that providesclinically significant (and diagnostically valuable) images of importanttissue characteristics is described. This is madepossible by an inverse-scatteringtechnique that providesaccurate, independent image s of speedof sound,density, and absorption (with extension to five viscoelasticconstants) at thevery high spatial resolution of 0.5 to 1.0wavelength of theincident ultrasound energy.Image size has increased from 16X 16 pixelsto 200X200 pixelsand to 32X32)<96 voxelswhile maintainingaccuracy and spatial resolution. No othermethods, for examplethe B-scan mode of diffraction tomographybased on the Rytovor Bornapproximations, have come close to matchingthis achievement. Furtherimprovement intissue imaging is possible by using the inverse scattering method in conjunctionwith a highperformance reflection mode imaging method called synthetic focusing. The synthetic focusing method in nearlyhomogeneous medium produces medium to verylarge size, high spatial resolution images. The synthetic focusmethod also can be made to produceexcellent images in themoderately high refracting environment of the humanbody by applyingtime shift and attenuation corrections obtained from medium resolution inverse scatteringimages of speedof soundand absorption. Regularization and constrained optimization methods havebeen used to improvethe conditioning and therefore the speed of theinverse scattering methods.

10:35

CCC6. Exact analytic reconstructionin multidimensionalinverse problems.Adrian I. Nachman (Departmentof Mathematics,University of Rochester,Rochester, NY 14627) Thispresentation will reviewsome recent mathematical breakthroughs in inverse scattering theory. Con- siderthe pressure wavep(r,s,•o) generated by a pointsource s oscillatingharmonically with frequency •o: Vr.{[l/p(r) ]Vrp(r,s,ro)}+ ro2K(r)p(r,s,ro)= - tS(r- s). The problemof determiningthe densityp(r) and the compressibilityK(r) from knowledgeof p(r,s,w) for sourcess and receiversr locatedon a givensurface S hasbeen considered notoriously difficult. Traditional approachesrely on Born or Rytovapproximations. A new constructive method for recoveringp and K from measurementson a surfaceS with arbitrarygeometry, at two frequencies•o•, w2, will be presented.The procedureinvolves the solution of certainintegral equations on S. No simplifyingapproximations are made, andthe reconstructionis, in principle,exact.

ContributedPapers 11:05 hadthe privilegeof usingall frequenciesand could observe the scattering CCC7. Scatteringinversion using the ramp response.Bill D. Cook from a multitudeof directions.Realistically, one has a limitedbandwidth (Cullen Collegeof Engineering,University of Houston,Houston, TX of frequenciesand often only viewsfrom a fewdirections. At the sacrifice 77204-4792) of inversiondetail, one can use the rampresponse that requiresa much smallerbandwidth. Shape, size, and volumeinformation can still be ex- The objectiveof inversionis to havea resultthat is interpretable. tractedfrom a few views.Experimental results at audibleand ultrasonic Impulseand frequency techniques suggest that all couldbe known if one frequenciesdemonstrate the viabilityof this technique.

S134 d. Acoust.Soc. Am. Suppl. 1, VoL85, Spring1989 117thMeeting: Acoustical Society of America S134 11:20 insonificationisperformed by short pulses. The frequency range is about CCCS. Phasespace and path integralmethods in direct and inverse from0.5 to 3 MHz. Thelongitudinal phase velocities of thetwo solids are scattering.Louis Fishman (Department of Mathematics,Colorado obtainedthrough an angularstudy. The FFT processingof parts of the signalis performed at normalincidence. The thicknessesof the twosolids Schoolof Mines,Golden, CO 80401) arethus derived. Absolute measurements of the specular echo give the Directand inverse wave propagation models in oceanseismoacoustics densityof thefirst solid. The density of thesecond solid is obtained from areoften complicated by the extended,variable, three-dimensional chan- an absolute measurement of the reflection coefficient of the whole struc- nelingenvironments encountered. Even for the zeroth-order picture of a ture.At obliqueincidence, at resonances,guided waves are generated. transverselyinhomogeneous environment, the domainof interestis en- Theirspectral analysis allows the shear phase velocity of thetwo solids to tirely withinthe scatteringregime, with the subsequentabsence of an be determined.All parametersare determinedwihin an error of 10%. "asympoticallyfree," or homogeneous,region. While thereare numerous [Work supportedby DRET DGA Contract87-:261. ] methodsfor attacking the one-way direct calculation, most approaches to thecorresponding inverse (tomographic) problems essentially rely on a linearizationabout a well-chosen,zeroth-order model. Phase space and pathintegral techniques, which extend homogeneous Fourier methods to inhomogeneousenvironments, lead to comprehensivemathematical and computationaldirect models, in additionto providingthe framework for 11:50 theexact solution ofthe transversely inhomogeneous refractive index pro- file reconstructionproblem. These pseudodifferential and Fourierinte- CCC10. Theoreticaldevelopment of acousticagglomeration of aerosol graloperator methods are largely based upon the properties and interrela- particles.Limin Song (Noise Control Laboratory,The Pennsylvania tionshipsof the correspondingoperator symbols. This talk will present StateUniversity, University Park, PA 16802) the mostrecent developments and applications of the phasespace and The orthokineticinteraction is recognizedas a major mechanismre- pathintegral methods, as applied to thescalar Helmholtz equations, for sponsiblefor rapidagglomerations of polydisperseaerosols in a sound one-waydirect and inverse modeling. [ Work supported by NSF, A FOSR, field. The acousticagglomeration theory basedon this mechanismwas ONR.] developedby Mednikovin the 1960s.However, this theory has two basic problemsthat are not answeredsatisfactorily: How manysmall particles in an agglomerationvolume created by a large particlewill actuallybe collectedin one cycle and how many small particlesoutside will be at- tractedinto the volumeso that agglomerationcan continue for successive 11:35 cycles?These problems have been solved to thefirst-order approximation CCC9. Inverse problem for an immersedsolid/liquid/solid plane in this investigation.A generalexpression for the specificacoustic agglo- structure. J. L. Izbicki, O. Lenoir, P. Rcmbert, G_ Maze, and merationrate is derivedby a statisticalapproach. The efficiencyof co!li- J. Ripoche(Laboratoire d'Electronique et d'AutomatiqueUltrasons, son betweenparticles in a sinusoidalwave field is given explicitly. In Universit6Le Havre, PlaceRobert Schuman, 76610 Le Havre, France) addition,the analysisof the relativemotion between particles was per- formedby includingthe effectsof acousticscattering from particles.The The scatteringfrom an immersedplane multilayer is studiedin order resultsshow that a small particle is stronglyattracted toward a larger to determinethe physical parameters of themultilayer. It iscomposed by particleonce they crossover eachother. This transverseattraction pro- two solidsthat are coupledby a film of waterabout 0.3 mm thick.The videsan efficientmechanism for the fill-upof the agglomerationvolume.

FRIDAY MORNING, 26 MAY 1989 NEWHOUSE II, ROOM 254, 8:15 TO 11:29 A.M.

SessionDDD. SpeechCommunication X: Perceptionand Analysisof Consonants

Cynthia N. Connine, Chairman Departmentof Psychology,SUNY at Binghamton,Binghamton, New York 13901

ContributedPapers

8:15 natural [ba,da,ga]syllables, but wherethe transitiondurations were var- DDD1. The role of rate of transitionin the perceptionof placeof ied in 15-mssteps between 15 and 120ms werepresented to listenersfor articulation.Renee A. E. Zakia and John Kingston (DMLL, Morrill two-interval,foreed-choice discrimination and for identificationalong a Hall, CornellUniversity, Ithaca, NY 14853-4701) stop--glidedimension. If listenersexpect longer transitionswith velars, thenthey should accept stimuli with longertransitions as stops when the Listenerscan reliably identify the placeof articulationof bilabialand formantsindicate a velar than whenthey indicatea bilabialor alveolar. alveolarstops in severelytruncated CV syllablesfrom just the initial20 Second,variation in F2 and V• transitionsbetween values appropriate for ms,but they need 40 msor moreto identifya velar.The need for a longer [da] andvalues appropriate to [ga] werecombined with variationin the intervalmay reflect listeners' expectations that rate of transitionshould be rate of transition;rate of transitionwas varied in 5-mssteps between 20 slowerfor velarsbecause of the sloweropening gesture at this placeof and 60 ms. Thesestimuli were also presentedto listenersin two-inlerval, articulation [Kewley-Port eta!., J. Aeoust. Soc. Am. 73, 1779-1783 forced-choicediscrimination and identificationof placeof articulation (1983) ]. This paperinvestigates the perceptualeffects of differencesin tasks.It is expectedthat fasterrates of transitionwill shift listeners're- rateof transitionin twoexperiments. First, synthetic CV syllables,where sponseto stimuliwith F2 and F_•transitions near the [d]/[g] boundary the directionand magnitudeof the F•, F,_,and F3 transitionsmatched toward[d] andslower transitions will shiftthem toward [g].

$135 J. Acoust.Soc. Am. Suppl. 1, VoL85, Spring1989 117thMeeting: Acoustical Society of America $135 8:27 (DCTCs) of the magnitudespectra. The databaseused in theseexperi- mentsconsisted of 2481 CVC syllablesspoken in isolationby ten males, DDD2. Effectsof first formantonset qualities on VOT judgmentscan be ten females,and ten children. In all experiments,15 speakerswere usedto explained by auditory processesnot specific to humans. Keith train the classifierand the other 15speakers were usedfor evaluation.For R. Kluender (Departmentof Psychology,University of Wisconsin, the caseof dynamicfeatures, DCTCs werecomputed over a 50-msinter- Madison, WI 53706} valbeginning with the burst using 7-ms frames spaced every 5 ms.For the Both F 1 transitionduration and F 1 onsetfrequency have been pro- staticcase, the DCTCs werecomputed from one25.6-ms frame beginning posedto beperceptually significant in categorizationof voiced and voice- at the burst. Automatic classificationresults, based on the test data, were lesssyllable-initial stops. Transition duration per semay not, however, 87.2% for thedynamic spectral shape features versus 60.1% for thestatic explainthe fact that, for longertransitions, longer F I cutbackis required case.Dynamic featurestimed to beginwith the formanttransition area in orderto perceivea stopas voiceless. Longer transitions result in lower resultedin 44.6% recognitionrates. Control experiments with formants F I onsetsat anyduration of cutbackgreater than zero, and it is possible resultedin muchlower recognition rates under every condition tested. In thatthe major effect of F i isdetermined by itsfrequency at onset.In this summary,these results are in agreementwith the theory that dynamic study,FI transitionduration, onset frequency, and slopewere varied spectralshape, spanning an intervalof approximately50 msbeginning at acrossfour types off I transitionin whichone of thethree variables ( onset the burst,carries most of the informationfor initial stopconsonants [D. frequency,duration, slope) was held constant while the othertwo were Kewley-Port,J. Acoust.Soc. Am. ?3, 322-335 (1983) ]. [ Work support- allowedto vary. Each of the four F I typeswas usedin syllableswith ed by NSF. ] higherformants appropriate for labial, aircolor, and velar places of articu- lation.By far, the bestpredictor of identificationof thesestimuli by hu- manlisteners was F I onsetfrequency; F ! duration,F I slope,and place of articulationhad little or no effecton labelingboundaries. Six Japanese quail (Coturnixcotunix japonica), trained to responddifferentially to voicedversus voiceless stops, evidenced "labeling" behavior almost iden- tical to humans'with the samestimuli. These results are takento provide 9.-O3 strongevidence that F 1 onsetfrequency is the primarydeterminant of shiftsin VOT boundariesacross place of articulation,and that an auditory DDD$. Effectsof speakingrate are moderatedby phonologicalstructure. mechanismnot specificto humansis responsible. LydiaE. Volaitis(Department of Psychology,Northeastern University, Boston, MA 02115)

Changesin speakingrate can alter the durationof propertiesthat conveysegmental information. For example,with an increasein syllable duration,the distributionof VOT valuesfor labial stops,especially the voiceless/p/, shiftsupward along the VOT continuum.Perceptual ad- justmentto thisrate effect entails a shiftin thecategory boundary toward

8'.39 longerVOT valuesfor longersyllables and, as recently reported, a change in whichstimuli along the VOT continuumare perceived to bebest cate~ DDD3. The perceptionof stopconsonants: Spectral tilt revisited.Kevin goryexemplars [I. L. Miller andL. E. Volaids,J. Acoust.Soc. Am. Suppl. H. Richardsonand JamesR. Sawusch(Department of Psychology, I 80, S125 (1986)]. The presenttwo-part investigationfocuses on SUNY at Buffalo, Amherst, NY 14260) whetherthe locationof bestexemplars is solelya functionof syllable duration,or dependsas well on the phonoiogicalstructure of thesyllable, The claim that invariantfeatures involving spectral tilt, as proposed specifically,the placeof articulationof the initial consonant.Results of by Lahiri et al. (1984), are usedby humanlisteners when classifying stop the productionstudy have confirmed that as placemoves from labial to consonantswas explored. Subjects were presented with stop-vowelsylla- alveolarto velar, VOT increases,and haveshown that this occursacross a blesrepresenting [hi, [d], and [g] with a rangeof vowelsin an identifica- rangeof syllabledurations. The parallelperception study, currently in tion task. Stimuli wereeither natural, synthetic(based on the natural set}, progress,addresses whether at any givensyllable duration, the location of or modifiedtokens (synthetic tokens containing a burstwhich, according the bestexemplars varies with place,in accordwith the productiondata. to the Lahiri et al. metric, should be misidentificd ). Results indicate that Sucha resultwould indicatethat the locationof the bestexemplars is a the changein spectraltilt playslittle role in stopperception. Only [g] functionof the phonologicalstructure of the syllable,in conjunctionwith showedany evidenceof a systematiceffect. To investigatefurther the its duration.[Work supportedby NIH.] differencefound in the identificationtask, tone analogsmimicking the [b], [d], and [g] CV setswere produced.Both speechand nonspeech groupswere run to examinethe perceptuallocus of anyeffects of change in spectraltilt. The resultsof thesetwo groupswill becompared to thoseof the speechgroups in the firstexperiment. The implicationsfor theoriesof auditoryto phoneticcoding of stopsand possibleinvariant attributes in stopperception will be disenssed. 9:15

DDD6. The effect of position of stress on the durations of stop consonants in American English. Alice E. Turk (DMLL, Morrill Hall, Cornell University, Ithaca, NY 14853-4701)

It has been documented for American English that/t/and/d/are 8:51 realizedas .very short alveoi.ars (flaps) following a stressed vowel nonfoot initially: [V_V( ... )] or [VCV_V( ... )] [Zue and Laferri/:re (1979}]. DDD4. Spectral shape factors for speaker-independentautomatic recognition of stop consonants. Zaki B. Nossair and Stephen This studyinvestigates the durationof otherstop consonants in the flap- pingenvironment to seewhether the shorteningof/t/and/d/is a phono- A. Zahorian (Departmentof Electricaland ComputerEngineering, Old Dominion University,Norfolk, VA 23529) Iogization of a more general phonetic principle. Stathopoulosand Weismet(1983) reportthat in nonsensewords, stop closure durations for A seriesof automatic recognitionexperiments was conductedwith all placesof articulation are shorter in the post-stressenvironment. In a naturallyproduced English stop consonants fo,p,d,t,g,k/in syllableini- study of two speakersusing natural speech,one speaker'sconsonants tial position.The objectivesof theexperiments were to investigatein detail shortenedsignificantly (p < 0.05) in the flappingenvironment. However, the effectivenessof spectralshape factors, as both dynamicand static the fact that the secondspeaker did not exhibitthe sameshortening pat- featuresfor automaticrecognition of stopconsonants. Spectral shape fac- ternsuggests the need to expandthe number of speakers;results from such tors were computed as the discrete cosine transform coefficients a larger subjectpool will be reported.

S136 J. Acoust.Soc. Am. Suppl. 1, Vol.85, Spring1989 117th Meeting:Acoustical Society of America S136 9:27 9:39

DDD7. Fricative perception:Frication and transition cues. Fan- DDDS. Integraltry in consonant perception: Vowel environment Gang Zengand Christopher W. Turner (CommunicationSciences and influencesconsonant perception. Gall R. Tomiak (Department of Disorders,Syracuse University, Syracuse, N¾ 13244-2250) Psychology,State Universityof New York at Buffalo, Amherst, NY 14260) By presentingfricative-vowcl tokens across a rangeof intensitiesand determiningthe audibility of variousportions of thetokens, the present studyinvestigated the cues for fricative perception. The fricationcue was Previousresearch designed to examine the nature of phoneticprocess- definedas grossspectral-shape ditferenc•s residing in the steady-state ingthrough the use of noise-toneanalogs to speechsyllables has demon- fricationnoise burst; while the transitioncuc was defined as dynamic stratedthat the phoneticcoding of noiseand tone segments as consonant formantchanges in the transitionportion between the fricativc and its andvowel within a syllableproceeds in a mutuallydependent (integral) adjacentvowel. Both natural and syntheticsyllables, with durationand fashion.However, the auditory coding of thesesegments is independent amplitudenormalized, were used in closed-setrecognition tasks hy four (separable}.The purposeof the presentexperiment was to determine normal-hearingSUbjects. The presentationlevels varied from 0%-100% whetherconsonant information is alsoprocessed in an integralfashion audibilityfor individual fricatives. Results suggest that the frication burst with respectto vowel informationcontained in an adjacentsyllabic. maybe a sufficientcue for theenrrect perception of fricatives;while the Tone-noise-toneanalogs of V_CV disyllableswere used in a speededclas- transitioncue, although it maynot be necessary, plays an importantrole sificationtask. The resultsindicate that the phonetic coding of thenoise as in helpingto identifythe place information, particularly at lowpresenta- a fricativcis integralwith respectto both the precedingand following tionlevels where the frication cue is always not audible. Two otherexperi- vowel.Thus the perceptualcoding of consonantsseems to proceedwith ments,using truncated stimuli, with frication or transitioncues presented referenceto a surroundingvowel environment regardless of syllableboun- independently,further supported our conclusions.[ Work supportedby daries.The implicationsof theseresults for the phoneticcoding of speech, SyracuseUniversity SenateResearch Grant and DeafnessResearch and recentproposals regarding the priorityof vowelinformation in per- Foundation.! ception,will be discussed.[Work supportedby NINCDS.]

9:51-10:05 Break

10:05 crosstermscan be attenuatedby time-frequencysmoothing (SWVD). Time andfrequency resolution may be chosen independently, thus avoid- DDD9. Phonerestoration. Bruno H. Repp (HaskinsLaboratories, 270 ingthe trade-offexisting in wide-and narrow-band spectrograms. Despite Crown Street, New Haven, CT 06511-6695) its apparentcomplexity, the SWVD can be computedabout four times Whena speechsegment is replacedby an extraneoussound of not too fasterthan a spectrogram.SWVD analysisof nasal-voweltransitions ac- dissimilarspectral structure, the speechoften seems intact (the "phoneme curatelyshows fine spectrotemporal details in the murmur release,initial restoration"effect). Does this occur becausethe missingphonoiogicai slopeof the formanttransitions, and abruptenergy changes. Identifica- segmentis filled in at the levelof lexicalaccess, or becausethe missing tion of placeofarticulation experiments performed on labialand alveolar phoneticinformation is filledin at a prelexicalstage? This issuewas inves- nasalconsonants in variousvocalic contexts in continuousspeech, using tigatedby probingsubjects' perception of the extraneousnoise burst that the SWVD of 20- to 60-mssegments around the transition,shows good replacedthe fricationof an [s] insidea shortsentence. The resultsshowed correlationwith previousperceptual experiments. thal the noisewas perceived as lower in "pitch" than an identicalnoise presentedbefore or after thesentence, or insertedinto thesilent closure of a [th ] in a similarsentence. This suggests that the [s] wasrestored pho- neticallyby auditorysubtraction from the noiseoccurring in its place, whichleft a perceivedextraneous residue that wasdepleted of high fre- quencyenergy. Additional experiments investigated whether this "phone restoration"was induced by phoneticcues to the missingsegment in adja- 10:29 centsignal portions, or whetherlexical access played a role. [Work sup- portedby NICHD. ] DDD11. Trainlng Japanese listeners to identify /r/ and /1/. John S. Logan and Scott E. Lively (Speech Research Laboratory, Departmentof Psychology,Indiana University,Bloomington, IN 47405)

Nativespeakers of Japaneselearning English generally have difficulty differentiatingthe phoneroes/r/and/I/, evenafter yearsof experience 10:17 with English.Previous research that attemptedto trainJapanese listeners DDDI0. Identification of placeof articulation in nasalphoneroes using a to distinguishthis contrast usingsynthetic stimuli showedlittle success, time-frequency approach. Edgar F. Velez, Richard G. Absher especiallywhen transferto natural tokenscontaining/r/and/I/was (Department of Electrical Engineering, University of Vermont, tested.In the presentstudy, a procedurethat differedfrom theseearlier Burlington, VT 05405), and James F. Lubker (Department of attemptswas used.Japanese subjects were trained in an identification Communication Science and Disorders, University of Vermont, paradigmusing as stimuli multiple natural exemplars contrasting/r/and Burlington,VT 05405) /1/from a varietyof phoneticenvironments. A pretest-posttestdesign combinedwith a test of generalizationcontaining novel natural tokens Acousticcues to placeof articulationare present in thehighly nonsta- wasused to assessthe effectivenessof training.Analysis of pilot data from tionary regionbetween nasal consonants and vowels.A needfor a speech a small group of subjectsshowed that the new proccclurcwas more robust processingtool capableof accuratelyrepresenting these transient events thanearlier procedures. The resultsdemonstrate the importance of stimu- led to considerationof the Wignet-Ville distribution(WVD). Previous lusvariability and task-related factors in trainingsecond language leam- usein speechanalysis was limited due to thepresence of multipleinterfer- en to perceivenovel phonetalccontrasts that are not distinctivein their enceterms (crossterms),which hinderedits direct interpretation.These nativelanguage. [ Work supportedby N 1H. ]

S137 J. Acoust.Soc. Am. Suppl. 1, Vol. 85, Spring 1989 117th Meeting:Acoustical Society of America S137 10:41 McGurkeffect was very strong and widespread. These results suggest that incompleteintelligibility of auditorystimuli is necessary for theMcGurk DDD12. An audio-visual investigationof linguistic stressperception. effect. Lawrence D. Rosenblum (Department of Psychology, Wellesley College,Wellesley, MA 02181) The trueacoustic correlate for linguisticstress has not yet been found. While it wasoriginally thought that listenersbase stress judgments on 11:05 syllableintensity, it hasbeen shown that intensity,fundamental frequen- DDD14. Larynx frequency information for lipreading speech in cy, duration,and spectral structure can all act aseffective information for Mandarin Chinese.Yuk Ching Ching (Departmentof English,Chinese stressperception [D. lsenbergand T. Gay, 1. Acoust.Soc. Am. Suppl.1 Universityof Hong Kong, Shatin,N.T., Hong Kong) 63, S2i (1963) ]. Becauseno singlesimple acoustic dimension seems to be dominant,it hasbeen proposed that listenersbase stress judgments on an Prosodiccontrasts are importantsources of informationin a tonelan- articulatoryproperty such as vocaleffort. Since such properties can be guagelike Chinese.Each syllable is characterizedby a tonalcontour that speq.ified optically as well as acoustically, a study to testthis hypothesis determinesthe lexicalmeaning of the word in isolation.In continuous wasconducted which usedconflicting audio-visual presentations of a speech,the overallstress and intonationpatterns contribute significantly speakerproducing tokens from two noun-verbpairs (CONvict-con- to understandingspeech. These contrastire speech patterns are directly VICT and PERmit-perMIT). The predictionwas made that if stress relatedto thefundamental frequency of thespeaker's voice, which is rela- judgmentsare basedon perceptionof articulatorydynamics rather than tivelyinvisible. When speech communication is dependenton lipreading, on simpleacoustic parameters, then judgments should be affected by visu- auditoryvoice pitch informationcan thusbe the mosteffective aid. That al as well as auditory information.It is shownthat stressjudgments are this is so in an English-speakingcontext has beenshown in numerous affectedby visual informationeven when subjects( I ) are instructedto studies.The presentwork evaluatesthe contributionof larynxfrequency basetheir judgmentson only what they hear and (2) cannotdetect a informationto lipreadingconnected discourse, and specificallyto resolv- discrepancybetween the audio and visual components. Similar results are ing ambiguitiesthat are primarily signaledby contrasfivestress patterns alsoshown for noun-verbtokens distinguished by an auditorydimension and tonepatterns in Mandarin Chinese.The resultshave important impli- that cannotbe specifiedvisually (fundamental frequency) indicating that cationsfor the designof speechprocessing aids and the developmentof a moregeneral articulatory property, such as vocaleffort, might be the speechperceptual assessments in a tonelanguage community. basisof stressjudgments.

11:17

DDDIS. Interpreting visual speechsignals using neural networks.Ben 10:53 P. Yuhas (SpeechProcessing Laboratory, Department of ECE, Johns HopkinsUniversity, Baltimore, MD 21218) DDDI3. Effects of lip-read information on auditory perceptionof Japanese syllables. Kaoru Sekiyama and Yoh'ichi Tohkura (ATR When the acousticspeech signal is degradedby noise,compensatory Auditory and Visual Perception Research Laboratories,Inuidani, informationcan often be obtainedby watchingthe speaker'smouth [W. Seikaeho,Kyoto 619-02,Japan) H. Sumbyand I. Pollack,J. Acoust.Soc. Am. 26, 212-215 (1954) 1. The aim of the work to be presentedis to explorethe structureof thiscompen- The MeGurk effectis a phenomenonthat demonstratesa perceptual satoryinformation, as it mightbe usedto assistautomatic speech recogni- fusionbetween auditory and visual(lip-read) informationin speechper- tion. Startingwith visualimages taken from laserdisc recordings ofspeak- eeptionunder visual-auditory discrepancy condition (using dubbed vid- er'sfaces [ Bernsteinet al., J. Acoust.Soc. Am. SuppL1 82, S22 (1987) ], a eo tapes).This paperexamined the relationbetween the "McGurk ef- small box centeredat the mouth is identifiedand extracted.A variety of fects" and the intelligibilityof auditory stimuli. A female narrator's neuralnetworks are then taught to processthese images based upon two speechwas video taped for ten Japanesesyllables (/bad,/pad,/mad, / interpretationschemes. The firstapproach is to classifythe visual images wad,/da/,/tad,/na/,/ra/,/gad,/lea/). The videoand audio signals for asbelonging to a particularclass. The secondapproach is to extract acous- theseten syllableswere combined,resulting in 100 audio-visualstimuli. tic constraintsdirectly from the image.Toward this end,neural networks Thesestimuli were presented to tensubjects who were required to identify are trained to estimatethe short-termpower spectralenvelope of the the stimulias heardspeech in both noisyand noise-freeconditions. For acousticsignal given the correspondingvisual imageas input. Perfor- bothconditions, the intelligibilityof the auditorystimuli was measured, manceis evaluatedon nine vowelsobtained from two speakers.These presentingthe auditory stimuli alone. In the noise-freecondition, the resultswill be reportedand compared with resultsfrom moretraditional McGurk effectwas small and found only in conditionsin whichthe intelli- classificationand estimationtechniques. [Work supportedby AFOSR gibilityof the auditorystimuli was not 100%. In the noisycondition, the Contract No. 86-0246.]

S138 d.Acoust. Soc. Am. $uppl. 1, Vol. 85, Spring 1989 117thMeeting: Acoustical Society of America S138 FRIDAY MORNING, 26 MAY 1989 COMSTOCK A, 8:30 TO 10:15 A.M.

SessionEEE. EngineeringAcoustics VIII: Scatteringfrom AcousticMaterials

Caroline L. Fu, Chairman ResearchEngineering Division, Boeing Aerospace Company, P.O. Box3999, Seattle, Washington 98124

ContributedPapers

8:30 A studyis presentedof the reflectionof a planecw soundwaveform incidenton a fluid-loadedelastic plate, quantitatively describing how and EEE1. Refractionand reflection of an obliquelyineldent finite amplitude howmuch this reflectionis selectivelyreduced by coveringthe platewith plane P wave at a plane solid-solidinterface. Kun-Tien Shu and Jerry an ideally bondedviscoelastic layer. The exact equationsof acoustics, H. Ginsberg(School of MechanicalEngineering, Georgia Institute of elastodynamics,and viscoelastodynamics(in the Kelvin-Voigt model) Technology,Atlanta, GA 30332) areused to describethe behavior of theexternal fluid, the elastic plate, and An earlierpaper [K. T. Shuand J. H. Ginsberg,J. Acoust.Soc. Am. the absorbingcoating, respectively. By meansof the principleof fading Suppl. I 84, S5 (1988)] proved that the significantfinite amplitude memoryand a recentlydeveloped formulation [Strifors and Gaunaurd, J. aspectsof modeconversion of a planedilatational wave obliquely incident Acoust.Soc. Am. 85, 995-1004 (1989) ] with an appropriatenumber of at a planestress-free boundary may be describedin termsof Earnshaw- time constants,the solutionis generatedin all threemedia. Once these typesolutions for the dilatationaland verticallypolarized shear waves. In fieldsare determined,the reflection(or transmission)coefficient for the the work describedhere, the methodis extendedto an obliquelyincident coatedstructure is easilyconstructed. A numberof calculatedplots for finiteamplitude plane dilatational wave at a planeinterface between two the echo-reductionlevels and their associatedphase shifts versus frequen- boundedisotropic solids. It isshown that, not as a consequenceof nonlin- cyare displayed to illustrate the versatility of thispredictive approach in a earinteraction effects, but rather as a consequenceof nonlinear self-action varietyof situations.The approachcan be used to evaluatethe reflection- effects,cumulative growth of higher harmonicsoccurs in the incident, reductioncapacity of theabsorbing layer. reflected,and refracted waves. A numberof specialcircumstances of wave reflection-refractionare examined,relative to the incidenceangle and the materialproperties of the two media.Also givenare the deformedinci- dent, reflected,and refracted waveformsnear one shock formation dis- 9:15 tance.[Work supportedby NSF and ONR.] EEE4. Forcedvibration of a submergedspheroidal shell using variationai principles.Pei-Tai Chenand JerryH. Ginsberg(School of Mechanical Engineering,Georgia Institute of Technology,Atlanta, GA 30332) Variationalprinciples are employed to study acoustic radiation from a 8:45 submergedprolate confocal spheroidal shell. Structural vibration is de- scribedby the methodof assumedmodes, based on Hamilton'sprinciple, EEE2. Experimentalvalidation of a modelfor predictingthe impedance in whichbending and membrane stresses are included in thestrain energy. of multilayersystems by the transfermatrix method.R. Woodcockand The surfacepressure is described by a variationalprinciple that is derived M. Hodgson(Grouped'Acoustique, DrpartcmentdeGrnieMrcanique, from the surfaceKirchhoff-Helmholtz integral equation. This approach Universit6de Sherbrooke,Sherbrooke, Qurbec J I K 2R 1, Canada) wasemployed earlier [J. Acoust.Soc. Am. Suppl.1 84, S6 (1988)] to As hasbeen demonstrated by variousauthors, transmission line theo- studya sphericalshell under a harmonic,concentrated force. A singular- ry is a powerfultechnique for studyingthe soundtransmission of multi- ity that occursin the setof coefficientsdescribing the couplingbetween layersystems with infinitelateral extent. This modelhas been extended to surfacedisplacement and pressure was found to require further attention. the studyof the surfaceimpedance of suchsystems. It is shownhow the In thecase of a sphere,evaluation of thecontribution of thissingularity, transfer matricies are derived from fundamental acoustic equations. whicharises in anintegration over the surface, is expedited by thefact that Theseequations contain information on the conventionsadopted con- thesingularity is independentof positionof the fieldpoint relative to the cerningthe assumedtime dependanceand orientationaxis. It is shown sourcepoint. The presentpaper addresses the evaluation of thecoupling that it is convenientto accountfor this during the juxtapositionof the coefficientsfor an arbitrarybody of revolution.Convergence is illustrated quadrapolesin cascade,this modelingthe superpositionof the various numerically,and resultsare comparedwith thoseobtained by Yen and layers.An experimentalvalidation of thismodel has been undertaken on Dimaggiofrom theiranalytical solution based on membranetheory [J. twotypes of mineralwool, placed in differentmultilayer configurations in Acoust.Soc. Am. 41, 618-626 (1967) ]. [ Work supportedby theOffice of an impedancetube, using the Chungand Blasertransfer function tech- Naval Research,Code 1132-SM. ] nique.The measuredimpedances are in excellentagreement with those predictedusing the Delany and Bazley impedancemodel. Finally, it is shownthat the modelis only valid if eachlayer of the systemis homoge- neous. 9:30

EEES. Applicationof the finite elementmethod to the modelingof plane wave scatteringfrom complianttube gratingsat obliqueincidence. A. C. Hennion, R. Bossut, J. N. Decarpigny (Institut Sup•rieur 9:00 d'Electroniquedu Nord, 41 BoulevardVauban, 59046 Lille Cedex, France), andC. Audoly (Grouped'Etude et de Recherchede D•tection EEE3. Reflection-reductionmodel for a viscoelasticallycoated plate. H. Sous-Marine,Le Brusc,83140 Six Fours lesplages, France) C. Strifors (Swedish Defense Research Establishment, S-10254 Stockholm, Sweden) and G. C. Gaunaurd (Naval Surface Warfare The modelingof complianttube gratings has been performed with the Center(R43), White Oak, SilverSpring, MD 20903-5000) helpof thefinite element method, using the ATILAcode [Decarpigny et

S139 d. Acoust.Soc. Am. Suppl. 1, Vol. 85, Spring t989 117th Meeting:Acoustical Society of America Sl 39 aL, J. Acoust.Soc. Am. 78, 1499-1507(1985) 1-To do this,only the unit of ambientnoise were made for specificenvironments. Data-analysis pro- cell of the periodicstructure, including a smallpart of the surrounding gramswere developedand usedto constructa model of the stationary fluid domain,has to be meshed,due to the useof a classicalBloch-type noiseenvironment and extractthe relevantparameters. These are usedto relationbetween the displacementcomponents of pointsthat are separat- definethe structure, parameter range, and computational requirements of ed by the gratingspacing. Then, the effectof the externalfluid domainis thenoise caneclef. [ Work supportedby the FloridaHigh Technologyand accountedfor by matchingthe pressurefield in the finiteelement domain IndustryCouncil. ] to simpleingoing and outgoingplane-wave expressions. This paperde- scribesresults obtained for the scatteringof a planewave from different complianttube gratings, including internal losses, at obliqueincidence. First,it showsthat a niceagreement has been found between predictions from an analyticalmodel and finiteelement results for the insertionloss of 10:00 an infiniteelastic plate, thus validating the method.Then it describesthe caseof cylindricaltube gratings embedded or not in a viscoelasticlayer, EEE7. Low-frequencytransmission loss by alternateresonance tuning andshows the effects of low-stiffnessencapsulant on insertionloss curves. (ART}. Donald B. Bliss and JamesA. Gottwald (Department of Finally, double-layergratings with differentseparations are alsoconsid- Mechanical Engineeringand Materials Science,Duke University, ered. Durham, NC :)7706}

Achieving adequatelow-frequency transmission loss through lightweightflexible paneled walls is an importantproblem, particularly for interiornoise reduction of propelleraircraft. Alternate resonance tun- ing (ART) isa newmethod of blockingsound transmission through such 9:45 structuresby controlling the dynamics of thewall panels. Adjacent acous- Eg-E6. Modeling of acousticenvironment for the purposeof noise ticallycompact panels are designed to haveresonant frequencies alter- cancellation.Osama A. Mohammed, Kang Yen, Vijay Raman, and natelyabove and below the frequencyto becanceled. At the designfre- Kurt Ramdin (Department of Electrical Engineering, Florida quency,such panels oscillate with equal amplitudebut nearlyout of InternationalUniversity, Miami, FL 33199) phase.The resultingcancellation from acoustic sources on adjacentpan- elscauses cutoffof the transmittedacoustic medes, which become evanes- The specificnoise-cancellation problem being considered here is the centand nonpropagating. The conceptdiffers from other noise reduction activecancellation of acousticnoise by the useof electroniccarphones. methodsin that it doesnot rely on reducingthe wall motion,but rather Sinceit isimportant to achievecancellation of ambientnoise only, and not altersthe wall wavenumber spectrum. There is noserious weight penalty of warningsounds and speech,an adequateunderstanding of the noise associatedwith themethod, and increasing the structural damping is not environmentin whichthe earphones are to be usedis required.A keystep advantageous.Experimental and analytical results are presented to dem- in the approachtaken by theseauthors is to initially extracl information onstratethe effectivenessof the ART concept.Experiments show that regardingspecific noise environments off-line. This information can then verylarge transmission losses with reasonablebandwidth can be achieved be used to define details of control structure and values for the caneclef in by a simpleART panelbarrier in a duct.These findings are corroborated that environment.During actual usage of thecarphones, the algorithm theoreticallyby an acousticbranch analysis, and results of a parametric mustadapt to fine-tuneitself to theenvironment at that time.Recordings studyare presented to showthe effect of varyingsystem parameters.

FRIDAY MORNING, 26 MAY 1989 REGENCY B, 8:30 TO 11:30 A.M.

SessionFFF. Musical AcousticsVII, PsychologicalAcoustics VIII, and PhysiologicalAcoustics VI: Musical Dynamics

William M. Hartmann, Cochairman Departmentof Physics,Michigan State Unioersity, East Lansing, Michigan 48824

Caroline Palmer, Cochairman Departmentof Psychology,Ohio State University,Columbug Ohio 43210

Invited Papers

8:30

FFFI. Unmasked and partially masked loudnessin musical dynamics. Eberhard Zwickcr (Institute of Electroacoustics,Technical University Mfinchen, 8000 M•inchen2, FederalRepublic of Germany) In music,two varieties of loudnessare important. In onecase, the loudness of thewhole orchestra is being judged.The sensationmay be characlerizedby the expression,"The finalewas impressivelyloud." In the secondcase, the loudnessof a singlevoice or instrumentthat is almosttotally masked by otherinstruments is beingjudged. Here, the sensationmay resultin a statementsuch as, "The voiceof the singerwas hardly audible."There are two reasonsfor suchmasking, both realizedin music:the spectral(simultaneous) partial maskingand the temporal (post-stimulus}partial masking.The first is more pronouncedin musicand in- fluencesthe transparency of the presentation.The secondis relatedto the reverberationtime. Dependenciesof partiallymasked loudnesses are outlined quantitatively using abstract and musical sounds. A videotapepresen- tationwill illustratethese effects using the temporalvariation of specificloudness-critical band rate distribu- tions outlined on the screen of these loudness meters.

S140 J. Acoust.Soc. Am. Suppl.1, VoL85, Spring1989 117th Meeting:Acoustical Society of America S140 9:00

FFF2. The communicationof dynamicsbetween musicians and listenersthrough musical performance. Toshie Nakamura(Department of Psychology,Osaka University. Toyonaka, Osaka, Japan) Musiciansperform music according to theirown interpretations. How doesa playerrealize his/her inter- pretationof a pieceof musicin the form of tones?How is his/her intentionunderstood by a listener?The relationsamong the performers'intentions, intensity of tonesproduced by the performers,and listeners' perceptionwere investigated quantitatively. The noteworthy findings were as follows. ( I ) Crescendowas easier to recognizethan decrescendo.(2} It appearedthat risingpitch enhanced an impressionof crescendo,and falling pitch enhancedthat of decrescendo.(3) The influenceof "impressionof the end" on crescendowas suggested.These findings were confirmed in the experimentsby meansof synthesizedsound sequences and under well-controlled conditions.

9:30

FFF3. Dynamicsof musicalexpression. Edward C. CartereReand RogerA. Kendall (Departmentsof Psychologyand Ethnomusicologyand SystematicMusicology, UCLA, Los Angeles,CA 90024) Variousaspects of thedynamics of musicalexpression in termsof bothacoustic and perceptual parameters werestudied. In onestudy, duets of sopranoorchestral winds performed brief musical passages in unisonand in simplediatonic harmony. Perceptual spaces, obtained by scaling,were compared with acousticalanalyses. Orderingsof instrumentpairs in three-dimensionalspace were influenced by context(unison versus harmon- izedsingle notes and melodicfragments) and by suchacoustic factors as combinationsof excitationmecha- nismsand tone-holelattice cutoff frequencies.In a studyof musicalexpression, single instruments, which differedin performerdegrees of freedom(piano, violin, trumpet,clarinet, and oboe), were playedat three levelsof expressiveness.The aim wasto explieatethe variablesused by the performerin successfullycommuni- catingexpressive intent. Acousticalanalyses were comparedby meansof a theoreticalmodel based on the interactionsof pitch.time. and dynamiccontour strata.

10:00

FFF4. How to treat dynamicrange if there is no dynamicspace. Adrianus .I.M. Houtsma (Institute for PerceptionResearch [PC, P.O. Box 513. 5600 MB Eindhoven,The Netherlands) Thelarge dynamic range of modern sound equipment isoften i•icompatible withthe playback situation. Compact-discmusic played at a low levelbecause of sensitiveneighbors. or car-radiomusic played against a backgroundof intenseand varyingnoise, is almostalways partly inaudibleunless signal levels are constantly adjusted.For a fixedceiling on sounddynamics or for constantlevels of backgroundnoise, as is often found in a typicalhome, use of dynamiccompression according to thefunction y = ,4x'"turns out quite satisfactory. with thecompression exponent m between1 (no compression) and 2/3 (maximumacceptable compression }. and attackand releasetimes equal to 5 and 180ms, respectively. For treatmentof musicand speechunder condi- tions of intenseand variablenoise, as is the casein a movingcar, severalsignal processing schemes are discussed.such as noise-dependentvolume control, noise-dependent frequency control, and noise-dependent amplitudecompression.

10:30

FFFS. Musicaldynamics with keyboardinstruments. Donald E. Hall (PhysicsDepartment, California State University,6000 J Street,Sacramento, CA 95819)

Keyboardinstruments provide the extremecases of wide or narrow dynamicranges. The mechanismapparently has a fixeddynamic level, aside from registrationchanges. But performersdo claimto have someexpressive control, and it may be askedwhether measureable physical differences can be demon- strated. The pipe orl•an usesboth swell box shadesand registration chartões,and what may be typical sound leveldifferences involved will be discussed.The clavichordand pianoare both moreakin to other instruments in havingoutput strongly dependent on the forcewith whichthe keysare struck..Comparisons among these casesraise questions about how muchperceived musical dynamics depends on mereloudness, and how much on timbre,articulation, and otheraspects of the musicalperformance.

$141 J. Acoust.Soc. Am. Suppl.1, VoL85, Spring1989 117thMeeting: Acoustical Society of America S141 10:s0

FFF6. Distinguishablemusical dynamics. Blake R. Patterson(Network ManagementDivision, AT&T Bell Laboratories,480 Red Hill Road, Middletown, NJ 07748) Loudnesschanges, which composers specify by musicaldynamics pp, p, top,mr, f, andif, makemusic exciting.The goalof thisstudy is a usableand rational specification of an "acceptable"dynamic range for musicians.Requiting that a noteat onedynamic level be at leasts dB moreintense than nearby notes at the next-lowerdynamic level leads to a minimumsolo=instrument per-note dynamic range (k- 1) (d + s), wherek is the numberof dynamiclevels and d is the maximumintensity difference between nearby notes at "constant" dynamiclevel. For six dynamiclevels and the bassoon,for whichd is about5 dB, a l-dB spacings between dynamiclevels gives a minimumdynamic range of 30 dB ["MusicalDynamics," Sci. Am. 231 (5), 78-95 (November1974) ]. Somerelated results published by others over the past 14 years are briefly noted. Prores= sionalperformances having different dynamic ranges are exhibited.A live demonstrationof distinguishable dynamicson the bassoonis presented.Much remainsto be studiedin thisrich field,for example,( 1) depend- enceof d on instrumentand dynamic level; (2) dependenceof (listener=perceived)loudness on musicalfactors otherthan intensity, such as pitch, timbre, note duration, and transients; (3) dynamiccomplexities of ensemble performance:solo levels, heterogeneous ensemble, "chorus" effects, ensemble with soloist,etc.; (4) depend- enceof musicaldynamics on musictype, performance environment, and performanceobjective.

I1:10

FFF7.Influence of hammervelocity in pianosound. Caroline Palmer (Pychology Department, Ohio State University,Columbus, OH 43210)and Judith Brown (Physics Department. Wellesley College. Wellesley, MA 02180and MIT Media Lab E15-483.Cambridge, MA 02139) Recentmodels of pianostring excitation suggest that stringmotion is proportionalto hammervelocity. Preliminaryto measuringdynamics in pianoperformance, the relationship between radiated piano sound and hammervelocities was studied. A computer-monitoredpiano allowed reproduction of a rangeof hammer velocities,and a microphoneplaced near a pianist'shead location recorded radiated sound. The first eperiment indicatedthat peak amplitude of thewaveform was directly proportional tothe hammer velocity of individual notesfor a widerange of frequencies and hammer velocities. A second experiment investigated the waveforms ofnotes struck simultaneously and compared these with the waveforms ofthe individual component notes. The peakamplitude of the dyadswas directly proportional (with proportionalityclose to 1) to the sumof the individualpeak amplitudes. A thirdexperiment extended these findings to a widerrange of dyadicpitch intervals.These findings suggest linear relationships between hammer velocity, amplitude of stringmotion, bridgemotion, and amplitude of thesoundboard vibration for singlenotes. The additivity of dyadsindicates that theprinciple of superpositionisobeyed with a smallenergy loss. [Work supportedby MIT MediaLab, OhioState University Small Research Grant, and a WellesleyCollege Brachman Hoffman Fellowship. ]

FRIDAY MORNING, 26 MAY 1989 NEWHOUSE I, ROOM A1, 9:00 TO 11:15 A.M.

SessionGGG. PsychologicalAcoustics IX: ComplexStimuli

Arlenc E. Carney, Chairman BoysTown National Institute, 555 North $OthStreet, Omaha, Nebraska68151

ContributedPapers

9:00 10th) to high (abovethe 25th) harmonicorder. Identificationperfor- GGGI. Pitch of complex tones with many high-order harmonics. mance was found to degradewith increasingharmonic order from an AdrianusJ. M. Houtsma(Institute for PerceptionResearch IPO, P.O. essentiallyperfect to an asymptoticlevel that wasclearly less than perfect but much better than chance. Just-noticeabledifferences in (missing) Box 513, 5600 MB Eindhoven,The Netherlands) and J. Smurzynski fundamentalfrequency were found to increase,with increasingharmonic (Division of Otolaryngology/Surgery,University of ConnecticutHealth order, from a fractionof i Hz to an asymptoticlevel of about 5 Hz. Center,Farmington, CT 06032} Influenceof phasewas found only for tonecomplexes of highharmonic Pitch identificationand pitch discriminationexperiments were per- order.Results support the existence of twoseparate pitch mechanisms in formedfor complextones with missingfundamentals between 200 and the auditorysystem, one basedon pattern matchingof resolvedfrequen- 300Hz andwith manysuccessive harmonics varying from low (belowthe cies,the other on periodicityof nonresolvedfrequencies.

S142 J. Acoust.Soc. Am. Suppl. 1, Vol.85, Spring1989 117thMeeting: Acoustical Society of America S142 9:15 10:00

GGG2. From acousticsto the socialsciences: The conceptof "sound GGGS. Forced-choice discrimination of complex tones. Annabel effects."Jean-Paul Thibaud (201 East 19thStreet, Apartment 9B, New J. Cohen (Departmentof Psychology,Dalhousie University, Halifax, York, NY 10003) Nova Scotia B3H 4J7, Canada)

The analysisof soundwithin contextis very complex.It requiresan The studyis part of a researchprogram examining the effects of small interdisciplinaryapproach in severalfields: physical, architectural, psy- integerfrequency ratio relations on memory for unfamiliar(microtonal) chologicaland physiological acoustics, and environmental sociology. The sets of tones. Previous work indicated the benefit of both successive and conceptof "soundeffect" involves concrete links between various forms simultaneoussmall integer context in an absolutejudgment task. In order of data. Soundeffect can be definedby three major characteristics.( 1) It to determinewhether such benefits were cognitiveas opposedto sensory is not the productof a cause,but rather the productof the relatiouship in origin,a quasifixed-standardtwo-alternative forced-choice discrimina- betweenthe signaland the context(i.e., Dopplereffect). Thus its defini- tion task was conductedthat had lower demandson memory than the tionnecessitates a recognition of the physicalsigns in questionand of the absolutejudgment task but could potentiallylead to the samecontext conditionsof propagationand soundperception. (2) It involvesa modal effects.Discrimination of ninecomplex tones of a microtonalscale rang- or instrumentallogic. (3) It permitsa generaldiscourse about sound, but ing from 545 to 636 Hz (tonesseparated and discriminanda differing by requiresexamples related to a particularsituation. The conceptof sound one-third semitone) was tested under simultaneousand successivecon- effect serves as a tool to uncover information about sound. It allows the textconditions. Preliminary data indicate that musically trained listeners, researchersto put the soundphenomena in a wider perspective.[Work comparedto untrained,showed a small but significantbenefit from a supportedby Centre National de la RechercheScientifique (CNRS, dichoticsimultaneous bass tone havingthe ratio 2:3 with onecentral tone France.] of the nine-tonescale but not from a dichotictone having a Unisonrela- tion with the central tone. Successive(melodic) contexteffects were less apparentin thisdiscrimination study than in the absolutejudgment ex- periments.

9:30

GGG3. Comparingmonotonic, diotic, and dichoticpresentation modes in synchrony detection. Virginia M. Richards (Psychoacoustics 10:15 Laboratory, Department of Psychology,University of Florida, Gainesville, FL 32611 ) GGG6. Detectionand recognitionof temporalpatterns. Daniel L. Weber (Departmentof Psychology,Wright State University,Dayton, OH In a 2IFC paradigm,listeners discriminated between sounds com- 45435) posedof two bandsof noisewhose center frequencies were 2500 and 5000 Hz, and whoseenvelopes were either identical or time delayed,one rela- The detection/recognitiontheorem [S. J. Starr, C. E. Metz, L. B. tive to the other. The extent of the temporaldelay necessaryfor 70% Lusted,and D. J. Goodenough,Radiology 116, 533-538 (1975)] was correctdiscriminations was estimated.Dichotic maskingnoise was con- usedto predicta listener'sability to recognize(identify) one of a pairof tinuouslypresent. Four presentationmodes were employed:diotic, temporalpatterns based upon the listener'sdetection performance. The monotic, dichotic, and monotic with contralateral maskers. In the six experimentalconditions compared all possiblepairs of four 860-ms monotic with contralateral masker condition, bands centered at 2500 and patterns.The four patterns consisted of eithertwo or four 1-kHzsinusoi- 5000Hz werepresented to theear contralateral to thesignal bands. Those dal componentsof either20- or 200-msduration. Specifically, the four "masker"bands were independentlychosen, and so were unrelatedto patternswere: two 20-mscomponents separated by 820 ms;two 200-ms eachother and the signal bands. Performance levels were best in thediotic componentsseparated by 460 ms;four 20-mscomponents separated by condition,an averagedelay of 3 msbeing needed for discrimination.Per- 260 ms;and four 200-ms components separated by 20 ms.All components formance levels in the dichotic, monotic, and monotic with contralateral weresquare gered on andoffer zerocrossings. In fourof thesecompari- maskerconditions were only slightly poorer. [Work supportedby theAir sons,stimuli differedon "one" dimension(either numberor durationof Force Office of Scientific Research and a National Institutes of Health components),whereas the other two comparisons involved differences in post-doctoralfellowship. ] "two" dimensions(both numberand duration of components).(Intersti- mulusgaps were necessarily confounded with numberof componentsand componentduration in all conditions.)Although the resultswere not uniform for all I1 listeners,comparisons that involvetwo dimensions generallyled to betterrecognition performance that] comparisons that involvedone dimension. More surprisingwas the apparent unimportance 9:45 of temporalstructure for theencoding of thesecomplex stimuli inferred GGG4. Signal parameters that reduce masking produced by fromthe general failure to reachpredicted recognition performance. [ Re- multicomponentsimultaneous maskers of uncertainfrequency. Donna searchsupported by AFOSR throughWPAFB AAMRL/BBA. ] L. Neff (BoysTown NationalInstitute, 555 North 30th Street,Omaha NE68131)

Largeamounts of simultaneousmasking can be produced by changing thespectral content of multicomponentmaskers with eachpresentation. This experimentexamined whether simple changes in signalproperties couldreduce this masking.The numberof maskercomponents varied GGG7. Effectsof phasechanges in low-numberedharmonics on formant from 2 to 100 acrossconditions. Thresholds for simultaneous masking frequencymatches. J. Denis McKeown and ChristopherJ. Darwin weremeasured for four listenersfor a 1000-Hzsinusoidal signal equal in (Laboratoryof ExperimentalPsychology, University of Sussex,Brighton durationto themasker (200 ms) andcompared to thresholdsmeasured as BN 1 9QG, England) signalduration was shortened and signal position varied. The largestre- leasefrom maskingoccurred for the shortest(10-ms) signaltemporally Phasechanges to singleharmonics 10:30(of a 125-Hzfundamental) in the centeredin the masker.Dichotic presentation also decreased thresholds firstformant (F 1) regioncan change the phoneme boundary between/1/ relative to diotic or monaural conditions. In contrast, the use of different and/e/alonganF 1continuum inan identificationtask [C. J. Darwinand signalspectra, specifically a narrow-band noise, AM, or QFM signal,all R. B. Gardner, J. Acoust.Soc. Am. 79, 838-845 (1986) ]. Physiological centeredat 1000 Hz, did not produceconsistent reductions in masking. correlatesof this effect have been noted in the ALSR responseof guinea- Overall,the resultsindicate that changesin the temporalor spatialrela- pigauditory nerve fibers [A. R. Palmeret al., in TheP•ychophysics of tion of maskerand signalare muchmore effective in reducingmasking SpeechPerception, edited by M. E. H. Schouten(Nijhoff, Dordrecht, thanchanges in frequencycomposition under conditions of maskerfre- 1987)] and in an auditorymodel with synchronysuppression. The pres- quencyuncertainty. [Work supportedby AFOSR. ] ent work demonstratessimilar phaseeffects using a matchingparadigm.

S143 J. Acoust.Soc. Am. Suppl. 1, Vol.85, Spring1989 117thMeeting: Acoustical Society of America S143 Subjectsmatched sounds along a continuumthat differed in F 1frequency example,having a valueof about10 ms at 2700Hz witha 20-dBmasker and could have additionalformants. The target sounds(fundamen- spectrumlevel and about 7 mswith a 40-dBmasker spectrum level. Tem- tal = 125 Hz; FI = 440 Hz) were taken from the matchingcontinuum poralwindow shapes can be used to producetemporal excitation patterns buthad the phase of a singleharmonic changed. Systematic and consistent that illustratethe effectof limited temporalresolution on the internal differencesin the matchedF 1 valuewere foundas a functionof phase. representationof acoustic stimuli. [Work supported by MRC, UK. ] Althoughthe starting phase of thecomponents influenced the size of the matcheddifference in F 1, the differencewas still presentfor randomized startingphases. The effectrequired at leastthree frequency components and variedwith fundamentalfrequency. 11:00

GGG9. Perceivingfractal noisesin pitch, loudness,and duration. Mark A. Schmucklerand David L. Gilden (Department of Psychology,

10.'45 Universityof Virginia,Charlottesville, VA 22903}

GGGS, Temporalwindow shape as a functionof frequencyand level. Threeexperiments examined discrimination among a familyof frac- tals possessingdifferent power law spectra.In experimentI, random ChristopherJ. Plack and Brian C. J. Moore (Department of numberssequences were generated so that their spectrahad slopes(in ExperimentalPsychology, University of Cambridge,Downing Street, log-log plane) or0 (white noise), - I {flickernoise), and -- 2 (brown CambridgeCB2 3EB, England) noise). The distributionswere used to producesequences that could vary The temporalwindow is an intensityweighting function that pro- in pitch, loudness,or duration.Listeners categorized each sequence as cessesthe internalrepresentation of auditorystimuli by integratingener- beingof one of the three noisetypes. Thurstonian scaling revealed that gy overtime. Temporal window shapes were measured using the tech- noisesegment classification could be accomplishedon the basisof pitch niquedescribed in anearlier article [ Mooreet aL, J. Acoust.Soc. Am. 83, and loudnessvariation, but not on the basisof durationchanges. Experi- ! 102-1116(1988) ]. Windowshapes were measured at fourdifferent fre- ment 2 exploredsimultaneous pitch and loudnessvariation, finding di- quencies(300, 900, 2700,and 8100 Hz} and at threedifferent masker mensionalredundancy for white/flicker discriminationsuggestive of a levelscovering a 20-dBrange at eachfrequency. The shapeof the tempo- pitch-loudnessinteraction. Experiment 3 examinedsensitivity for dis- ral windowwas well describedby modelingeach side as the sumof two criminationof noisesas a functionof the powerlaw exponent.Listeners rounded-exponentialfunctions. The equivalentrectangular duration heardtwo sequences of tonesand indicated whether they had the same or (ERD) of the windowwas roughly constant at about8 ms for center differentpower law exponent.The rangeof exponentsspanned the inter- frequenciesfrom 900 to 8100Hz, but increasedto about13 ms at 3{30Hz. val [0, - 3 ], with thestimuli under comparison differing by 0.2, 0.4, 0.6, The increaseat 300 Hz may be explicablein termsof "ringing" in the or 0.8. ROC analysesrevealed some variation in sensitivityto the fractal auditoryfilter. The ERD decreasedsomewhat with increasinglevel, for exponentsas a functionof positionin the [0, -- 3 ] interval.

FRIDAY MORNING, 26 MAY 1989 REGENCY C, 9:00 A.M. TO 12:00 NOON

Session HHH. Underwater Acoustics VIII: Sea Surface Noise I

Herman Medwin, Chairman Departmentof Physics,Naoal PostgraduateSchool, Monterey, California 93943

Chairman's Introduction---9.'00

Invited Papers

9:05

HHHi. Noisegeneration by newly created bubbles. Michael S. Longuet-Higgens'l (La JollaInstitute, 7855 Fay Avenue,La Jolla, CA 92037) Air bubblestrapped at a free surfaceby breakingwaves, or emergingfrom an underwaternozzle, or splitting,or coaleseingin variousways, all undergostrong "shape oscillations" before settling into a spherical shape.In a fullynonlinear theory (not theusual l inearizedapproximation ), theshape oscillations can be shown to emit a strongmonopole radiation of sound.Second-order calculations suggest that thisis a significant, perhapsdominant, source of bubblenoise in theocean. Resonance between the second harmonic of eachshape oscillationand the radial "breathing" mode of a givenbubble leads to enhancedemission of soundat or nearthe breathing-modefrequency. There can also be coupling between a bubbleand the free surface from which it is detached.Oceanic data and laboratory experiments relating to thesepredictions will bediscussed, particularly the well-knownexperiments by Fitzpatrickand Strasberg( 1957); also,broadband spectra of oceanicnoise from a varietyof locationswill be discussed.'• On leavefrom Departmentof Applied Mathematicsand TheoreticalPhysics, University of Cambridge,England.

S144 J. Acoust.Soc. Am, Suppl. 1, VoL 85, Spring 1989 117th Meeting:Acoustical Society ol America $144 9:25

HHH2. Ambientsound beneath breaking surface waves. David M. Farmer (Institute of OceanSciences, P.O. Box6000, Sidney, British Columbia VSL 4B2,Canada) and Svein Vagle (Department of Physics,University of Victoria, P.O. Box 1700, Victoria, British Columbia V8W 2Y2, Canada)

Ambientsound measurement obtained beneath breaking surface waves over the frequency range 44-20 000 Hz are described. The observations are obtained from an instrument located 24-32 m beneath the surface duringexperiments both in openocean and continentalshelf environments. Individual breaking events are positivelyidentified using underwater video photography, and it isconfirmed that they radiate sound through- out the observedfrequency range. A distinctivefeature of the acousticsignature is the presenceof spectral peaks,the frequency of whichmay remain generally consistent from one breaking event to thenext, but which canchange significantly over the course of a stormor fromone storm to another.A theoryis proposedbased on theconcept of trappingof a portionof the soundin the surfacewaveguide formed by the oceansurface bubble layer.Simultaneous measurements of the bubblepopulation and sizedistribution obtained with a multifre- quencyinverted echo sounder allows calculation of the resulttug(dispersive) sound-speed anomaly profile. Comparisonof the observedspectral peak frequencies with thosepredicted yields good agreement.

9:45

HHH3. BubblesourcesoftheKnudsenspectraofoceannoise.Herman Mealwin(PhysicsDepartment, Naval PostgraduateSchool, Monterey, CA 93943) The sourcelevels, frequencies, and damping constants of individualbubbles, catastrophically generated by spillingbreakers, have been measured in theNPS OceanAcoustic Wave Facility, OAWF. OAWF consistsof a 17-m-longX1-m-deepX l-m-wide water channelin which wavesare drivenby an oscillatingplunger. The wavesgrow and then form spilling breakers on thesurface of a large,nonreverberant volume at theend of the channel.Two calibratedhydrophones suffice to identifythe typeof bubble,its surfacelocation, and its dipole axial sourcestrength. The sourcesof the breakernoise have thereby been identified as transientbubbles of resonancefrequency 350 Hz to 50 kHz, with lifetimesfrom 2 to 20 ms.These bubbles radiate as dipoles from positionswithin a fewhundred/tm to a fewmm of thesurface. The long-termaverage of thebubble radiations hasthe same slope as the Knudsen wind wave spectra at sea,5 dB/oct. [Work supportedby the Office of Naval Research.]

10:05

HHH4. Underwatersound from whitecapsat sea.Reginald D. Hollett (SACLANT UnderseaResearch Centre, I19026 La Spezia,Italy) Observationsare presented of theunderwater sound from whitecaps atsea. A verticalarray of hydrophones wasused to form an end-firebeam towards the seasurface, receiving the soundfrom a patchof the surface abovethe array. At thesame time, the surface patch was visually monitored using a video-recordingfacility. The timeseries of thesound from thepatch was spectrally analyzed at intervalsof a fractionof a second,over the bandfrom 187.5to 1500Hz. The resultingtime variationof thesound spectrum shows distinct bursts of sound.The strong bursts coincide with visual detections of whitecapsabove the array. The burst of soundfrom a whitecaplasts for severalseconds and is seen to beassociated with the breaking phase. The sound spectrum duringthe breaking phase has notable low-frequency content, the spectrum appearing almost flat from 187.5 Hz up to about 1000Hz.

10:25

HHH5. Somestatistics of seanoise. P. A. Crowther (Marconi UnderwaterSystems Limited, Croxley Mill, Wetford WDI 8YR, United Kingdom) Surface-derivedambient noise has beenmeasured on a long-termbasis by the useof a bottom-mounted narrowbeam sonar, in depthsof 65-80 m, overwindspeeds 3-20 m/s, in frequencybands over 6 50 kHz. Resultsare presented as time histories and derived statistics. It isfound that, after detection and smoothing, the noisepower in a narrowbeam fluctuates widely, "spikes" in timebeing identifiable with individual breaking waves.The stallsticsof fluctuationis foundto dcpcndon beamwidth,the cocfficicmofval iationbeing typically 10/beamwidthin meters.Time autocorrelationfunctions of noisepower are presented,which also depend on beamwidthand windspeed. The mean horizontal speed of thenoise sources can be deduced and is approximate- ly halfthe windspeed in a well-developedsea. These results are interpreted in thelight of knownspectra of sea waves,and simple assumptions about the natureof the wavebreaking process.

S145 d. Acoust.Soc. Am. Suppl. 1, Vol.85, Spring1989 117thMeeting: Acoustical Society of America S145 Contributed Paper

10:45 At seaacoustic and video observations of low seastate microbreaking were carried out with a subsurface instrument in the summer of 1988. HHH6. In situ acousticsignature of low sea state microbreaking.Garr Correlationof subsurfacevideo images of ri•es and their acousticsignals E. Updegraffand Victor O. Anderson(University of California,San will bepresented. A four-hydrophonearray provides spatial localizations Diego, Marine Physical Laboratory of the Scripps Institution of of individualbubble signatures. Spectral and intensity distributions of the Oceanography,San Diego, CA 92152) bubblesignatures will be presented.

11:00-12:00

Panel Discussion

Chaired by: David Farmer Instituteof OceanSciences. Sidney, BC, Canada

S146 J. Acoust.Soc. Am. Suppl.1, Vol. 85, Spring1989 117th Meeting:Acoustical Society of America $146 FRIDAY AFTERNOON, 26 MAY 1989 NEWHOUSE II, ROOM 254, 1:15 TO 4:30 P.M.

SessionIII. SpeechCommunication XI: Production,Laryngeal Effects, Kinematics,and Intonation

Lawrence Rosenblum, Chairman Departmentof Psychology,Wellesley College, Wellesley, Massachusetts 02181

Contributed Papers

1:15 ingflow rates were taken during phonation, induced by laryngealnerve stimulation.Results shows that, during constant vocal fold stiffness, sub- III1. Pers•ctives on soundin Sanskritliterature on natural philosophy. glotticpressure did notrise significantly with increased airflow. Increas- M. G. Prasad (Department of Mechanical Engineering, Stevens ing flow rate wasassociated with an increasein the openquotient as Instituteof Technology,Hoboken, NJ 07030) measuredgiottographically. Data from thisexperiment were compared It is knownthat the literaturein Sanskritlanguage that includes"Ve- with the theoreticaltwo-mass model of the larynx. Model parameters das and Upanishads"represents some of the earliestknown references wereadjusted to approximatethe canine vocal folds and the in vivoexperi- dealingwith varioustopics of naturalphilosophy and science. The histori- mentalpressure-flow relationships were simulated. The larynxin thein cal backgroundof thesereferences has beenestimated to be of several uivocanine model exhibits flow-dependent decreasing impedance during thousandyears BC. In spiteof the lack of a precisehistorical account of phonationin thatincreasing flow rate is not accompanied by increasesin the developmentof the literaturein Sanskritlanguage, there havebeen subglottaland transglottal pressure. {Work supported by VA Technical manyworks of translationfrom Sanskritto severalEuropean languages Merit Review Grant.] includingEnglish. The topic of "sound"seems to havereceived funda- mentalimportance in Sanskritliterature in the areasof both natural phi- losophy,science, and art. This paperdescribes the perspectiveson sound as foundin Sanskritliterature particularly in "Vedasand Upanishads." The paperalso discusses some of the importantapplications of theknowl- 1:51 edgeand perspectiveson soundthat are reflectedin acousticphonetics of Sanskritlanguage, Vedic chants, and classicalmusic and danceof India. III4. An experimentaldesign for testingthe validity of the collapsible tubemodel of thelarynx. Gerald S. Berke,David P. Arnstein,Marshall E. Smith,Manuel Natividad(Division of Head& Neck Surgery,62-132 CHS, UCLA MedicalCenter, 10833 Le ConteAvenue, Los Angeles, CA 90024-1624), and William A. Conrad (30 West 71st Street •3D, New York, NY 10023) 1:27 The in •i•o caninemodel of the larynxwas used to measuretransglot- III2. Acoustical manifestations of veinpharyngealclosure during tic pressuresand airflow during phonation. Direct intraglottal pressures swallowing.Sandra L. Hamlet, Duane M. Smith (Department of weremeasured at variouspositions within the glottis.Conditions of su- Otolaryngology,Wayne State University, Detroit, MI 48201), and praglottalresistance were also simulated. Pressure drop-flow curves were Lewis Jones(Department of Radiology,Harper Hospital,Detroit, MI comparedwith data on collapsible tubes. The in vioocanine model of the 48201 ) larynxdemonstrates a number of thedescribed features similar to oscilla- tion in collapsibletubes. [Work supportedby VA TechnicalMerit Re- In normalswallowing, velopharyngeal (VP) closuretransienty iso- view Grant. ] latesthe nasopharynx from theaerodigestive tract for a periodof approxi- mately 700 ms. Although there are intrinsic soundsgenerated during swallowingthat canbe recordedfrom thethroat surface [ Hamletet al., J. Acoust.Soc. Am. Suppl. I 83, S23 (1988)], VP closureis ordinarily a silent event requiringspecial techniques for its acousticaldetection. A 500- or 1000-Hz tone is introducedinto one nostril, and its presenceis 2:03 detectedusing a miniatureaccelerometer taped to the throatjust below IIIS. /s/ and/J'/ asa functionof linguapalatalg•oove place and width. S. the angleof the mandible.During VP closure,there is attenuationof this G. Fletcher (Department of Bincommunication,UAB, University componentof the accelerometersignal recorded during swallowing. The Station,Birmingham, AL 35294) and D. G. Newman (Universityof onsetof theperiod of attenuationcorresponds to theonset of velarclosure Queensland,6 Rock Street, St. Lucia4067, Queensland, Australia) determinedradiologically. The timeof VP reopeningcan be detected with lesscertainty, possibly owing to resonanceeffects, and the positionof the Palatometricfeedback was used to guidethree normal talkers in sys- epiglottisand base of thetongue at thatmoment in somesubjects. Medical tematicallyvarying the placeand width of the sibilantgroove. Lingua- applicationsof thisprocedure are discussed.[ Work supportedby NIH. ] palatalcontact was manipulated to produce2- to 12-mm-widegrooves in eachof seven-eight rows of contact sensors spanning the front third of the palate.Both the rowsand thesensors in eachrow were 2 mm apart.The subject'stask was to establisha stipulatedgroove, then channelair throughit to producea "hissing"noise. These responses were tape record- edthen later low-pass filtered, digitized, and shaped to fit normalsibilant 1:39 intensity,duration, and onset/offsettimes. The resultantsounds were III3. Pressure-flowrelationships in the larynx. Marshall E. Smith and playedten times each in randomorder to 14listener judges in individual Gerald S. Berke (Division of Head and Neck Surgery, 62-132 CHS, listeningsessions. The listenerswere instructed to labeleach sound heard as "definitelyan 's,' .... probablyan 's,..... probablyan 'sh,' "or "definite- UCLA Medical Center, 10833Le Conte Avenue, LosAngeles, CA 90024- 1624) ly an 'sh.'" Statisticalanalysis of theseobservations yielded main effects for bothgroove width and place. The findingswill bediscussed from the Measurementsof air pressureand flow were made usingan in vivo viewpointsof binmechanicaland auditoryshaping hypotheses. [Work caninemodel ofthe larynx.Subglottic and supraglotticpressures at vary- supportedby NIH Grant NS 24697.]

$147 J. Acoust.Soc. Am. Suppl.1, Vol. 85, Spring1989 117th Meeting:Acoustical Society of America S147 2:15 (Bauer, 1988), the children'smonthly vocalization samples were ana- lyzedfor phoneticcontrast. The numberof observedphones in fivediffer- 1116. Alterations in lower Ill; and jaw kinematics of stutterers and ent consonantlike(place of articulation)and threevowellike (tongue nonstutterersas a function of sl;eechrate. Luc F. De Nil and James advancement)categories was multiplied to yielda phoneticproduct for H. Abhs (University of Wisconsin,Speech and Motor Control eachvocalization. The resultswere summarized and plottedfor the six Laboratories, Madison, Wl 53705) children'smonthly vocalization samples with microcomputersoftware. Previousarticulatory kinematic studies of stutterersand normally flu- The resultsindicated a generalincrease in the phoneticproduct of vocali- ent speakersduring perceptually fluent speech have revealed subtle, but zationsas a functionofchronological age. Individual trends for eachchild possiblysignificant, between-group differences. Such observations lend are discussedin relationshipto the generalfunction in our searchfor supportto the hypothesisthat stutterersand nonstuttererssomehow dif- generalmeasures spanning the prelinguistic-to-linguistic period. fer in their basicmotor control ability for speech.Comparing the influ- enceof speechrate on stutterers'and nonstutterers'articulatory kinema- tics would providea further test for this hypothesis.To this end, seven adultstutterers and seven normal speakers produced repetition sequences of the syllable/bae/at sixdifferent rates. Multiple kinematicmeasures of the lowerlip andjaw movementsduring oral closurewere applied. Peak 2:81 velocityand displacementwere observed to differto subtleways between 1119.On/r/-/w/substitution in child sl•eech.Kevin G. Lindland and the two groups,with greaterdifferences apparent at fasterspeaking rates. ElzbietaB. Slawinski(Department of Psychology,The Universityof Stutterersalso differed from normal speakers in timingof peakvelocities Calgary,Calgary, Alberta T2N IN4, Canada) at variousspeech rates. The resultsprovide additional information on the possiblerole of motorcontrol processes in stuttering.[ Work supportedby The role of phoneticcontext in/r/-/w/substitution errorswas inves- NIH Grants N$-13274 and NS-16373.] tigated.The subjectpopulation consisted of 20 childrenwith normally developingarticulation skills, 33 to 52 monthsin age.The subjectswere givena minimalpairs discrimination task in orderto assessthe accuracy of theirperception for "r" and"w" consonants.Subsequently, the sub- jectswere administered a testof productionin whichthey had to identify andproduce the namesof objectsdrawn from a commonset presented to them.Acoustical analysis of themisarticulated /r/ revealsthree patterns, 2:27 whichcan be distinguished acoustically by differentformant values and/ or theirchanges in time.Results indicate that substitution errors are high- III7. Electrolmlatogral•hicevidence for long-rangecoarticulatory effects ly contextdependent, with thepercentage errors for theentire population in VCVCV sequences.Daniel Recasens (Haskins Laboratories, 270 rangingfrom 0% when/r/was in thefinal position to 36% in the initial Crown Street, New Haven, CT 06511) positionin theword. These findings suggest the possible importance of a This studyreports some electropalatographic data on tonguedorsum cognitivestrategy, as well as the presence of shiftedcategorical boundar- contactshowing coarticulation to extendup to threeor four phonetic ies.Results are discussed in termsof thedeveloping child's limited mental segmentsaway from the target gesture. Coarticulatory effects in degreeof resourcesand perceptualskills. palatalcontact for V = [i] vs [a] andfor C = [•f] vs it] wereanalyzed alongall possibleVC [ • ] CV combinationsof thosesame vowels and con- sonants.It was predictedthat the temporaldomain of coarticulation wouldvary accordingto the degreeof tonguedorsum contact involved duringthe productionof the contextualphoneroes. The findingsshow 3:03 that, in general,the coarticulatoryeffects are inversely dependent on the degreeof tonguedorsum contact for thosephoneroes that are immediately III10. Influenceof nationallanguages on learning English. Pan Jianping adjacentto thetarget (e.g., C2 for the V3-dependentanticipatory effects). (Department of Information Technologyin Education, East China Moreover,carryover effects reached the segmentslocated at the otherside NormalUniversity, North ZhongshanRoad, Shanghai 200062, People's of [o] in specificcircumstances (e.g., whenC2 = it] ). The theoretical Republicof China) implicationsof the resultsof this experimentare discussedin light of recentfindings in the literature. Everylanguage can be described in termsof a setof phoneroes,includ- ing, in part, vowels,diphthongs, semivowels, and consonants.In China, Mandarinis the standardspoken Chinese, i.e., the nationallanguage. Thereare manyadditional dialects, each with its ownset of phoneroes. Fluentspeakers in Mandarinand another dialect can therefore pronounce twosets of phoneroes.The phonemesare produced mainly by operations of the vocal tract. The connections between vocal tract movements and phonemesare establishedin childhood,first for the dialectand then for 2:39 Mandarin.This led us to comparethe abilityto learnto speakEnglish IIIg. Phonetlcproduct estimates of infantphonetic develol•ment. Harold amongChinese speakers using different dialects and thereforedifferent R. Bauer (Division of Speechand Hearing Science,The Ohio State setsof phoneroes.It wasobserved that the greaterthe similarityof the University, Columbus,OH 43210) and Michael P. Robb (John A. Burns dialectto English,the more intelligibleand natural were the initial at- Schoolof Medicine,Division of SpeechPathology and Audiology, temptsto speakEnglish. This was in spiteofsimilar fluency in thenational Universityof Hawaii, Honolulu, HI 96822) language,Mandarin. It wasconcluded that early learning of Englishwas important,independent of the nationallanguage, and it washypothesized The phoneticde•empment of six childrenwas estimatedacross the that similar resultswould be obtainedin other non-English-speaking first 2 years of life. Using a phoneticproduct measurementscheme countries.

3:15-3:30

Break

S148 J. Acoust.Soc. Am. Suppl. 1, Vol.85, Spring1989 117thMeeting: Acoustical Society of America S148 3:30 matching[Ney, IEEE Trans. SMC-12 (1982)] for F0 determination with excellentresults, but thesetechniques do not yieldthe epoch loca- III11. Glottai sourceestimation using a sumof exl•onentialsmodel. A. tions.The method described in thispaper applies dynamic programming K. Krishnamurthy(Department of ElectricalEngineering, The Ohio toselect waveform maxima directly from a short-time-energy-normalized StateUniversity, 205 Dreese Laboratories, 2015 Nell Avenue,Columbus, LPC residual.The cumulativepath costsare normalizedby the path OH 43210) length.Local costs are basedon peakamplitude and quality,transition Thispaper describes an algorithmfor simultaneouslyestimating the costson periodand pulse similarity. The output is theset of pulseloca- parametersof a modelfor theglottal source and the vocaltract filter. The tionsthat globally satisfy the cost constraints over all voicedregions. Data glottalsource signal is described by t.he four-parameter LF model[ Fantet to bepresented indicate that theseestimates reliably match those obtained al., SpeechTransmis. Lab. Q. Prog.Stat. Rep. (1984) ]. The vocaltract is semiautomaticallyfrom simultaneously recorded electroglottograph sig- modeledas an all-polefilter; however, to allow for the effectsof source- nals. tract interaction,a separatemodel is usedin the closedand open glottal phases.Under these assumptions, it is shown that the output speech signal canbe modeled as a sumof complexexponential signals. The parameters of thespeech signal model are estimated using the algorithms described in Kumaresanand Tufts [IEEE Trans. Acoust. SpeechSignal Process. ASSP-30,833-840 (1982) ]. The electroglottographsignal is usedto ob- taina preliminaryestimate of thelocation of theclosed and open phases in 4:06 eachpitch period. The analysis of steady vowel sounds from several speak- ers indicatesthat this methodprovides a very accurateestimate of the III14. A newupproueh for speechdynamics studies. Mohamed Mrayati glottalsource and the vocal tract formants. [ Work supportedby theOSU (Centre d'Etudeset de RecherchesScientifiques, BP 4470, Damascus, SeedGrant program.] Syria), Ren6 Cart6, and Eric Castelli (Institut de la Communication Parl•e, 46 avenueF•lix Viallet, 38031 Grenoble, France)

A newdynamic model for vocaltract configurationbased on a theo- reticalquantification of dynamicarea function//(x,t) into distinctivere- gionshaving areas S(r,t) is proposed.Articulation is transcodedinto changesof these$(r,t) through three modes[Mrayati et al., Speech Comm. 7, 257-286 (1988) ]. A dynamiccontrol strategyof S(r,t) is ex- 3:42 tremelysimple to apply and correlateswell with humanspeech organ iII12. The effectof macroprososdiccontext on consonantperturbations musculaturemovements. This strategytransprojects the classical longitu- of fundamentalfrequency. John Kingston (DMLL, Morrill Hall, dinal displacementof the constrictioninto a transversalarea function Cornell University,Ithaca, NY 14853-4701) variationof S(r,t). This dynamicstrategy can incorporateeasily context- dependentallophonic variations, such as: coarticulation,reduction, as- Kohler argues,on the basisof German data, that differencesin F0 similation.... The distinctiveregions, along the vocaltract, are associated beforeor aftervoiced and voiceless stops (the microprosodies)may be with specificconsonants and vowels.These new "phonetic regions" con- obliteratedby thelarger scale effects on F0 of thesurrounding intonation ceptcan be usedto vectoriallycode target configurations for consonants contour(the macroprosodies)[Kohler, Phonetica39, 199-218 (1982) ]. and vowels.The newconcept relates, in a simplefashion, changes in the In a similarfashion, Silverman claims, on the basisof Englishdata, that acousticdomain to changesin regionalcross-sectional areas. Some results thedirection of F0 changeafter stops differing in voicingdepends on the on VV, CV, VC, and VCV commandstrategies are presented. surroundingmacroprosodic contour [Silverman,Phonetica 43, 76-91 (1986) ] ;The macroprosodiccontour in which word-initialconsonants [p, t, b, d, sp,n] wereembedded at twolevels was manipulated: ( 1 ) The consonantoccurred either immediately before a stressedvowel or before an unstressedvowel, e.g.,palace versuspolice; and (2) thewords occurred eitherin focusor with focuson the precedingword, e.g., 1 sawa few churcheson Monday,but manyP,4L4CES on Wednesdayversus 1 saw 4:18 onlya few on Monday but MANYpalaces on Wednesday.These manipola- tionswere entirely orthogonal and allow us to examineboth the effects of IIllS. Closant curve characteristics of infant vocalizations. Michael wordinternal as well as syntactically determined macroprosodies on the P. Robb (John A. Burns School of Medicine, Division of Speech extentand direction of consonantaleffects on F0 in English. Pathologyand Audiology,University of Hawaii, Honolulu,HI 96822) and Harold R. Bauer (Division of Speechand Hearing Sciences,The Ohio State University, Columbus,OH 43210) The"closant curve" reflects thechange inratio of the frequency of consonants(closants) to vowels(vocants) in early vocaland speechde- 3:54 velopmentof youngchildren ( Bauer, 1988). CIosantcurves were plotted 'III13. Voicing epoch determination with dynamic programming. for sevenchildren's monthly vocalizationsacross the first 2 yearsof life. David Talkin (AT&T Bell Laboratories,Room 2D-448, Murray Hill, The closantcurves were then comparedto monthly data plots of each NJ 07974) child's vocal fundamentalfrequency and vocalizationduration. Assess- ment of developmentaltrends for the phoneticand acousticdata was During voicedspeech, the point of maximumflow changein each basedon visualexamination of thedata plots and curve fitting procedures. glottalcycle corresponds to the pointof maximumexcitation of the vocal The resultingdevelopmental functions are discussedin relation to the tract. Accurate,reliable detection of this "epoch"beginning (or end) is reported dosant curves underlying environmentaland physiological usefulfor pitch synchronousanalysis/synthesis in a variety of contexts. characteristicsof languageacquisition. These analyses provide an acous- Dynamicprogramming has been applied to correlationfunction peak se- tic and phoneticframework from which to study early speechdevelop- lection [Seerestand Doddington,ICASSP-83] and laggedwaveform ment. [Work supportedby U. H. ResearchCouncil. ]

S149 J. Acoust.Soc. Am. Suppl.1, VoL 85, Spring1989 117thMeeting: Acoustical Society of America $149 FRIDAY AFTERNOON, 26 MAY 1989 REGENCY A, 1:30 TO 4:00 P.M.

SessionJJJ. Physical AcousticsX: Inverse Problemsin AcousticsII

Yves H. Berthclot, Chairman Schoolof MechanicalEngineering, Georgia Institute of Technology,Atlanta, Georgia 30332

ContributedPapers

1:30 An elasticgeneralization of the geometricaltheory of diffraction[ P. L. Marston,J. Acoust.Soc. Am. 83, 25-37 (1988) ] wasused to describe JJJ1. Determinationof the elastic constantsof anisotropiccomposite the backscatteringof shorttone bursts from an elasticspherical shell in materials via laser photoacoustics. Bernard Castagnede, water [S. G. Kargl andP. L. Marston,J. Acoust.Soc. Am. 85, 1014-1028 WolfgangSachse (Department of Theoreticaland AppliedMechanics, (1989) ]. In the presentresearch, steady-state backscattering amplitudes Cornell University,Ithaca, NY 14853), and Michael O. Thompson aresynthesized. The GTD modelcontains explicit terms for the specular (Department of Materials Scienceand Engineering,Cornell University, reflectionand individualLamb surfacewave contributions in a Fabry- Ithaca, NY 14853) Perotform. Numerical calculations compare the exact partial-wave series This paperpresents the solutionof the inverseanisotropic medium resultwith the GTD synthesisfor the frequencyrange 7 < kA < 100. problemin whichthe elastic constants of an anisotropiccomposite mate- Thesecomputations correspond to a stainlesssteel shell with an inner-to- rial are determinedfrom ultrasonicwave speed measurements made in outerradius ratio b/a = 0.838.An importantfeature of theGTD modelis nonprincipaldirections of a specimen.The ultrasonicwaves were gener- that onlytwo parametersare needed to fully describethe individual Lamb ated via the point-source/point-receivertechnique using a 2-ns pulsed waveresonance amplitudes. These parameters are the ratio of the Lamb Nd:Yag laseras a sourceand a 2.5-mm-diamcapacitive or a 1.3-ram wavephase velocity to the velocityof soundin water (c//c) and the radi- piezoelectrictransducer as a receiver.Data were acquiredduring an ationdamping ,O/. These should depend on localproperties of the shell- isoangularscan of the sourcerelative to oneof the principalacoustic axes watersystem. This simpleparametrization of the directscattering prob- of symmetry.In eachwaveform, the arrivalsof thequasilongitudinal and lem should facilitate novel approachesto the inverse problem. the two quasishearbulk modcswere measured.The elasticconstants of Identificationof a scatterermay be achievedthrough an examinationof the materialwere then recoveredusing an optimizationalgorithm. Ex- the Lambwave resonances via a numericalfitting of theseparameters. perimentalresults are presentedfor a transverselyisotropic composite [Work supportedby ONR.] material.It wasfound that the nonlinearfit betweenthe experimental and the recoveredslowness values is excellent.Some discrepancies are ob- served for the two shear modes. These are shown to be related to the complexityof the detectedsignals.

2:15

JJJ4. Transverse Pearcey patterns observed in the reflection of ultrasoundfrom curvedsurfaces. Carl K. Fredericksonand Philip 1:45 L. Marston (Departmentof Physics,Washington University, Pullman, WA 99164-2814) JJJ2. On the acousticdetermination of the elasticmoduli of anisotropic solidsand acousticconditions for the existenceof symmetryplanes. This researchconcerns the reflectionof lightand sound from smooth Andrew N. Norris (Departmentof Mechanicsand MaterialsScience, curvedsurfaces to producetransverse cusp caustics (and associated wave RutgersUniversity, Piscataway, NJ 08855-0909) fields) and the inferenceof shapeinformation from suchcaustics and The21 elasticmoduli of a homogeneousanisotropic solid can be deter- wavefields. From the generic wave front shape associated with transverse mined from the second-order acoustical tensors associated with wave mo- cusps[P. L. Marston,J. Acoust.Soc. Am. 81, 226-232 (1987) ], it has tion in six phasedirections. The acousticaltensor can be calculatedfrom bccncalculated that reflectionof soundfrom a pointsource offofa surface the threephase speeds and displacementpolarizations for a givenphase whoseheight h(x,y) = h,x2 + h•y•xq- h3y • (with h2•0) producesa direction.The sixdirections may be quite arbitrary as long as they cannot transversePearcey pattern [P. L. Marston,in AcousticalImaging (Ple- becontained in lessthan threedistinct planes through the originand do num, New York, 1988), Vol. 16, pp. 579-588]. The imagingof such notall lic on thecurves formed by theintersection of theunit sphere with patternsby rasterscanning of a smallhydrophone in wateris described. anelliptical cone. It isshown, for example, how the general procedure can The ultrasonicburst incident on thesurface is sufficiently long to simulate be usedto find the elasticmoduli for a thick plate specimen,for which the reflectionof a steady-statesine wave. When the soundsource was acousticaccess is limited to inspectionfrom the two parallel faces. Acous- replacedby a lightsource (and the hydrophone replaced by a photodetec- tic conditionsthat are both necessaryand sufficient,that a solidpossess a tor), the correspondingoptical cusp caustic was imaged and used to infer planeof materialsymmetry, will alsobe discussed. [Work supportedby theshape parameter h: for thepolished metallic reflecting surface. These NSF.] parametersfacilitated a comparisonof observedand predicted acoustic wavefields. [Work supportedby ONR.]

2:00 2:30 JJJ3. GTD synthesisof resonanceamplitudes in the backscatteringfrom an elastic spherical shell. Steven G. Kargl and Philip L. Marston JJJ$. Examination of finite amplitude ultrasonic pulses using light (Department of Physics,Washington State University, Pullman, WA diffraction.J. W. Wolf (Department of PhysicsUltrasonic Research 99164-2814) Laboratory,Georgetown University, Washington, DC 20057)

S150 J. Acoust.Soc. Am. Suppl.1, Vol. 85, Spring1989 117thMeeting: Acoustical Society of America 5150 Finiteamplitude pulses are examined acousto-optically with a light An importantinverse problem in biomedicalacoustics is the deter- diffractionapparatus. Using an empirical model of transducer frequency minationof the compositionof a tissuebased upon measurements of its response,ultrasonic pulse Fourier spectra are derived for input to a light acousticproperties. Under manycircumstances, the tissuecan be mod- diffractionmodel. To then simulate harmonic distortion, the pulse spectra eledas an idealmixture of components,each with knownor assumed areused for input to a computationalmodel based on the Burgers' equa- properties.The measuredproperties of the mixtureas a wholeare then tion for propagationof finiteamplitude acoustic waves in a nonlinear relatedto thoseof the componentsthrough a setof mixturelaws. Once medium.Several examples are presentedthat illustrategood agreement formulated,the problemcan be invertedto yield the volumeor mass betweenexperimental light diffraction patterns and those predicted by the fractionsof thecomponents present in the tissue.In thislaboratory, the pulsespectrum, propagation, and light diffraction theories. [Work sup- useof theacoustic nonlinearity parameter B /A tohelp infer the composi- portedby ONR. ] tion of mixturesof bioligicalmaterials has been studied. Various mixture modelshave been investigated, and a modifiedversion of Apfel'smodel [J. Acoust.Soc. Am. 79, 148-152 (1986)] hasyielded the mostuseful results.This modified mixture model will bepresented, along with precise datathat have been obtained on biological mixtures using a novelacoustic 2:45 interferometrytechnique reported earlier [J. Acoust.Soc. Am. Suppl.1 80, S4 (1986)]. [Work supportedby the U.S. National Institutesof JJ J6. An equationfor acousticpropagation in aninhomogeneous medium Health throughGrant R004GM30019]. with relaxatlonloss.Adrian I. Nachman(Department of Mathematics, University of Rochester,Rochester, NY 14627), JamesF. Smith, Ill, and Robert C. Waag (Departmentsof Electrical Engineeringand Radiology,University of Rochester,Rochester, NY 14627)

An equationfor acousticpropagation in an inhomogeneousmedium with relaxationloss is systematicallyderived from the classicaldynamic 3:30 equationstogether with an equationof statefor relaxation.The derivation assumessmall acoustic perturbations but accommodatesarbitrary spatial JJJ9. Biologicalcell characterizationusing inverse acoustic scattering. inhomogeneitiesin material compressibility, density, and parametersof X. Chenand R.E. Apfel (Departmentof MechanicalEngineering, Yale relaxation.The linearizedwave equation obtained for n relaxationmecha- University,P.O. Box 2159, New Haven, CT 06520) nismshas order n + 2, is causal,and yields the expecteddependence of attenuationon frequency. Exact analytic expressions valid at all frequen- The acousticscattering properties of biologicalcells, especially red ciesare givenfor the spatiallyvarying attenuation coefficient, as well as bloodcells, have been studied both theoretically and experimentally. An phasevelocity. A Green'sfunction is calculatedfor the equation.The apparatusconsisting of two confocallypositioned transmitter/receivers resultsmay be usedto modelscattering for imagereconstruction and the and a Coulter-typevolume sensingzone was reportedpreviously [J. determinationof statisticalproperties, such as average differential scatter- Acoust.Soc. Am. Suppl.1 84, S163 (1988) ]. An inversescattering theory ing crosssection. incorporatingthe experimentaldata yieldsthree bits of infomationfor eachcell: volume, density, and compressibility.Since both the densityand compressibilityof biologicalcells are almostlinearly related to protein concentration,it mightbe possible to determinethe protein concentration of thesecells. The resultsobtained from severaltypes of biologicalcells usingthis method will bepresented. The changesin densityand compress- 3:00 ibility, and hence protein concentration,when cells undergovolume changesthrough swelling, shrinking, or heatingwill be assessed.[Work JJJ7. Extraction of informationfrom low-frequencysounds generated within the human body. T. Douglas Mast and Allan D. Pierce supportedby the U.S. National Institutesof Health throughGrant 5R01GM30419.] (Graduate Programin Acoustics,Pennsylvania State University, 157 HammondBuilding, State College, PA 16800) The analysisof soundsgenerated within the body has been a stapleof medicaldiagnostics since Laennec's invention of the stethoscope(c. 1804). Also, interest in muscle soundsdates back to Grimaldi's treatise on opticspublished in 1665. More recentwork by Oster and Jaffe (1980), Barry (1987), and Frangioniet al. (1987) hasled to quantitativeinsight 3:45 on the physicalprocesses that generatesuch sound. A feasibilityanalysis is presentedhere for the problemof sourcecharacterization using infor- JJJ10. Higher-order time-domain ultrasonic scattering. Thomas mationtaken outside the humanbody, with emphasison sourcesof fre- J. Cavicchi(DepartmentofElectricalEngineering, UniversityofAkron, quenciesless than 250 Hz. The availableinformation is the displacement Akron, OH 44325) timehistory of all pointson thebody's surface, although one would want to measuredisplacements at a restrictednumber of points.The bodyis To improvethe reliability of diagnosisof tissuepathologies (e.g., modeledas a dissipativefluid-filled sphere or a finitecylinder. It isargued cancers)based on ultrasonicimaging, quantitative images of physiologi- that sourcesof interestcan be idealizedas compact, rather than distribut- calparameters, such as speed of soundand/or absorptioncoefficient, can, ed, combinationsof monopoles,dipoles, and quadrupoles.Thus the un- in theory,be obtainedby inversescattering procedures. Previous studies knownsto be determinedin regardto any frequencycomponent are the [T. J. Cavicchi, S. A. Johnson,and W. D. O'Brien, Jr., IEEE Trans. sourcecoordinates and thestrengths and relativephasing of the probable UFFC-35, 22-33 (1988) ] employeda momentmethod matrix formula- multipoles.Results reported include measurement accuracies necessary tion undera monofrequencyassumption. Periodicities of the field phasors for satisfactorysource characterization. [ Work supportedby the William causeda nonuniquenessproblem in the inversescattering solution for E. Leonhardendowment to PennsylvaniaState University. ] scattererswith phaseshift magnitudes greater than •, in practicalmedical imaging,the phaseshift wouldbe hundredsof •r. A reformulationof the methodin the time domainappears more promisingbecause the phase shifts are now merely time delays.The time-domainmoment method formulationis presentedfor forwardscattering. A preliminarynumerical 3:15 studyhas been undertaken using the momentmethod equations and the internal field calculated by the inverse discrete Fourier transform of the JJJS. Mixture compositiondetermination from measurementsof the well-knownmonofrequency solution solved at many frequencies.Using acoustic nonlinearity parameter. E. C. Everbach and R. E. Apfel the exact field within the integral producesa resultinggood approxima- (Department of Mechanical Engineering,Yale University, P.O. Box tion of the exact field. Current studies are aimed at inversion for the for- 2159, New Haven, CT 06520) ward-scatteredfield; future work will addressinverse scattering.

S151 J. Acoust.Soc. Am. Suppl.1, Vol. 85, Spring1989 117th Meeting:Acoustical Society of America $151 FRIDAY AFTERNOON, 26 MAY 1989 REGENCY C, 1:30 TO 5:00 P.M.

Session KKK. Underwater Acoustics IX: Sea Surface Noise II

Herman Medwin, Chairman Departmentof Physics,Naval Postgraduate School, Monterey, California 93943

Chairman's Introduction--l:30

Invited Papers

1:35

KKK1. Soundgenerated by fluid interfaces--Insightsinto seasurface noise. Douglas H. Cato (DSTO MaritimeSystems Division, P. O, Box706, Darlinghurst, NSW 2010,Australia) A theoryof soundgeneration by motlopof fluidinterfaces has been developed and applied to thesea surface.The only assumptionsare that the densitydiscontinuity at the seasurface can be modeledas a Heavisidefunction, and that the relationship c¾/ap = c2 applies within a fluid,wherep is pressure, p is density, andc issound speed. The theory shows that the motion of aninterface generates sound with source strengths dependingon the difference between the product of thedensity and the square of thesound speed on either side of theinterface. Distributed monopole and dipole sources are possible. The insightthis provides into sound generatedby surfacemotion, bubble cloud oscillation, bubbles, droplets, and spray will bediscussed. Most sourceswould be expected to showdipole directionality with axesclose to, but notnecessarily, vertical. Wind- inducedturbulent pressure fluctuations across the sea surface are shown to benot a significantsource of noise in the ocean,even though they havebeen considered as such.

1:55

I•I•K2. Low-frequencynoise: Wave turbulenceinteraction and bubblecloud oscillations. W. M. Carey, D. G. Browning(Naval UnderwaterSystems Center, New London,CT 06320), andJ. W. Fitzgerald(Kildare Corporation,New London,CT 06320) Low-frequencyoceanambient noise data, when not dominated byshipping noise, show evidenc• forwind- dependentnoise at frequenciesless than 500 Hz. Vertical directionalitymeasurements have a horizontal componentwith a broadfrequency characteristic. This effectis partlydue to the couplingof wind-generated noiseinto the sound channel by either a shallowingsound channel or a down-slopeconversion process due to basin boundaries and sea mounts. Omnidirectional measurements made below the sound channel critical depth,in sparselyshipped basins, and at highsea states indicate two distinct regions divided by theoccurrence ofbreaking waves. Prior to wavebreaking, a possiblesound generation mechanism isthe interaction of surface wavesand turbulence in thenear-surface layer [ I. Z. V. Gonchavov,Atmos. Oceanic Phys. 6( I 1) ( 1970);Yen and PertoneNUSC TR5833 ( 1979) ]. Wave breakingproduces bubble clouds. The dynamicevolution of these bubbleclouds is a mechanismfor the productionof soundof frequenciesless than 500 Hz. Theseclouds of micron-sizebubbles are regionsof low sonicvelocity described by Wood'svolume fraction equations. These regionscan be treatedas a compressiblebody with a compositemixture speed and density that canexhibit a collectiveresonant oscillation and radiate as monopole and dipole sources. However, due to theproximity of thesea surface, only the monopole and its image, an effectivedipole, would be of importance.When driven by the wavebreaking vorticity and turbulence,these regions are shownto resultin sufficientradiated sound to producenoise levels comparable to thoseobserved and are also pronounced scatterers of low-frequencysound.

ContributedPapers 2:15 gravity/capillary dispersionmodel for surface wavesare found to be KKK3. On ambientnoise generation by "solitoh"surface waves. Robert much too low aboveabout 10 Hz. This discrepancymay restin the wave model rather than the mechanism itself. Surface-wave measurements in H. Mellen and David Middleton (Kildare Corporation,95 Trumbull Street, New London, CT 06320) flumesshow no evidenceof dispersionat higher wavenumbers.To ac- countfor dispersionlesspropagation, a nonlinearmodel in whichthe sur- Wave-waveinteraction is oneof the morepromising mechanisms for facefine structure is treatedas a random ensembleofsolitonlike hydraulic wind-generatedambient noise. However, levels calculated with the linear bumps rather than dispersivewaves has been proposed.The "soliton"

S152 J. Acoust.Soc. Am. Suppl.1, Vol. 85, Spring1989 117th Meeting:Acoustical Society of America $152 modelappears toaccount for measured acoustic backscattering strengths California,Marine Physical Laboratory of the ScrippsInstitution of andassociated Doppler spectra at moderatesea states. Effects of themod- Oceanography,San Diego, CA 92152) el on ambientnoise prediction are examined.

In seastates, two-six monomolecularfilms on the oceansurface have beenpreviously reported to dramaticallyreduce the ambientnoise field beneaththem. The mechanism was presumed to beassociated with ocean 2:30 whitecapping.A recentseries of low seastate tests with films,in the ab- senceof whitecapping,has found an even more pronounced ambient noise KKK4.Effect of monomolecularfilms on theunderlying ocean ambient reductionif theocean surface agitation is above a certaincritical level. The noisefield at lowsea states. Jim Rohr (Naval OceanSystems Center, mechanismthrough which the filmsreduce surface noise at low seastates Code634, San Diego, CA 92152)and Garr E. Updegraff(University of is explored.

2:45-3:10 Panel Discussion

Moderator: Douglas Cato DSTO, Madtimes SystemsDivision, Darlinghurst, Australia

3:10-3:15 Break

Invited Papers 3:15

KKKS.Monitoring oceanic precipitation using ambient sound--An assessment. Jeffrey A. Nystuen(Code 68Ny,Department of Oceanography,Naval Postgraduate School, Monterey, CA 93943) Severalyears ago, the idea that rainfall could be measured by monitoringthe unique underwater sound generatedby the rain was introduced. Two mechanisms bywhich raindrops can produce sound underwater havebeen identified. Data will be presented from current laboratory experiments exploring the relative impor- tanceof thesetwo mechanismsfor differentsized drops at terminalfall velocities.The influenceof windon thesemechanisms isnot understood and currently prevents quantification of rainfall rate from ambient sound; however,oceanic data from the Canadian Atlantic Storms Program will be presented that demonstrate that precipitationcan be detected acoustically even in conditions of highwinds (20 m/s) andlarge waves (4-6 m).

3:35

KKK6.Underwater noise due to precipitation.LawrenceA. Crum, HughC. Pumphrey(NationalCenterfor PhysicalAcoustics, University of Mississippi,University, MS 38677), Andrea Prosperetti(Department of MechanicalEngineering, Johns Hopkins University, Baltimore, MD 21218), and Leif Bjorno (Industrial AcousticsLaboratory, Technical University of Denmark,DK-2800 Lyngby,Denmark) In 1959,G. Franz publisheda thoroughinvestigation of the underwatersound produced by liquiddrop impacts[G. Franz,J. Acoust.Soc. Am. 31, 1080(1959) ]. He discoveredthat, under certain conditions, a gas bubblewas entrained by theimpacting droplet, and the subsequent oscillation of thisbubble resulted in a large amountof radiatedsound. Recently, Scrimget has measured the underwater sound produced by rainfalland hasdiscovered that a well-definedspectral peak exists near 15 kHz [ J. A. Scrimget,Nature 318, 647 ( 1985) ]. Thesound produced by the impact of waterdroplets on a watersurface, both for individual and for multiple eventssuch as those produced by artificialand naturalrainfall, has been examined. The studiesindicate that the major contributionto the underwaternoise produced by both rain and snowis that associatedwith the oscillationsof gasbubbles introduced into the water by theimpact. Both experimental and theoretical evidence for theseconclusions will bepresented, including numerical studies of thedrop impact process. [Work sup- portedby the ONR. ]

S153 J. Acoust.Soc. Am. Suppl.1, Vol. 85, Spring1989 117thMeeting: Acoustical Society of America S153 3:55

KKK?.Bubblecloudsassourcesandscatterersofunderwatersound,A. Prosperetti, N.Q Lu, andA. Lezzi (Departmentof MechanicalEngineering, The JohnsHopkins University, Baltimore, MD 21218) A modelof a bubblecloud based on a setof averagedequations is usedto studythe acousticemission and scatteringproperties of theseobjects. From a studyof the normalmodes of thecloud, it is inferredthat the lowestmodes have a frequencymuch lower than that of the individualbubbles. This indicatesthat cloudsof bubblescan radiateat suchlow frequenciesif thesemodes are excited.The resultsof somescattering calcula- tionsat differentwavelengths are alsoshown as a functionof the incidenceand scatteringangles. [Work supportedby ONR.]

ContributedPaper

4:15 impactson the water surfaceand air bubbleresonances). For example, eachof thesetwo sourceshas been alternatively proposed as a major con- KKKS. How raindrop impactsand air bubbleresonances contribute to tributorto the spectrumas well as theorigin of a spectralpeak around 15 underwatersound spectra. Fr•d6ric Laville (Groupe d'Acoustiquede kHz. High-speeddata acquisitionand processingof underwatersound l'Universit6 de Sherbrooke,D6partement de G6nie M6canique, recordedin a lake under real rain and artificial raindropconditions were Universit6 de Sherbrooke,Sherbrooke, Qu6bec .IlK 2R1, Canada), usedto identifythe two soundsources in the time domainand determine GraysonD. Abbott, and Matthew J. Miller (Create Incorporated,P.O. their respectivecontributions to the long-termspectrum. Bubble reso- Box 71, Hanover, NH 03755) nanceswere found responsible for the spectralpeak around 15 kHz and very dependentupon surface condition, whereas raindrop impacts were Usingunderwater sound to measurethe rate of rainfallover the oceans foundresponsible for a broadbandspectrum rich in frequenciesbelow 15 is a verypromising approach. However, there are conflictingmodels on kHz and lessdependent on surfaceconditions. [Work supportedby the spectralcontributions of the two rainfall soundsources (raindrop DOE. I

4:30-5:00 Panel Discussion

Moderator: Lawrence A. Crum National Centerfor PhysicalAcoustics, University, Mississippi

FRIDAY AFTERNOON, 26 MAY 1989 REGENCY B, 1:30 TO 4:00 P.M.

Session LLL. Late Arrivals

Junru Wu, Chairman Departmentof Physics,University of Vermont,Burlington, Vermont 05405

ContributedPapers

1:30 region.At lowparticle concentrations, aggregations ofmicrospheres form at half-wavelengthintervals near the axial positionsof acousticpressure LLL1. Streaming generatedby aggregationsin a rotating ultrasonic amplitude (PA) minima, as expectedbecause of rotationaland acoustic waveguide.Glenn Whitworth (Physics Department, University of radiationforces. At higherconcentrations, additional particle distribu- Vermont, Burlington, VT 05405) tionsare oftenseen that suggestthe presenceof flow. When high concen- trationsof larger particlesare used,small aggregationsalso form at axial A chambercavity, which has a squarecross section and pressure- positionsof PA maxima.To accountfor the flow, theory for acoustic releasewalls, is usedto producea well-defined,160-kHz standingultra- streamingin a rotatingfluid wasdeveloped and appliedto flow near the sonicfield. A suspensionof latex microspheresin aqueousmetrizamide larger aggregations.Reasonable agreement with observationswas ob- fills the chamber.The chamberrotates about a horizontalaxis producing tained when a term was added arising from drag on the aggregations. the centripetalforce necessary to containthe buoyantspheres in the axial [Work supportedby NIH Grant CA42947.]

$154 d. Acoust.Soc. Am. Suppl.1, Vol. 85, Spring1989 117th Meeting:Acoustical Society of America Sl 54 1:45 the Ocean,The Bahamas.The horizontallydirected ambient was mea- sured usingvertically oriented line arraysand was observedfor wind LLI2. Experimentalstudies of a quasitwo-dimensional nonprol•gating speedsranging from I to 30 kn. The resultingdatabase was used to esti- hydrodynamicsolitoh. Erik M. Winkletand/unru Wu (Departmentof matethe statisticsof anisotropic"noise gain" relativeto the isotropic Physics,University of Vermont,Burlington, VT 05405) noisegain. The resultingnormalized array performance was found to bea A nonpropagatinghydrodynamic soilton was first observed by Wu et continuousfunction of totalacoustic intensity and a discontinuousfunc- aL [Phys.Rev. Lett. 52, 1421(1984) ] in a rectangularwater trough that tion of windspeed. Differences in the functionaldependence and residual wasparametrically driven at a frequencybelow twice that of the linear statisticswere found for two cases:whitecaps present or not present.The cutofffrequency of (0, I } mode.A solitonof the sametype was recently relationof theseresults to thetotal directional spectra and a modelof the studiedthat formswhen the trough is driven at a frequencybelow twice near-surface distribution of acoustic sources are discussed. that of the linearcutoff frequency of (0,2} mode.The profileof the solitoh in lengthdirection as well as in width directionis determined.A video tape of the experimentwill be shownduring the presentation.[Work supportedby NSF andVermont Epscor.] 2:45

LLLr. Modeling word-boundaryphonological processes in continuous speechrecognition. Briony Williams (Centre for SpeechTechnology Research,80 SouthBridge, Edinburgh EHI l HN, UnitedKingdom) and 2.-00 Henry Thompson(Department oral, 80SouthBridge, Edinburgh EHI LLL3. Measurements of transmission loss to ultrasound through two- IHN, United Kingdom) dimensionalensembles of trappedbubbles versus the amplitudeof the The automaticrecognition of continuousEnglish speech, as against incident wave. Junru Wu and Wesley L. Nyborg (Department of isolatedwords, must contend with phonologicalprocesses at word boun- Physics,University of Vermont,Burlington, VT 05405) dariesthat candistort the mappingbetween surface form and lexical en- In continuationof workreported previously, the frequency spectra of try. Pastrecognition systems have used generatire phonological rules in a transmissioncoefficients to ultrasoundthrough sheets of gas-filledmicro- precompilationstage to expandthe workingdictionary. However, this poresat incidentamplitudes up to 3X 104Pa have been measured. It is greatlyincreases the bulkand complexity of thelexicon. It isalso possible foundthat as the amplitudeof the incidentwave is increased,the peak to useanalytic rules to undothe putativeeffect of phonologicafprocesses frequencyof transmissionloss through a bubbleensemble shifts to lower at the timeof recognition.However, this can lead to the postulationof valuesby as muchas 47%. Resultsof the cxperimcntsand the possible nonwordsand to slowerprocessing times. A solutionthat blendsthe ad- theoreticalexplanation will be presentedand discussed.[Works of JW vantagesof bothapproaches, with the disadvantagesof neither,is to use aresupported by NSF andVermont Epscor. Works of WLN aresupport- finitestate transducers (FSTs) asfilters on permittedmatchings between ed by NIH CA42947.] inputstrings and lexical entries. These were implemented in a recognition system,and found to increasethe percentage of wordsrecognized by three percentagepoints, at a costof halvingthe signal-to-noise ratio, compared to the samesystem without phonological FSTs.

2:15

LLIA. Acoustic radiation forces used to control the motion of a glass 3:00 mieroneedle.Junru Wu (DepartmentofPhysics,Universityof Vermont, Burlington,VT 05405), StevenS. Work, and David M. Warshaw LLL7. Spontaneousemission of acousticwaves from shock fronts. F. Xu (Departmentof Physiologyand Biophysics,University of Vermont, (Institute of Mechanics, Academia Sinlea, Zhongguancun,Beijing Burlington,VT 05405) 100080,People's Republic of China} A methodhas been developed using a glassmicroneedle to tug on Thecriterion for spontaneousemission of acousticwaves from shock proteinfilaments and to measuretheir tensilestrength (the forceneces- fronts, sary to breakthe bondbetween individual protein molecules) [A. Ki- shinoand T. Yanagida,Nature 334, 74-76 (1988) ]. To preciselycontrol I -- M 2-- (oo/v•)M• do the motion of sucha glassmicroneedle, a techniquethat usesacoustic i•--M'•+ (Oo/o,)M' co/k•< Cv supportedby NSF and Vermont Epscor;DMW supportedby NIH Then, the causesfor the discrepancybetween these two criteriaare dis- AM34872 and AHA. ] cussedand some comments on the previouspapers are made. In addition, the amplificationof the shockfront is investigatedand the resultsare comparedwith thoseof previousworks [G. R. Fowles,Phys. Fluids 24, 220 ( 1981); P. Harris,Tech. Rep. ARLCD-TR-78041 (1978) ].

2:•0

LLLS. Measured wind Slant dependenceof the underwateracoustic ambient vertical directional spectra at high frequcoeies. Robert M. Kennedy, Thomas K. Szlyk, and Susan M. Wentworth (Naval 3:15 UnderwaterSystem Center, AUTEC, West Palm Beach,FL 33402-7517} LLLS. Attenuation of Lamb wavesin a plate loaded by a liquid under A measurementof the acoustic ambient arriving from a horizontal pressure.Paolo Diodati and Mete Severcan(Universira degli Studi dl directionalong with total acousticintensity spectra allows one to infer Perugia,Dipartimento di Fisica,Via Elcedi Sotto,06100 Perugia, Italy) both the total directionalspectra and somephysical characteristics of the sourcesof "sea surfacesound." A long-term measurementof thesetwo Attenuation of Lamb wavesin a steelplate loadedon one sideby a quantitieswas made at highfrequency, i.e., 8 to 64 kHz, in the Tongueof fluid was measuredas a functionof the fluid pressure.A monobloc,rec-

S155 J. Acousl.Soc. Am. Suppl.1, Vol. 85, Spdng1989 117th Meeting:Acoustical Society of America S155 tangular,steel cavity was constructed and a l-cm-thicksteel plate was Physics(INFN) exists,was placed a seismometer(to taperecord seismic used to shut pressureproofthe cavity which containedcastor oil, eventswith a frequencyup to 100Hz), a geophone3d (for oscillationsup C• •H•oO6, in it. Acousticpulses at 1.7MHz werelaunched on the plate to 30 kHz), and four transducers(broadband, 50 kHz-2 MHz), for AE usinga plasticwedge and a secondwedge was used to detectthe received measurements.In a perforationmade on the top and 1.5 km deep,at 1000 pulses.The attenuationfor differentLamb medes was observed to in- m from the surface,a seismometer,a geophone, and two transducersfor creasewith pressurefor all themodes except for thelow-order modes, So, AE wereplaced. In addition,on thetop a geophoneand two transducers ao,s, a, anda 2, for whicha decreasein attenuationwas observed. Over for AE wereplaced. This acquisition system of seismicdata will makeit therange of pressure used, considering the change in thewave velocities in possible,bymeans o.fa computer network, tosend all the data to a unique theliquid and the steel plate, normally an increase in attenuation would be integratedsystem to analyzethe physicalparameters. expected.The unexpecteddecrease in attenuationfor low-ordermodes canbe explainedby the decreasein the powerlost in the liquidnear the plateboundary by the leakywaves, due to theshifting away from the phase-matchingcondition with thechange in pressure. 3:45

LLLI0. Depth dependenceof high-frequencyambient ocean noise. Albert B. Caron (Naval UnderwaterSystems Center, Newport, RI 02841) Little or no publisheddata exist on the depthdependence of ambient oceannoise at frequenciesabove 9 kHz. In this higherfrequency region, 3:30 absorptionbecomes a majoreffect in reducingsurface-generated noise as receiverdepth increases. To investigatethis effect, two experimentswere LLL9. Acousticemission from the Gran SassoMountain (AEGS). conducted.The first, conductedin the Tongueof the Ocean,off Andros P. Diodati (Dipartimentodi Fisica, Universit/•di Perugia,Perugia, Islandin the Bahamas,utilized bottom-mounted hydrophones at a depth Italy), G. Paparo(Istituto di AcusticaOM Corbino,Roma, Italy), and of 1500m to observeambient noise levels covering sea states 1-3 over a R. Scarpa(Dipartimento di Fisica,Universitfi de l'Aquila, Aquila, Italy) frequencyspan of 13 to 37 kHz. Near surfacenoise measurements were Rectangularparallelepiped samples extracted from a tunnel10.2 km alsomade for comparison.The secondexperiment, conducted in Hawaii, longand 10013 m abovesea level and from the top of thehighest mountain covereda 9- to 25-kHzspan with bottom-mounted hydrophones at depths in the Appenninesunderwent laboratory studies for theiracoustic emis- of 751, 1173, 1769, 2481,3981, and 4505 m. Resultsin both casesshow a sion(AE). The differentresponses are reported and explained. These are reductionin ambientnoise levels with increasingdepth and frequency, as thepreliminary results of theAEGS projectwhich will involvecollecting predictedfrom models developed by Uriek andothers. Closest agreement datafrom sensors located in differentplaces of themountain. In thecenter wasobserved with the assumptionof a dipolesurface intensity radiation of the tunnel, wherea laboratoryof the National Institute of Nuclear patternat the highersea states.

S156 J. Acoust.Soc. Am. Suppl.1, Vol. 85, Spring1989 117thMeeting: Acoustical Society of America S156