PROGRAM OF

The 113th Meeting of the Acoustical Society of America

Hyatt RegencyHotel © Indianapolis,Indiana ß 11-15 May 1987

MONDAY EVENING, 11 MAY 1987 CELEBRATION HALL, 7:00 TO 9:00 P.M.

Tutorial Lecture

Digital signalprocessing. Lawrence R. Rabiner(AT&T Bell Laboratories,Speech Research Department, Room 2D-533, Murray Hill, NJ 07974)

In all fieldsof acoustics,the responseof systemsof interestinvolves the analysisand the processingof a signal.This signalcan be the radiatedacoustic pressure from a hydrophone,the accelerationof a massdue to localacoustic excitation, the speech of a spokenword, or themelodious pattern of a musicinstrument. In each of thesecases the signal has to beprocessed and analyzed. The field of digitalsignal processing isone area that hasbeen attracting more interest over the last few years. In thistutorial the field of digitalsignal processing (DSP) will beexplained together with the theory of linearsystems, sampling, and spectrum analysis. Compari- sonsbetween digital and analog processing will be discussed.Other topics that will be presentedare discrete Fourier series,sampling, aliasing, FIR and fIR filters,spectrum analysis, and fast Fourier transform.The sessionwill concludewith detailedexamples of applicationsof digitalsystems in differentareas of interestsuch ascommunication in generaland speechprocessing.

TUESDAY MORNING, 12 MAY 1987 REGENCY BALLROOM A & B, 8:15 TO 11:54 A.M.

SessionA. SpeechCommunication I: SpeechPerception

Robert A. Fox, Chairman Departmentof Speechand HearingScience, Ohio State University,Columbus, Ohio 432]0

Chairman's Introduetion---8:15

ContributedPapers

8:20 tiveand negative attributes, the implications of whichwill bediscussed for a neuromorphictheory of speechperception. [Work supported,in part, A1. The problem of serial order in auditory word recognition.Howard by NIH. ] C. Nusbaum (Department of BehavioralSciences, The Universityof Chicago,58;48 S. UniversityAvenue, Chicago, IL 60637), Steven L. Greenspan(AT&T Bell Laboratories,Naperville, IL 60566), and Mathew Jensen(Department of BehavioralSciences, The Universityof 8:32 Chicago,Chicago, IL 60637) A2. The neighborhoodactivation model of auditory word recognition. Recently,there has been a resurgenceof interestin paralleldistributed PaulA. Lute (SpeechResearch Laboratory, Department of Psychology, processingmodels of humanperception. When speechperception is mod- Indiana University, Bloomington,IN 47405) eledin thistype of spatiallydistributed network, a problemarises in cod- ing the temporalorder of perceptualunits such as phoneroes or words.In The neighborhoodactivation model (NAM) of auditoryword recog- general,three solutions to thisproblem have been proposed: First, percep- nitiondescribes the processes by whicha stimulusword is identified in the tual unitsmay be contextcoded such as in context-sensitiveallophones. contextof phoneticallysimilar words activated in memory.Stimulus in- The orderof unitspresented at differentpoints in time canbe determined put activatesa setof acoustic-phoneticpatterns in memorythat mustbe by matchingthe context"edges" of eachactivated unit. Second,different discriminatedand chosenamong. These acoustic-phonetic patterns re- portionsof the networkmay representdifferent time frames.By this ap- ceiveactivation levels proportional to their similaritiesto the stimulus proach,the recognition of eachsuccessive perceptual unit activates repre- input.The activationlevels may thenbe adjustedby biasesarising from sentationsin successivesegments of the network.Finally, temporalorder higher-levelinformation, such as word frequency.The interactionof the may ba representedin the computational dynamicsof the network. In this bottom-up sensoryinput and top-down biasinginformation is assumedto case,expectations about serial order are used to shiftthe focus of process- takeplace within individualprocessing units called word decisionunits. ing attentionwithin the network.Thus, while the first two approaches These units monitor the activation levelsof their acoustic-phoneticpat- recodetemporal order into a spatialor spatial-likerepresentation, the terns, any higher-levelinformation that may optimize decisionsamong third usesa temporalrepresentation. Each of theseapproaches has posi- the competingpatterns, and the activity of all other word decisionunits.

Sl J. Acoust.Soc. Am. Suppl.1, Vol. 81, Spring1987 113thMeeting: Acoustical Society of America Sl The NAM statesthat increasingthe numberof acoustic-phoneticpat- of talkeruncertainty on encoding speech into memory. In orderto exam- ternsactivated in memoryby thestimulus input will slowprocessing and inethis problem, a serial-orderedrecall experiment was conducted. The reduceidentification accuracy. It alsostates that effects of wordfrequency stimuliwere CVC monosyllabicEnglish words produced by different are directly tied to the numberand nature of similar wordsactivated in maleand female talkers. Listeners were presented with lists of tenitems memoryand that wordfrequency is notintrinsic to theactivation levels of producedby a singlertalker or listsof tenitems produced by multiple the acoustic-phoneticpatterns. [Work supportedby NIH Grant NS- talkers,and were required to recallthe items in theorder presented. Per- 12179.] centcorrect recall in theprimary region of theserial position curve was loweras the amountof talkervariability within the listsincreased. The resultssuggest that the encoding of speechinto memory is affectedby uncertaintyfrom trial to trial due to talker variability. The hypothesis that 8:44 perceptualprocesses involved in talker normalizationare locatedat an auditory-to-phoneticlevelwill be discussed. [Work supported by NIH.] A3. Auditory word recognitionis not more sensitiveto word-initial than to word-final stimulus information. M. J. van der Vlugt and S. G. Nooteboom (Institute for PerceptionResearch, Eindhoven, The Netherlands) 9:20

Severalaccounts of the humanrecognition of spokenwords assign A6. The lexicalstatus effect on placeof articulationand voice onset time specialimportance to stimulus-wordonsets. The experimentdescribed contrasts.Marjorie A. Reed (Departmentof Psychology,Cleveland herewas designed to findout whethersuch a word-beginningsuperiority StateUniversity, Cleveland, OH 44115) effectis due to a specialsensitivity of the word recognitionprocess to Ganong [J. Exp. Psychol.:Hum. Percept.Perform. 6, 110-125 word-initialstimulus information, or ratherto the specialimportance of (1980) ] firstreported that the presenceof a wordat oneend of a voice word onsetsfor the proper alignmentof stimuli with word candidates. onsettime seriesinfluenced the classificationof stimuli near the bound- Twenty-eightpolysyllabic monomorphematic test words were selected, ary.Fox [Percept.Psychophys. 34, 526-540(1983)] reporteda similar all havingthe special characteristic that their left-to-right and right-to-left effectusing place of articulationstimuli. In thepresent experiment, the recognitionpoints coincided in the samephoneme. These words were lexicalstatus effect on two voice onset time continuua (/bot/to/pot/and synthesizedfrom diphones, and, of eachword, four versionswere pre- /bok/ to /pok/) wascompared to that on two placeof articulation pared:(a) withoutnoise; (b) with noisemasking segment perception in continuua(/bon/ to /don/ and/bop/ to/dop/). Resultsshowed effects theword-initial fragment; (c) with noisemasking segment perception in of lexicalstatus for bothtypes of stimuli.Ambiguous tokens near the the word-finalfragment; and (d) with noisemasking the wholeword. categoryboundary were perceived in favorof theword, while the classifi- Thesestimuli were, appropriately blocked, distributed over four stimulus cationof endpointstimuli was not influenced.The lexicalstatus effect was tapes,and presentedto four groupsof 12 subjectsfor word recognition. significantlylarger for voice onset time stimuli than for place of articula- Percentagescorrectly recognized real words were, for thefour conditions: tionstimuli. This difference may result from the time required for the (a) 89%, (b) 54%, (c) 59%, and (d) 13%. The differencebetween (b) lexicalstatus effect to develop, suggesting alternate interpretation ofFox's and (c) wasnot significant. This is interpretedas evidence that ( 1) audi- data on the time courseof the effect.Implications for interactiveand tory word recognitionis not moresensitive to word-initialthan to word- separatestage models are discussed. finalstimulus information, and (2) stimulusinformation from all partsof a spokenword can be used efficiently, as long as its proper time alignment with word candidates in the mind of the listener is ensured. 9:32 A7.Context effects in spoken language. Robert Pedlow (Speech 8:56 ResearchLaboratory, Department of Psychology,Indiana University, Bloomington,IN 47405) A4. Effects of talker uncertaintyI: Auditory word recognition.Iohn W. Mullennix,David B. Pisoni,and ChristopherS. Martin (Speech Theeffects of differenttypes of linguisticcontext on theintelligibility ResearchLaboratory, Department of Psychology,Indiana University, of spokenlanguage were examined. A setof wordswas produced by the Bloomington,IN 47405) samespeakers in threedifferent types of linguisticcontext: ordinary sen- tences,anomalous sentences, and a word list context. The anomalous The productionand resulting acoustic composition of spokenwords sentenceswere constructed by changing one nonadjacent-to-target word varyas functions of individualtalker characteristics. However, the effects to an anomalousalternative. The wordlist contextwas set up as short, of talkerdifferences on auditoryword recognition processes have been sentencelikestrings, seven words in length,including the target word. In largelyignored by researchers working in speechperception. In thepres- theproduction phase of the experiment, speakers were instructed to speak entstudy, the effects of talkerdifferences on perceptionof spokenwords withthe same intonation over all thematerials. To encouragethis, the were examinedby manipulatingtwo factors:talker uncertainty(i.e., differentcontext types were randomly interleaved in the materialswhich wordsproduced from a singletalker or from 15 talkers) and lexicalstruc- speakersread. No significantdifferences were found in theintelligibility ture (i.e., high-or low-densitylexical items). In the firstexperiment, ofthe words produced in thedifferent context conditions. It is argued that identificationperformance for wordspresented in noisewas worse when theseresults demonstrate that, contrary to thefindings of (Lieberman, theitems were produced by different talkers, than by a singletalker. In the 1963), it isthe overall speech "mode," rather than the immediate linguis- secondexperiment, latencies and accuracyin a namingtask were also ticcontext, which acts to determinethe intelligibility with which individ- worseunder multiple-talker condition. In bothexperiments, lexical den- ual wordsare produced. sityalone did nothave a significanteffect on performance.The relation- shipof theseresults to theunderlying processing operations involved in auditory word recognitionwill be discussed.[Work supportedhy NIH.]

AS. Perceptualdifferentiation of spontaneousand read utterancesafter 9:08 resynthesiswith monotonefundamental frequency. R. E. Remcz,R. S. Brcsscl(Department of Psychology,Barnard College, 3009 A5. Effectsof talker uncertaintyII: Encodingspeech into memory. Broadway,New York, NY 10027),P. E. Rubin,and N. Rcn (Haskins ChristopherS. Martin and John W. Mullennix (SpeechResearch Laboratories,270 Crown Street,New Haven,CT 06510) Laboratory, Department of Psychology,Indiana University, Bloomington,IN 47405) Ourprior research revealed that naive listeners can differentiate spon- taneousspeech and read speech cvcn when lcxieal, syntactic, and seman- Individualtalkers vary in a largenumber of articulatoryand acoustic ticcomponents areequated in thetwo modes of production. On a typical characteristics.Little research has been conducted concerning the effects trialin ourtests, a listenerhears a pairof excerptsidentical in thesethree

S2 J.Acoust. Soc. Am. Suppl. 1, VoL 81, Spring 1987 113thMeeting: Acoustical Society of America S2 levelsof description,taken from a spontaneousand a readmonologue tionswere tested: whole sentence comparisons, initial-half-sentence com- producedby the same talker. The perceptual task is to identifythe spon- parisons,and final-half-sentence comparisons. Subjects performed above taneouslyproduced member of thepair. In thepresent case, LPC resynth- chancewhen listening to wholesentences only, indicating the existence of esiswas employed to createconstant Fo versionsof highlydifferentiable residualinformation for productionmode in theabsence of Fovariation. pairsof sentences,to testour working hypothesis that the variation of Fo Implicationsand extensions of thisfinding will bediscussed. [Work sup- servesas the most reliable index of perceptualperformance. Three condi- portedby NINCDS and NICHHD. ]

9:56-10:06 Break

10:06 reading/writingconfounds. The ANOVA, probitanalysis, and signal de- tectionanalysis were used to evaluatefindings. As a group,poor readers A9. Forward recognitionmasking: Another look at the "Echo." Gail demonstratedsignificantly weaker categorical perception for the/da ga/ R. Tomiak (Departmentof Psychology,Park Hall, StateUniversity of boundaryin stimuli lacking bursts.Burstless signals produced severe New York at Buffalo, Buffalo, NY 14260) problemsfor somepoor readers; others performed similarly to thehigher Auditorybackward recognition masking effects have been interpreted averagedperformances of the goodreaders. Individual differenceswere as reflectingthe existenceof an echoicmemory: an uncncodedsensory noted:impaired perception regarding place, manner,or boundariesoc- storewhose contents decay rapidly and are easily overwritten by succeed- curredin thefull-stimulus condition, and more often for thepartial condi- ingauditory stimulation. However, it isequally likely that masking effects tion.The dataare relevant to theoriesthat proposea hierarchyof acoustic reflectthe timecourse of an earlystage of auditoryprocessing. To distin- cuesfor the perceptionof linguisticcontrasts and alsosuggest a possible guishthese alternative conceptualizations, vowel stimuli were used in a perceptualdeficit that may be involvedin someforms of dyslexia. forwardrecognition masking procedure. The interstimulusinterval (ISI) remainedconstant, while the mask duration (and hencethe stimulus- onsetasynchrony, SOA) wasvaried. The simplestorage model predicts that the efficacyof a mask is a functionof the time betweenmask offset 10:42 and targetonset (ISI}. Sincethis intervalwas constant, equal masking effectswould be expected at all SOAintervals. The perceptual processing A12. Effects of precedingcontext on perceptionof voice onset time. view predictsthat targetrecognition performance would improve with BrunoH. Repp (HaskinsLaboratories, 270 Crown Street,New Haven, increasingmask duration (increasing SOA). As maskd uration/SOA in- CT 06511-6695) creases,it is likely that processing of themask would be completed before When discriminatingpairs of stimuli from an acousticvoice-onset- targetonset. The results,and the implicationsof thesefindings, will be time (VOT) continuum,English-speaking listeners typically show a per- discussed.[Work supportedby NINCDS.] formancepeak in theregion of thephonetic category boundary. An ongo- ingseries of experimentsdemonstrates that the location and height of this peakare affectedby precedingphonetic context. While any preceding 10:18 contextappears to lowerdiscrimination performance, perhaps by inter- feringwith auditorymemory, a preceding[s] alsoshifts the peak towards A10. Releaseburst maskingeffects for temporal order identification. the short-VOT end of lhe continuumand, correspondingly,increases Richard E. Pastore,Jody K. Layer, Robert J. Logan, and Crystle "voiceless"responses in a labelingtask. This latter effect (trivial withina B. Morris (Department of Psychology,SUNY University Center, syllablebecause of Englishspelling conventions) occurs even when a Binghamton,NY 13901) word boundaryintervenes and doesnot seemto be mediatedby the dura- tion of the silentclosure interval following the [s]. A hypothesiscurrently Nearly•threedecades ago, Hirsh [J. Acoust. Soc. Am. 31, 759-761 beingpursued is that phonologicalvoicing decisions for word-initialstop (1959) ] foundthat the thresholdfor identificationof temporalorder of consonantsare sensitiveto the voicingstatus of precedingphonetic seg- onsetis significantlylonger than the thresholdfor detectionof onset ments.[Work supportedby NICHD.] asynchrony,and proposedthat the order identificationthreshold might serveas a basisfor the contrastbetween voiced and unvoicedaspirated stop consonantsin initial position.In the last decade,a number of re- searchershave argued that temporalorder identificationthreshold does not play a significantrole in voicingcontrast. One basisfor this argument 10:54 againsta phoneticperception role is that the 15- to 20-msrange of typical A13. Evaluation of the constant ratio rule for consonant confusions. orderidentification thresholds for simplestimuli are significantlyshorter Theodore S. Bell, Donald D. Dirks, and Gail E. Kincaid (UCLA thanVOT boundariestypical for syntheticstop consonants which include Schoolof Medicine,CHS 62-142, Los Angeles,CA 90024) an initial releaseburst. The current researchinvestigated the possible contributionof an initial noiseburst analog as a maskingstimulus. The The constant-ratio rule for consonant confusions asserts that the ratio initialnoise burst shifts temporal order identification thresholds to signifi- oferrors of anyconsonant to anyothers remains constant regardless of the cantly longeronset asynchronies which are equivalentin magnitudeto size of the matrix from which the cellswere chosen.In this study, log- VOT voicingcontrast boundaries. linearmodels were applied to testthe constant-ratio rule. Normal-hearing youngadults were presented various closed-set arrangements of syllable tokens,spoken by a maleand female speaker, and selected from a setof 14 VCseach paired with thevowel/o/. Stopconsonants and fricatives, both 10:30 voicedand voiceless, were presented at threepresentation levels as isolat- ed sets(by feature)and in combination.The relationshipsamong voice- A11. Perceptionof onsetbursts in/on da ga/syllablesby goodand poor lessstop consonants remained constant irrespective of thesize and nature readers.Judith A. Parker (Departmentof Cognitiveand Linguistic Sciences,Brown University, Providence, RI 02912) of the responsefoil. Similarly,voiceless fricatives were unaffected by the natureof theclosed set. In contrast,patterns of errorsamong voiced stops In identificationand discriminationtasks, good and poor readerslis- were dependenton the set of alternatives,as were voiced fricatives. tenedto tapesof synthesizedstimuli consisting of 350-msfull (burst Speakerdifferences, individual differences among listeners, and implica- + formanttransition) and partial (formant transition only) acousticsig- tionsrelating to the generalizabilityof confusiondata collectedin small nalsfor voicedstop CV syllables.A freeidentification procedure was used closed-setarrangements are alsodiscussed. [Work supportedby a grant to elicitpercepts and an oral responsemethod was used to avoidpossible from NINCDS. ]

$3 J. Acoust.Soc. Am. Suppl. 1, Vol.81, Spring 1987 113thMeeting: Acoustical Society of America S3 11:06 Englishas an InternationalLanguage and Departmentof Linguistics, Universityof Illinois, Urbana, IL 61801} A14. Effects of messageredundancy on the calculationsof speech intelligibility.Chaslav V. Pavlovic(Department of SpeechPathology In the presentstudy, the perceptualperformance of 24 Englishmono- andAudiology, University of Iowa, Iowa City, IA 52242) lingualsand 24 German-dominantGerman-English bilinguals was sub- jectedto detailed analysis. Stimuli consisted of 57semantically anomalous The articulationindex methods used today assume that the distribu- naturaland vocodedEnglish sentences. Results revealed that the mono- tionover frequency of theusable information content of speechdoes not lingualsmade an averageof 5.92errors and the bilinguals66.58 errors in dependon varioussequential or contextualconstraints existing in the the naturalcondition, while the monolingualsmade an averageof 30.58 message.This assumption has repeatedly been shown to be inaccurate, but errorsand the bilinguals83.17 errorsin the vocodedcondition. For both thesuggested alternative approaches reduce the generality of thetheory. groups,phonemie errors predominated, although approximately 30%- Theyrequire a separatefrequency importance function for eachdegree of 40%of theerrors were morphosyntactic and/or lexicosemantic. {These redundancy.In thisstudy, the frequency importance function for thema- latter resultswere essentiallyin agreementwith previousfindings [M. terialof averageeveryday redundancy is derived.The functionis flat on Mack and B. Gold, MIT LincolnLaboratory Tech. Rep. 703 (1985) and theBark scale. This suggests that the speech code is optimally matched to J. Acoust.Soc. Am. Suppl.I 77, SI0-SI I 0985)].} Further,the bilin- the receiver(auditory system}.The optimizationrefers to maximizing guals'responses to the vocodedstimuli suggested that theywere employ- the receptionrate of information. ing a theory-drivenrather than a data-drivenresponse strategy, presum- ablydue to the difficultyof the task. [ Work sponsoredby the Department 11:18 of the Air Force.]

A15. Responsetime to a sentenceverification task as a function of LPC narrow-bandprocessing and bit error rate, A. Schmidt-Nielsenand Howard J. Ka!lman (Naval Research Laboratory, Code 7520, Washington,DC 20375)

The comprehensionof narrow-banddigital speech with bit errorswas testedusing a sentenceverification task. The diffeulty of the verification task was variedby usingpredicates that were either stronglyor weakly 11.-42 relatedto the subjects.(A toad haswarts./A toad haseyes. ) In addition, AI7. Listener-talkerinteraction: Is therean "autophonetic"effect? John half of the sentenceswere about categoryrelationships, and half were W. Hawks and JamesD. Miller (Central Institutefor the Deaf, 818 aboutproperty relationships. (A salmonis a bird./A camel has horns.} South Euclid Avenue, St. Louis, MO 63110) The test conditionsincluded unprocessed speech and speechprocessed usinga 2400bit/s linearpredictive coding (LPC) voiceprocessing algo- Basedon recentphysiological evidence for neuralselectivity to self- rithm with randombit error ratesof 0%, 2%, and 5%. In general,re- producedsong in theauditory system of theWhite-Crowned Sparrow, a sponseaccuracy decreased and reactiontime increasedwith LPC process- hypothesisstating that the human perceptual mechanism for speech may ing and with increasingbit error rates. False sentencestook longer to be mostacute for self-producedspeech sounds was tested. A testof the verify than did true sentences,but there werefewer errors for the false abilityto identifymonosyllabic words was presented in a noiseback- sentences.Weakly relatedtrue sentencesand stronglyrelated false sen~ ground.The samesubjects served as both talkersand listeners.A small, tenceswere more difficult than their counterparts.Interactions between but statisticallynonsignificant, advantage is foundwhen listener and talk- sentencetypc and processingconditions will be discussed. er are the sameperson. Additionally, while variationbetween talkers was nearlytwice the variation between listeners, the performance of a particu- 11:30 lar talker-listenerpair could be predicted by a simpleequation. This equa- tiongives equal weight to thetalker's and listener's average performance, AI6. Perception of natural and voeodedsentences among English and thusthe talkers,by virtueof their greatervariance, tend to havea monolingualsandGerman-Englishbilinguals.Molly Mack (Division of greaterinfluence. [Work supportedby NIH.]

TUESDAY MORNING, 12 MAY 1987 MT. RAINIER, 8:30 TO 11:35 A.M.

SessionB. Noise I and Psychologicaland PhysiologicalAcoustics I: History and Developmentof Hearing Protection Devices

Elliott H. Berger,Chairman E-d-R Diuision,7911 Zionsville Road, P.O. Box 68898,Indianapolis, Indiana 46268-0898

Chairman'sIntroduction--•:30

Invited Papers

8'.35

Bl. Historyand development of hearingprotection devices. W. Ian Acton(ISVR, University,Southampton, S09 5NH, United Kingdom) Military needhas spurred the invention of hearingprotectors since the times of Greekmythology. Earplugs werepatented in 1864and canal caps attached to an adjustableheadband in 1884as protection for soldiersand sailors.Attempts to limit gunfirenoise by mechanicaldevices commenced in 1905,leading to Mallock-Arm- strongplugs for usein the First World War. Disposableearplugs were patented in 1914also. Systematic

S4 J. Acoust.Soc. Am. Suppl.1, VoL81, Spring1987 113th Meeting:Acoustical Society of America $4 developmentofearplugs for forces during the Second World War culminated in theV-51R. Leather flaps over theears were supposed to protectthe crews of militaryaircraft. The increasednoise of jet enginesled to the productionof recognizableearmuffs, although the stiffnessof the cushionsrequired a strongheadband to ensurea sealagainst the head. This caused a vicelikegrip. The problem was overcome with the development of fluid-filledcushions by Shawin 1954.Progress has continued towards comfort and acceptability, with glass- downappearing in the late 1950's,conformable foam plugs in the 1970's,and nonlinearelectronic systems incorporatedinto muffsin the 1980's.

9:05

B2. Analytical conceptsand models for calculating hearing protector attenuation. Edgar A. G. Shaw (Division of Physics,National ResearchCouncil of Canada,Ottawa, Ontario K 1A 0R6, Canada)

In principle,the idealhearing protector is a rigid airtight coveror plug that enclosesa volumeof air in contactwith the eardrumand is sealedto an immovableobject (the heador the externalear) by a resilient airtightcushion or interface.According to thissimple view, the sound attenuation curve is solelydependent on a few lumpedelements: the massand area of the coveror plug, the acousticimpedance presented by the enclosedspace, and the stiffnessand mechanicalresistance of the cushionor interface.In practice,the attenu- ationis alsodependent on air leakage,body-conducted sound, the lack of rigid support,wave effects, and mechanicalimperfections. These factors and others have been measured, estimated, and modeled with consid- erablesuccess though perfect agreement between theory and experiment remains elusive. So, perhaps there is still room for furtherwork of a fundamentalnature. In the meantime,despite their limitations,the classical analyticalmodels continue to providean invaluablefoundation for hearingprotector design.

9:35

B3. Developmentof a uniquepassive level-dependent hearing protector. C. H. Allen (The ClaytonH. Allen Corporation,80 SouthRoad, Chcbeague Island, ME 04017-9710)and E. H. Berger( E-A-R Division,Cabot Corporation,P.O. Box 68898, Indianapolis,IN 46268-0898) Theneed for protectionof heatingagainst intermittent high-level sounds and the opposite need for retain- inghearing sensitivity during low-level intervals, have led to thedevelopment of level-dependent,commonly called"nonlinear," hearing protectors. This paper deals with the design and refinement of passivemeans for automaticallyand instantaneously altering the amount of attenuation,provided at theear, in responseto the incidentsound level. The earlysuccessful development of a nonlinearearplug for protectionagainst gunfire is followedthrough laboratory and field tests, and the advantagesand limitations of suchan earplugare dis- cussed.The morerecent application of a nonlinearorifice to earmuffs,for variousapplications, introduces severalnew difficulties.Their identificationand the meansthat have beenfound suitablefor usein practical level-dependentearmuffs are discussed. Test data are presented showing acoustic characteristics over a range of incident soundlevels from 100 dB, or lower, to 160 dB, or higher. Resultsobtained with steadystate, broadband,and narrow-band noise are compared and are shown to be similar to resultsobtained with impulse noise,such as experienced,for example,from gunshotsor forginghammers.

10:05

B4. Historyand development of activenoise reduction hearing protection. Richard L. McKinley (Harry G. ArmstrongAerospace Medical Research Laboratory, Wright-Patterson Air ForceBase, OH 45433) Eversince Lueg's 1936 patent, the application of activenoise reduction technology to hearingprotection hasbeen a goalof numerousresearch groups. This paper will describethe various efforts to applyactive noise reductiontechnology to carcupsover the time span from ]936through the present. Each of thevarious efforts will bedescribed in termsof basiccancellation technique, hardware realization, and both laboratory and field performancewhen available. In addition,a workingmodel of thecurrent active noise reduction headset developedjointly by the Air Forceand Bose Corporation, similar to the unit used on the around the world flight of the Voyager,will be presented.

10:35

B5. Noise attenuatingearphones for audlometrictesting. Mead C. Killion (Etymotic Research,61 Martin Lane, Elk Grove Village, IL 60007) and Elliott H. Berger (E-A-R Division,7911 ZionsvilleRoad, Indianapolis,IN 46268) Testsof the noiseexcluding properties of theTDH,50P/MX-41AR, the Audiocup,and the ER-3A insert earphonewere performed in a diffuse-fieldfacility complying with ANSI SI 2.6-1984.Data on attenuation were obtainedmonaurally with the nontestear pluggedand muffed.Results generally agreed well with previously reportedmeasurements. A broadband noise, shaped by a multifilter,allowed a directtest of the ANSI S3.1- 1977permissible background noise levels for testingto audiometriczero under TDH-39/MX-41AR head- phones.This "ANSI noise"raised the average thresholds of 15normal-hearing test subjects by 3 to 5 dB at the 500-to 4000-Hzoctave frequencies. With a noiseshaped to the lessstringent OSHA-1983 regulation, average

$5 J. Acoust.Soc. Am. Suppl.1, Vol. 81, Spring1987 113thMeeting: Acoustical Society of America S5 thresholdswere raised 9 to 17 dB. Introduction of an "ENT office noise" with 55 dB(A) overall level raised averagethresholds at those frequencies by 1I, 5, 1,and 0 dBwith the Audiocups and less than 2 dBwith the recommendedfully ("deeply")inserted ER-SA eartips.Measured threshold elevations agreed closely with predictionsbased on a criticalratio calculation utilizing actual sound field noise levels and measured attenu- ations.A conservativerule of thumbfor testingto audiometriczero with theER-3A earphoneappears to bean office noise level of 45 dB(A) or less.

ContributedPapers

11.-05 11:20

B6. Hearing protectorattenuation for impulsenoise. S. E. Forshaw B7. The developmentof hearingprotective systems for usein the high- (Defenceand Civil Instituteof EnvironmentalMedicine, P.O. Box 2000, noiseenvironments of army combatvehicles. Mitchell S. Mayer and Tat Downsview, Ontario M3M 3B9, Canada) Y. Fung (U.S. Army CommunicationsElectronics Command, AMSEL- RD-COM-TR-3, Fort Monmouth, NJ 07703-5202) The studyof the effectivenessof hearingprotection for impulsenoise posesseveral problems. Due to the transientnature of the noise,real-car- Military vehiclesarc d•igned for maximumcapabilities in areasof at-threshold(REAT) data are not readilyapplicable since current im- performance,armament, and endurance.Acoustic noise suppression at pulse-noisecriteria are basedon either (1) peakpressure, some measure the sourceis not consideredin the systemdesign because of its degrada- ofimpulseduration, and the number of impulses,or (2) total A-weighted tion on performance,as well as its costimpact. Therefore, it is left to the energy.It is possibleto measurethe effectof an earmuffon theseparam- crewhelmet to providefor the hearingprotection of the crewmember. In etersby positioninga miniaturetransducer under the muffat the wearer's orderto protectthe hearingand improve the job performanceof thecrew, earcanal. An alternativearrangement which permits the study ofboth ear thereare two majornoise paths to beconsidered: first is the noisepickup muffsand plugs involves the use of an acoustictest fixture. The testfixture by thc communicationmicrophone, along with the speechcommunica- must simulate those characteristics of the head and outer and middle cars tion;second is the environmentalnoise that penetratesthe earcup.It is that affectthe attenuationof hearingprotectors on real ears.These in- believedthat additionalimprovements to suchdevices as noise canceling clude the viseoelastic characteristics of the circamanful and intra-aural microphonesand earcup/transducer assemblies have reached their prac- skin,the inertialproperties of the head,the frequencyresponse of the tical limits.Therefore, research efforts are presentlybeing conducted to auditorycanal, and the mechanisms of boneconduction and physiological incorporateactive speech processing for rejectingnoise picked up by the masking.DCIEM hassponsored by contractthe developmentof sucha communicationmicrophone, and active noisereduction to reducethe test fixture [C. Giguereet aL, $. Acoust.Soc. Am. Suppl. I 78, S5 environmentalnoise penetrating the earcup.These efforts will be dis- (1985) ]. Attenuation resultswith the test fixture comparereasonably cussed,along with newtypes of testequipment and evaluation procedures well with REAT-deriveddata. Agreementbetween the two methods that havebeen developed to moreaccurately evaluate existing communi- couldbe improved for earplugsiftbe thicknessof theartificial intra-aural cationcomponents and futureactive speech processing/noise reduction skinwere reduced. On-going research is directed towards studying human systems. intra-anralskin, and measuring the peak attenuation, waveform-duration increase,and linear and A-weightedenergy reduction of protectorsfor short-and long-durationimpulses.

TUESDAY MORNING, 12 MAY 1987 REGENCY BALLROOM C, 8:30 A.M. TO 12:00 NOON

SessionC. Psychologicaland PhysiologicalAcoustics II: Cochlea,VllI Nerve, and Evoked Responses

Donald Wong, Chairman Indiana UniversitySchool of Medicine,Medical Science 258, 635 BrownhillDrive, Indianapolis, Indiana 46223

ContributedPapers

8:30 insertedinto the membraneand movedradially and longitudinallyap- proximatelyparallel to the membranesurface. When vitally stainedwith C1. Tectorial membrane:Static mechanicalproperties in vivo. Jozef Janusgreen, the membraneshowed astonishing toughness and resilience J. Zwislocki, Steven C. Chamberlain, and Norma B. Slepecky in both directions.Its deformationpatterns resembled those of a rubber (Institute for SensoryResearch, Syracuse University, Syracuse,NY band. When vitally stainedwith AleJanblue, its tensilestrength was de- 13244-5290} creased,and it tore rathereasily. Subsequent microscopic investigation of In a mammaliancochlea, stimulation of the hair cellsmust be associat- the membrane in vitro showed that the two stains bind to different struc- ed with shearmotion between the organof Corti and the tectorialmem- tures. brane.Knowledge of themechanical properties of thetectorial membrane in its natural environmentis essentialfor our understandingof this pro- tess.Recently, the present authors have been able to visualizethe tectorial 8:45 membranein liveMongolian gerbils by fenestrating the scala media of the secondeochlear turn without disturbingReissner's membrane. The ana- C2. Perilymph volume flow measuredunder physiologicalconditions. tomicalconfiguration of the cochleain theseanimals allowed us to ob- Kenji Ohyama,Alex N. Salt,and RuedigerThaimann (Department of servethe tectorialmembrane over its entire width. A micropipettewas Otolaryngology,Washington University, St. Louis, MO 63110)

S6 J. Acoust.Soc. Am. Suppl. 1, Vol. 81, Spring 1987 113thMeeting: Acoustical Society of America S6 This studymade use of an ionictracer (trimethylphenylammonium, chanicalprocess of theorgan of Corti. [Supportedby NSF, NINCDS, the TMPA) to markperilymph in oneregion of thecochlea. Perilymph flow SouthernHearing and SpeechFoundation, Kresge Foundation, and the was assessedby monitoringtracer movementto other regionswith ion LA LionsEye Foundation.] selectiveelectrodes. Small, nontoxic, quantities of tracer(typically a 50-nl bolusof 150nM TMPACI ) wererequired, since concentrations as low as ! pM werereadily detected. Stringent precautions were taken to sealthe injectionand recording electrodes into the perilymphatic sealee so that no 9:30 artifactualflow wasinduced by perilymphleakage. Results were com- C5. Anatomical effects of intense tone stimulation in the goldfish ear: paredwith a mathematicalmodel of tracerdispersion by volume flow and Dependenceon sound-pressurelevel and frequency. Mardi Cox, Peter passivediffusion. For scala tympani, TMPA dispersioncorresponded to a H. Rogers (George W. Woodruff Schoolof Mechanical Engineering, flow rate of 1.6 nl/m in the epical direction.This rate was significant Georgia Institute of Technology, Atlanta, GA 30332), Arthur (p < 0.05), althoughthe physiologicaleffects of sucha lowflow rate are N. Popper,and William M. Saidel(DepartmentofAnatomy,Schoolsof presumedto be negligible.Perforation of thecochlear apex resulted in Medicine-Dentistry,Georgetown University, Washington, DC 20007) flowrates of over I/•l/m, almost1000 times the physiologicalrate. In scalavestibuli, no significant flow could be detected under normal condi- The finalresults of an experimentalinvestigation to studythe extent of tions.These results demonstrate that in the sealedstate, longitudinal vol- frequencyregionalization in the ear of goldfishare presented.Goldfish umeflow of perilymphis extremely low. Artifactual volume flow is readi- about6 in. in bodylength were subjected to intensetones at 250 and 500 ly inducedby procedureswhich involve perforation of theotic capsule. Hz, and four differentsound-pressure levels. They wereplaced in a wave- [This worksupported by NIH. ] guideand constrained as closeas possibleto a pressureantinode so that theprimary response of theinner ear was due to theinduced motion of the swimbladderand WeberJanossicles. Both saccularand lagenarmaculae were examinedunder a scanningelectron microscope to determinethe locationand extentof hair cell damageas a functionof frequencyand 9:00 sound-pressurelevel. The resultsare not inconsistentwith the grossfre- C3. Mechanismof endocochlearpotential generation by stria vascularis. quencyregionalization in thesaccular macula of codfishdetermined by P. AlecN. Salt,Ivo Melichar,'• andguediger Thaimann (Department of S. Enger [Hearingand SoundCommunication in Fishes(Springer, New Otolaryngology,Washington University, St. Louis,MO 63110) York, 1981), pp. 243-255]. In addition,the resultsindicate a possible breakdownof the Weberianapparatus at extremelyhigh sound-pressure It iswidely assumed that the endocochlear potential (EP) isgenerated levelswhere the primarysite of damageswitches from the saeeuleto by electrogenieion transportby the marginalcells of striavascularis lagena.This is consistentwith the behaviorof the systembased on its (SV). It hasrecently been reported [I. Melieharand J. F. Syka,Hear. viscoelasticproperties as postulated by R. MeN. Alexander[J. Exp. Biol. Res.25, 35-43 (1986) ] thata potentialup to 10mV higherthan EP was 38, 747-757 ( 1961) ]. Work supportedin part by ONR and N IH. ] recordedas microelectrodeswere advanced through SV. Dye marking studiesdemonstrated that thispotential is associatedwith the marginal cellregion. The present authors have studied this potential further using small-tipped(0.5-2.0/• o.d.), double-barreled potassium selective elec- 9:45 trodes.As the electrodeswere advanced through SV, a regionof highK C6. The effectsof hypoxia and temperaturechange on tuning and rate contentwith near zero potential was observed, corresponding to the basal suppressionin goldfishauditory nerve fibers. R. Fay and T. Ream cells.Immediately following, a regionof positivepotential (higher than the EP) andlow K contentwas observed. In mostcases endolymph was (Parrely Hearing Institute,Loyola Universityof Chicago,Chicago, IL 60626) thenreached, but sometimestwo distinguishable regions of positivepo- tentialand high K wereobserved, corresponding to marginal cells and Goldfishauditory (saccular) nervefibers are modestlytuned with endolymph,respectively. The observation ofa positivelypolarized low K bestfrequencies (BF) between200 and 1500Hz. Many fiberstuned below regionis not consistent with the role of the marginal cells as the generator 400 Hz alsoexhibit rate suppression for signalswell above BF. To investi- of EP. On the basisof the observationthat K is closeto equilibrium gatethe origins of thisfrequency selectivity and suppression, the respon- betweenthe basalcells and the extracellularspace of stria,it is proposed sivenessof saccularfibers was measuredduring and after transienthy- thatEP is generated bypassioe diffusion of K acrossthis boundary. [This poxia, and during changesin body temperatureof about ñ 5 øC. worksupported by NIH. ] i• Alsoat CzechoslovakAcademy of Sciences, Respiratorwater temperature controlled body temperature (monitored Prague,Czechoslovakia. in the brain). In hypoxiastudies, the respiratorwater was turned off for about20 min. Low temperatureand hypoxiahad similareffects: a reduc- tion in spontaneousactivity, sensitivity, and responsiveness,and greater adaptationand suppression.Although temperature reduction and hy- 9:15 poxiacaused a reductionin the mostexcitatory frequency at any given intensity(suggesting a loweringof the fiber'sBF), the presentauthors CA. Cytochalasin D suppressesthe compound action potential and couldnot clearlydistinguish between these effects and thosecaused sim- summating potential of the guinea pig cochlea. S. E. Barron, R. plyby reducing sound intensity. Thus, tuning is not strongly dependent on P. Bobbin, P. S. Guth, and C. H. Norris (Department of temperatureor oxygensupply, and the mechanismsof suppressionin the Pharmacology, Tulane Medical School and Department of saceularnerve are likely differentfrom thoseoperating in the cochlear Otorhinolaryngology,LSU MedicalSchool, New Orleans,LA 70112) nerveof mostother vertebrates. [Work supportedby a ProgramProject Althoughaetin has been localized in haireelIs, evidence for its rolein Grant from NIH and NINCDS.] intactcochlear preparations is lacking.The present study was undertaken to testthe hypothesisthat actinis involvedin cooblearfunction (e.g., the activeprocess) by observingthe effectsof a potentfilamentous muscle 10:00 actin inhibitor,cytochalasin D, on evokedcochlear potentials. Perilym- phaticspaces of guineapig cochleawere perfused with Ringersolutions C7. Otoacousticemissions evoked by bone-conductionstimuli. Lu Yuan- containingeither eytochalasinD (10-8 to 10-s M) or DMSO yuanand Zhang Qin (DeafnessResearch, Shanghai College of Chinese (0.00005% to 0.05%) at a rate of 2.5/•l/min for 10 rain [Bledsoeet el., TraditionalMedicine, 530 Lingling Road, Shanghai, People's Republic of Hear. Res. 4, 109 ( 1981) ]. Immediatelyafter each period of perfusion, China) the compoundaction potential (CAP), eochlearmicrophonics (CM), and summatingpotential (SP) evokedby 10-kHz tone burstsof varying Bone-conduction stimuli evoked otoacoustic emissionscould be clear- intensitywere recorded from an electrodein the basalturn. Cytochalasin ly recordedin normal-hearingsubjects. The soundprobe was a l/8-in. D suppressedCAP and SP in a dose-dependentfashion but did not affect microphonemounted in a rubberyearplug inserted in theear canal. A CM. DMSO had no effect.These results provide pharmacological evi- bone-conductvibrator (RADIOEAR B-71, which was formerly usedin dencethat actin is involvedin cochlearfunction--possibly the activeme- an audiometer)as a stimulator,was applied to the surfaceof arcusof

S7 d. Acoust.Soc. Am. Suppl. 1, Vol.81, Spring1987 113thMeeting: Acoustical Society of America S7 zygmaticus.Stimuli were generated by delivering 0.l-ms rectangular dec- 10.-45 tricalpulses to thevibrator. With the exception of stimuli,the recording CI0. Statisticalproperties of auditorythreshold selection in guineapigs. procedurewas the same as Kemp's [J. Acoust. Soc. Am. 64, 1386-1391 Linda J. Hood, Elizabeth K. Barlow, and Charles I. Berlin (Kresge (1978)]. Bycomparison in the same ear, both wave patterns and frequen- Hearing ResearchLaboratory, Department of Otorhinolaryngology, cyspectra of the response evoked by bone conduction were quite similar to LouisianaState University Medical Center, New Orleans,LA 70112) thoseevoked by clicksounds at the stimuluslevels approximate to the subjectivethresholds. Because the frequency components above 800 Hz of Measurementof electrophysiologicalthresholds for specificfrequen- skullvibrations go directly to the innercar ratherthan being conducted ciesin animalshas been limited due to spectralproblems when using brief throughthe middle ear bones, the finding of thepresent study provides broadbandpulse stimuli necessary to elicitsynchronous neural discharge. newevidence to supportthe hypothesis that otoacoustic emissions origi- Frequencyspecific stimuli usually frei to yieldresponses any closerthan natefrom the cochlea.The newmethod of applyingthe stimulusalso has 10-20dB to actualbehavioral thresholds. When a compoundaction po- theadvantage of simplifyingthe structure of thedetective probe and im- tential obtainedfrom a pulseor tone-burststimulus is subtractedfrom a provingits frequencyresponse. potentialobtained with the originalstiumuis plus a low-intensitycontin- uous pure-tonemasker, estimates of thresholdsare near behavioral thresholdsthan measurementsobtained using short duration stimuli alone.The effectsof presentationrate (27.7 to 77.7/s), numberof sweeps 10:15 (625 to 10 000), and level of the continuoustone stimulus ( -- 10 to 50 dB SPL) in a seriesof guineapigs have been examined. Optimal recording cg. Reciprocalrelation between the growthof an emittedcubic distortion conditionsyielded thresholds to sinewaves that are within 5 dB of beha- productand the suppressionof a spontaneousotoacoustic emissi on. E. vioraldata presented by Hefthereta/. [ J. Acoust.Soc. Am. 49, 1888-1895 G. Pasanen, C. C. Wier, and D. McFadden (Department of Psychology,University of Texas,Austin, TX 78712) ( 1971) ], andsomewhat less sensitive than data presented by Prosenet al. [L Acoust.Soc. Am. 63, 559-566 (1978) ]. [Work supportedby DRF. ] Emittedcubic distortion products were generatedin earshaving a spontaneousotoacoustic emission (SOAE). The frequenciesof thepri- 11:00 marytones were set to yielda distortionproduct 20 Hz belowthe frequen- cy of the SOAE; the levelsof the toneswere equal and werevaried over a Cll. Individual differencesin auditory-evokedpotentials: Variability of widerange. With primariesbelow about 35 dB SPL, bothemissions were middle-latencyresponses, including comparisons with brain-stemAEPs. presentand could be measuredseparately. As the levelsof the primaries JudithL. Lauter and RoanneG. Karzon (Departmentof Speechand were increased,and the amplitudeof the distortionproduct rose, the Hearing Sciences,University of Arizona, Tucson, AZ 85721 and SOAE wasprogressively suppressed from its level in the quiet until, at Department of Otolaryngology,Washington University School of somelevel of the primaries,it wasno longermeasurable. Over the range Medicine, St. Louis, MO 63110) whereboth emissionswere detectable,the rate of declineof the SOAE asa functionof the level of the primarieswas approximatelyslope -- 1.0, The variabilityof anditory-evokedpotentials has been studied based while the rate of growthof the emitteddistortion product was approxi- on a repeated-measuresdesign where individualsare testedunder the matelyslope + 1.0--suggestingperfect energy conservation. For higher sameconditions in a seriesof eightweekly sessions. In previousreports to primarylevels, where the SOAE wasno longermeasurable, the growth this Society,it hasbeen shown that for auditorybrain-stem responses functionshowed saturation, being of lower slope,or evennonmonotonic (ABRs): ( 1) within-subjectvariability of waveformparameters such as in somecases. Moderate doses of aspirinabolished the SOAEsof all sub- peaJklatency and amplitudeis smallerthan between-subjectvariability; jects,but only slightlydiminished the distortionproducts. [Work sup- (2) individualsubjects show characteristic variability profiles which can, portedby NINCDS Grant NS 15895.] in turn, classifyindividuals into groups;and (3) variabilitymeasures re- vealdifferences in auditory-systemresponse to right, left, and binaural stimuluspresentations. In thispaper, these measures are extended to mid- die-latencyresponses (MLRs), representedby threevertex-negative and two vertex-positivepeaks. As expected,variability profiles for MLRs 10:.30 showmuch higher degrees of variabilitythan for ABRs, evenin within- individualcomparisons; however, sensitivity to individualdifferences and C9. Coehlcarmodel for acousticemissions. M. Furst and M. Lapid ear of inputare still apparent.In addition,our variabilitymeasure pro- (Departmentof œ]ectronicSystems, Faculty of Engineering,Te!-Aviv videsyet another means of distinguishingbetween the reputed brain-stem University,Ramat-Aviv 6997g, Israel) componentof theMLR andlater MLR peaks.[Work suppoRedin part Acousticemissions, both spontaneous and evoked, were measured in by AFOSR. ] humansand in severalanimals. There weresignificant differences in the experimentalresults. In all animalsa strongacoustic distortion product (ADP) wasobtained, whereas in 60%-70% of the humansubjects ADP 11:15 was unmeasorable.Those human ears that emittedADP usuallypos- C12. Effect of highstimulation rates and paired stimuli on the electrically sessedspontaneous emission (SE) andalso Kemp's echo. The amplitude evoked brain-stem response. D. D. Brown and R. T. Miyamoto of the ADP was strongerwhen its frequencyor the primary-tonesfre- (Departmentof Otolaryngology--Headand Neck Surgery,Indiana quencywas in the vicinityof SE or neara peakof the Kemp'secho spec- UniversitySchool of MedicMe, Indianapolis,IN 46223) trum. In animals,the SE and Kemp's echo were rarely measurable.In orderto understandthe differencesof the emissionproperties observed in Temporalcues are a primary sourceof informationfor the single- variouspeople and animals,a modificationof the cochlearnonlinear channelcochlear implant subject. Two temporalfeatures of the electrical transmission-linemodel is suggested.On eachbranch of the transmission auditorybrain-stem response (EABR) in patientsimplanted with single- line, a noise source was added to simulate cochlear internal noises.To charreeldevices are beinginvestigated. In the first of thesestudies the simulatea localcochlear damage, the verticalresistance was modulated. stimulusrate is variedfrom 10 to 150/sand changes in waveV amplitude The emittedspectrum predicted by the modelcontained a frequency andlatency are recorded.Increasing the stimulus repetition rate causes a whoseCF is at the locationof the damage.When introducinga two-tone prolongationof wave V latencyand a decreasein amplitude.These stimulus(f• andf a), the emittedspectrum predicted by the modelcon- changesare particularly prominent for stimulationrates exceeding 70/s. tainedcomponents of the DP frequencies(i.e., 2fl -f• and2f• --f• ). The In the secondexperiment the EABR responseto the secondstimulus of a amplitudeof the DPs increasedwhen there was a local damageat the CF stimuluspair is computedas the timeinterval between the two stimuliis of eitherthe primary tones or theDP frequencies.Following this research, variedfrom 0.5 to 10ms. Initial dataindicate a significantinteraction only it is concludedthat (a) normallyADP in humansis muchsmaller than in for interstimulus intervals lessthan 4 ms. In thesetwo studies,variations animalsbecause of the differentloads at the oval window, and ( b } a local acrosspatients have been found and an attemptis being made to correlate damagein the basilarmembrane causes the rise of spontaneousemission thesevariations with other measuresof the subjects'implant perfor- and an increaseof ADP amplitude. mance.Findings and clinicalimplications will be reported.

S8 d. Acoust.Soc. Am. Suppl. 1, VoL81, Spring1987 113thMeeting: Acoustical Society of Amedca S8 11:30 11:45

C13. Effect of acoustic tone perception on brain-generated C14. Signaldetection analyses of neonates'responsiveness to sound. electromagneticwaves: Preliminary evidence. Philip L Stocklin LincolnGray (Departmentof Otolaryngology,University of Texas (Mentee, Inc., 439 Blue Jay Lane, SatelliteBeach, FL 32937), Glenn Medical School,Houston, TX 77030) M. Cohen (Florida Institute of Technology, 150 W. University Boulevard,Melbourne, FL 32901),NormaL. Stocklin(Consultant, 439 Receiveroperating characteristics (ROC curves)were generated frommomentary delays in theregular peeping of newbornchicks that Blue Jay Lane, SatelliteBeach, FL 32937), and Ron G. Blackburn (Consultant,3218 Wind SongCourt, Melbourne,FL 32935) occurin responsetoacoustic stimuli. Areas under these curves have been usedto evaluatethe effects of age,intensity, and habituation. In thepres- Brain-generatedmicrowaves were detected and measured for eachof entpaper, such ROC curves are used to evaluatethe effect of prestimulus foursubjects in the frequencyrange of the lowestelectromagnetic stand- behavioralstate on poststimulusresponsiveness. Neonates are known to ingwave (mode) of theadult human brain/skull cavity ( 200-400MHz) cyclethrough periods of high and low activity, and undoubtedly through in the presenceand absence of a loudacoustic tone. In eachcase, the periodsof increasingand decreasing attention toexternal stimuli. Signal- centerfrequency of themode was found at, or within,a megahertzof that detectionanalyses can be used to breakthe circularity in theargument measuredfor eachsubject 1 yr earlier,and is differentfor eachsubject. In that"neonates are more responsive when alert," and to helpdecrease the all cases,mode center frequency is within 10% of that theoreticallypre- highvariability inneonatal data. As expected, desirable prestimulus states areat moderatelevels of activity;psychophysical performance isreduced dictedbased on a subject'sskull dimensions [P. L. Stocklinand B. F. duringperiods of high and low activity. Interestingly, the older subjects Stocklin,T.I.T.J. Life Sci.9, 29-51 (1979) ]. In theabsence of the acous- performbest when they are slightly more active than average, while the tic tone,mode structure consists of a clusterof frequencyspikes, each 2 to youngestsubjects perform best when they are slightly less active than 3 kHz wideextending over 30 to 50 kHz. In thepresence of a loud 1500- average.Similar analyses should be useful in other studies that depend on Hz continuousacoustic tone, the cluster of narrowspikes coalesces to one thechanging rate of repetitiveresponses. [Work supported by NIH. ] or twonarrow spikes, 3 to 10dB abovethe cluster average. [Work supø portedby Mentee,Inc. ]

TUESDAY MORNING, 12 MAY 1987 MT. McKINLEY, 8:30 A.M. TO 12:15 P.M.

SessionD. UnderwaterAcoustics I: Propagationof UnderwaterSound: Range-Dependent, Three;Dimen- sional, and Nonlinear Media

David F. Gordon, Chairman Naval OceanSystems Center, Code 711, San Diego,California 92152

ContributedPapers

8:30 vergeneezones without requiring caustic corrections. Because of these attributes,GBM may be useful also for sound field propagation in a realis- DI. The finite elementmethod applied to oceanacoustic propagation. ticallyrange- and depth-dependent ocean. However, in itsconventional JosephE. Murphy(Department of Physics,University of NewOrleans, andfacile implementation viaa discretizedstack of paraxiallyapproxi- New Orleans,LA 70148) and Stanley A. Chin-Bing (Naval Ocean matedbeams, GBM isnot a disciplinewith a prioripredictive capability. Researchand DevelopmentActivity, NumericalModeling Division, By comparisonwith various canonical test problems, the accuracy of NSTL, MS 39529-5004) GBM hasbeen found to dependstrongly on the choiceof arbitrarily The finiteelement method offers the possibility of a full-wavesolution assignablebeam and stacking parameters. Here, the method is tested on for range-dependentacoustic propagation. It allowsan accuratetreat- previouslynot investigated multiply reflected fields in a range-indepen- mentof the basicphysics of the problemin realisticrange-dependent dentduct bounded by a rigidbottom. The fieldson theboundary are environments,and thus, for thoseproblems not amenable to exactanalyt- computedby asymptoticray theory (ART), GBM, andby a rigorous ic solutions,it could serveas the benchmarkagainst which adiabatic generalizedray integral whose numerical evaluation serves as a reference. It is foundthat a beamstack "tuned" for accuracyalong a ray that has mode,coupled mode, parabolic equation, and other models might be com- pared.The two majorproblems to be solvedin implementinga finite undergonea given number of reflectionsbecomes successively lessaccu- rateas the observer moves to a raysegment with a lesseror greaternumber elementmodel for oceanacoustic propagation are (i) thehuge systems of ofreflections. Retuning removes this deficiency but requires again a refer- equationswhich must be solved, and (ii) accuratetreatment of the radi- ationcondition at thecomputational boundary of themodel. Solutions for enceresult for comparison. This circumstance illustrates again the basic both of theseproblems will be proposed. difficultywith GBM. Possible spectral remedies [ Lu, Felsen, and Ruan, Geophys.J.R. Astron.Soc.(1987) ] are discussed, butthey are less readi- ly computable.[Work supported by NJIT andONR.]

8:45

D2. Critical testof Gaussianbeam method for multiplyreflected fields in 9:00 a surfaceduct. E. Niver, C. J. Ruiz, M. S. Vogas (Departmentof ElectricalEngineering, New Jersey Institute of Technology, Newark, NJ D3. Rapidcomputation of acousticfields in three-dimensionalocean 07102}, and L. B. Felsen(Department of ElectricalEngineering and environments.Michael B. Porter, W. A. Kuperman, F. Ingenito ComputerScience, Polytechnic University, Farmingdale, NY 11735) (Naval ResearchLaboratory, Washington, DC 20375), and Andrew A. Piacsek(Planning Systems, Incorporated, McLean, VA 22102) The Gaussianbeam method (GBM) has found wide application in seismologyforcharting high-frequency wave propagation through heter- A wave-theory-basedtechnique for the rapid computation of propaga- ogeneousenvironments. Unlike ray fields, Gaussian beams negotiate con- tionloss over a widegeographical area with a complexthree-dimensional

S9 J.Acoust. Soc. Am. Suppl. 1, Vol. 81, Spring 1987 113thMeeting: Acoustical Society of America S9 environmenthas been developed. The methodrelies on an adiabaticnor- A parabolicequation model requires a startingfield; that is, the values realmode approach that reducesthe waveequation to a setof coupled of the fieldmust be givenas a functionof depthat a fixedrange. A desir- equationsin thedepth variable z and the plan variables (x,y). Thecoupled ablestarting field must satisfy two requirements:( 1 ) It shouldexcite the equationsare solved with a fastalgorithm based on dividingthe (x•v) propagatingmodes with the properamplitudes; and (2) it shouldexcite domaininto triangular patches. A uniquefeature of thetechnique, which nonpropagatingmodes only to theextent that their effects can be filtered greatlyspeeds the computation,is the precalculationof an impedance out with increasingrange by the falsebottom usually added under the surfacethat replacesthe oceanographicallystable portion of thesound- oceanfloor, which can more than double the depths involved. In practice, speedprofile and the geo-acousticstructure of theocean bottom, both theusual approach is to usean easilycomputed result such as a Gaussian, derived from archival information. Once the modes are calculated, new filteredGaussian, sine, or uniformocean starting field. The falsebottom is source/receiverconfigurations are easilytreated since the modesdo not thenincreased to meetthe second criterion. The advantageof thenormal needto be recalculated.Because of the precalculatednature of the algo- modestarting field is that it doesnot exciteunwanted nonpropagating rithm, areaswith complextopography or bottomstructures require no modes, which minimizes the need for the false bottom, which in turn additionalrunning time oversimpler environments. As an example,a reducesthe running time of themodel proportionally---once the starting deepwater scenario containing both a seamountand an eddyis consid- fieldis computed. ered.

9:15 D7. A shallow-waterrange-dependent acoustic propagation problem with IM. Low-frequencyunderwater acoustic waves from an ice plate.edga a stepw'secoupled mode solution. Richard B. Evans (ODSI Defense leaky Rayleigh wave. JacquesR. Chamuel (Sonoquest/Advanced Systems,Inc., North StoningtonProfessional Center, North Stonington, UltrasortiesResearch, P.O. Box i 53, WellesleyHills, MA 02181 ) CT 06359) and JamesM. Syck (Code 3331, New London Laboratory, Naval UnderwaterSystems Center, New London,CT 06320) Leaky Rayleighwaves propagating along the bottomside of floating sea-iceplates experience cylindrical geometrical spreading and have their A particularshallow-water range-dependent environment was chosen low-frequencylimit determinedby the ice plate thicknessthat corre- andthe stepwisecoupled mode model COUPLE wasapplied. The prob- spondsto about560 Hz. A secondtype of leakyRayleigh wave can exist lemconsisted of a refractingwater layer overlying an isospeedliquid sedi- alongice plateedges propagating with no geometricalspreading and has ment.The waterdepth varied between 120 and 210 m overa rangeof 50 its low-frequencylimit determinedby the largeplate horizontal dimen- kin.The calculations were done at 50 and300 Hz. The mainrange-depen- sions.Laboratory ultrasonic modeling results are presenteddemonstrat- denteffect considered was the redistributionof energydue to forwardand ingthe detection of low-frequencyRayleigh waves radiated from ice plate backscattercaused by both large and small scale bathymetic changes. The largescale changes, that evolveslowly with range,produced a smooth edges.In oneexperiment, the plate-edge leaky Rayleigh wave wavelength wasgreater than 12 times the ice plate thickness. The resultssuggest that a transitionof energybetween different sized sets of locallypropagating 3-m-thickice plate in theArctic may easily radiate 10- to 100-Hzcompo- modes.The morerapid, small scale, changes caused a pronouncedenergy nentsfrom its edges. The iceplate edge acting nearly as a finitelength line lossdue to forwardscattering into highlyattenuated high-angle modes. sourceproduces high directionalityof the radiatedleaky Rayleigh wave The effectsofbackscatter were negligible. The resultsare compared in this into the water.The low-frequencyplate-edge leaky Rayleigh waves may paperto IFD/PE and, in a subsequentpaper, with otherparabolic equa- tion models. be detectedin the waterat significantdistances from the iceedge. Addi- tional physicalinsights into the controversialleaky Rayleigh wave are providedby comparing water/ice and Freon- l 13/iceinterface conditions wherea high-densitylow-velocity liquid is used.[Work supportedby 10:15 ONR.] Dg. A comparisonof parabolicequation models with stepw'secoupled modesin a shallow-waterrange-dependent environment. James M. Syck andJoseph M. Monti (Code3331, Naval UnderwaterSystems Center, 9:30 New London, CT 06320)

DS. Time domainpropagation studies with the NPE: Two short movies. Parabolicequation calculations are compared with stepwisecoupled B. Edward McDonald (NavalOceanR&D Activity, NSTL, MS 39529), mode COUPLE calculations for a set of runs for which the two models Dan Plante,John Ambrosiano(Berkeley Research, Inc., Springfield, haveoverlapping capability. The PE calculationswere then extended to VA 22150), and William A. Kuperman (Naval ResearchLaboratory, considerthe additional case of refracting sediment. Normal mode start-up Washington,DC 20375) fieldswere used in thecalculations. PE modelshave capabilities differing The nonlinearprogressive wave equation { NPE) modelhas been used in theareas of wideangle capability, treatment of thebottom, and numeri- to investigatethe propagationof linearand nonlinearbroadband signals cal methods.The intent of this paperis to discusswhich of thesediffer- in a range-dependentshallow water waveguide. The NPE isthe nonlinear encesmake a difference.The environmentchosen was that presented in timedomain equivalent of thefrequency domain parabolic wave equation theprevious paper. Calculations were performed at 50 and300 Hz. Water (PE). Resultsfrom each of thestudies are given in shortcomputer-gener- depthsvaried somewhat, but averaged about 150 m, correspondingto 3 atedmovies illustrating a four-cyclesine-wave pulse propagating a total of wavelengthsand 15wavelengths at 50 and 300 Hz, respectively.The de- 20 km in isovelocitywater {c = 1500m/s) overa bottom(c = 1600m/s) pendenceof depth with range took two forms. The first consistedof whosedepth profile contains a shelfof slope0.15 connectingregions of smoothlyvarying linear segments,the secondwas the sameas the first constantdepth 225 and 150m. Effectsevident in the moviesare: radiation with a numberof spikelikeirregularities added in. Differencesare dis- into the bottomresulting in headwaves that re-radiateback into the w,ter cussedin termsof numericalissues and the physicsincorporated in the models. column;energy dumping following reflection from the slopingbottom and surface;and mode separation at late times.Early time resultssuggest that bottom penetrationis greaterwhen nonlinearityis included. 10:30

D9. Hybrid ray-PE analysisof guided high-frequencypropagation. T. Ishihara (Departmentof ElectricalEngineering, National Defense 9:4• Academy, Hashirimizu, Yokosuka,239 Japan) and L. B. Felsen (Department of Electrical Engineering and Computer Science, D6. Comparingeffects of different starting fields for parabolic equation PolytechnicUniversity, Farmingdale, NY 11735} models. E. Richard Robinson and David H. Wood (Code 3332, New LondonLaboratory, Naval UnderwaterSystems Center, New London, Surfaceguiding of high-frequencysound fields may take place near a CT 06320) concaveboundary in a homogeneousmedium or neara planeboundary in

S10 J. Acoust.Soc. Am. Suppl. 1, VoL81, Spring1987 113thMeeting: Acoustical Society of America S10 a refractingmedium. Multiple reflected ray fields excited by a sourcenear equations.The geometryis assumedto havea rigidouter surface and a theboundary form caustics that pile up at longranges around the source locallyreacting inner surface. Predictions are made ofdirectivity patterns depth.Conventional caustic corrections are inadequateto dealwith this of diffractedsound, with particular interest in theeffect of liningcharac- catastrophe.It is shownhere that the narrowangular spectrum interval teristicson levelsof on-axisnoise. At eachchosen frequency the solution occupiedby the troublesomecaustic-forming rays can be filled alterna- to theboundary-value problem is checked by confirming the power bal- tivelyby a narrow-angleparabolically approximated (PE) wavefield.The ancebetween that injectedat the incidentsource, and the sum of corre- hybridcombination of legitimaterays and narrow-anglePE canbe re- spondingradiated and lining-dissipated values. The effect of finite length gardedeither as correcting via PE the failureof ray acousticsat long oninput energy is established upon comparison to that for the similarly rangesnear the source depth, or asremoving the narrow-anglerestriction linedinfinite waveguide. from PE by fillingthe wide-anglespectra with rays.The theoryis illustrat- ed with calculationsfor a range-independentducting environment, and alsofor a range-dependentducting-to-antiducting transition. [Work sup- portedby ONR. ] 11:30

D15. The airbornenoise path for an acousticsource inside a fluld-loeded cylindricalshell. Edmond Y. Lo (CambridgeAcoustical Associates, Inc., 54 CambridgeParkDrive, Cambridge,MA 02140) 10:45 The radiationof noisefrom machinerylocated inside a submerged D10. HYPER: A hybrid parabolicequation-ray model for underwater elasticstructure involves both a directstructure-borne and flanking air- soundpropagation in the vicinityof smoothcaustics. Frederic Tappert bornepath. Calculationswere performed to assessthe importanceof the (Universityof Miami/RSMAS, Miami, FL 33149)and Henry Weinberg latterfor a cylindricalshell excited by an interiormonopole source. An (ODSI DefenseSystems, Inc., North Stoningt0nProfessional Center, analyticsolution for the interiorpressure field is derivedfor a prescribed North Stonington,CT 06359-1738) wallimpedance using the Helmholtz integral equation approach, Farfield pressuresare evaluatedfor a baffledsection of the shell.Transfer func- The hybridparabolic equation-ray model (HYPER) usesmodified tionsof farfieldto interiorpressures are presented over a frequencyrange ray tracingof geometricalacoustics to locateimportant propagation encompassingthe ring frequency.The excessinsertion loss arising from paths.Then HYPER solvesa modifiedparabolic equation in a smallre- the interiorapplication of variousabsorptive blankets is evaluated. gionnear the raysto computethe pressurefield. This paperapplies the HYPER modelto investigateacoustic propagation in the vicinity of smoothcaustics. Results are comparedwith ordinaryray theory,modi- fiedray theory, and the wave solution for a range-independentcase. Some range-dependentexamples are also presented. [ Funding for thiswork was 11:45 providedby the AEAS ProgramOffice, ONR Detachment,Code 132.] DI4. Resolutionof low-frequencyattenuation anomalies in the Southern Hemisphere.R.N. Denham, R.W. Bannister,K. M. Guthrie (Defence Scientific Establishment, Naval Base Post Office, Auckland, New Zealand), R. H. Mellen (PSI--Marine Sciences,95 Trnmbull Street, New London, CT 06320), and D. G. Browning (Naval Underwater 11:00 SystemsCenter, New LondonLaboratory, New London,CT 06320) DI1. Fast field computationsusing transmutation. Robert P. Gilbert DuringProject KIWI ONE [D. G. Browninget al., Nature 282,820- (Department of Mathematical Sciences, University of Delaware, 822 (1979) ] anomalouslyhigh valuesof low-frequencyattenuation were Newark, DE 19716) and Daivd H. Wood (Code 3332, New London observed in the central South Pacific Ocean. Similar results were obtained Laboratory, Naval Underwater SystemsCenter, New London, CT alonga track from New Zealandinto the SouthernOcean during Project 06320) TASMAN TWO [ R. W. Bannisteret al., 1. Acoust.Soc. Am. 62, 847-859 Fast fieldcomputations without rangedependence are basedon com- (1977) ]. A recentanalysis of oceanographicdata by Mellenshows that puting the Hankel transformof the Green'sfunction of the separated both regionsare includedin a relativelyhigh pH contourat the sound depth-dependentordinary differential equation. As usual,the required channelaxis. The correspondingpredicted values of attenuationare in Grecn'sfunction is expressedin termsof two solutionsof the homogen- reasonableagreement with the measureddata. eousdifferential equation, the first satisfyingthe boundarycondition at the surfaceof the ocean,the secondsatisfying the boundarycondition at the bottom of the ocean, and the Wronskian of these two functions. In our approach,one solutionis givenin termsof one transmutationthat pre- servesthe surface boundary condition, and theother is givenin termsof a 12:00 different transmutationthat preservesthe bottomboundary condition. Oncethe two differenttransmutation kernels are found, they are applied 1)15. Anisotropy of compressionalvelocity in sea ice cores. Paul to trigomctricfunctions that satisfythe respectiveboundary conditions, J. Vidmarand Jo B. Lindbergat (AppliedResearch Laboratories, The and the Green'sfunction is numericallycomputed. A fastHankel trans- Universityof Texasat Austin, Austin, TX 78713-8029) form (the usualfast Fourier transformapproximation was used) com- pletesthe calculationof the field versusrange. Laboratorymeasurements of the propagationvelocity of ultrasonic compressionalwave pulses were made at fourorientations (vertical and at three horizontaldirections) on fivecores from first year seaice. Accurate- ly measuredrelative velocities( ñ 0.9%) showedthat velocitieswere slightlyanisotropic (generally • 5% ). As in freshwaterice, it wasfound that the velocitiesparallel to the c axis (which was in the horizontal 11:15 plane) are fasterthan horizontalvelocities perpendicular to the c axis. D12. Numerical solutionfor the diffraction of internal soundsources by a However, the measuredvertical velocityis fasterthan velocityparallel to free-flooded cylindrical shroud. Rudolph Martinez (Cambridge thec axisin our seaice cores. This is surprisingsince the velocityalong the AcousticalAssociates, Inc., 54 CambridgeParkDrive, Cambridge, MA c axisin freshwaterice is fasterthan the perpendicularvelocity. Velocities 02140) at 45 ø to the c axis were found to be either faster or slower than velocities parallelto the c axis,depending primarily on temperature.[This work The problemof determiningvirtual source distributions for an insoni- wassupported by the ONR. ] a•Currently at BDM ManagementServices fledfree-flooded pipe of finitelength is posedas a pair of coupledintegral Co., Austin, TX 78759.

$11 J. Acoust.Soc. Am. Suppl.1, Vol. 81, Spdng1987 113thMeeting: Acoustical Society of Amedca Sl 1 TUESDAY MORNING, 12 MAY 1987 CELEBRATION HALL, 9:00TO 11:00A.M.

SessionE. ArchitecturalAcoustics I: Researchin Building and Room Acoustics

Steven M. Brown, Chairman SteelcaseInc, TC-1W-04, P.O. Box 1967, Grand Rapids,Michigan 49501

Chairman's Introductions9:00

ContributedPapers

9:O5 asthe baselinemasking spectrum. The PNC35 hasan overalllevel of 43 dBA,and is representativeof low-to-moderatelevels of soundmasking. A El. Comparisonof a fan-shapedand a rectangularhnll. J. S. Bradley few trendsemerge from thisstudy. The sittingof workstationsnear hard (Institute for Researchin Construction,National ResearchCouncil, room boundariescan be expectedto have poorer speechprivacy than Ottawa, Ontario KIA 0R6, Canada) correspondingworkstations away from suchroom boundaries.Second, Newer auditorium acoustics measures were used to evaluate and com- the acousticallyhard screenswhose NRC is 0.1 or lesswill havepoorer parea fan-shapedand a rectangularauditorium. Measurements included speechprivacy than will acousticallysoft screenswhose NRC is 0.5 or reverberationtimes, early decay times, clarity C80, overallstrength, and more. lateral fractions each measured in octave bands from 125 to 8000 Hz. Measurementswere made at combinationsof 3-5 sourcepositions and 12 receiverpositions. The results indicate that the shape of thehall influences 9:50 the within-hallvariation of theseacoustical quantities. The fan-shaped hall is thoughtto havea lessdiffuse early sound field that causeslarger E4. Study of acoustic response of anisotropic steel structures. seat-to-seatvariations in acousticalquality and a systematicvariation in P. Cordonnicr, D. Biron, and S. Pauzin (ONERA/CERT/DERMES, acoustical characteristics from the front to the rear of the hall. 2 Avenue Edouard Belin-B.P. 4025, 31055 ToulouseCedex, France)

Thepurpose of ourexperiment is to learnthe influence of sfiffeningon the acousticresponse of steelplates. The investigationis carriedout on a rectangularplate that is clamped in anopening ( 1.20X2 m 2) betweena 9:20 reverberant room and a test room. The sound transmission loss is deter- mined by usingtwo differentmethods: a methodthat is basedon the E2. Theoretical functionsof transient diffnsibility in reverberantrooms. soundpressure measurement and the two-microphoneintensity method. Yu-an Rao (Institute of Physiology,Academy of Sciences,Shanghai, The meanradiation efficiency is obtainedby measuringthe panelvibra- People'sRepublic of Chinaand Department of Psychology,University of tion velocitywith a regular mesh. The measurementsare made over a California, Los Angeles, CA 90024) and Edward C. Carterette frequencyrange from 250 to 10000 Hz for a diffusefield excitation. The (Departmentof Psychology,University of California,Los Angeles,CA 90024) followingseries of samplesis tested:a 1.5-mm-thick-steelplate; a plate reinforcedwith uniformlyspaced tubular stiffcriers;a plate reinforced Much efforthas been spent in investigatingthe relationshipbetween with uniformlyspaced line stiflenets;and a corrugatedpanel (the space the physicalproperties of reverberantsound fields and the parametersof betweenthe corrugations is the sameas the spacebetween the stiffeners). soundqualities. A singleform of parameter,which is a functionof both Theacoustic effect of variationof bendingstiffness isdiscussed, and all the spaceand time, that mighthelp in establishinga relationship between its experimentalresults provide comparison elements for computedresults. real-timevalue and subjectivecriteria is sought.Based on a simplified modelof spatiallydirectional diffusibility, a generalsolution to the differ- ential equationof transientdiffusibility d(t) and the definitenessratio 10.'05 D(t) is given.Computed and measuredcurves are consistentwith each other;in particular,an explanationof the nonmonotonicV shapeof d(t ) ES. Sound transmissionloss single numberratings. Keith W. Walker curvesby meansof theoreticalcalculations and mathematicalderivations (US(3 Corporation,P.O. Box 460, Round Lake, IL 60073) is provided.It is suggestedthat d(t) andD(t) couldserve as quantitative, predictiveparameters in applicationsto architecturalacoustics and the Severalsingle number ratings, including STC, for rating the sound controlof soundquality in acousticengineering. insulationproperties of wallswere correlated with the A-weightedsound reductionsof a groupof gypsumboard partitions for severaltypes of soundsource. None of theratings fared well for thebroad range of sound types.It is shownthat a singlerating method cannot deal with all sound 9'.35 sources.Two newratings are proposed to supplementSTC forcoverage of indoor and outdoor noise reduction. E3. Meesurementof speechprivacy in openplan offices.J. B. Moreland (WestinghouseElectric Corporation, Researchand Development Center, 1310Beulah Road, Pittsburgh,PA 15235) The properdesign of an openplan officefor speechprivacy and for 10:20 overallacoustical comfort considers many variables, all of which interact E6. A sourcespectrum for simplifiedsound isolat'on tests specifically for to producethe final acoustical environment. Using a loudspeakerto repre- results correlated to NIC ratings, Nigel D. Breitz (Acoustical sentthe talker,the sound spectrum that wouldbe heard by a listenerin an Consultant,212 Belt Mcgurim, Rehov MosheDayan, Kfar Saba,Israel) adjacentworkstation is measured.From thesemeasurements, the articu- and H. (3. Leventhall (Atkins Researchand Development, Epsom, lationindex (AI) betweenadjacent workstations is calculated.Adjacent SurreyKTI 85BN, Un/ted Kingdom) workstationsarc focusedupon because it is generallymore difficult to obtaingood speech privacy for theoccupants of theseworkstations than it Using one-thirdoctave-band sound transmission and reverberation isfor workstationsthat are farther apart. Also, a PNC35 spectrumis used time data of 54 party walls (ISO717, ISO140), the differencesin dBA

S12 J. Acoust.Soc. Am. Suppl.1, VoL 81, Spring1987 113th Meeting:Acoustical Society of America $12 valuesbetween rooms were simulatedas a functionof wideband (90 Hz- Research and Development, Epsom, Surrey KTI 85BN, United 3.5 kHz) sourceroom spectra. An optimalsource room spectrum was Kingdom) obtainedby minimizingthe standarddeviation of (AdBA•- NIC 0 (i = 1.54} from the meanvalue. The rank correlationcoefficient was seen For reproducibilityof simplifiedsound isolation tests [when a large to increasefor decreasingstandard deviation. The absorptiondata of the (- • m) approximatelyspherical, omnidirectional sound source is not roomswere used to extendthe resultsto thesound power spectrum of the used], it is appropriateto specifyrequirements for sourceplacement. A source.Results, examples, statistical data, and comparisonwith other scalemodel of a buildingwith an exaggeratedlopsided but reasonable workerswill be given. quantityof absorptionin one room (panel absorberson wall surfaces aroundone coruer) was used to investigatedeviation of radiatedpower for thecoruer position from rigid wall conditions,the objective being to excitemodes to an extentdepending on their frequencyand not mode 10:35 number.The modeland experimentwill be discussed,and the resultsfor this model as well as thosefor a full-sized baffledloudspeaker will be E7. On cornerpositioning of the soundsource for soundisolation tests. given.The placementis of more importancein countrieswhere the 100- Nigel D. Breitz (AcousticalConsultant, 212 Belt Megurim, Rehov Hz, one-thirdoctave band is included.In light of annoyancefrom hi-fi Moshe Dayan, Kfar Saba, Israel) and H. G. Leventhall (Atkins bass,the Europeanrange would seem more appropriate.

10:50--11:00 Discussion

TUESDAY MORNING, 12 MAY 1987 REGENCY BALLROOM D, 9:00 TO 11:30 A.M.

SessionF. Physical AcousticsI: Scattering I

Philip L. Marston,Chairman Departmentof Physics,Washington State Unioersity, Pullman, Washington 99164

ContributedPapers

9.•0 groupswith certain frequencycomponent concentrations and distinct timedelays. Such features were exploited to revealtheir relationship with Fl. A rigid backgroundanalysis of the acousticscattering from solid the shapeof the sphereand the velocityof soundwave propagation elastic targets. D. H. Trivett, Gary S. Sammelmann,and Roger throughthe structure. The time separationamong different delayed wave H. Hackman(Naval CoastalSystems Center, Panama City, FL 32407) groupsprovides the characteristicparameters of the scattereras their At previousmeetings of the AcousticalSociety of America [ L. H. destructiveinterference will form strongnulls corresponding to the sharp Green,D. H. Trivctt, and L. Flax, J. Acoust.Soc. Am. Suppl. I 77, S79 spectrumlines predicted from the resonance scattering theory. Utilization (1985) ], it wasdemonstrated that, for the analysisof the elasticexcita- of time-frequencyanalysis as a practicalapproach to describea reflective tiousin the acousticscattering from elastictargets, the properback- elasticsphere is discussed. groundto subtractis a rigid background.This choicewas utilized to analyzethe low-frequency scattering from spherical and infinite cylindri- 9:30 cal shellsover a broad rangeof frequenciesand shell thicknesses.How- ever,in a recentpaper on the acousticscattering from elastic spheroidal F3. Classificationof resonancesand remote aspect-ratiodetermination of solids[M. F. Werbyand G. J. Tango,L Acoust.Soc. Am. 79, 1260-1268 submergedspheroidal elastic shells.O. C. Gaunaurd (Naval Surface (1986) ], it is concludedthat a rigidbackground is inappropriatefor elas- WeaponsCenter, White Oak, R-43, SilverSpring, MD 20903-5000)and tictargets that have either low shear speeds or lowdensities. A complete M.F. Werby(Naval OceanR&D Activity,Code 22 I, NSTL Station,MS reexaminationof the scatteringfrom e/asticsolids is presentedto demon- 39529) stratethat the 6gid background isthe appropriate choice in thiscase, too. In the courseof this analysis,it is alsodemonstrated that Werby and Acousticscattering was studiedfrom submerged,steel, spheroidal Tungohave misinterpreted the nature of theelastic response of thescat- shellsin their resonanceregion. Arbitrary angularincidences were con- terer. sideredto analyzethe possible aspect-angle dependence of theresonances. The shellsare sufficientlythin so that the "properbackgrounds" of the RST [G. C. Gaunaurdand M. F. Werby, Int. L SolidsStructures 22, 9:15 1149-I 159 (1986) ] canbe suitablysuppressed, and the resonancescan be adequatelyisolated. It is shownthat the shellresonances are causedby F2. Time-frequencyanalysis of acousticreflection waves from elastic surfacestanding waves propagating at discretefrequencies with an almost spheres.N. Yen, Louis R. Dragonette (Physical AcousticsBranch, constantphase velocity. From this (surface)standing-wave interpreta- Naval Research Laboratory, Washington, DC 20375-5000}, and tion (viz., geodesics)accurate resonance locations have beenderived. Angie Sarkissian(Sachs/Freeman Associates, Landover, MD 20785) Only two basicvibrational modes seem to exist,one along and the other A processingalgorithm based on the Wignerdistribution function is normalto the axisof symmetry.Thus, only resonancescorresponding to usedto analyzethe acousticreflection from a solidsphere in a joint time thesetwo directionsare possible. Furthermore, the fixedresonance loca- and frequencyrepresentation. Test casesfor spheresconstructed from tionsseem to have amplitudesthat changewith incidenceangle. Hence, variouselastic materials were computed from the theoreticalform func- this procedurepermits the classificationof resonances,and it can he ex- tionsin the frequencyrange for ka from 0.3 to 20. It is observedfrom such ploitedto extractthe aspect ratio of thespheroidal shell from its returned time-frequencydisplays that the behaviorof the scatteredwave from echo.These points are illustratedwith numerouscomputational exam- thosepenetrable scatterers can be expressedin severalrelated wave pies.[Work supportedby NAVELEX and ONR.]

$13 J. Acoust.Soc. Am. Suppl.1, Vol. 81, Spring1987 113th Meeting:Acoustical Society of America S13 9:45 radiationfrom the Lamb waves on the shell [R. Hickling,J. Acoust. Soc. F4. Acousticresonance scattering by largeaspect-ratio solid targets. L. Am. 36, 1124-1137(1964) ]. Theangular dependence of the largest Lambwave echo has been modeled and measured as the receiver is shifted H. Green, C. GeorgeKu (Martin Marietta BaltimoreAerospace, an angley awayfrom the backscattering axis. The sphere was made of Baltimore,MD 21220),and M.F. Werby(NORDA, NSTL, MS 39529) stainlesssteel with an inner-to-outerradius ratio b/a = 0.84. For the fre- Previously,Werby and Tango [J. Acoust.Soc. Am. 79, 1260-1268 quenciesused, 50 < ka< 65and the largest Lamb echo is predicted to be (1986)] examinedthe resonance response of solid spheroidal targets as a thelowest flexural mode. Previous SWT results (for solid spheres) were functionof materialproperties. Results were presented for severaldiffer- appliedto calculatethe surface wave's phase velocity c,w and angular entmaterials for targets with an aspect ratio <2. Herethe previous analy- dampingparameter,8 and were extended toinclude a subtle effect of• on sisis extendedto highaspect-ratio targets. The transitionmatrix ap- the Lamb echo amplitude p,,,. It is found that proachto acousticscattering utilizing spherical basis states is used. p,,,=ps.4oIJo (u) - i/gyJ:(u) [, whereps is thespecular amplitude at Resultsfor several different materials are presented over a KL/2 rangeof y = O, u=kayc/c•,.4 o = [Olexp[ -- 2•(rr- 0•w) ], sin•8,• = c/c•w, 0.5-16.0for targetswith aspectratios from 1-10. It isdemonstrated that andO isa couplingcoefficient. Measured p•w near the central peak at thephase velocity of the Rayleigh resonances onsolid spheriods isclosely y = 0 generallyagree, but near the • whcrep,wisminimized, dispersion relatedto theshear speed of thematerial. In addition,high Q resonant (notincluded in themodel) becomes significant. [Work supported by peaksare shown to dominatethe backscattered response for many high ONR.] aspect-ratiotargets.

10:45 lO:OO Fg.Hyperbolic-umbilic focal sections: The wavefield and the merging of FS.Scattering of acousticwaves by a finitecylindrical shell containing a rays at causticlines. Philip L. Marston(Department of Physics, mixture of wax and colophonyimmersed in water. X. Bao, V. WashingtonState University, Pullman, WA 99164) V. Varadan,V. K. Varadan(Laboratory for Electromagneticand AcousticResearch, Department of EngineeringScience and Mechanics A wavewhose amplitude in tbexy planeis exp[ik(g - ct)] propa- and ResearchCenter for the Engineeringof Electronicand Acoustic gates to produce a hyperbolic-umbilicfocal section (hufs) if Materials,The PennsylvaniaState University, University Park, PA g(x,y)= (ax3 + 3yy:x)/6+ a,(x• + y•) withsgn(a) = sgn(y)and 16802),Q. Xu, andT. Wang(Institute of Acoustics,Academia Sinica, a•<0. Sucha wavemay be produced, e.g., by reflectingsound from a Beijing,People's Republic of China) curvedsurface. The hufs lies in a plane a distancez = - (2a•)- *from the xy plane.Let u and • denotethe transversecoordinates in the hufssuch A methodemploying boundary and finite element approaches aswell thatthe axes are parallel to thex andy axes,respectively. The uo plane asmodel analysis isused to studythe scattering of acoustic waves by a containscaustic lines which meet at (u,o)= (0,0)with an apex angle q• finitecylindrical shell immersed in water.The cylindrical shell contains a givenby tan (q•/2) = (y/ct)•/• = • [ P. L. Marston,J. Acoust. Soc. Am. mixtureof waxand colophony and thus the elastic wave propagation in Suppl.I 80, S73 (1986) ]. Thepresent research describes how the rays thismixture is also considered. The computed frequency response and mergeso that the caustics locate a transitionfrom a four-ray region to a uv directionpattern of the backscatteringtarget strength show excellent regioncontaining norays. The diffraction integral was also approximated agreementwith measurements. forthe hufs wavefield inthe case a > 0 bychanging g in an analysis pre- viouslygiven [P. L. Marston,J.Acoust. Soc. Am. 81, 226-232 (1987)] for the transversecusp. The amplitudein the hufsis (k */32n/3•r/ 10:15 ira:/3l?)exp(ikr)Ai(q•)Ai(q:),where r = (z: + u• + o:)•/: andthe Ai areAiry functions ofthe indicated arguments: q•= - k :/3(u+/? - •)/ F6. Couplingcoefficient G for the Fabry-Perotrepresentation of (2a)•/•z,j = 1,2.[Work supported byONR.] backscatteringfrom spheres and cylinders: Quantitative GTD for elastic objectsin water. Philip L. Marston (Departmentof Physics, WashingtonState University, Pullman, WA 99164) Foreach class of elastic surface wave, the contributionf• to the total 11:00 formfunction may be written in a Fabry-Perotrepresentation [K. L. 1;9. An iterativeT matrix for scatteringfrom boundedobjects. Williamsand P. L. Marston,J. Acoust. Soc. Am. 79, 1702-1708(1986) ]. Guy Norton,Richard Kciffcr, and M. F. Wcrby(Numerical Modeling For backscattering •w I = Iø exp[-- 2B(Ir-- O,,•) ]/ Code, NORDA, NSTL, MS 39529) [j+exp(--2rrl?+t2rrxc/c,,•)][, wherex=ka and for spheres j = + 1.The surface wavc's phase velocity and angular attenuation coef- The extendedboundary condition (EBC) methodof Watermanhas ficientsare c,• andfi whilesin •,,• = c/c,,,.The exact form function was beenused extensively over the last few years to describe scattering from synthesizedbysumming vafiousf•,• with a specularterm. An expression boundedobjects and usually leads to a mapping(the T matrix)that re- forG, which had to be evaluated by numerical differentiation, was derived latesthe knownincident field with the scatteredfield. This methodarises forsolid spheres via a Sommerfeld-Watson transformation. In the present froman expansion ofrelevant physical quantities ina partialwave space research,a simple approximation for]G I isderived by matchingf, wwith (i.e.,the incident and scattered fields) that upon truncation ofthe partial the RST resultnear a resonancewhen /5' is small.This gives waveseries leads to a finitematrix problem. The level oftrnncation relates IGI= 8•rllc/qwfor sphereswhile for circularcylinders j = -- 1 and to convergenceand it is notalways possible to knowat.what truncation IGl=8rr•'l(rrx)•/•. Comparisonwith the exact IO(x)l for Rayleigh levelone has arrived at convergence. Aniterative T matrix approach has waveson solid tungsten carbide and aluminum spheres gives agreement beendeveloped at NORDA thatstarts at sometruncation level (N terms evenwhen 2rr/?is not ,• 1.These approximations of IG [ shouldalso apply inthe expansion) and leads via simple vector operations tothe N + 1case. tothe scattering of short tone bursts and to thef,,• for hollow elastic shells. Thismethod can obviate the problem of convergencebyinteracting up- [Work supportedby ONR. ] warduntil enoughterms are included to yielda stablesolution. In addi- tionto dealingwith the convergence problem this method is able to treat theproblem of ill-conditionedmatrices often encountered in scattering problemsmore effectively than the directmatrix method. The derivation 10:30 of thismethod is presentedalong with somenumerical results. F7. Focusedbackscattering from hollow spherical shells in water:Lamb wavesand the acoustical glory. Steven G. Kargland Philip L. Marston (Departmentof Physics,Washington State University, Pullman, WA 11:15 99164) FI0. Acousticalholography based on Bojarski's exact inverse scattering Whena shorttone burst is incidenton a sphericalshell in water,the theory.Woon S. Gan (AcousticalServices Pte Ltd., 29 TelokAyer firstbackscattered echo is thespecular reflection. This is followedby Street,Singapore 0104, Republic of Singapore)

S14 J.Acoust. Sec. Am. Suppl. 1,Vol. 81, Spring 1987 113thMeeting: Acoustical Society ofAmerica $14 This paperinvestigated the useof Bojarski'sexact inverse scattering to beperformed using different insonifying waves of differentfrequencies theory(BEIST) asthe basis of acousticalholography (AH). Thepurpose to determinethe object'sproperties. This is the sameas what is donein is to improvegeneralized holography although generalized holography diffractiontomography experiment. The holographicfield equation was originatesfrom BEIST. Generalized holography isnot the complete solu- obtainedusing the BEIST. It includedthe scattering amplitude. A setof tion of BEIST and someinformation is missing.Generalized holography simultaneousequations was obtained relating the object (or scatterer) to (GH) has to be recastas an inversescattering problem and not as an the recordedscattering amplitudes as specifiedfor somediscrete sets of inversesource problem. By interpretingGH as inversescattering, one frequencies.These simultaneous equations were solved for thescatterer in takesaccount of sounddiffraction and refractionwithin an inhomogen- termsof themeasured scattering amplitudes. A newtype of exactinverse eousobject, giving detailed information on the object that is not available scatteringalgorithm for AH is proposed. in GH. In thepresent AH setup,more than one scattering experiment has

Sl 5 J.Acoust. Soc. Am. Suppl. 1, Vol. 81, Spring 1987 113thMeeting: Acoustical Society of America S15 TUESDAY AFTERNOON, 12 MAY 1987 REGENCY BALLROOM A & B, 1:00 TO 4:30 P.M.

SessionG. SpeechCommunication II: Vowel Perception(Lecture and PosterSession)

Winifred Strange,Chairman Departmentof Communicology,University of SouthFlorida, Tampa, Florida $3620

Invited Papers

1:00

GI. Evolvingtheories of vowelperception. Winifred Strange(Department of Communicology,University of SouthFlorida, Tampa, FL 33620) In thepast 15 years, research on the perception of spokenvowels has givoa rise to newconceptions of vowels asarticulatory, acoustic, and perceptualevents. This papertraces the evolutionof voweltheory starting from "simple"target models in which vowelswere characterizedarticulatorily as staticvocal tract shapesand acousticallyas pointsin an F I/F2 vowelspace. Within this conceptualframework, two majorproblems in perceptionto beaccounted for werethe Speaker Normalization problem and the Target Undershoot problem. Theoreticaldevelopments have taken two directions: ( 1 ) "Elaborated"target theories have been hypothesized whichaccount primarily for perceivers'solution of the SpeakerNormalization problem; (2) dynamicspecifi- cationmodels have been offered (a) to dealwith the TargetUndershoot problem and (b) to characterizethe perceptualsignificance of voweldiphthongization. Findings of perceptualstudies are summarizedthat moti- vatethese theoretical developments and a characterizationis offeredof vowelsas dynamic gestures giving rise to temporallydistributed acoustic information that perceiversutilize in identifyingcoarticulated vowels. [ Re- searchsupported by NINCDS. ]

1:30

G2. Auditory-perceptualinterpretation of the vowel.James D. Miller (Central Institutefor the Deaf, 8 lõ S. Euclid, St. Louis, MO 63110)

An accountof the simple.vowels of AmericanEnglish will be givenin termsof the author'sauditory- perceptualtheory. Data from manysources will be usedto illustrateand supportthis view.In additionto theoreticalsuggestions concerning an auditory-perceptual transformation and a segmentationrule, the pereep- tualizedspectral patterns associated with the nonretrofiex vowels will beshown to fall intoregions within a slab in a three-dimensional,aaditory-pereeptual space. These regions form a "vowelmap" that by simplerotations can be relatedto various"vowel charts" such as thoseof Jones,Pike, or Fant. While the presenttheory is an elaborationof traditionalformant-ratio theory, it will be shownthat a conceptof a perceptualreference is needednot only for talkernormalization but alsoto disambiguatevowels not distinguishedby simpleformant- ratio theory.Additionally, loci for the retroflexand nasalizedvowels illustrate the utility of describingvowel spectraby five numbers combined into three dimensions. SimpleF 1 by F2 descriptionsare not adequate except for enigmatophiles.[Work supportedby NINCDS and AFOSR.]

2:00

G3. Static, dynamic, and relational factors in vowel perception.Terranee M. Nearey (Department of Linguistics,University of Alberta, EdmontonT6G 2E7, Canada} This paperreviews theories and empiricalfindings that bearon the perceptionof Englishvowels, with emphasison thecomparison of data-analyticpattern recognition studies with resultsfrom speech perception experiments.Methodological approaches and empiricalresults from researchat the Universityof Alberta [e.g.,T. M. Neareyand P. F. Assmann,J. Acoust.SOc. Am. 80, 1297-1308(1986)] will be comparedand contrasted to work in other laboratories. Issues to be considered include: ( ! ) the role F 1 and F2 and that of fundamentalfrequency and higher formants; (2} "vowel-spaceand speakingrate normalization" (global speakercontext); (3) vowel-inherentspectral change (diphthongizatiun); and (4) localphonetic context (e.g., consonantalcontext). While all of the abovefactors have been shown to havereliable effects on vowel perception,the relativeweight of sucheffects and the circumstance•which may alter theseweights remain far fromclear. Analysis of theseproblems in currentresearch and suggestions for futurestudies will be presented.

S16 J. Acoust.Soc. Am. Suppl. 1, Vol.81, Spdng 1987 113thMeeting: Acoustical Society of America S16 ContributedPapers {Poster Session}

2:30-3:30 All posterswill bedisplayed from 2:30 to 3:30p.m. To allowall contributorsan opportunityto seeother posters,contributors of odd-numberedpapers will beat theirposters from 2:30-3:00 p.m. and contributors of even-numberedpapers will beat theirposters from 3:00-3:30 p.m.

G4. Front vowel perception in fluent speech. Larry H. Small AmericanEnglish producing the nine pure vowels of Englishin isolation (Department of CommunicationDisorders, Bowling Green State andin SOhorantcontext. The recordingswere digitized at 20 000 Hz with University,Bowling Green, OH 43403) 14-bitprecision and analyzed using ILS. The formantand fundamental frequencyinformation was extracted from the ILS analysisfiles. The data This studyinvestigated the perceptualeffects of misarticulatingthe arenow in the processof beingsmoothed in the log-frequencydomain and Englishfront vowels/iJ,e,•,•e/located in two-syllabletarget words. Sub- arebeing transformed into pathsin the three-dimensionalauditory per- jectswere instructed to shadowa tapedprose passage containing the mis- ceptualspace. By examiningnot only the pure vowels but also vowels in articulatedtarget words. All misarticulationsoccurred along the height sohorantcontext, the aim is to establishthe coarticulatoryeffects on rela- dimension,in referenceto the traditionalvowel quadrilateral.Also, all tivespectral prominence positions of precedingand following [1] and misarticulationsinvolved the stressedvowel of eachtwo-syllable target [ w ]. [ Work supportedby NINCDS andAFOSR. ] word. The subjectstended to repeatwords containing the vowel misar- ticulationsas heardon the tape, insteadof restoringthe target wordsto their originalform, indicatingthat the articulatorychanges were notice- ableto the subjects.If the changeswere not noticeable,a greaternumber of restorationresponses would have occurred. Subjects appeared to rely moreon the acoustic-phoneticproperties of the misarticulatedvowels G7. Judgments of coarticulated vowels are based on dynamic than on the contextualconstraints of the passage.Since vowels are more information. DavidR. Williams (HaskinsLaboratories, NewHaven, CT intenseand greater in durationthan consonants, it is possiblethat listen- 06511-6695) ers utilized stressedvowel informationas a perceptualanchor during wordrecognition. That is,stressed vowel information may guide a listener Due to coarticulation,formant frequencies for vowelssuch as [ u ] and duringword recognition. [Work supportedby theAxe-Houghton Foun- [t] are lower betweenlabial consonantsthan in isolatedproductions. dation, New York. ] When askedto categorizestimuli from three-formant or analogousthree- tone[u]-[l] and [wuw]-[wlw] continuamatched on formantmidpoint frequencies,listeners place their category boundaries closer to [tJ] forthe [w w ] stimuli.However, listeners asked tojudge the relativepitch height of the samethree-tone stimuli do not showa shiftin categoryboundary locations[Williams et aL,J. Acoust.Soc. Am. Suppl.1 74, S66 (1983) ]. GS. The influenceof extraneouscomponents on vowel FI estimation. To determinewhether or not thislack of a shiftresulted because midpoint Brian Robertsand Brian C. J. Moore (Departmentof Experimental frequenciesof the [w_w] stimuliwere isolatedperceptually, subjects Psychology,University of Cambridge, Downing Street, Cambridge judgedeither vowel class or pitchheight of thesame stimuli with reference CB2 3EB, England) to isolated[ u ] and [ 1]. While vowelcategorization results were similar to thoseobserved previously, pitch heightboundaries now exhibited a shift The contributionof extraneouscomponents to vowelF 1 estimation oppositeto that for the voweljudgments. Thus listenersapparently inte- wasinvestigated by constructinga continuumperceived as changing from grated acrossmost (or all) of the duration of the [w w] stimuli when /I/to/e/as F I wasvaried. The phonemeboundary location is a measure judging their pitch. Thesefindings indicate that auditorymechanisms of theperceived F i, andhence of theinfluence of theextraneous compo- whichisolate and interactivelyprocess successive time-varying and more nent. Adding an extraneouscomponent whose frequency is an integral stableregions of the speechsignal cannot account for the perceptionof multipleofF0/2 givesa complexconsisting only of components harmoni- coarticulatedvowels. IWork supportedby NICHD Grant HD-01994.] cally relatedto FO/2. This componentmay therebybe incorporatedby actingas a "falseharmonic." Adding a falseharmonic on the lowerskirt of F !, at a levelabove the vowelspectral envelope, shifts the phoneme boundaryupwards. However, adding a componentat anyother frequency in thisregion has a similareffect. The effectof furtheradding several false harmonicsremote in frequencyfrom FI, at levelsequal to the spectral envelopeof the vowel,is currentlybeing investigated. Preliminary results suggestthat addingthese components increases the incorporationof the GS. Perceptual dimensionsof alaryngeal vowels.Michael D. Trudeau componentadded in theF 1 region,but onlyif that componentfrequency and Robert Allen Fox (Speech& Hearing Science,The Ohio State is an integralmultiple of F0/2. [Work supportedby the SERC and the University,324 Derby Hall, Columbus,OH 43210-1372) MRC, U.K.] The presentstudy uses multidimensional scaling to examinethe per- ceptualdimensions underlying the perceptionof alaryngealvowels and comparesthese dimensions with thosecommonly found in MDS studies utilizing normally voicedvowels. A set of 11 vowels([ ile•eanoutJu•] producedby a competentesophageal speaker represented the stimulus vowels.These vowels were compared (pairwise) on a nine-pointsimilar- G6. Measurements of vowels in isolation and in sonorant context. ity/dissimilarityscale by 20 listenersand the resulting perceptual distance Marlos Fourakis and JamesD. Miller (Central Institute for the Deaf, datawere analyzed using INDSCAL. Threeperceptual dimensions were 818 S. Euclid, St. Louis, MO 63110) obtained( significantlycorrelated with F 2, F 1-F0, andF 3, respectively), which accounted for 67% of the variance. These dimensions are similar to In Miller'sauditory-perceptual theory vowels are hypothesizedto oc- thoseobtained in studiesusing normally voicedvowels and suggestthat cupy nonoverlappingzones in a three-dimensionalspace defined by the alaryngealvoice quality doesnot disruptthe useof thesecommon percep- relativepositions of the first threespectral prominences of the short-term tual dimensions(which dependonly upon vocal tract configurations}. spectrumand by a referencerelated to the speaker'scharacteristics. In The natureof theseperceptual dimensions will be discussedin termsof order to validatetarget zonesdrawn on the basisof the data availablein ß both acoustic(i.e., formants) and auditory (i.e., bark-transformedfor- the literature, we have recordedtwo male and two female speakersof mants) measures.

S17 J. Acoust.Soc. Am. Suppl. 1, Vol. 81, Spring 1987 113th Meeting:Acoustical Society of America S17 G9. The perceptionof reducedvowel stimuli. Laurie F. Garrisonand GI2. Why ls th• formant frequencydifference Hmen asymmetric? ]amesR. Sawuseh(Department of Psychology,Park Hell, $UNY at Hynek Hermansky(Speech Technology Laboratory, 3888 StateStreet, Buffalo, Amherst, NY 14260) Santa Barbara, CA 93105)

Most theoriesof vowelrecognition employ the firsttwo spectralpeaks Flanagan[I. Aconst.So<:. Am. 27, 613-617(1955)] observedasym- (F 1 andF2) or sometransform of theseas perceptual dimensions for the metriesin formantfrequency difference limen in the perceptionof some vowelspace. This experimentwas designed to investigatehow humans synthesizedvowel-like sounds and attributedthose asymmetries to the categorizevowels that do not containthe usualF0, F 1, andF2. Subjects proximityof neighboringformants. This hypothesisabout the originof werepresented with singleformant vowels (270-2938 Hz; F0 of 125or theasymmetries in theperception of differences in vowelformant position 215 Hz) andasked to identifythem using 12 vowellabels. The data show is tangibleand is widelyaccepted. The perceptualexperiments of Her- high-frequencystimuli were identified as front vowelsand low frequen- manskyand Jaykin [J. Aconst.Soc. Am. Suppl. I 80, S18 (1986)] cieswere identifiedas back vowels.The [i] categorywas used for both showedthat the asymmetriesin formantfrequency difference !imen can extremehigh and low frequencies.The tensevowel labels [u], [o], [a], bereversed by smallchanges in fundamentalfrequency in theexperiment. and [ i ] predominated.A secondset of stimulicons/sting of toneanalog to Thisobservation questions the contribution of neighboringformants as a FI and F2 (no F0) was presentedto subjectsfor identification.These factorin theperception ofsmall differences informant position. Results of stimuliwere also consistearly categorized. As with the singleformant experimentsin the perception of syntheticvowel-like sounds will be pre- stimuli,subjects used the tensevowel labels most often. Resultswill be sented.They suggest that the formant distribution was not a majorfactor discussedwith referenceto modelsand the natureof prototypesin vowel contributingto perceptualasymmetries in Flanagan's experiment. The recognition.[Work supportedby NINCDS.] roleof formantstructure in vowelperception isdiscussed.

GI0. A comparison of two models of human vowel recognition. D. GI3. Perceptual learning of vowels in a neuromorphicsystem. Todd Lauren Dutton, James R. Sawusch, and Kam-CheongTsoi M. Morin and Howard C. Nnsbaum (Department of Behavioral (Departmentof Psychology,Park Hall, SUNY at Buffalo,Buffalo, NY Sciences,The University of Chicago, 5848 S. University Avenue, 14260) Chicago, IL 60637)

Two modelsof humanvowel recognitionwere simulatedand their Linear nenromorphicsystems assume that stimuliare perceivedas performancescompared. The firstwas proposed by Syrdaland Gopal [J. linear combinationsof a set of underlyingfeatures represented as the Acoust.SOc. Am. 79, 1086-1100(1986) ] andmodified for implementa- eigenvectorsof the stimulusspace. Learning in this type of systemis an tion.Five dimensions composed of criticalband differences between spec- autoassociativeprocess that induces prototypes for eachperceptual cate- tralpeaks (including F0) were•:omputed foreach input stimulus. Identi- gory.Anderson et al. [ Psychol.Rev. 84, 413-451 (1977) ] proposedthat ficationwas based on the bestmatch of the input to a setof prototypes. humanlisteners learn vowel categories through just this type of computa- The secondwas a full octavefiltering model simulating central auditory tional mechanism.To investigatethis claim, a linear autoassociating processing.Parallel filters combined all spectralpeaks within three erifi- networkwas trained on a setof prototypicalAmerican-Enghsh vowels. cal bandsinto a singlepeak. The matchbetween each stimulus and the Performanceof thisnetwork was examined for learningand classifying prototypeswas then used as the basisfor categorization.The prototypes vowelsproduced by an averagemale talker. In addition,the effectsof usedin eachmodel were based on Petersonand Barney[J. Acoust.SOc. differentauditory coding representations were compared on recognition Am. 24, 175-184'(1952)]. The performanceof the two modelsin identi- performancefor the malevowels. Since it is necessaryfor the underlying fyingvowels will bedescribed. In addition,performance of themodels was featurespace to be linearlyindependent, the perceptualrepresentation of comparedto data of humansubjects for toneanalogs of voweland single the vowelscan affectlearning. Furthermore, the extentto whichthe un- formantvowels. Relative strengths and weaknesses of the two modehwill derlyingfeature space learned from a set of vowelsis sharedbetween be discussed.[Work supportedby NINCDS.] talkersis investigated.For thistype of networkto bea plausiblemodel of vowel perception,it must be capableof perceptualconstancy across talkers.Finally, the effectsof differentlearning algorithms on the devel- opmentof vowelcategories in perceptualspace were compared. The re- suitsof thesestudies and their implicationsfor simple,linear network modelsof speechperception are discussed.

GII. Vowel identification:Are formants really necessary?Amir J. Jagharghiand StephenA. Zahorian(Department of Electricaland ComputerEngineering, Old DominionUniversity, Norfolk, VA 23508)

It hasgenerally been assumed at !es.stsince the time of thecomprehen- GI4. Identification of "hybrid"vowels in sentencecontext. James sive studyby Petersonand Barney [J. Aconst.SOc. Am. 24, 175-184 L Jenkins and WinfiredStrange (Departmentof Psychology, (1952)] thatthe formant locations in vowelspectra are the most signifi- Universityof SouthFlorida, Tampa, FL 33620) cantcues to vowelidentity. In thisexperiment vowel spectra were repre- sentedby two methods:(A) by the locationsof the firstthree formants, It hasbeen demonstrated that listeners can identify the intended vowel and (B) by the overallsmoothed spectral shape in termsof a discrete in n CVC syllableeven when the vowelnucleus has beenattenuated to cosinetransform of thepower spectra. Stimuli consisted of fourrepeti- silence,leaving only unglides and offglides (Silent-Center syllables ). Ver- tionsof thewidely separated vowels/u/,/i/,/a/, spokenby eachof 12 bruggeand Rakerd [ Lang.Speech 29, 39-57(1986)] constructed"hy- female and 12 male apeaker• (4.24,3 = :288stimuli total). For eagh of brld" Silcnt-C•ntersyllables by cross-splicingonglides and offglidesof thetwo spectral encoding methods, A andB, thevowel data were project- citation-formCVC syllablesspoken by a maleand a femaletalker such ed to a three-dimensionalspace such that the vowelcategories would be that the formant trajectorieswere discontinuous.Identification of the well separatedand the vowelswithin each category wall clusteredIS. A. intendedvowel in hybridsyllables was no lessaccurate than vowel identi- Zahorianand A. J. Jagharghi,J. Acoust.Soc. Am. SuppLI 79, S8 ficatiooof the single-talkerSilent-Center syllables. The presentstudy (1986) ]. Significantlybetter clustering was obtainedwith methodB, replicatesthis research with syllables spoken in a eartiersentence "I say basedon overallspectral shape, than for methodA, basedonly on the first theword/dVd/somemore," using ten American-English vowels. Hybrid threeformant frequencies. Since these results are not basedon perceptual Silent-Centerstimuli were prepared by crossing the stimulus sentences so experiments,no direct conclusion can be drawn regarding the perceptual that the sentencestarted with one talker and switchedto the other talker importanceof spectralpeaks versus overall spectral shape for humanper- afterthe silentportion of the teststimulus. Silent-Center Control stimuli ceptionof vowels.However, the resultsdo indicatethat automaticma- werealso prepared for eachtalker. The findingssuggest that dynamic chineidentification of vowelscan be improvedby parameterizingthe syllablestructure provides talker-independent information about an ar- overallspectral shape rather than only the spectralpeaks. tieulatory/acousticevent. [Research supported by NINCDS.]

S18 J. Acoust.Soc. Am. Suppl. 1, VoL81, Spdng1987 113thMeeting: Acoustical Society of America $18 G15. Explorations in speaker normalization. John J. Ohala and ResearchLabs., Twin 21 MID Tower, 2-1-61 Shiromi,Higashi, Osaka, Yoko Hasegawa(Phonology Laboratory, Department of Linguistics, 540 Japan) Universityof California,Berkeley, CA 94720) Somepreliminary efforts are reported at speakernormalization based onthe assumption that listeners are tacitly aware (a) thatthey are listen- A mathematicalmodel of the targetprediction mechanism based on ing to an instrument(the humanvocal tract) whichwhen uniform ( un- psychologicalexperiments [Furui and Akagi, 12th ICA Toronto,A2-6 constricted)should have resonances whose lowest frequencies are spaced (July 1986}] is evaluated.In continuousspeech, spectral undershoot is accordingto theratios 1:3:5:7, etc., (b) thatthe exact frequencies of these producedby coarticulationand the speechspectrum seldom meets its resonancesdepend on the lengthof the vocaltract, and (c) that what is idealtarget. It isassumed for themodel that the undershoot iscompensat- relevant in resonancesfrom a nonuniform tract is the ratio of these lowest ed by a predictionmechanism in the auditorysystem, realizing the target resonancesto their uniformvalue. There are probablyseveral cues the spectrumas an internalrepresentation of speechspectrum. In thispaper, listenercould use to estimatethe sizeof the speaker;for starters,we use three viewpointsare discussedcomparing the resultsof the model with themean (long-term) F4. The referenceresonances for F 1,, F2,, F3,, thoseof psychologicalexperiments. { 1) The model compensatesfor a i.e.,those from the "uniform" tract, are 1/7, 3/7, and5/7, respectively,of transitionalpart of connectedJapanese vowels and decreases the lengthof meanF4. The normalizationconsists in convertingmeasured formant the transitionalpart that producesspurious vowel spectrum. (These spec- frequencies,F 1,,, etc.,into the ratiosof logF 1,•/log F 1,. The resultsof tra are actuallyunperceived under any speakingconditions. } (2) A per- applyingthis normalizationto the entirevoiced portion of vowelsin a ceptualcritical point, where the following vowel in JapaneseC-V syllable varietyof CVC syllablesis reported. [Work supportedby a Sloangrant to isinitially perceived, corresponds well with its physicallyestimated point BerkeleyCognitive Science Program. ] by the mod•l. (3) The modelis alsoapplicable for compensatingthe transitionalpart of consonantsin Japanesesyllables and achievesthe ex- tracti6nofstable acousticfeatures for consonants.The resultsindicate G16. Evaluation of a spectrum target prediction model in speech that the modelrecovers phoneme characteristics neutralized by the coar- perception.Masato Akagi (ATR Auditory and Visual Perception ticulationand corresponds well to thehuman hearing mechanism.

Invited Discussants

3:30

Peter Ladefoged PhoneticsLaboratory, Department of Linguistics,UCLA, LosAngeles, California 90024

3:45

Michael Studdeft-Kennedy HaskinsLaboratory, 270 CrownStreet, New Haven, Connecticut06510

Open Discussion

4:00-4:30

$19 J. Acoust.Soc. Am. Suppl.1, VoL81, Spdng1987 113th Meeting:Acoustical Society of America S19 TUESDAY AFTERNOON, 12 MAY 1987 MT. McKINLEY, 1:15TO 4:50 P.M.

SessionH. Underwater AcousticsII: Scattering

JacquesR. Chamuel,Chairman Sonoquest/,4dvancedUltrasonics Research, P.O. Box 153, WellesleyHills, Massachusetts02181

Chairman's Introducfion--l:15

ContributedPapers

1:20 gy in a patternthat closely resembles radiation from an acousticdipole. Likewise,the reradiationfrom a leadwhose separation is smallcompared H1. High-frequencyreflection and scatteringof soundby ellipsoidally to a wavelengthcan resemble radiation from a quadrupole.The reason for embossedsurfaces. R. J. Lucas=! and V. Twersky (Mathematics thisbehavior, and its significance in thetotal low-frequency scatter from Department,University of Illinois,Chicago, IL 60680) theArctic canopy, is discussed in termsof wedgetheory and the laborato- Earlier resultsfor coherentreflection and incoherentscattering by ry scalemodel experiments, which confirm this interpretation.[Work randomdistributions of relativelyarbitrary bosseson rigid or free base supportedby ONR. ] '• OceanAcoustics Associates, 4021 Sunridge Road, planes[V. Twersky,$. Acoust.SOC. Am. 29, 209-225 ( 1957);73, 85-94 Pebble Beach, CA 93953. (1983) ] are appliedto rigid and free ellipsoidalbosses with axeslarge comparedto wavelength.The asymptoticprocedures used originally for circularcylinders and spheres( 1957) and subsequentlyfor ellipticcylin- ders [$. E. Burke and V. Twersky, J. Acoust. Soc. Am. 40, 883-895 2:05 (1966) ] are generalizedto triaxial ellipsoids,and resultsfor the corre- H4. Dependenceof low-frequencybackscatter on the sizeand orientation spondingbosses are obtainedby the original imagemethod. Illustrative of lineal Arctic scatterers. Michael L Browne and Herman Medwin curvesexhibit the effectsof bossshape and orientationon the coherent (Physics Department, Naval PostgraduateSchool, Monterey, CA reflectioncoefficients and incoherentdifferential scattering cross sections 93943) per unit area. To facilitate comparisonwith availablelow-frequency curves,the sameisotropic and anisotropicsurfaces were consideredas The backscatterof low-frequencyunderwater sound from the Arctic before[R. J. Lucasand V. Twersky,J. Acoust.Soc. Am. 78, 1838-1850 icecanopy is generally caused by leads and ridges of a vastvariety of sizes, (1985)] and emphasizeanisotropic forward (specular) and back- orientations.and spacings.Laboratory scale-model experiments, guided scatteredeffects for applicationsto sea-air,sea-bottom, and sea-icepro- by the theoryof sounddiffraction from wedges,have been used to deter- grams.'• Visitingfrom Departmentof MathematicalSciences, Loyola minethe dependenceof low-frequencybackscatter on the geometrical University,Chicago, IL. parameters.The specific variation with the orientation and length of the lineal scattereris demonstrated,and it is shownthat the predominant scatteroccurs when there is a sectionof the leador ridgethat is azimuthal- ly perpendicularto thesound path. [Work supportedby ONR.]

•, Ray scattering from a collection of ice kcel•. David F. Gordon (Naval OceanSystems Center, Code 711, San Diego, CA 92152-5000) 2:20 An tee-keelprogram that was described at theSpring 1985 meeting [$. Acoust.Sac. Am. Suppl. I 77, S56 (1985)] is usedto investigatethe HS. The validity of the perturbationapproximation for rough surfaco acousticscattering properties of ice keelsat high frequency.Keels are scattering.Eric I. Thorsosand Darrell R. Jackson(Applied Physics modeledas parabolas.Same sets of keelsare generatedusing published Laboratory,College of Ocean and Fishery Sciences,University of distributionsof spacingand sizes [O. I. Diachok,J. Acoust.Soc. Am. 59, Washington,Seattle, WA 98195) 1110-1120(1976) ]. A largenumber of raysare directedtoward the keel The accuracyof the first- and second-orderperturbation theory ap- setand the emergingrays are collceted into angularbins. Reflections from proximationsfor randomlyrough, pressure-release surfaces has been ex- and refractionthrough the ice are employed.Specular reflection coeffi- aminedthrough comparison with exactnumerical results based on solv- cientscomputed in thismanner are similar to Diachok'spublished results ing an integralequation. A Gaussianroughness spectrum was chosen for above3 ø grazing angle. No significantspecular reflection is foundat lower the surfaces,and a MonteCarlo procedurewas used to obtainthe average grazingangles. The scatteredrays tend to be directedpredominantly into bistaticscattering cross section. Results will bepresented to showthat the anglesnear the specularangle. [Work supportedby NOSC Independent conditionh/A ( 1, whereh is the rms waveheightand ,• is the acoustic Research.] wavelength,is not sufficientto ensurethe accuracyof first-orderpertur- bation theory. An additional constraintmus! alsobe imposedon the sur- facecorrelation length. [Work supportedby ONR.]

1:$o 2:35 H3. Quasldipole and quasiquadrupolescattering from Arc•• leads. HermanMedwin and Ken $. Reitzel'J (PhysicsDepartment, Naval H6. First-orderthree-dimensional scattering from roughinterfaces and PostgraduateSchool, Monterey, CA 93943) the effects of shadowing. local reflection coefficients, and surface gradient terms. Richard Keiffer and M. F. Werby (Numerical The leadingand trailing edges of a planeice plate and the perimeterof Modeling Division, NORDA, NSTL, MS 39529) a polynyarepresent arrangements of wedgescatterers that aremirrored in the adjacent,pressure-release, water-air interface.As a result,an edge It is usualin the developmentof roughinterface models to limit theory that isexposed to low-frequencyunderwater sound will backscatterener- to two-dimensionalmodels or to ignoreshadowing and penetrationinto

S20 J. Acoust.Soc. Am. Suppl.1, VoL 81, Spring1987 113th Meeting:Acoustical Society of America S20 thesurface as well as surface gradient terms that arise in theformal deriva- of a 3-mvertical by 150-mhorizontal rectangle oriented transverse to the tionof theequations. The secood-order term has recently been examined raypath.Extensive oceanographic measurements are availableto charac- todetermine its importance in scattering from rough interfaces. The pur- terizethe deterministic and stochastic sound velocity field of thescatter- poseofthis study is to examine the effects of (a} shadowing,(b) penetra- ingvolume. The scattering parameters yand.Yrangeover 145-31 500and tion, and (el surfacegradient terms on the overallcalculation of some 0.094-0.016,respectively. Earlier publications focused on a 6-dayintensi- representativesurfaces. Moreover, a full three-dimensionalmodel can tytime series. The newly processed data extend the time series to 15days allowfor out-of-planescatter, and thiseffect will alsobe examined. The andprovide 8 daysof datameasured simultaneously at the horizontally methodof treatmentof penetrationinto the surface is via a localreflection separatedreceivers. These measurements of the complex field, together coefficient.Preliminary results show that the majority of theseeffects are withthe space/time sound velocity measurements, provide a unique data mostimportant in backscatter,where they tend to enhance the magnitude setwith whichto testpredictions of the variousacoustic field moments. relative to the forward direction. Resultswill be presented for single receivers and vertically and horizon- tallyspaced pairs. Theoretical predictions, where available, will becom- pared.Implications of theresults to ourunderstanding of WPRM will be discussed.[Work supportedby ONR.] 2:50

H7. Numerical investigationsof rough surface scattering.David H. Berman and Iohn S. Perkins (Code 5160, Naval Research Laboratory,Washington, DC 20375) 3:35

An improvedpoint matchingmethod [H. lkuno and K. Yasuura, HI0. Geometrical theory of diffraction for high-frequency coherence Trans.IEEE AntennaPropagat. AP-21, 657-662 ( 1973)] is usedto cal- functionsin a weakly random mediumwith inhomogeneousbackground culatesurface scattering amplitudes for periodicirregular interfaces. Re- profile. R. Mazar and L. B. Felsen (Department of Electrical sultsof thismethod can be examined both for energyconservation and Engineering and Computer Science, Polytechnic University, least-squaresatisfaction ofboundary conditions. Because ofthe speed of Farmingdale,NY 11735) this algorithmand simplicityof programming,it hasbeen possible to examinefluid-fluid interface scattering in two dimensions,for grazing The localizationof high-frequencywave propagation around ray tra- anglesas low as 5 deg,and Dirichlet scattering for simpletwo-dimension- jectoriesand the reflection,refraction, and/or diffractionof theselocal al surfaces.Large-period surfaces with arbitrary structure within a period plane wave fieldsby boundaries,inhomogeneities, and/or scattering havebeen used to mimicrandom rough interfaces. Reasonable averaged centershave beencombined via the geometricaltheory of diffraction scatteringcross sections for therandom rough surface problem have been (GTD) intoone of the mosteffective means for analyzinghigh-frequency obtained,using ensembles of 10 or 20 surfacerealizations. When the wave phenomenain complex deterministicenvironments. These con- roughsurface is describedby a steeppower-law spectrum, ensemble aver- structsare here incorporated into a stochasticpropagation and diffraction agedcross sections may be dominatedby a singleensemble member, in theory for statisticalmoments of the high-frequencyfield in a weakly effectgiving a falsealarm. Doppler effects for movingsurfaces have also fluctuatingmedium with inhomogeneousbackground profile, provided been calculated. that the correlationlength I, of the fluctuationsis small,compared with the scaleof variation, but large, comparedwith the local wavelength A = 2rr/k = 2n'c/coin the fluctuation-freebackground, with k beingthe local wavenumber,c the local wavespeed, and to the radianfrequency. 3.'05 The majoranalytical building blocks for coherencefunctions and paired HS. Modelingthe generalpdf of intensityin termsof the scattering randomfunctions (PRF} includepropagators described in localcoordi- parametersfor WPRM. T. E. Ewart (AppliedPhysics Laboratory and natescentered on the curvedGTD ray trajectoriesin the deterministic Schoolof Oceanography,University of Washington,Seattle, WA 98105) inhomogeneousbackground environment; multiscale expansions in these coordinatesto solvefor statistical measures of theparabolically formulat- The intensitycorrelations for WPRM canbe predictedfor forward ed ray fields;Kirchhoffor physical optics (PO } approximationsfor fields scatterfrom solutions of theparabolic 4th moment when the space-time reflectedfrom extendedsmooth surfaces; and "pointscatterer" solutions autocorrelationfunction, the scatteringstength parameter y, and the for smallscatterers aud edges.The PRFs are usefulfor correlatinginci- scaledrange Xare known. Thus, the intensity variance and its time/depth dent and backwardfields traversing the samepropagation volume. The correlationscan be predicted.However, the intensitypdf hasnot been theoryis illustrated for forwardpropagation in a fluctuatingmedium with predictedfor all rangesof y andX. T. Ewart andD. Percival[J. Acoust. inhomogeneousand causticforming background, for reflectionsand re- Soc.Am. 80, 1745-17:53( 1986 ) ! haveshown that the generalized gamma fractiondue to a planeor smoothlycurved interface in sucha medium, distributionfunction (GODF) modelsthe probability distribution of in- andfor diffraction due to a wedgeand a smallscatterer. [Work supported tensityin forwardscattering over wide ranges in y andX. In thisstudy the by RADC and ONR. ] two parametersof theGGDF areobtained as functions of y andX by fittingthe distributionto manyrealizations of simulatedintensity data. Realizationsof theintensity were generated by Monte-Carlo techniques [C. Macaskilland T. Ewart,IMA $. Appl.Math. 33, 1-15 (1984)]. The mappingof thedistribution parameters to y andX providesa convenient 3:50 wayto examinethe behaviorof thedistributions as they vary smoothly fromlognormal to exponential with increasing X for constant values of),. HII. An approximationfor propagatingthe fourthmoment through a A heuristicmodel of themapping is presented.Implications and future fluctuatingocean. David H. Bermanand Dalcio K. Dacol (Code5160, expectationsare discussed.[Work supportedby ONR.] Naval ResearchLaboratory, Washington, DC 20375) In this paperan approximationfor fourth momentand secondmo- ment(two-frequency) path integrals is presented.The approximationis similarin spiritand form to anapproximation recently developed by Us- 3:20 cinskiet al. lB..L Uscinski,C. Macaskill,and M. Spivak,]. SoundVib. H9, Extendedtime and spaceresults from MATE. Terry E. Ewart and 106,509-528 (1986)]. However,the present approximation has the ad- S. A. Reynolds (Applied Physics Laboratory and School of vantagethat, for the cross-frequency intensity, it factorizesto productsof Oceanography,University of Washington,Seattle, WA 98105) thecross-frequency coherence for longranges when the latter is calculat- ed in the sameapproximation. In addition,it is easilydemonstrated that In the Mid-OceanAcoustic Transmission Experiment (MATE) thepresent approximation is thesecond of a sequenceof approximations pulsedtones and Taylor-weightedFM slidesat 2.083, 4.167, 8.333, and thatwill convergeto theexact path integral. The idea of theapproxima- 12.5kHz werereceived, after propagation over an 1g. 1 -km wholly refract- tionis to replacepaths appearing in phasestructure functions by "classi- edFennat path, at fourtower-mounted transducers located at thecorners cal"paths plus a numbertimes the Green's function for thespreading or

S21 J. Acoust.Soc. Am. Suppl. 1, VoL81, Spring1987 113thMeeting: Acoustical Society of America S21 Jacobiequation. The calculation then reduces to a phasescreen calcula- ciescan be predicted [B. L. Merchantet aL, J. Acoust.Soc. Am. 80, 1754 tion,with thecoefficient of theGreen's function appearing as the position (1986)] for prolatespheroidal objects, in the spec/alcase of axialincl- at whicha ray crossesthe screen. dence.Here sound-soft,prolate-spheroidal targets subject to obliquely incidentsignals are considered.The generatedsurface waves propagate alonggeodesics of helicoidaltype, for whichwe obtainthe condition for closing,and the set of discrete"pitch angles" at whichclosing takes place. 4,'O5 An integralcondition is formulatedfor the phasematching of helicoidal surfacewaves, using local wavelengthsof Franz'ssurface waves. It is H12. The influenceof channelboundaries on remotely sensedtarget solvednumerically for thecomplex resonance frequencies, found to agree resonances.G. C. Gaunaurd (Naval SurfaceWeapons Center, White closelywith them > 0 (i.e.,containing azimuthal components ) resonance Oak, R-43, Silver Sprins, MD 20903-5000) and M. McCarthy frequenciesobtained from an independentT-matrix calculation.This (National Universityof Ireland,Galway, Ireland) agreementconfirms the validity of theprinciple of phasematching for the Targetresonances are uniquecharacteristics of scatterersand serve to l•neral case,and the accuracyof the T-matrixresults. [Work supported identifythem unambiguously.In the vicinityof enironmental boundar- in partby theOffice of NavalResearch. l ies,the way resonancesare perceivedby sensorsis differentthan in the absenceof boundaries.Thus, eventhough the resonancesthemselves do not change.the way in whichthey manifest themselves in the scattering crosssection of scatterersas sensed at thereceiver, changes near an envir- onmentalboundary. A formalismis developed to studythis change and to 4:35 assessthe effectof boundariesupon the way elasticscatterers are excited into resonantvibration by incidentsound waves. This formalismreduces HI4. Blstatic resonantscattering from elasticspheroidal shells and the to an earlierone developed [ J. Acoust.Soc. Am. 73, 1- 12 (1983) ] for an resonanceorder. Michael F. Werby (NORDA, NSTL, MS 39529), infinitemedium lacking boundaries. In general,the effectof boundaries Herbert'0befall, and Anton Nagl {Departmentof Physics,Catholic onthe resonance features present in thesonar cross section depends on the Universityof America,Washington, DC 20064) azimuthalwavenumber m, evenfor sphericalscatterers. It alsodepends Bistaficscattering at a resonancefrequency can determine the order of on thedepths H andh of theelastic scatterer and the receiver,beneath the theresonance, as demonstrated experimentally [ G. Maze andJ. Ripache, freesurface z = 0 of the half-space.The boundary'sinfluence is greatest J. Acoust.Soc. Am. 73, 41 {1983}] and theoretically[M. F. Werby and for m = 0, or Hg 1, or both. The method relies on addition and transla- H. 0berall,I. Acoust.Soc. Am., in press]for elastic bodies of separable tion theorems for various wavefunctions. geometry( cylinders, spheres ). For obstaclesof moregeneral shape, mode mixingtakes place, but it wasfound (e.g., for solidprolate spheroids) [H. 'tiberall,M. F. Werby,S. H. Brown,and J. W. Dickey,J. Acoust.Soc. 4:•0 Am. Suppl.I 80, S128(1986)] that, for moderateaspect ratios (up to H 13. Resonancefrequencies and the phasematching of helicoidalsurface 3:1}, onemode remains dominant in thebistatie pattern, and may serve to waveson impenetrablespheroids. Barbara L. Merchant,Anton Nagl, characterizethe resonance,even while a crossingof Rayleigh and andHerbert (•oerall (Department of Physics, Catholic University of WhisperingGallery resonancestakes place. This methodis applied to the America,Washington, DC 20064) resonancesof sphericaland spheroidalshells, characterized by low-fre- quencyresonances related to the plateLamb-wave modes. Our applica- The existenceof the (complex)resonance frequencies of acousticscat- tion of the bistaticmethod confirms these relations, showing again that terersis explainedby the generationof surfacewaves that matchphases mode-orderassignments remain valid for moderatespheroids' eccentric- after repeatedcircumnavigations of the objects.The resonancefrequen- ities. [Work supportedin part by the ONR.]

S22 J. Acoust.Soc. Am. Suppl. 1, Vol.81, Spring1987 113thMeeting: Acoustical Society of America S22 TUESDAY AFTERNOON, 12 MAY 1987 MT. RAINIER, 1:30TO 4:15 P.M.

SessionI. Noise II: Evaluationof Hearing ConservationPrograms

Larry H. Royster,Chairman Departmentof Mechanicaland AerospaceEngineering, North CarolinaState University, Raleigh, North Carolina 27695-7910

Invited Papers

1:30

11. Audiomelrie data base analysis IADBA): Opening comments.Larry H. Royster (Department of Mechanicaland Aerospace Engineering, North CarolinaState University, Raleigh, NC 27695-7910)and Julia Doswell Royster (EnvironmentalNoise Consultants, Inc., P.O. Box 144, Cary, NC 27511-0144) The primarygoal of audiometricdata baseanalysis (ADBA) proceduresis the determinationof the effectivenessof an existinghearing conservation program in termsof the program'sability to preventsignifi- canton-the-job noise induced hearing loss. To be ableto achievethis goal in the real world,it is necessarythat one or more reliableindicators be definedthat can be implementedpractically within the managementand personnelframework of existingindustrial hearing conservation programs. The paperpresents some history- relatedinformation regarding past effortsin developingADBA proceduresand the effortsof the $12.12 WorkingGroup ( Evaluationof HearingConservation Programs), and the objectives for thisspecial session on ADBA procedures.Some considerations for therequirements of an ADBA procedureto beuseful in indicating the levelof effectivenessof a hearingconservation program will be reviewed,as well as factorsthat havebeen shownor are assumedto significantlyinfluence audiometric data and therebyaffect the outcomeof applying differentADBA procedures.

1:45

I2. The need for and benefits of audiometric data base analysis procedures,Alice H. Suter (Industrial Audiology,1501 Red Oak Drive, SilverSpring, MD 20910} Somenoise-exposed employees are losing their hearing despite the implementation of hearingconservation programs{ HCPs}. Employersdo notknow how to evaluateHCP effectiveness,and audiograms arc often filed away after testing.Employers lack guidancefrom professionals.They also lack regulatoryguidance, since OSHA'shearing conservation amendment has no provisionsfor evaluatingHCP effectiveness.Compounding theconfusion is OSHA's policynot to issuecitations for averagenoise exposure levels between 90 and 100dBA when"the resultsof audiometrictesting indicale that any existingcontrols and hearingprotectors are ade- quatelyprotecting employees." OSHA givesno guidance,however, as to the assessmentof adequateprotec- tion. Audiometricdata baseanalysis (ADBA} procedurescan yield valuableinformation on HCP effective- hess.They encourageaccountability by management,consultants, employees, and complianceofficers. They providefeedback to supervisors,motivating them to promoteand enforcegood HCPs in their departments. They providefeedback to employees,which can changeor reinforcetheir behavior,as appropriate,toward hearingprotector use. ADBA proceduresprovide the meansfor identifyingand the stimulusfor improving poorHCPs, and they provide a sourceof satisfactionand potentialreward for effectiveones.

2:15

13. Predictinghearing loss for noise-exposedpopulations using ISO 1999. Daniel L. Johnson(Larson-Davis Laboratories,280 South Main, PleasantGrove, UT 84062)

The InternationalOrganization for Standardization(ISO) ispublishing a standard,commonly called ISO 1999,entitled "Acoustics--Determination of occupationalnoise exposure and estimationof noise-induced hearingimpairment." The predictive procedures of this standard will be discussed. Three different nonoccupa- tionalnoise-exposed data bases will beused to illustratethe relation between noise exposure, aging, and the screeningprocedures used in selectingthe nonoccupational noise-exposed data base. The authorwill provide backgroundfor limitingthe resulting hearing th•shold level associated with both age and noise (H') to less than the simpleaddition of age (H) and noise-inducedpermanent threshold shift (N) by the equation tt' = H + N- HN/120. Finally,a procedurefor usingISO 1999to predictthe effectsof changingnoise exposures(such as workers exposed to 95 dB for 10 years,then 85 dB for 30 years)will be presented.

S23 J. Acoust.Soc. Am. Suppl. 1, Vol.81. Spring1987 113thMeeting: Acoustical Society of Amedca S23 2:45

I4. PredictingTI'S for a noise-exposedpopulation. W. Dixon Ward (Universityof Minnesota,Department of CommunicationDisorders and Otolaryngology, 2630 University Avenue SE, Minneapolis, MN 55414) Onesource of test-retestvariability in serialaudiomerry isthe temporary threshold shift (TTS) causedby priorexposure to sound above 75 dB SPL. In industrialaudiomerry, TTS isalways convolved with the effects of othersources of variability,such as earphone placement, headband tension, instrument calibration, internal physiologicalnoise level, listener criterion, "learning," etc., as well as with the "true" permanent change in hearingthreshold level that is generally the only statistic of interest. However, enough is known about TTS that relativelyvalid prediction can be made of themean and standard deviation of theTTS to beexpected at test frequency.4in an ear with a pre-exposurehearing threshold level orb dB,measured C minutes after exposure toa noisehaving spectral characteristics D, level E, durationZ', and temporal pattern G. Two propositions will beexamined: ( 1 ) thatthis knowledge can be utilized in order to "correct"group audiometric data for TTS, i.e., thatTTS can be deconvoluted from the total variance, and (2) thatadequacy of useof hearingprotection devicescan be assessedby meansof TTS.

3:15

IS. Resultsfrom applyingvarious audiometric data baseanalysis procedures to data providedto the ANSI S12.12Working Group. Julia Doswell Royster(Environmental Noise Consultants, P.O. Box 144,Cary, NC 27511-0144)andLarryH. Royster(Department ofMechanical and Aerospace Engineering, North Carolina StateUniversity, Raleigh, NC 27695-7910) The ANSI S12.12 Working Group hasreceived over 20 audiometricdata basescontributed by U.S. and Canadianindustries from their hearing conservation programs (HCPs). The datainclude at leastfour approxi- matelyannual audiograms for about12 000 male employees and at leasteight audiograms for about 3000 male employees.The authorsapplied various analyses to thedata to identifystatistics which differentiate the level of protectivenessof the HCPs represented.Some statistics are based on variabilityin the audiometricthresholds (percentagesof employeesshowing defined hearing changes either for betteror for worse).Other statisticsare basedon the rates of changein groupmean audiometric thresholds over time, compared to expectedage-effect changesfor nonindustrialreference populations. Desirable ranges for the statisticsare suggestedbased on determiningthe resultsfor non-noise-exposedand low-noise-exposed populations.

3:45-4:15'

Panel Discussion

S24 J.Acoust. Soc. Am. Suppl. 1, Vol. 81, Spring 1987 113thMeeting: Acoustical Society of America S24 TUESDAY AFTERNOON, 12 MAY 1987 REGENCY BALLROOM D, 1:30TO 4:15P.M.

SessionJ. PhysicalAcoustics II: Nonlinear,Loss and BubblePhenomena

Mack A. Breazeale Chairman Departmentof Physics,Unioersity of Tennessee,Knoxville, Tennessee 37996

ContributedPapers

1:30 seriesexpansion of thesound pressure to reducethe KZK equationto a set of coupledparabolic equations. The basicalgorithm has been modified by Jl. Third-order effect• in the propagationof finite amplitude stress introducinga coordinatesystem that followsthe convergent geometry of waves.Kun-tien Shu and Jerry H. Ginsberg (School of Mechanical focusedsound fields. In this way, more efficientnumerical evaluation of Engineering,Georgia Institute of Technology,Atlanta, GA 30332) the detailedfield structurewithin the focalregion is achieved.Arbitrary The propagationera finiteamplitude stress wave through a homogen- axisymmetricsources can be modeled.Here, circular sources having lin- eous,isotropic elastic solid is analyzed for cases of one-dimensionaldilata- ear focusinggains of order 50 will be considered.The calculatedtime tion and sheardeformation. The strainenergy function is expandedin waveforms,propagation curves, and beam patternsillustrate clearly the invariantform as a fourth-orderpolynomial in displacementgradients. combinedeffects of nonlincarity,diffraction, and absorption on finiteam- The displacementequations of nonlineardynamic elasticity are solved by plitudesound that passesthrough a focalregion. Among the newresults perturbationtechniques that yielda uniformlyvalid approximation. The are powercurves that showthe exchangeof energybetween harmonies resultfor a dilatationalwave, which matchesprevious predictions, is es- and beampatterns that showthe locationof nonlinearlygenerated side- sentiallylike a planarwave in a fluid,aside from redefinition of thecoeffi- lobesin the focalplane. [Work supportedby ONR. i cientof nonlinearity.The primarynonlinear effect for a dilatationalwave is encounteredat the secondorder. In contrast,the shearwave case, which wasnot fully analyzedin previousinvestigations, has no analog in inviscid 2:15 fluids.The first-ordershear displacement leads to a second-orderdilata- tiehaldisplacement, which then influences the sheardisplacement at the J4. Finite amplitude acoustic waves generated by a baffled, third order. The overall effectof nonlinearityis to produceamplitude multiharmonic transducer. James B. Edgerton, Jr. and Jerry dispersion,as well as a smallphase shift in thewaveform. [Work support- H. Ginsberg(School of MechanicalEngineering, Georgia Institute of ed by the NSF.] Technology,Atlanta, GA 30332) Arbitrary periodicexcitation of a baffledpiston transducer leads to harmonicand intermodulationdistortion when finite amplitudeeffects are considered.An analysisof the radiationsignal in sucha situationis initiatedby representingthe linearizedsignal as a sumof King integrals J2. Diffraction and nonlinear distortion in soundbeams as interacting associatedwith each harmonic in theexcitation. A nonuniformlyaccurate wavephenomena. J. H. Ginsberg,H.C. Miao, andM.A. Foda (School expressionfor the velocitypotential is derivedusing a singularperturba- of MechanicalEngineering, Georgia Institute of Technology,Atlanta, tion procedurethat identifiesthe dominanttendency of nonlinearityto GA 30332) generatesecond-order interactions. This form is obtained from an asymp- Discrepanciesbetween the nonlinear King integral[ J. H. Ginsberg,J. toticintegration, which leads to spectraldecomposition of the signalinto Acoust.See. Am. 76, 1201-1214(1984) ] for a soundbeam and experi- groupsof quasi-one-dimensionalwaves. The renormalizationversion of ment are encounteredin the nearfieldin high-frequency,high-intensity the methodof strainedcoordinates is usedto obtain a uniformly accurate situations.It is shownthat the nonlinear,as well as linear, signalat all expressionfor the acousticpressure at all locationspreceding the forma- locationsmay be representedas groups of quasiconicalwaves converging tion era shock.[Work supportedby the ONR, Code 1125-UA.] and divergingon the axis,as they propagateaway from the transducer. Nonlinear distortion to the nearfield arises from interaction of different transversewavenumber modes in eachgroup, and alsofrom interaction betweenthe groups. The lattereffect ceases to besignificant in thefarfield, 2:30 whereasthe self-distortionarising in eithergroup grows. The nonlinear King integralis shown to bethe limiting form for longranges. The results J5. Temperaturedependence of the ultrasonicnonlinearity parameters of for nearfieldlocations are extremelychallenging to evaluate,and an ap- NaCi. Wenhwa Jiang, M. A. Breazeale (Department of Physics, proximationthat can be usedto evaluatewaveforms in somesituations is University of Tennessee,Knoxville, TN 37996), and Ali Kashkooli discussed.[ Work supportedby the ONR, Code 1125-UA.] (Departmentof Physics,Appalachian State University,Boone, NC 28608)

The ultrasonicharmonic generationtechnique using a capacitivede- teeturhas been used to measurethe ultrasonicnonlinearity parameters of 2:00 sodiumchloride single crystals between 300 and 77 K. SinceNaCl is a J3. Nonlinear effects in focused sound fields. Timothy $. Hart typicalionic crystal, its ordinaryelastic constants have been of interestto (Departmentof Electricaland Computer Engineering, The Universityof many physicists.Likewise, its nonlinearproperties, its third-orderelastic Texas at Austin, Austin, TX 78712-1063) and Mark F. Hamilton constants,and their temperaturedependence have been of interestto sol- (Departmentof MechanicalEngineering, The Universityof Texasat id-statetheory. However, to date the largethermal expansion coefficient Austin, Austin, TX 78712-1063) andthe fragilityof NaCI havethwarted measurement of the temperature dependence of its nonlinearity parameters. Differential e•pansion Focusedfinite amplitude sound fields are investigatedwith numerical betweenNaCI and a bondedquartz transducer often has resulted in sam- solutionsof the Khokhlov-Zabolotskaya-Kuznetsov(KZK) equation. plecleavage. A specialtechnique for bondingthe quartz transducer to the The numericalsolution is based on thealgorithm developed by Aanonsen NaCI samplehas been developed. With the aid of thistechnique, ultra- et al. [J. Acoust. Sec. Am. 75, 749-768 (1984)], who useda Fourier sonicnonlinearity parameters of threedifferent oriented samples of NaCI

S25 J. Acoust.Sec. Am. Suppl. 1, VoL81, Spring1987 113thMeeting: Acoustical Sociely of America S25 havebeen measured for the firsttime in the temperatureranges of 300 to surfaceroughness, will causenegligible attenuation. [Work sponsoredby 77 K for the ( 100} sample,300 to 100K for the (110) sample,and 300 to the Air Force Wright AeronauticalLaboratories/Materials Laboratory 110 K for the ( 111) sample.The TOE constantC. and two combina- underContract No. W-7405-ENG-82 with Iowa StateUniversity. ] tionsof theother TOE constantsand their temperature dependence have beenobtained. The resultsare comparedwith theorydescribing inter- atomicforces in alkalihalide crystals. {Research supported in partby the ONR and the UT-ORNL ScienceAlliance. ] 3:30 J9. Effects of fiber motionon the acousticalbehavior of an anisotropic, flexible fibrous material. Milo D. Dahl, Edward J. Rice, and Donald E. Groesbeck(National Aeronauticsand SpaceAdministration, Lewis Research Center, Cleveland, OH 44135) 2:45 The acousticbehavior of a flexiblefibrous material was studied experi- J6. Dissipativestructure of shockwaves in fluidshaving large specific mentally.The materialconsisted of cylindricailyshaped fibers arranged heat.M.S. Cramer(Department of EngineeringScience and Mechanics, in a battingwith the fibersprimarily aligned parallel to the faceof the Virginia PolytechnicInstitute and State University,Blacksburg, VA batting.This typeof materialwas considered anisotropic with the propa- 24061 ) gationconstant depending on whether the direction of soundpropagation Recentstudies indicate that the nonlinearityparameter I -F B/2.4 wasparallel or normalto thefiber arrangement. Normal incidence sound maybecome negative in fluidswhose specific heats are sufficiently large. absorptionmeasurements were taken over the frequencyrange of 140- The presentstudy examines the dissipative structure of weakshocks in 1500Hz andwith bulk densities ranging from 0.(g)46-0.067 g/cm 3. When such fluids and contrasts the results obtained with those of the classical the soundpropagated in a directionnormal to the fiberalignment, the Taylorstructure. Fatimatea for thethickness will alsobe presented. Con- measuredsound absorption showed the uccurrence of a strongresonance ditions under which the thicknessinc•ases, rather than decreases,with that increasedabsorption above that attributedto viscousand thermal increasingshock strength will be given. effects. A model for the material indicated that this resonance was due to fibermotion. When the soundpropagated in a directionparallel to the fiber alignment,indications of the additionalsound absorption due to fiber motion were not presentin the data.

3:00

J7. Ultrasonic absorption in the critical mixture of methanol and 3:45 eyclohexane.Steven I. Fast,S.S. Yun, and F. B. Stumpf(Department of Physicsand Astronomy,Ohio University,Athens, OH 45701) J10. Effect of ambient press re on the pressmeWave from the rapidly expandinglmbble.Ho-Yotmg Kwak '• (SibleySchoolofMechanicaland The ultrasonicdata for thecritical mixture of methanoland cyclohex- AerospaceEngineering, Cornell University, Ithaca, NY 14853) axe are analyzedusing the dynamicscaling theory. The experimental valueof the slope of all 2at thecritical temperature versus f- •.o•is cora- Calculationon theintensity of evaporationand the rapidlyexpanding paredto the theoretical value. The plot of all • atthe critical temperature bubbleformed from the dropletat the superheatlimit is calculated.An versnsf-•.o• yields a straightline as predicted by theory. The experimen- analysisis presentedfor the amplitudeof the pressurewave generated by tal valuesof a/a½ for methanoland ½yclohexaneare comparedto the the rapidlyexpanding bubble. For estimatingthe amplitude, linear acous- scalingfunction F(r.o*) and to thevalues of aisc of 3Heand Xe. ticstheory for the evaporatingdroplet and the Rayleighequation for the expandingbubble are employed. The resultshows that theamplitude and the frequencyof the pressurewave depend crucially on the differencein pressurebetween vapor within the bubbleand the surroundingliquid. This resultis in qualitativeagreement with previousexperiment. 'DOn 3:15 leaveof absencefrom Chung-AngUniversity, Seoul, Korea.

Jg. Anomaliesin the scattering-inducedattenuation of backscattered ultrasonicwaves. Peter B. Nag,] and Laszlo Adler (Department of WeldingEngineering, The OhioState University, Columbus, OH 43210) Scattering-inducedultrasonic attenuation offers a simpleway to char- acterizequantitatively material inhomogeneitics. This methodhas a wide rangeof applicationsfrom tissuecharacterization to ultrasonicNDE such 4,'OO as grain sizemeasurement in polycrystallinematerials and porosity Jll. Forced radial oscillations of single cavitation bubbles: Period- sessmentin castmetals. The scattering-inducedattenuation of a through- doubling,chaos, and hysteresis.R. G. Holt and L. A. Crum (Physical transmittedwell-collimated ultrasonic wave can be readilyrelated to cer- AcousticsResearch Laboratory, Department of Physics,University of tain characteristicsof the inhomogeneityvia its total scatteringcross Mississippi,Oxford, MS 38677) section.In many cases,ultrasonic attenuation measurement is not feasible exceptfrom the backscatteredsignal. For want of betterapproximation, Utilizingan optical scattering technique previously reporte•l the scattering-inducedattenuation is presumedto havethe samerelation Acoust.So:. Am. Suppl.1 80, S24 (1986) ], the radialresponse of a single to the inhomogeneityas if it weremeasured by the simplertransmission bubbleto an acousticfield hasbeen observed and analyzed.A scattered technique.Experimental r•sulta are prca•nt•l to show that the back- light intensity versusradius transfer function has been obtained for the scatteredsignal is much lessattenuated than is predictedby the plane- system,enabling a quantitativedescription of the radius versustime. wave approximation,and that this effectis not simplydue to multiple Someuniversal features of driven nonlinearsystems have been observed, scattering.Furthermore, it is shownthat the scattering-inducedattenu- among them period-doubling,chaotic solutions(with corresponding ation of the incoherentbackscattered signal is mainly due to backward fractalattracting sets in thephase plane), and histability due to hysteresis scattering,while stronglyforward scatteringinhomogeneities, such as in the resonancestructure. [Work supportedby ONR.]

S26 J. Acoust.Soc. Am. Suppl. 1, Vol.81, Spring1987 113thMeeting: Acoustical Society of America S26 TUESDAY AFTERNOON, 12 MAY 1987 REGENCY BALLROOM C, 1:30 TO 4:15 P.M.

SessionK. Psychologicaland PhysiologicalAcoustics III: BinauralProcessing

Gary L. Gibian,Chairman Departmentof Physics,American University, 4400 Massachusetts Avenue N. W., Washington,DC 20016

ContributedPapers

1:30 2.'OO

K1. Predictions for binaural masked detection with frozen-noise K3. The dependenceof binauraldetection and interauraldiscrimination maskers.Gary C. Kline and H. StevenColburn (ResearchLaboratory on interaural time and intensity in normal and impaired iistoners. of Electronics,Massachusetts Institute of Technology,Cambridge, MA J. Koehnke and H. S. Colburn (ResearchLaboratory of Electronics, 02139 and BiomedicalEngineering Department, 110 Cummington MIT, Cambridge,MA 02139and Boston University, 100 Cummington Street,Boston University, Boston, MA 02215) Street,Boston, MA 02215)

A modelof binauralheating based on combinationsof interauraltime Measurementsof binauralperformance by normaland hearing-im- and intensitydifferences [Gabriel et al., J. Acoust.Soc. Am. Suppl.1 74, pairedlisteners are reported for largereference values of interauraltime S85 (1983) ] wasused to predictresults obtained previously [R. H. Gil- delay (ITD) and interauralintensity difference (IID). NoS•rdetection key,D. E. Robinson,and T. E. Hanna,J. Acoust.Soc. Am. 78, 1207-1219 thresholdsand just-noticeable differences (jnds) in ITD and IID were ( 1985) ] in a binauralmasked detection experiment with repeatablesam- measuredwith l/3-oct noisebursts at 500 and 4000 Hz, usingreference plesof maskingnoise. The narrow-band model generates its decision vari- ITDs andIIDs up to 600/zsand 34 dB. As expected,jnds and thresholds ablesthrough a linearcombination of interauraltime and intensity differ- for normaland impaired subjects increase as the referenceIID increases. encesfollowed by a sluggishnessfilter (averager).A computersimulation In contrast,increasing the reference ITD showsrelatively small effects for of the modelwas used to predictthe hit andfalse-alarm rates for eachof mostsubjects. The presentdata are consistent with thosedescribed pre- tenindependent, frozen-noise masker samples, and for target phase angles viously[C. Passaro,J. Koehnke,and H. S.Colburn, J. Aeoust.Soc. Am. of 0 degand 90 deg.Model predictionsdisagree with the experimental $uppl.1 79, S21-$22 (1986) ] butare more pronounced with larger refer- resultsin tworespects. First, the false-alarm rates predicted by themodel enceITDs andIIDs. Forexample, performance isgenerally poorer for the showalmost no variationacross masker samples, while the experimental impairedlisteners than the normal listeners. Also, for both groups, mea- resultsshow changes from 5% to 80%. Thisdisagreement illustrates the surementsof IID jndsconsistently result in smallerjnds for the canceling inadequacyof the additiveinternal noise assumption of the model.Sec- combinationsof referenceITD and IID than reinforcingcombinations. ond,the model predicts changes in thehit rateas large as 80% whenthe [Work supportedby NIH. ] tonephase changes from 0 to 90 degfor a givenmasker sample, while the experimentalresults show changes less than 20% for a givenmasker sam- ple(although hit ratesvary over a rangeof 75% acrossmasker samples). 2:15 Thissignificant correlation in hit ratesfor thesetwo phaseangles is not K4. Nonlinear spectralinterferometry (NLSI): A new approachto easilyexplained within a modelbased on interauraldifferences since the modelingbinaural hearing and aural communicationchanneling. interauraldifferences in the stimulusare uncorrelatedfor thesephase NathanCohen (Departmentof Natural Sciences,Bentley College, angles.[Work supported by NIH.] Waltham, MA 02254) and Dean Cummins (Harvard Biological Laboratories,Harvard University,Cambridge, MA 02138) A biointerferometricmodel for spatialhearing is describedin which binauralinformation is processedas an interferometricresponse via a nonlinearspectral transform of thecross-correlation function. Relevant observablesinclude phase delay, phase delay rate, visibility amplitude, 1:45 andvisibility phase, Our modelaccounts for a broadrange of hearing K2. Extendingthe position-variable model: Dependence of lateraliz•tlon phenomenaincluding: ( 1) localizationbelow diffraction limited frequen- on frequencyand bandwidth.Glenn D. Shearand RichardM. Stern ciesby overtonegeneration at thecochlea; (2) localizationacuity by su- (Departmentof Electricaland Computer Engineering, Carnegie-Mellon perresolutionof thesynthesized beam; (3) beamsynthesis by visibility University,Pittsburgh, PA 15213) planesampling through overtone content in speechand eochlearre- sponse;(4) thebinaural advantage in intelligibility through interferomet- The position-variablemodel [R. M. Stern,Jr. andH. S. Colburn,J. ricrejection and neuronally driven beam steering; and (5) transformation Acoust.Soc. Am. 64, 127-140(1978) ] isextended to describethe subjec- fromphase to amplitudelocalization cues through loss of visibilityphase tivelateral position of tonesas a functionof frequencyand ITD, andthe abovethe phase-locked frequency range. This model obviates the need for lateralizationof bandpassnoise as a functionof bandwidth,ITD, and multiplecue and/or component models and has distinct advantages over interauralphase shift. The two major modifications made to themodel are other cross-correlationmodels. Additional psyehoacoustic tests to cor- ( 1) theuse of a frequency-dependentform of thefunction that expresses roborate this NLSI model are described. the relative number of binaural coincidencedetectors as a function of their characteristicdelay and (2) additionalprocessing of thedisplay of inter- auralcross correlation to emphasizethose regions of thefunction which 2:30 exhibitpeaks at thesame internal delay across a rangeof frequencies.For mostnaturally occurring broadband stimuli, these regions indicate the set KS. The effect of head-induced interaural time and level differences on ofprimary modes of thecorresponding cross-correlation functions, there- speech intelligibility in noise. A. W. Bronkhorst and R. Plomp by enablingthe centralprocessor to determinewithout ambiguitythe (Department of Otolaryngology,Free University Hospital, P.O. Box valueof ITD presentin thestimulus. The extendedmodel describes later- 7057, 1007 MB Amsterdam, The Netherlands) alizationdata for a muchwider rangeof stimulusfrequencies than the originalmodel, which could only describeresponses elicited by 500-Hz The effectof interaural time delay (ITD) and acousticheadshadow tones.[Work supportedby NIH.] on binauralspeech intelligibility in noisewas studied. A free-fieldcondi-

S27 J. Acoust.Soc. Am. Suppl. 1, Vol.81, Spring1987 113thMeeting: Acoustical Society of America S27 tionwas simulated by presentingrecordings, made with a KEMAR mani- 3:15 kin in an anechoicroom, through headphones. Recordings were made of KS. The duplexnature of the brain-stembinaural interact'on component: speech,reproduced in front of themanikin, and of noise,emanating from sevenangles in the azimuthalplane, ranging from 00 (frontal) to 180ø in Frequency, rate, and intensity effects. T. K. Parthasarathy and stepsof 300.From this noise, two signals were derived, one containing only G. Moushegian(Communication Disorders, Collier Center, University of Texas at Dallas, Dallas, TX 75235) ITD, theother containing only headshadow. Speech-reception thresholds for sentencesin noisefor a groupof normal-hearingsubjects showed that As in a previousstudy [J. Acoust.Soc. Am. Suppl.1 79, S6 (1986) ], for noiseazimuths between 300 and 150',the gaindue to ITD liesbetween stimuliwere varied to evaluate the binaural interaction component ( BIC ) 3.9 and 5.1 dB, whilethe gaindue to headshadowranges from 3.5 to 7.8 of theauditory brain-stem response {ABR) in normalhearing adults. In dB. A secondexperiment with similarstimuli, presented monaurally or additionto a clicklikesound, tone bursts (0.5, 1.0,and 2.0 kHz), having with a 20-dBinteraural level difference, indicated that for noisewith only two cyclesof rise-fall time and one of duration,were presentedat two headshadow,the gainrelies on theear presentedwith the mostfavorable intensities(85 and 100dB SPL). Binauralwave Ill and V amplitudes signal-to-noiseratio, but decreases when the noise presented to theother weresmaller with shorterlatentlea than summedtooneural amplitudes car becomesrelatively loud. and latentleaat both intensitylevels of the click and 2.0-kHz toneburst. Increasingstimulus rate produced longer latentlea and smaller peak am- plitudesof thebinaural interaction components and concornitantly longer latenciesand smaller wave IlI and V amplitudesof ABR. WaveV latency shiftwas greater at 85 than at 100dB SPL, whereasthe BIC exhibited greaterlatency shifts at 100than at 85 dB SPL. The derioedfrequency 2:45 followingresponse ( FFR ) to0.5 and 1.0 kHz [J. Acoust. SOe. Am. Suppl. i 79, S6 (1986) ] had shorterlateneies and largeramplitudes at 100than K6. Motion aftereffects with horizontally moving sound sources. D. at 85dB SPL.All of thefindings suggest that the BIC, in conformitywith Wesley Granthamand Lynn E. Luethke (Bill WilkersonHearing and the findingsfrom medullaryneuronai physiology, is differentiallysensi- SpeechCenter, 1114 19thAvenue South, Nashville, TN 37212} tive to rate, frequency,and intensity. Continuoussounds were presented in an aneehoicchamber through two horizontallyrotating loudspeakers that traverseda full 360* around the observerat ear level(distance: 1.5 m). At 10-sintervals this "adapta- tion stimulus"was interrupted and a 750-ms"probe stimulus" was pre- 3:30 sentedfrom a pairof stationaryloudspeakers (separated by 7.5*) 1.6m in K9. Soundlocalization in the budgerigarand the interauralpathways. frontof theobserver. The probecould itself be stationary or could"move" ThomasPark, Kazuo Okanoya,and Robert Dooling (Departmentof (employinga stereophonicbalancing algorithm ) in eitherdirection. Dur- Psychology,University of Maryland, CollegePark, M D 20742) inga run the adaptationstimulus was held at a constantvelocity { - 200ø to + 200ø/s),while probes with velocitiesvarying from -- 100to + 100/s Soundlocalization presents a problemfor animalswith smallheads werepresented in a randomorder. Observers judged the directionof mo- (closelyspaced ears ) andpoor high-frequency hearing. In recenttests of tion ("left" or "right") of eachprobe tone. When the frequency content of spatialresolving power, several small songbirds ( i.e., great tit, canary,and theadaptation stimulus was the same as that of theprobe stimulus (either zebrafinch} showrather largeminimum audible angles (MAA) on the 500-Hz low-passor 6300-Hz high-passnoise}, stationary probes were order of 15-20 deg.These results are expectedif conventionalbinaural consistentlyjudged to movein thedirection opposite to that of theadapta- time and intensitydifferences are used.Budgerigars ( 17-ram interaural tion stimulus.This effectincreased with the velocityof the adaptor. Possi- distance),on the otherhand, demonstrate an MAA ofabout5 deg,which blesensory and nonsensory mechanisms underlying this aftereffect will b• approachesthe excellentability of the barn owl with a muchlarger head discussed.[Work supportedby NIH.] (50-raminteraural distance ). Recentwork hassuggested that interaural pathwaysconnecting the two cars of birds could be involved in sound localization.Using latex injection medium, we havedemonstrated inter- auralpathways in thebudgerigor, canary, and zebra finch. Taken togeth- er, the resultsof thesebehavioral and anatomical studiesindicate that the budgerigormay usethe interauralpathway in soundlocalization.

3:00

K7. A comparisonof the effectsof time andintensity during the auditory 3:45 brain-stemresponse to lateralizedclicks. Mark Stephenson(Armstrong Aerospace Medical Research Laboratory, Biodyoamies and KIO. Performanceof adult subjectson a diehotic speechtest under both BioengineeringDivision, Biological Acoustics Branch, Wright-Patterson directedand free recall Hstening conditions. JaueA. Baran(Department AFB, OH 45433)and William Melnick { Departmentof Otolaryngology, of CommunicationDisorders, University of Massachusetts,Amherst, The Ohio StateUniversity, Columbus OH 43210) MA 01003 and Dartmouth-Hitchcock Medical Center, Hanover, NH 03756) and Frank E. Musiek (Dartmouth-Hitchcock Medical Center, A groupof 12otologically normal subjects were presented with binau- Hanover, NH 03756) ral clicksat 70 dB nHL. During onecondition, subjects delayed the onset of theclick to theleft caruntil a singleimage was percieved either midway Twenty-fiveyoung adult subjects with negativeotologic histories were betweenthe centerof the headand the rightear (referredto asthe "mid- administereda dichoticrhyme test under three different listening condi- way" location),or until the imagewas perceived just at the right ear. In a tions:{ 1) free recall,(2 } directedlistening to the rightear, and (3 } direct- secondcondition, subjects attenuated the click to the left ear until the ed listeningto theleft ear.The dichoticrhyme test used is composed of 30 acousticimage was lateralized either midway towards the right ear, or just well-alignedsynthetic CVC wordsthat werepresented at 50 dB SL (re: at the right ear. Thesesame stimuli conditionswere then usedto evoke speechreception thresholds). The nature of the test is such that under auditory brain-stemresponses (ABRa). When clicks were lateralized normal conditions(i.e., free recall}, listenerstend to repeateither the midway, ABR latenciesfrom delayedversus attenuated clicks were not word presentedto the left ear or to the right ear. Normal performanceis significantlydifferent. However, when clicks were lateralized just at the approximately50% correctidentification in eachear, with a slightright right ear, therewere statistically significant differences between latencies ear advantageevident. In an earlierinvestigation using a diehoticCV test, from delayedversus attenuated clicks. There wasalso a consistentordinal Keith etal. [Ear Hear. 6, 270-273 (1985) ] demonstrateda clear left ear relationshipnoted: In nearlyevery case, delayed clicks yielded longer advantageon a directedleft eartask and an obviousright ear advantage on latenciesthan attenuatedclicks. The clear perceptualequivalence ob- a directedright ear task. In thepresent investigation, no significant differ- servedpsychoacoustically was not fully reflectedin the corresponding encesin the testscores were observed when the right and left ear scores auditorybrain-ste/n responses. [Work supportedby AFOSR.] werecompared with the sameear scoresacross the threetest conditions.

S28 J. Acoust.Soc. Am. Suppl. 1, Vol.81, Spring1987 113thMeeting: Acoustical Society of America S28 In all threetest conditions, a' slight right ear advantagewas noted.The speechperception (RASP) test.There has been some controversy over implicationsof thesefindings as they relate to ourunderstanding of how the clinicalvalidity of thistest. The purposeof thisstudy was to investi- dichoticstimuli are processedwill be discussed. gateinformation contained in a singlechannel of theRASP. Twenty-four normalhearing subjects listened to onechannel of the RASP:twelve to channelI, twelveto channel2. Sentencescores for a singlechannel of the 4:00 RASP rangedfrom 0% to 70%, with meansentence scores for subjects KI1. Monaural perceptionof the rapidly alternatingspeech perception listeningto channels 1and 2 of 37.72%and 20.8%, respectively. An ideal binaural fusiontest would contain no, or very little, informationwhen test(RASP}. Richard W. Harris,Ruth Kaspar,and RobertH. Brey (131 TLRB, CommunicationSciences and DisordersArea, Brigham listeningto onlyone channel. It is possiblethat a singlechannel of the RASP containstoo much information.Many of the sentenceswere re- YoungUniversity, Provo, UT 84602) peatedcorrectly, in theirentirety, by at leasta fewof thesubjects listening One test that claims to measurebinaural fusion, and is routinely uti- to either channelin isolation,a task previouslyassumed to be possible lizedas a measureof centralauditory function, is the rapidlyalternating only in the binauralcondition.

TUESDAY AFTERNOON, 12 MAY 1987 CANYON HALL, 2:00 TO 5:00 P.M.

SessionL. Musical AcousticsI: Demonstrationof Computer-BasedPiano PerformanceReproduction System

Uwe J. Hansen, Chairman Indiana State University,Terre Haute, Indiana 47809

Chairman's Introduction--2:00

Invited Paper

2:05 LI. Computer-basedi•iano performance reproduction system. Hal Vincent(Kimball World, P.O. Box460, Jasper,IN 47546) Thissession will consistof a demonstrationof theBosendorfer 225SE computer-based piano performance reproductionsystem. The system incorporates anoptical sensing mechanism tomonitor and record individual keypositions for subsequent exact reproduction ofperformance dynamics. The demonstration willtake ap- proximatelyI h,followed bya 1/2-hquestion and answer period. It will be repeated again from 3:30-5:00 p.m., andagain on Wednesday from 10:00-11:30 a.m., and on Friday from 9:00-10:30 a.m. The instrument will also beavailable, by arrangement,for smallgroup hands-on evaluations.

S29 J. Acoust.Soc. Am. Suppl.1, Vol. 81, Spring1987 113th Meeting:Acoustical Society of America S29 TUESDAY AFTERNOON, 12 MAY 1987 CELEBRATION HALL, 2:30 TO 5:05 P.M.

SessionM. Architectural AcousticsII: Computersin Architectural Acoustics

David Braslan, Chairman DavidBraslau Associates Incorporated, 1313 5th StreetS.E., Suite322, Minneapolis,Minnesota 55414

Chaiman's Introductions2:30

Invited Papers

2:35

M1. Computersin architectural aeonsties.Manfred R. Schroeder (Drittes PhysikalisehesInstitut, Univcrsit•tG6ttingen, Federal Republic of Germanyand AT&T Bell Laboratories,Murray Hill, NJ 07974) Alreadyin the 1950%difficult problems in acousticswere being successfully attacked by computersimula- tion.One of the firstdigital simulations of a signalprocessor was that of an artificialreverberator to produce natural-soundingreverberation. Other early applications of computersused Monte-Carlo simulations to study random wave interferencein enclosures.Later, computerswere used extensivelyin the measurementsin PhilharmonicHall (now Avery FisherHall) in New York City. This work alsoled to the developmentofnew methodsfor measuringreverberation time. In the 1970s,with thesupport of theGerman Science Foundation, a largenumber of concerthalh wereinvestigated with the helpof soundfield reproduction and multidimensional scalingmethods using digital computers. The mostimportant new parameter emerging from thesestudies was "interauraldissimilarity." The diffuselyreflecting surfaces called for by theseresults are basedon number- theoreticprinciples [M. R. Schroeder,Number Theory in Scienceand Commuication(Springer, New York, 1986) 2nd enlargeded.]. Computershave also been used to crack complicatedintegral equations to yield accuraterelationships between reverberation time and sound absorption that are sensitiveto absorberlocation and sound diffusion.

3:05

M2. Predictionof point-to-pointacoustic transfer functionwithin a three-dimensionalenclosure using ray pathmethods. James L. Wayman,'• RobertV. Esperti(Delco SystemsOperations, MS 101,Goleta, CA 93117}, and JamesP. ¾anyo(Department of Mechanicaland EnvironmentalEngineering, University of California, Santa Barbara, CA 93106)

This reportdetails a studyconducted for the GeneralMotors Corporation to constructa modelfor predict- ing point-to-pointacoustic transfer functions in automobilepassenger compartments for the purposeof pre- dictingentertainment system performance. The modelis basedon ray pathmethods and includeseffects of curvedenclosure surfaces and complex boundary impedances. Comparisons between model results and experi- mentallyobtained transfer functions are promising. '• Nowwith Ford Aerospace and Communications Corpo- ration, SystemsTechnology Development Department, X-21, 3939 Fabian Way, Palo Alto, CA 94303.

3:30

M3. Determinationof the direction, time, and intensity of arrival of acousticsignals. Fartel M. Becker (Audio Artistry, P.O. Box 56, Kensington,MD 20895) There is currentlymuch interest in lateralreflections in concerthalls. Attempts to quantifylateral reflec- tionshave, up to now, beenlimited. Lateral energyratios have been measured using a bidirectionalmicro- phone.This techniquelacks the resolutionnecessary to investigatedirection other than side to sideversus front to back.A newtechnique, known as the polarenergy time curve,will be presented.Utilizing specialsoftware for equipmentalready in common use, this techniqueextracts accurate directional information from four energytime curve (or impulseresponse) measurements made with an ordinarycardioid microphone. The directionof arrival versustime or intensityis displayedin polar form. The time, intensity,and exactangle of arrival may be determinedin any plane of interest.Three-dimensional displays of energyarrival are also possible.Conventional lateral energy fractions, as well as otherquantities, may be computed.

S30 J. Acoust.Soc. Am. Suppl. 1, Vol.81, Spring1987 113thMeeting: Acoustical Society of America S30 3:55

M4. Evaluationof roomspeech transmission index and modulation transfer function by theuse of timedelay spectrometry.D. B. Kceic,Jr. andDonald Eger (Techron,Division of CrownInternational, Inc., l ? 18West Mishawaka Road, Elkhart, IN 46517)

Theliterature shows that the modulation transfer function (MTF) andspeech transmission index (STI) can be computedfrom the squaredimpulse response of a linearpassive system. This paperdescribes an extensionof thismethod to measurementsof systems using time delay spectrometry (TDS). The newmethod makesuse of boththe realand imaginary parts of thecomplex analytic impulse response of thesystem (the energy-timeresponse). This allows more accurate determinations of STI andMTF becausethe calculations are basedon a measurementthat moreclosely follows the trueenergy decay in the room.The methodrequires fewersamples of the room'ssound field and less spatial averaging to yielda givenaccuracy.

4:15

MS. Criteria and snalysis for fan/floor vibration isolation in elevated mechanical rooms. Angelo J. Campanella(Campanella Associates, 3201 RidgewoodDrive, Columbus,OH 43220) In selectingisolators for fansand othermechanical equipment mounted on elevatedmechanical room floors,it is necessaryto know the degreewith whichtheir vibrationswill affectthe occupantsof the floor on which it is mounted,as well as the floor below.A computationalprocedure was developed based on a two degreeof freedommodel representing the resultingfloor motion for knownmasses, resonances, and damping of thefloor and fan mount. A computationalcriterion was developed for vibrationinput and human vibration tolerancebased on valuescommonly found in the literature.A FORTRAr•program featuring interrogatory inputprompts and a screengraphics output of thefloor vibrational velocity over the frequency band of concern executesin about30 s. With thistool, one can immediately judge the effectivenessof various fan massesand springconstants. Two casestudies are discussed.

ContributedPapers

4:35 eventsin timeand the decay process through time. The processand results of this researchwill be surveyed. M6. A presentationof acousticalimpulse responses with an analog-to- digitalconverter.Edward G. Clautice(DepartmentofArchitecture, 231 ARCH, Universityof Florida,Gainesville, FL 32611) 4:50

M7. The use of an IBM personalcomputer (PC) for performingroom A researchprogram in architecturalacoustics at the Universityof acousticsmeasurements. Richard H. Talaske (R. L. Kirkegaard & Floridahas been using analog electrical equipment to processsignals. An Associates,Inc., P.O. Box 186, Downers Grove, IL 60515) analog-to-digitalconverter was acquired to allow fasterand better signal analysis.Several computer programs were written that controlthe ana- The generalacceptance of the PC microcomputerand the subsequent log-to-digital converter and subsequent processing of thedigital data. The availabilityof additionalhardware and software have offered researchers ability of the analog-to-digitalconverter to analyzesome properties of and practitionerssome formidable tools for acousticalinvestigations. Us- known signalswas evaluated.The analog-to-digitalconverter was then ing an IBM portablePC, ILS signal-processingsoftware, and additional usedto evaluatesignals from magnetictapes which had the recorded signalgathering and signalconditioning equipment, an inexpensiveand acousticalimpulse response from several positions in a 1500seat auditor- portableroom acoustics and data collection system was developed for the ium. The processingprograms were usedto produceechograms. Those purposeof investigatingthe acoustics of theaters,concert halls, and other digitalechograms were able to duplicatethe echogramsproduced by the assemblyspaces. This systemwill bedescribed, and the resultsof datawill laboratory'sexisting instrumentation in termsof the relativelocation of be presentedand discussed.

S31 J. Acoust.Soc. Am. Suppl.1, Vol. 81, Spring1987 113thMeeting: Acoustical Society of America S31 WEDNESDAY MORNING, 13 MAY 1987 MT. RUSHMORE, 8:00TO 9:30A.M.

SessionN. Education in Acoustics:Modeling in AcousticsEducation

Gary W. Siebein,Chairman Departmentof Architecture,University of Florida, Gainesville,Florida 32611

Chairnan's Introduction4:00

Invited Paper

8:05

N1. Acousticalscale modeling in the classroomat Mrr. RichardG. Cann (GrozierTechnical Systems, Inc., 157Salisbury Road, Brookline,MA 02146) This is an actualdemonstration of theacoustical scale modeling methods that havebeen used by the author for severalyears to helpteach some basic acoustics to studentsin two classesat the Departmentof Architec- ture. One classin the curriculumof BuildingTechnology, instructed by Cad Rosenbergof BBN, usesscale modelingto showhow the reverberantsound within an interiorspace forms from numerouswall reflections. Echogramsfrom various model room configurations illustrate simple defects that mayoccur in the qualityof the interiorsound. Also, studentssee demonstrated clearly the differencebetween the reductionof noiseby surfaceabsorption and by transmissionloss. Another course attended by equalnumbers of undergraduateand graduatestudents is instructedby Tim Johnsonand John Furlong. It exploresvarious aspects of the microcli- mate.One part, acoustics,is presentedin the form of onelecture and a brief acousticalscale madcling demon- strationimmediately followed by a laboratoryactivity in whichstudents investigate the control of soundfrom a highwayinto a nearbycommunity. Students use the scale modeling instrumentation to helpselect the appropri- atenoise barrier that will givean acceptablecommunity noise level, or/and noisereduction, at the lowestcost. Thereis noone solution to theproblem, but studentsmust show their understanding of acousticsby justifying their selectionquantitatively.

8:50-9:00

Break

ContributedPapers

9:00 9:15

N2. A methodto evaluatethe acousticaleffects of designdecisions in the N3. A microcomputer-baseddemonstration system for musicalacoustics architectural studio class. Gary W. Sicbein (Department of education.Robert Maher and JamesBeauchamp (School of Music, Architecture,231 ARC, Universityof Florida, Gainesville,FL 32611) Universityof Illinois at Urbana--Champaign,2136 Music Building, 1114 West Nevada, Urbana, IL 61801 ) The resultsof a researchproject in acousticalmodeling conducted by the authorwere used to facilitatethe investigationof acousticalissues in the conceptualstage of the designprocess of studentsin a fourth-year While an ideal musicalacoustics education laboratory would include architecturalstudio. The studentsworked on a semester-longproject to an extensivecollection of electronicmeasurement, recording, and display designa multipurposeperforming arts center. The intent of thestudio was equipmenttogether with appropriatespace, staff, and maintenancestaff to look at the potentialof acousticsas a formgiverin architecture.The to supportstudent use, this situationis seldompossible because of limited acousticalmodeling technology was used as a mechanismto evaluatethe funds.Our solutionhas been to configureand programa microcomputer proposedsolutions. The techniqueallowed students to receiveimmediate (IBM PC AT) to serve as a mobile multifunction demonstration station. feedbackon the acousticalquality of a proposedscheme. The resultsof The stationis capableof high-resolutioncolor display, stereo audio/digi- testsin modelsof the students'designs were comparedto the resultsof tal input/output, hardwareFFT analysis,and MIDI input/output. Thus similar testsmade in many differentauditoria gatheredas a part of the far, the following demonstrationshave been completed:(1) animated researchproject. Studentswere able to test many alternative design displaysimulation of wave propagationon stringsand within pipes;(2) schemesand understandthe resultingchanges in acousticalquality (as waveform/spectrumdisplay and soundsynthesis from givenFourier am- evaluatedby newobjective design criteria such as early to late temporal plitudesand phases;(3) singleframe spectrumanalysis of audio signals; energyratios and reflectograms)in small-sizestudy models. Once a basic (4) display simulationof modeson squareand circular vibrating mem- solution was reached, more detailed architectural and acoustical refine- branes;and (5) soundsynthesis comparison of just, Pythagorean,and mentof thescheme followed. The highenergy level and enthusiasm of the equal-temperedscales. One advantageof this microcomputer-basedsys- studentsand the most satisfactory design projects at theend of the semes- tem is that newdemonstrations can be incorporatedeasily by writing new ter attestedto the successof thisnew design tool. [Work supportedby programsfor the existing hardware. [ Work supportedby an IBM grantto NSF.] UIUC.]

S32 J. Acoust.Soc. Am. Suppl. 1, VoL81, Spring1987 113thMeeting: Acoustical Society of America $32 WEDNESDAY MORNING, 13MAY 1987 REGENCY BALLROOM C, 8:30TO 11:45A.M.

SessionO. Psychologicaland Physiological Acoustics IV: ComplexSignals

Marjorie R. Leek, Chairman Universityof Minnesota,Department of CommunicationDisorders, 115 $hevlin Hall, 164Pillsbury Drive S.E., Minneapolis,Minnesota 55455

ContributedPapers

8:30 dimensionwere highly discriminable. In a classificationtask involving combinationsof dimensionalvalues, listeners showed an impressiveabil- O1. Detection of time-varying sequential constraintsin finite-state ity to integrateinformation over pulses within sequences, with perfor- auditory pulsetrains. Irwin Pollack (Mental Health ResearchInstitute, manceat about5% to 10% belowideal performance for all sequence Universityof Michigan,Ann Arbor, MI 48109) lengths.However, performance was not a simplefunction of the discri- Listenersdiscriminated between auditory pulse trains generatedby minabilityof the individualdimensions, and there were major differences (a) unconstrainedfinite-state random sequences and (b) statistically amonglisteners' tendencies to differentiallyattend to eachof the dimen- constrainedfinite-state sequences. The natureof the statisticalconstraint sions.[Work supportedby USN/NMRDC andby AFOSR.] wasto makeone half of the possibleset of successiven-tuples more likely than the remaininghalf. The statisticalconstraint was changedperiodi- cally and aperiodicallyabout an averagezero constraintlevel. Discrimi- nationperformance deteriorates as the statisticalconstraint is changed 9:15 morefrequently, as might be anticipated with a fixedinformational inte- grationperiod or "auditorymoment." 04. Multiple observationsand internal noise. B. G. Berg and D. E. Robinson (Department of Psychology, Indiana University, Bloomington,IN 47401)

A multipleobservalion task was used to evaluatemodels of "internal 8:45 noise." On each trial, n tones (n = 1,2,3,4,6,8,10, or 12 within a block) were independentlysampled from one of two probabilitydensity func- 02. The effectsof decorrelationon the discriminabilityof noisesamples. tionson frequency;each was normal in form with a standarddeviation of SusanM. FallonandDonaldE. Robinson(Departmentof Psychology, 100Hz. The twodistributions had means of 1000and 1100Hz, respective- Indiana University,Bloomington, IN 47405) ly. The samplewas presented through headphones as n, 50-mstone bursts separatedby 50 ms.The subjects'task was to decidefrom which of the two In a previousstudy, it wasdemonstrated, using a same-differentpara- distributionsthe toneswere sampled. A modelpartitioning internal vari- digm,that the discriminability of samplesof reproduciblenoise is a func- anceinto peripheralvariance, added to eachobservation prior to formu- tion of the correlationbetween members of a pair of samplesto bediscri- latinga decisionstatistic, and centralvariance, added to the decisionsta- minated[S. M. Fallonand D. E. Robinson,J. Acoust.Soc. Am. Suppl.1 tistic, provideda good descriptionof the data of all four subjects.A 78, S46 (1985}]. On "different"trials, the secondsample of a pair was subsequentstudy counterbalancedtwo levelsof the differencebetween generatedby repeatinga temporalsegment of thesample presented in the distributionmeans (Ap = 100or 150Hz) with two levelsof thestandard firstinterval, and combining it with a newsegment of noise.The data from deviation(a = 100or 150Hz). IncreasingAp did not affectestimates of that experimentindicate that discriminabilityat "threshold"is indepen- internalvariance. However, increasing a resultedin increasedestimates of dent of the total duration of the sample,but is highly dependenton the internalvariance for bothlevels of A/•. One interpretationof this resultis interpaircorrelation (proportion of commonelements ). Discriminability thatexternal and internal variance are not independent. [ Work supported wasalso affected by the temporalposition of the newsegment of noise.In by AFOSR and NMRDC. ] thework reported here, the correlation (proportion of commonvariance) betweena pair of identicalsamples was varied by addinga new,indepen- dentsample of noiseto the samplepresented during the firstobservation interval.The durationand position of the addedsample were also varied. The similarities and differences between the two methods used to decorre- 9:30 latethe pairsof sampleswill bediscussed. [Work supportedby AFOSR and NMRDC. ] 05. Frequencyresponse and perceived sound quality. All Gabrielsson, Bj6rn Hagcrman,and Ore Till (Departmentof TechnicalAudiology, Karolinska Institute, KTH, S-10044 Stockholm,Sweden)

The perceivedsound quality of sound-reproducingsystems can be 9:00 describedin termsof perceptualdimensions as clarity, fullness, bright- 03. Perceptionof multidimensionalcomplex sounds. Gary R. Kidd and ness,spaciousness, and otbers [A. Gabrielssonand H. Sj6grcn,3. Acoust. Charles S. Watson (Department of Speechand Hearing Sciences, Soc. Am. 65, 1019-1033 (1979)], and fidelity may be consideredas a IndianaUniversity, Bloomington, IN 47405) weightedcombination of the perceptualvariables. The frequencyre- sponscprobably affects all thesevariables. An experiment,in which the Listeners'abilities to perceiveinformation independently encoded in frequencyresponse was manipulated, showed that, among other things, differentdimensions of complexsounds were examined in experiments brightnessand sharpness increased with increasedfrequency response at thatrequired simultaneous attention to threedimensions. Stimuli consist- higher frequencies,fullness and nearnessdecreased with decreasedre- edof sequences ofone, three, five, or sevenbrief pulses that were generated sponseat lowerfrequencies, and clarity increased with a certainrise above byadding five 100-ms sinusoidal components. Each pulse had one of two I kHz in comparisonwith a fiat response.The resultswere more pro- valueson each of the following complexdimensions: ( 1) harmonicity nounccdfor normal.hearingthan for hearing impaired persons,but both (harmonicversus inharmonic relations among the components);(2) categoriespreferred a frequencyresponse increasing above 1 kHz to a fiat spectralshape (linearly decreasing amplitude versus a two-peakedampli- response.Similar results were obtained from an analysisof the frequency tude profile);and (3) amplitudeenvelope (slow versusrapid riseand responseof high-fidelityloudspeakers used in an extensivelistening test decay times). Stimuli were selectedsuch that the two values on each [A. Gabriclssonand B. Lindstr6m,J. Aud. Eng.Soc. 33, 33-53 (1985) ].

S33 J. Acoust.$oc. Am. Suppl. 1, Vol. 81, Spring 1987 113thMeeting: Acoustical Society of America S33 Thiswas especially evident when the frequency response was measured ulationdetector is summed by a secondintegrator in a similarmanner as directlyin thelistening room. seenin a broadbandsignal detection task.

10:30 9:45 09. Evidencefor sensitivityto ratesof changeof frequencyand intensity. 06. Temporalresolution in preschoolchildren. F. L. Wightman,T. Gary J. Dooleyand BrianC. J. Moore (Departmentof Experimental R. Dolan, P. Allen, and D. Jamieson (Waisman Center on Mental Psychology,University of Cambridge,Downing Street, Cambridge Retardation and Human Development, University of Wisconsin, CB2 3EB, England) Madison, WI 53705 ) Thresholds for the detection of differences in duration were measured An adaptivethree-alternative forced-choice paradigm, in theform of a in a two-alternativeforced-choice task for four typesof signals,all cen- videogame, was used to testauditory temporal processing skills in young tered at 2 kHz with a mean level of 65 dB SPL: ( 1) sinusGirlsfixed in children.Thirty childrenbetween the agesof threeand sevenwere asked frequencyand level; (2) sinusoidsof fixedfrequency whose level was to detecta temporalgap in a burstof octaveband noise, centered at 400 or swept up or down by 5 or 10 riB; (3) sinusGirlsof fixed level whosefre- 2000 Hz. The minimumdetectable gap (gap threshold) wasestimated by quencywas swept up or down by 100 Hz; and (4) sinusoidswhose level takingthe medianof the thresholdestimates from at leastthree 20-trial was sweptup or down by 10 dB and whosefrequency was swept up or adaptiveruns. While the variability in themedian threshold estimates was downby 100Hz. The durationof the standardwas either fixed at 500 ms, substantial,the data suggest that low-frequency gap thresholds were high- or wasvaried randomly from trial to trial by up to + 7% about500 ms. er for the childrenthan for adults,with the youngerchildren producing The patternof resultswas similar for all four subjectstested. Thresholds higher thresholds.High-frequency gap thresholdswere comparableto for the signalswhich were sweptin leveland/or frequencywere lower adultvalues for all children.All the individualadaptive runs were "adult- than thosefor the fixedsignals, typically by 10 to 20 ms. This indicates like," suggestingthat the subjectswere concentrating on the task.How- that subjectswere sensitive to the rate of changeof frequencyand/or ever, run-to-run variability,as well as subject-to-subjectvariability, was intensity,and coulduse this as a cuefor durationdiscrimination. [Work high. It seemedthat the childrenhad "gooddays" and "bad days,"and supportedby the MRC, United Kingdom.] that the youngerchildren were more influencedby thesevariations than their older colleagues.[Work supportedby NICHD Grant 5 P30 HD03352.] 10:45 'O10. Perceptionof bird calls by budgerigarsand humans:A multidimensionalscaling analysis. Susan 13. Brown and Robert ]. Dooling (Departmentof Psychology,University of Maryland, College 1o:oo Park, MD 20742) o?. Detection of envelopephase disparRy. Gregory H. Wakefield A combinationof behavioraltesting and multidimensionalscaling (Department of Electrical Engineeringand Computer Science, analysiswas used to testbudgerigar perception of a naturalvocalization: Universityof Michigan,Ann Arbor, MI 48109) the"contact" call. For comparison,humans were tested on the same set of The sensitivityof the auditory systemto temporalvariations across sounds.Individual differencesmultidimensional scaling (SINDSCAL) frequencyin the time-varyingspectrum of a signalby measuringthe de- revealedthat budgerigarsand humansperceive budgerigar contact calls tectabilityof a phasedisparity between the envelopesof two sinusoidally differently.Acoustic properties of the callsthat covaryalong the dimen- amplitude-modulatedcarriers is discussed.Signals were 500 ms in dura- sionsdetermined by multidimensionalscaling were identified.For hu- tion and were gatedby a 30-ms linear window. A 2IFC procedurewas mans,the absolutepitch of the call wasmost salient, while, for budgeri- usedto obtainpsychometric functions for relativephase between the en- gars,the spectralshape was most salient. These results are discussedin velopesof a 0.5- and 2-kHz carrier.The resultsindicate that the psycho* termsof the basicauditory capabilities of buderigarsand humansand in metricfunction is'independent of modulation frequency from 8 to 64Hz. termsof the codingof informationin budgerigarvocal signals. A phaseshift of approximately45 degis necessaryfor a d' of 1.Changes in the uppercarrier frequency(e.g., I or 4 kHz) do not affectsensitivity. Furthermore,little changein performanceis observedwhen additional 11:0o SAM carriersare present.[Work supportedby the EECS Department, KresgeHearing Research Institute, and AFOSR. ] o 11.When theory and practice collide: The useand abuse of statisticsin bioacoustics.Leslie A. Wheeler (Laboratoired'Acoustique Animale, E.P.H.E., INRA-CNRZ, F78350, Jouy-en-Josas, France and MassachusettsInstitute of Technology,Room 36-511,Cambridge, MA 02139) and Rent-Guy Bushel (Laboratoire d'AcoustiqueAnitaale, E.P.H.E., INRA-CNRZ, F78350 Jouy-en-Josas,France) 10:15 All of ushave been guilty of favoringstatistical procedures that sup- 08. Temporal integration of amplitude modulation. Stanley Sheft portour hypotheses. This is fine if ourhypotheses are correct. But what if (Program in Audiology and Hearing Impairment, Northwestern they are false?No matter.By useof appropriatestatistical procedures, University,Evanston, IL 60201) appliedin just the right way, eventhe saggiestof hypothesescan be The thresholdfor detectionof sinusoidalamplitude modulation of a proppedup. This paper explains how. As an example, the usefulness of 14 gated broadband noise carrier was measured for modulating signal dura- uselessacoustic features in the differentiationand recognitionof lovebird tionsvarying from 12.5to 400 ms.Stimuli were shaped by a 25.6-msrise- callswill be shownstatistically in two differentways. fall time with modulationonset subsequent to shaping.Carrier levelwas first adjustedto compenstefor changein rms due to modulation,then randomized + 3 dB abouta meanspectrum level of 25 dB SPL to ensure 11:15 detectionnot basedon changein overalllevel. As in the resultsof Viemeis- ter [J. Acoust. Soc. Am. 66, 1364-1380 (1979)], modulation transfer O12. Englishand prevoicedVOT (voice-onset-time)discrimination by functionsfor gatednoise carriers exhibited a bandpasscharacteristic. Ad- monkeys and humans. Joan M. Sinnott and Frank S. Adams ditionof a 500-msfringe proceeding modulation indicated that the high- (Department of Psychology,Indiana University, Bloomington,IN passsegment was not due to fast-actingadaptation. For modulationfre- 47405 ) quenciesabove the high-passsegment, the amplitudeof the modulating signalat thresholddecreased roughly 7 to 8.5 dB per decadeincrease in Discriminationof syntheticEnglish and prevoiced VOT (voice-onset- modulationduration. Results suggest that theoutput of an auditorymod- time)continua was assessed in Old World monkeys and humans using a

S34 J. Acoust.Soc. Am. Suppl.1, VoL 81, Spring1987 113th Meeting:Acoustical Society of America S34 repeatingstandard AX procedureand positive-reinforcementoperant differencesin the rateof frequencychange for the transition.To examine conditioningtechniques. The DLs weremeasured at VOTs of + 70 ms this question,difference limens (DLs) for initial transitionsof isolated (English/pa/), 0 ms (Englishfoa/), and - 70 ms(prevoiced/tuba/). secondformants were established using a four interval"same•lifferent" MonkeyDLs for foa/(standard)-/pa/(target) were17 ms, compared procedure.These single formant signals were 300 ms in duration(60-ms to 8 msfor humans. Monkey DLs for/pa-ba/were 25 ms, compared to I 1 transitionsand 240-mssteady-state portions). The DLs for startingfre- msfor humans.More pronounceddifferences between monkeys and hu- quency,and thusrate of frequencychange, were established for three mansappeared for prevoicedVOT. Monkey DLs for foa-mba/( 35 ms) standardswhich variedin rate and directionof transition;all had steady wereabout four times humans' ( 8 ms). Monkeysdid not reliably discrimi- states at 1800 Hz. One standard had no transition and two had transitions nate/mba-ba/, althoughhumans experienced no difficulty with thiscon- of 2.5 Hz/ms that either fell from 1950 Hz or rose from 1650 Hz. The DLs trastand produced DLs of 18ms. Monkey VOT sensitivityis compared wereestablished for transitionswith startingfrequencies above and below with that of humaninfants previously tested with the samestimuli by eachstandard condition. The DLs for threeof four experiencedlisteners Aslinet al. [Child Dev. 52, 1135-1145( 1981) ]. [Work supportedby weresmaller for transitionsin the frequencyrange above the steadystate NIH.] than for transitionsin the frequencyrange below the steadystate. Mean 11:30 discriminabledifferences in startingfrequency were 67 and 87.5 Hz in the frequencyranges above and below the steadystate, respectively. [Sup- O13. Secondformant transition discrimination. Joan Besing, '1 John portedby NINCDS andthe LouisianaLions Foundation. ] a• Louisiana K. Cullen,Robert J. Porter,s• RandalRampp, and M. JaneCollins '• StateUniversity, Baton Rouge, LA 70803.b• University of NewOrleans, (Kresge Hearing ResearchLaboratory of the South, LSU Medical New Orleans, LA 70112. Center, New Orleans, LA 70112)

The ability of listenersto processinformation conveyed by second formanttransitions may be expected to belimited by their abilityto detect

WEDNESDAY MORNING, 13 MAY 1987 REGENCY BALLROOM A & B, 8:30 TO 11:57 A.M.

SessionP. SpeechCommunication III: SpeechProduction

Diane Kewley-Port, Chairman Departmentof Speechand HearingSciences, Indiana Unioersity,Bloomington, Indiana 47405

Chairman's Introduction4:30

ContributedPapers

8:35 Syrdaland Gopal [J. Acoust.Soc. Am. 79, 1086-1100(1986) ]. The F I- F0 dimensionrepresents vowel height and theF 3-F 2 dimensioncorre- PI. From acoustic tube to acoustic cues. G. M. Kuhn (IDA-CRD, spondsto vowelplace of articulation.The linearcorrelation between F I- Thanet Road, Princeton, NJ 08540) F0 and w2 was -- 0.86 (p < 0.001) andthat betweenF 3-F2 andwl was The relationbetween sound propagation in the acoustictube and for- --0.96 (p < 0.001). mant-basedacoustic cues for the phoneticdimension of placeof articula- tion is illustrated.The modelfor soundpropagation comes from Chiba and Kajiyama [ The Vowel(Phonetic Society of Japan,Tokyo, 1941) ]. The evidencefor the acousticcues comes from the experimentalliterature 8:59 publishedafter 1941.The followingare emphasized:(1) constrictionof tubesand changesin formantfrequencies; (2) constrictionof tubesand P3. Difference in second-formanttransitions between aspirated and invariantsin the changesin formantfrequencies; and ( 3 ) complexitiesof unaspiratedstop consonantspreceding [o]. Hwei-Bing Lin (Haskins the changesin formant frequenciesand simplifyingrules derived from Laboratories, 270 Crown Street, New Haven, CT 06511-6695 and perceptualtests. A tape of modeledspeech sounds will be played. Departmentof Linguistics,University of Connecticut,Storrs, CT 06268) and Bruno H. Repp (Haskins Laboratories,270 Crown Street, New Haven, CT 06511-6695)

Perceptualexperiments with syntheticspeech have shownthat the 8:47 categoryboundary on an acoustic[ po-to ] continuum(obtained by vary- P2. Articulatory parametersused to generatevocal tract shapesand bark- ing the onsetfrequencies of the secondand third formants) is closerto the differencedimensions. Donald C. Wold (Department of Physicsand labialendpoint than the boundary on a [ pho_t h o ] continuum.Of several Astronomy,University of Arkansasat Little Rock, 2801 $. University possibleexplanations, the mostplausible seems to bethat naturalunaspir- Avenue, Little Rock, AR 72204) ated and aspiratedstops have different formant transitions.To supple- ment limited data in the literature, an acousticanalysis of CV syllables In this study,the correlationbetween two artieulatoryparameters producedby ten malespeakers of AmericanEnglish was conducted. The usedto generatevocal tract shapesfrom formantfrequencies and three resultsshow very clearly that thesecond formants of [p"o] and [t"o] bark-differencedimensions were examined. Ladefoged et al. [J. Aeoust. start 100-200Hz higherthan those of [po] and [to ], andreach compara- $oc. Am. 64, 1027-1035 (1978)] identified the articulatory parameters ble frequencyvalues only at voicingonset. This difference,which is prob- wl and w2 as the front-raisingand back-raisingproportions of tongue ably an acousticconsequence of subglottalcoupling during aspiration, shapeand showed how they may be calculated from formantfrequencies. seemsto bepart of a listener'stacit knowledgeof phoneticregularides and The ten AmericanEnglish vowels of Petersonand Barneywere used for thusexplains the perceptualboundary shift. It alsoneeds to be takeninto menand women.The threebark-difference dimensions were described by accountin realisticspeech synthesis. [Work supportedby NICHD.]

S35 J. Acoust.Soc. Am. Suppl.1, Vol. 81, Spring1987 113th Meeting:Acoustical Society of America S35 9:11 tenflyhighest for condition(b), lowerfor condition(a), and lowestfor condition(c). Theseresults, therefore, argue against vowel-independent P4. Observationson the releaseof/t/. SandraL. Hamlet (Department cuesto stopconsonant recognition and are moreconsistent with studies of Hearingand SpeechSciences, University of Maryland, CollegePark, which concludethat the perceptionof stop consonantsis stronglyin- MD 20742) fluencedby the followingvowel [ for example,M. F. Dotman et al., Per- Palatographicdata wereexamined for the releaseof prevocalic/t/ in cept.Psychophys. 22, 109-122(1977) ]. Thusattempts to isolatethe per- both aspiratedand unaspiratedcontexts. Thirty-two tongue contact ceptually important cues to stop consonantidentity should take into pointsin the alveolarregion were sampled every 2 ms.Although a plosive account the vowel context. burstis a suddenacoustical event, the dynamictongue release gesture is moregradual. The burstis associatedwith the suddenopening of a narrow centralchannelbetweenthe tongueand palate.The tonguethen continues to pull away from contactcentrally, with the final contactsremaining 9:47 laterallyeven after voicingfor the followingvowel has commenced. At somepoint during the releaseof/t/, the tonguecontact pattern passes P7. An investigationof someacoustic characteristics of prennsalized througha configurationvirtually identical to that for the greatestcon- stops.Martha W. Burtonand SheilaE. Blumstein(Department of strictionof/s/. This impliesthat a brief periodof fricationgenerated at Cognitiveand LinguisticSciences, Box 1978, Brown University, the point of releasemay follow the burst. The sequenceof acoustical Providence, RI 02912) eventsat the releaseof aspirated/t/would be:burst-frication-aspiration. Tongue releasesin a unaspiratedcontext (/st._/) were also examined. Prenasalizedstops occur in a numberof languages,often contrasting The palatographicpattern of tonguerelease was no differentfor the una- phonemicallywith prevoieed stops, voiceless stops, and nasal consonants. spiratedcontext, although the timingof its initiationwas later relativeto The presentstudy compares and contraststhese sounds in Morn, a Cen- the beginningof the followingvowel. [Work supportedby NIDR.] tral Sudanielanguage. A singlespeaker of Morn producedreal word to- kenswith word-initialprenasalized stops, voiced stops, voiceless stops, andnasal consonants in various vowel environments. Acoustic analyses of thesetokens included duration measurements and critical band analyses. Theresults indicated that prenasalizedstops may be characterized by a 9:23 nasalmurmur followed by a 10-dBdrop in amplitude,lasting approxi- mately25-30 msprior to the release.Critical band analyses of the mur- PS. The F1 structureinfluences final-consonant voicing decisions. Walter murand prevoiced portions of the prenasalized stops and prevoieed stops, V. Summers(Speech Research Laboratory, Department of Psychology, respectively,suggested that the spectralproperties differ. In contrast,the IndianaUniversity, Bloomington, IN 47405) spectralproperties at therelease appear to besimilar. These findings will Previousacoustic analyses [W. V. Summers,J. Acoust.Soc. Am. be consideredin relationto bothphonetic and phonological theories of Suppl.I 79, S36 (1986)] showedhigher F I steady-statefrequencies and speech.[Work supportedby NIH. ] higherF 1 offsetfrequencies for consonant-vowel-consonant(CVC) ut- terancesending in voicelessconsonants than voicedconsonants. These analysesexamined the vowels/a/and/•e/and the final consonants/b/, /p/,/v/, and/f/. The presentexperiments examined whether these dif- 9:59 ferencesin F I structureprovide perceptual information to the listener PS. "Post-stoppednasals": An acoustic investigation. Marjorie K. concerningfinal-consonant voicing. The CVC stimuli were synthesized M. Chan (PhoneticsLaboratory, Department of Linguistics,UCLA, with formatsteady-state frequencies appropriate to/a/or/•e/and with Los Angeles,CA 90024) and Hongmo Ren (Linguistic Institute, finalformant transitions appropriate to the bilabialstops,/b/and/p/. ChineseAcademy of Social Sciences,Beijing, People'sRepublic of Severalseries of syntheticstimuli were created differing in F 1 steady-state China) frequency,F 1final transition slope, and F 1offset frequency. Stimuli with- in a seriesvaried in steady-statevowel duration. At eachsteady-state In somedialects of Chineseand Miao, the nasalsin syllable-initial duration, stimuli containinghigher F 1 steady-statefrequencies were positionhave been described as being accompanied by a hornorganicstop, heard as containingvoiceless final consonantsmore often than stimuli whichare often transcribed with superscripts: [ mb ], [ na ], and[ rjz ], asa containinglower F 1 steadystates. TheF I offsetfrequency also influenced deliberateattempt to characterizethese segments as phonetically distinct voicingjudgments with higher offsetfrequencies producing more voice- from prenasalizedstops, [mb], [nd], [•g]. In our study,the acoustic lessresponses: The F 1 final transition slopedid not have a consistent natureof these"post-stopped" nasals will be explored,since no instru- influenceon voicingjudgments. [Work supportedby NIH.] mentalstudy has been conducted on them. A preliminaryinbestigation of datafrom two Zhongshan Chinese speakers confirm that thesenasals are differentboth perceptually and acoustically from the prenasalized stops in other languages.It is found that the so•called"stop" componentin Zhongshansyllable-initial nasalsis not a stop, but a burst that occurs 9:35 simultaneouswith the oral releasefollowing the nasal.Such bursts occur P6. Evidence against acoustic invarlance in initial voiced stop sporadicallyin English,but are consistentlyproduced in the Zhongshan consonants.Stephen A. Zahorian, Zaki B. Nossair (Departmentof nasals,and are perceivedas homorganiestops accompanying the nasals. Electrical and Computer Engineering,Old Dominion University, The waveformsalso show a characteristicshape, with a sharprise in Norfolk,VA 23508),and Robert F. Coleman(Eastern Virginia Medical amplitudeat vowelonset. The resultssuggest the precisesynchronization of velic closure with oral release. School, P.O. Box 1980, Norfolk, VA 23510)

A p•rccptualexperiment was'conducted with naturallyspoken intitial stopconsonants in orderto testrecent claims for acousticinvariance in the initial portionsof stopconsonants [ for example,S. E. Blumsteinand K. N. Stevens,J. Acoust.Soc. Am. 67, 648-662 (1980) ]. The originalstimu- 10:11 li consistedof tokensof the stops/b,d,g/withthe vowels/i,a,u/asspoken P9. Pronunciationvariation within and across speakers. Michael by two male and two femalespeakers. A computergraphics waveform H. Cohen, Jared Bernstein, and Hy Murveit (Speech Research editor wasused to locatethe initial portionsof the waveformup to the Program,SRI International,Menlo Park, CA 94025) first, second,fourth, and sixth voicingpulses. Three experimentalcondi- tionswere evaluated: (a) the initial segmentonly; (b) the initial segment An understandingof the structureof pronunciationvariation over a plusthe originalsteady-state vowel; and (c) the intitial segmentplus an populationof speakersand over time in the utterancesof one speaker alternatesteady-state vowel. Ten listenersparticipated in a forced-choice shouldbe usefulin designingspeaker-independent speech recognizers. recognitionexperiment to determinethe conditionsfor which perceptual This paperreports a seriesof experimentsdesigned to showdifferent kinds cuesto consonantidentity are retained.Recognition accuracy was consis- of patternsobserved in alternativeforms of words in constantcontexts

S36 J. Acoust.Soc. Am. Suppl. 1, Vol.81, Spring1987 113thMeeting: Acoustical Society of America $36 (e.g., the presenceor absenceof fricationin the "y" in "had your"). An ( 1) speakerscan be clusteredinto low variationgroups such that the analysisis presentedof transcribeddata from 630 speakersreading two variationwithin a groupis significantly less than the population variation, samplesentences as well as data from four speakers reading the same two and (2) individualspeakers show greater consistency than comparable sentences24 timeseach, separated by fillermaterial, in threeseparate clusteredsubsets of thepopulation. Finally, it issuggested how this struc- sessions.The analysis quantifies the relative usefulness ofcompating mod- turemay be used to guiderapid, automatic adaptation in speechrecogni- els of variation in information theoretic terms. The results indicate that tion. [Work supportedby NSE. ]

10'.23-10.-•

Break

10:• 10:57

PlO. Motor-motoradaptation. Linda I. Shuster(Department of Speech PI2. Interart'culatory timing and single artienlator velocity- Pathologyand Audiology,West Virginia University,Morgantown, WY displacementrelationships in English stresspairs. Kenneth deJong 26506-6122} (Department of Linguistics,Ohio State University, Columbus,OH 43210) Perceptuomotoradaptation experiments have demonstrated that a purelyperceptual task can havea significanteffect upon a subsequent productiontask. Cooper has argued that theseperceptual effects upon Evidencehas been brought forward that thereexists a directtiming productionreflect a link betweenthe cognitivesystems underlying per- relationshipbetween the articulatormovements associated with vowel ceptionand production.This argumentmight be strongerif it couldbe productionand thoseassociated with consonantproduction. Tuller and demonstratedthat the effectthat a repetitiveperceptual task (suchas othershave interpreted such results as evidence for a modelof speech selectiveadaptation) has on production is the same as that obtained using productionthat positsa metricalrelationship between vowels and their a repetitiveproduction task. An experimentaltechnique was developed eoproducedconsonantal neighbors [cf. Harris et al., in Invarianceand calledmotor-motor adaptation.In this task, subjectsproduced a mono- lnvariabilityin SpeechProduction, edited by J. Perkelland D. Klatt ( Erl- syllabicCV repeatedly(the adaptor}.After 20-40 repetitions,the subject baum,Hilldale, N J, 1986};and Tuller et al., J. Exp.Psychoi. 9, 829-833 produceda secondCV syllableonce (the testsyllable). There were two (1983)]. A morestrictly segmental ordering of speechevents could be adaptors( [bi] and[ phi[ ) andtwo test syllables ( [di] and[ th i ] ). Each positedto handlesuch data. The differencebetween these models can be testsyllable was produced in eachadaptor condition. Subjects produced broughtto light by makingreference to statisticalcorrelations between only a singleadaptor and a singletest syllablewithin eachof the four the timing latenciesof variousarticolatory events [cf. K. Munhall, J. blockedconditions. Analysis of the obtainedvoice onset times indicated Acoust.Soc. Am. 7g, 1548-1553(1985}[. This studyinvestigates the that for the voicelesstest syllable,VOT was significantlyshorter after effectsof stresspattern and syllable structure on articulator timing, using adaptationto [phi] thanto [hi[. However,for thevoiced test syllable, x-raymicrobeam traces of jaw, tongue blade, and lip movement.Unlike in therewas no significant difference obtained between the two adaptor con- earlierstudies, real English words were used. Each token was placed in ditions.These findings are similar to thoseCooper obtained using percep- two contexts,natural sentencesand short, frame sentences.The effectsof tuomotoradaptation and will be discussedwith regardto possiblelinks thesetwo environmentsare alsoto be noted. The traceswill alsobe usedto betweenspeech perception and speech production. replicatethe velocity-displacementrelationship in themovement of the jaw, foundin earlierstudies of reiterantspeech [ Kelsoeta!., J. Aeonst. Soc.Am. 77, 266-280 (1985)].

10:48

Pll. Artienlatormovement in anticipatorycoarticulation. Gina M. Lee (Departmentof Linguistics,Ohio StateUniversity, 1841 Millikin Road, Columbus, OH 43210) 11:09 The resultsof previousstudies examining EMG activity(and, to a P13. Vocal fold contactarea. !ngo R. Titze (Departmentof Speech smallerextent, articulator movement} in anticipatorygestures have not Pathologyand Audiology, The Universityof Iowa,Iowa City, IA, 52242 beenconsistent. In somestudies, the onset of activityfor a givenfeature and the Recordingand ResearchCenter, Denver Center for the wastime locked, in thatit beganat a fixedinterval prior to theacoustic Performing Arts, 1245 Champs Street, Denver, CO 80204), onsetof thecorresponding segment. This suggests that timingplays an David Druker,and Paul Durham (Departmentof SpeechPathology intrinsicrole in theorganization of speech production, and that segmental and Audiology,The Universityof Iowa, Iowa City, IA 52242) targetsare dynamic.Other studieshave shown evidencefor feature spreading,where the onset of activitybegins within the earliest preceding Vocalfold contact area is generally inferred from the electroglottogra- segmentwhich makes no contradictorydemands on the articulators,re- phic(EGG) signal.To our knowledge,only one attempt has been report- gardlessof thelength between the onset of activityand the acoustic onset ed to measurecontact area directly [Scherer,Druker, and Titze, Vocal of therelevant segment. This suggests that time is extrinsicto segmental Fold PhysiologyConference, Tokyo, Japan (1987)]. This direct mea- specification,and that targetsare representedas static. However, Geller, surementis neededto identifyartifacts and ambiguities in the EGG signal Beli-Berti,and Harris (1985) andPerkeli (1986) arguethat thedifferent that maylead to questionableinterpretations of vocalfold movement. In findingsmay bedue to experimentaldesign:/s/and/t/, the consonants particular,the spatialdistributions of contactarea (anterior-posterior usedin suchstudies, may not be unspecified with regard to lipprotrusion, andvertical) is notalways clear by simpleinspection of the EGG signal. aspreviously assumed. In thecurrent study, the issue of featurespecifica- In thisstudy, excised dog larynges were prepared and mounted such that tion for presumedneutral segmentsis considered.Pellet tracesfrom se- onevocal fold couldvibrate against a sheetof electroconductiveglass. The lectedbases of x-ray microbeam data were examined. The point of onset of areaof contactwas then extracted by videostroboscopyand image pro- lip pwtrnsionwith respectto the acousticonset of the roundedvowel in cessingtechniques. Comparisons are made between thrce-parameter and VC, u utteranceswas measured. Velocity patterns of articulatormove- four-parametersimulation models of EGG andthe experimentally deter- ment were also considered. minedcontact area. [Work supportedby NINCDS.]

S37 J.Acoust. Soc. Am. Suppl. 1, VoL 81, Spring 1987 113thMeeting: Acoustical Society ol America S37 11:21 ingsemitones and spontaneously sang down and up thescale to thelower and upper limits of their range.These data were collectedthree timesin PI4. Source-systemcoupling in voice productionin excisedlarynges. one day, and three timeson a secondday 10-12 weekslater. The elicited Donald S. Cooper and Steven H. Florman (Department of frequencyproductions were converted to semitones(ST), and lowestand Otolaryngology,University of SouthernCalifornia, Hoffman 903, 2025 highestproduction and total rangewere calculated. For both elicitation Zonal Avenue,Los Angeles,CA 90033) methods,within-day and between-dayvariability were examined for all An apparatuswas constructed to studythe effectsof subglottaland measures.Results indicate that similarfrequency range values are ob- supraglottalresonances on voiceproduction in excisedhuman larynges. tainedregardless of elicitationmethod. However, for bothlower and up- Theapproach was based on anearlier study ofW. Trendelenburgand H. per limit of range,the matchingprocedure yielded somewhat more ex- Wullstein[ summar3,by D. S.Cooper in Otolaryngology--Headand Neck tremevalues (0.2 ST, 0.4 ST). Within-dayand between-dayvariation Surgery,edited by C. W. Cummingset al. (Mosby, 1986), Vol. 3, pp. weresimilar to what haspreviously been reported ( 3- 2 ST). 1766-1776].The resonanceof the pseudolungwas adjustable, while vari- ationof supraglottalresonances was achieved by constructionof vowel resonatorsbased on Fant'sarea functions. Activity of intrinsiclaryngeal muscleswas simulated by weights attached through pulleys to thelarynx. 11:48 In order to examinethe effectof acousticloading with a full rangeof variationof the first formant,voice production with supraglottalreso- PI6. The perceptionof voicingin word-finalCatalan stops. Jan Charles- nancesbased on/i/and/o/was comparedwith phonationwithout the Luce(Department of Linguistics,Indiana University, Bloomington, IN 47405) resonator.The restingglottal configurationand averageair flow were maintainedconstant, while the effects of varyingsupraglottal resonances It hasbeen demonstrated previously that Catalandoes not always onvoice production were observed in termsof acousticand giottographic exhibitcomplete acoustic neutralization of the underlying voice contrast measurements. in word-finalstops. The presentstudy investigated whether listeners can usethe acoustic differences distinguishing underlying voicing to identify thevoicing of work-final stops. Native Catalan and English speakers were auditorilypresented with natural tokens of threeCatalan minimal pairs 11:33 differingin theunderlying voicing of theword-final stop. For these mini- PIS. The stability of phonationalfrequency range when elicited by malpairs, vowel duration significantly distinguished underlying voicing two different methods. Connie Cook Spencer and Marylou in two-sentenceroedial position, but not in a sentencefinal position. The PausewangGeller (Department of Speech and Hearing Sciences, minimalpairs were excised from the sentences and presented in isolation. Indiana University,Bloomington, IN 47405) Theresults showed that neither the Catalan nor the English listeners were ableto identify significantly above chance the underlying voicing of word- Previousinvestigations of phonationalfrequency range suggest that finalstops produced in anyof thesentential positions. Thus, the acoustic themethod of elicitationcan affect the stability of thisrange. The method differencesdifferentiating the underlying voice contrast do not appear to of matchingtones [R. Coltonand H. Hollien,J. SpeechHear. Res. 18, beperceptually functional for distinguishing minimal pairs. The apparent 708-713 (1972)] appearedto yieldmore stable data than did spontan- dichotomyof productionand preception grammars and the implications eouslyproduced scales IX. Geller,J. Acoust.Soc. Am. Suppl.I 79, S82 for phonologicalneutralization will bediscussed. [Work supported by (1986)]. In thepresent study, subjects matched descending and ascend- NIH TrainingGrant NS-07134.]

S38 J.Acoust. Soc. Am. Suppl. 1, Vol. 81, Spring 1987 113thMeeting: Acoustical Society of America S38 WEDNESDAY MORNING, 13 MAY 1987 MT. McKINLEY, 8:30 A.M. TO 12:00 NOON

SessionQ. Underwater AcousticsIII: Numerical Solutions of Two Benchmark Problems

LeopoldB. Felsen,Chairman

Departmentof EECS,Polytechnic University, Farmingdale, New York11735

Chairman's Introductions8:30

The FirstSpecial Session on AccuracyAssessment of Numerical Codes was held at the I 12thMeeting of the AcousticalSociety in Anaheim,California, 8-12 December1986. An outcomeof that sessionwas a consensusto posespecific benchmark problems for numericalimplementation. Accordingly, two range-depen- dentpropagation problems have been posed and distributedto the underwateracoustics community, and contributionshave been solicited for presentationat thismeeting. Because the outcomeof the calculations couldnot be predicted at thesubmission deadline for abstracts,the traditional procedure has been modified to requirepotential serious contributors to submitonly their name(s)and affiliation(s), with a statementof whichproblem(s) they plan to attackand what code(s) they intendto apply. Presentorsare expectedto discusshow well their codeis suitedto the problemat hand,what accuracycontrols were imposed, what computationaldifficulties were encountered, what computation time was required, etc. It hasbeen requested thatdata are plotted in a standardizedformat so as to facilitatedirect comparison between results produced by differentalgorithms. Problem I dealswith upslope propagation in a wedge-shapedchannel while Problem II modelsa planeparallel waveguide with range-dependentsound-speed profile.

Problem l--Coordinators and Discussion Leaders:

M. Buckingham MassachusettsInstitute of Technology,5-204, Cambridge, Massachusetts 02139

F. Jensen GroupLeader, Environmental Modeling, N/I TO,SACLANT Research Centre, APO New York, New York 09019 R. Stephen WoodsHole Oceanographic Institution, Woods Hole, Massachusetts 02543

Problem II--Coordinators and Discussion Leaders:

J. DeSanto Centerof WavePhenomena, Department ofMathematics, Colorado School of Mines, Golden, Colorado 80401

D. Wood Naval UnderwaterSystems Center, Code 3122, New London, Connecticut 06320

Contributors: (Presentationorder and time to be determinedby coordinators.)

QI. Analyticsolutions to threewedge problems. Michael J. Buckingham Q4. Paraxialray solutions.Gregory L. Duckworth,Jung M. Lee,and (Massachusetts Institute of Technology, Cambridge, MA 02139) and RogerTurpening (Earth Resource Laboratory, Massachusetts Institute Alexandra Tolstoy (Naval ResearchLaboratory, Washington,DC of Technology,Cambridge, MA 02139) 20375)

QS. Convergencerate of Gaussianquadrature for classicalray tracing. Q2. Parabolicequation and coupledmode solutions. Alastair Cowley EdwardR. Floyd(Arctic Submarine Laboratory, Naval Oceans System and Roy G. Levers (Admiralty ResearchEstablishment, Portland, Center,San Diego, CA 92152) Dorset DT5 2JS,England)

Q6. Modelexperiments for 3-D propagationcharacteristics in a wedge- Q3. F. E. parabolic equationcode. Michael D. Collins (Northwestern shapedocean. Stewart A. L. Gleggand Jong R. Yoon (Florida Atlantic University, Evanston, IL 60201 ) University, Boca Raton, FL 33431)

S39 J. Acoust.Soc. Am. Suppl. 1, Vol.81, Spring1987 113thMeeting: Acoustical Society of America S39 Q7. Coupledmode and parabolic equation solutions. Finn B. Jensen Q10. Finite differencesolutions. Ralph A. Stephen(Woods Hole (SACLANTASW Research Centre, 19026, La Spezia,Italy ) OceanographicInstitution, Woods Hole, MA 02543)

QII. Wide angle 9arabolic equation solutions.David Thomson QS. Split step Fourier algorithm with high angle approximation. (DefenceResearch Establishment Pacific, FMO, Victoria,British Lan Nghiem-Phu(Daubin Systems Corporation, Miami, FL 33149) ColumbiaV05 IB0, Canada)

QI2. Numerical implementation of DeSanto's parallel wavegulde Q9. Parabolic equationimplicit finite difference(IF!}} solutions.J. problem. David Thomson, Gary Brooke (Defence Research S. Robertson,D.C. Arney (U.S. Military Academy, West Point, NY Establishment Pacific, FMO, Victoria, British Columbia V05 IB0, I0096) W. L. Siegmanand M. J. Jacobson(Rensselaer Polytechnic Canada), and John DeSanto (Colorado School of Mines, Center for Institute,Troy, NY ! 2180) Wave Phenomena, Golden, CO 80401 )

Other Contributions:

Becauseof the shorttime between the benchmarkproblem statement and the abstractdue date, a few additionalcontributions will beaccepted. Please contact Prof. L. B. Felsen.

Chairman's Summary:(Time determined bychairman and session coordinators.)

WEDNESDAy MORNING, 13MAY 1987 MT. RAINIER, 9:00 TO 11:35 A.M.

SessionR. NoiseIII andShock and Vibration I: InstrumentationCalibration--Facts and Fallacies

John P. Seller, Chairman MineSafety & HealthAdministration, U.S. DepartmentofLabor, 4800 Forbes Avenue, Pittsburgh, Pennsylvania 15213

Chairman's Introducti0n--9:00

Invited Papers

9:05

Rl. lnstrumentcalibration: A legalperspective in the context ofenforcement. ManuelR. Lopez(Officeofthe Solicitor,U.S. Departmentof Labor,4015 Wilson Boulevard, Arlington, VA 22203) Thereis widespread use of noisedosimeters, sound level meters, and acoustical calibrators in statutory enforcementschemes. As a generalrule, there are three prerequisites to bemet in orderfor evidenceobtained throughthe use of theseinstruments to be sufficient and admissible. First, in theperformance of the intended function,the scientific reliability of the instrument must be established. This is often accomplished byshowing thatthe instrument is permitted by law or acknowledgedasreliable by the e6urt. Second, it mustbe established thatthe instrument has been properly operated. This is done by showing that the operator is properly trained, followedapplicable instructions, and is familiar with the instrument.Third, the accuratecalibration of a particularinstrument that is used in a givencase must be shown; statutory calibration procedures, where they exist,must be strictlyadhered to; acousticalcalibrators where used to calibrateother instrumentsmust also be calibrated;and, should the accuracyof the instrumentto be calibratedcontain a variance,enforcement allowances should be made.

S40 J.Acoust. Soc. Am. Suppl. 1, Vol. 81, Spring 1987 113thMeeting: Acoustical Society of America $40 9:35

1•. Traceabilityof acousticalinstrument calibration to reciprocitycalibrations of laboratorystandard microphonesat the NationalBureau of Standards.Victor Nedzclnitsky(National Bureau of Standards, Building233 (Sound),Room A149, Gaithersburg, MD 20899) Criticalneeds of publicand private acoustical calibration laboratories for traceabilityto a reliablesource haveled to measurementservices based upon the pressure and/or free-fielc• calibration of laboratorystandard microphonesby establishedreciprocity methods over wide frequency ranges at the NBS.These primary methodsand measurement services provided by the NBS at fixedcost to otherlaboratories are described, and the frequency-dependentuncertainties associated with thesemethods and servicesare discussed.Instrument calibrationhierarchies comprising direct or impliedchains of traceabilityto theNBS may involve at leastfour differentdefinitions oftrace'ability, and one or moreof a varietyof secondarycalibration methods. Assessing theadequacy of a particularsystem for realizingtraceability involves judging the capacityof that systemto ensuremeasurements of acceptable accuracy for theirintended purpose. Examples of traceabilityand the frequency-dependentuncertainties in somemethods used to achieveit arc discussed.

10.'05

R3. Calabrationcapabilities-Army Primary StandardsLaboratory. James R. Arrington (U.S. Army TMDE SupportGroup, ATTN: AMXTM-SP, RedstoneArsenal, AL 35898-5400) The Army Primary StandardsLaboratory (APSL) generatesand maintainsmeasurement standards in acousticsand vibration.Army measurementactivities are supportedby a three-levelsystem that provides increasingdegrees of accuracystarting with field calibrationteams and endingwith APSL. Traceability, calibrationmethods, calibration accuracy, transducer densities, and transducertypes are discussed.

10:35

R4. Laboratorycalibration of acousticalcalibrators and noisedosimeters. Michael A. Crivaro and Dennis A. Giardino(U.S. Departmentof Labor,MSHA, 4800Forbes Avenue, Pittsburgh, PA 15213) The Mine Safetyand Health Administration ( MSHA ) maintainsa laboratoryto calibratenoise dosimeters and acousticalcalibrators. Dosimcters and calibratorsaxe usedby Federal mine inspectorsto determine compliancewith occupationalnoise regulations. Topics covered include reasons for creatingthe laboratory, testsystem design philosophy, test procedures, and estimatesof uncertainties.

11:05

RS. The calibration of integrating-averagingsound level meters: A manufacturerspoint of view. Peter Hedegaard(Briicl & Kjeerlndustri A/S, Na:rum, Denmark) Theintroduction of theintegrating-averaging SLM intocommon use has given rise to somenew calibration andtesting problems compared with those already known from th.e ordinary SLM. Determinationof reasona- ble requirementsfor the integrating-averagingsection and how to verifythe performancehas been a matterof discussionin connectionwith the nationaland international standardization work overthe pastyears. Some aspectsconcerning the requirementsand the testmethoiogies and philosophies are discussed. The newoppor- tunityto carryout spatialaveraging in a simpleway has given new life to the old discussionabout free-field and random-fieldcalibration. The free-field/random-fieldphilosophies are summarizedand someideas about the possibilitiesfor a final closingof "the Atlantic divide" are given.

S41 J.Acoust. Soc. Am. Suppl. 1, VoL81, Spdng 1987 113thMeeting: Acoustical Socie• of America $41 WEDNESDAY MORNING, 13 MAY 1987 REGENCY BALLROOM D, 9:00 A.M. TO 12:00 NOON

SessionS. Physical AcousticsIII: Scattering II: Waveguides,Imaging, Flow, and Probes

JosephA. Clark, Chairman MechanicalEngineering Department, Catholic UniversiO,, Washington, DC 20064

ContributedPapers

9.•0 observed"fine structure" of the scatteringresonances of thesphere in the waveguideand to theoccurrence of"superresonances." Here, this analy- SI. Comparisonof backscatteredand forward scattered fields for objects sis was extendedto a waveguidewith a (liquid) penetrablebottom to immersedin a shallowwater waveguide.M. F. Werhy and Guy Norton morecompletely explore the dependence of theresonance spectrum of the (NavalOcean Research and Development Activity, Numerical Modeling sphereon the acousticenvironment. For a spherein the sedimentlayer, Division, NSTL, MS 39529) the effectsof the sedimentloading and of the partial "unloading"by the A noisesource will form a guidedwave in a suitableenvironment at nearbysediment-seawater boundary are discussed.[Work supported,in sufficientlyhigh frequencies.When the guided wave encountersa sub- part, by the Officeof Naval Research.] mergedobject, the fieldscattered from the object will itselfform a guided wavewhen suitably far from the object.The objectscatters the field in a fairlycomplicated manner and depends on the relativedirection of mea- surement from that of the incident field as well as the orientation of the objectrelative to the guidedwave. A recentnumerical development at NORDA enablescalculations to be simulatedfor sdchphysical situa- tions.The objectiveof this studyis to assessthe relativeimportance of forwardscattered to backscatteredfidds. Calculations are performed and S4. Seatteringofacousticwavesinawaveguide.Rahul Sen(Department comparedfor severalfrequencies for the two configurationsand will be of EnginecringScience and Mechanics, Virginia Polytechnic Institute and presented.Results indicate that, abovea frequencylimit, forwardscatter State University, Blacksburg,VA 24060) and CharlesThompson is stronger,while, below that frequency,backscatter is favored. (Department of Electrical Engineering,University of Lowell, One UniversityAvenue, Lowell, MA 01854) The problemof scatteringfrom boundarydiscontinuity in a wave- gnidcis discussed. The relationship between the static and dynamic repre- 9:.15 sentationsof the scatteredpressure field will be investigatedfor those $2. Acousticscattering in an oceanenvironment: IIL Scatteringin an frequenciesfalling below the first c.ross mode of the duct. Special attention ispaid to theinfluence of cutotfcrossmodes to thesolution of thepressure inhomogeneouslayered waveguide. Roger H. Hackman and Gary field.It isshown that the method of matchedasymptotic expansions can S. Sammdmann (Naval Coastal SystemsCenter, Panama City, FL 32407) be successfullyused to determineglobally valid pressurefield junction conditionsnear a boundarydiscontinuity. The matchingof exponentially Previously,the formalsolution to thescattering from an elastictarget decayingterms of the innersolution is shown to, in turn,contribute to the in a waveguidewith an arbitrary numberof homogeneouslayers was junctionimpedance and extendthe frequencyrange of the solution'sva- presentedJR. H. Hackmanand G. S. Sammelmann,$. Acoust.Soe. Am. lidity. Suppl. I 78, S76 (1985) ]. The solutionis valid to all ordersof multiple scatteringamong the targetand waveguide boundaries. Here, this scatter- ing formalismis extendedto an inhomogeneouslayered waveguide with an arbitrarynumber of layers.As a firstapplication of thisformalism, the long-range,low-frequency scattering from an elasticspherical shell in a range-independentwaveguide with a sound-speedprofile of thekind lead- 10:00 ingto causticformation is considered. The focusof thisstudy is theextent to which the elasticinformation in the scatteredwave is modifiedby the s5. Exlmriments on junction inertanee. Zili Li and A. H. Benade propagationofboth the incidentand scatteredsignals through a conver- (Departmentof Physics,Case Western Reserve University, Cleveland, gencezone. [Work supportedby the Officeof Naval Research.] OH 44106) The conceptof junction inertante at thejoint betweentwo axisymmet- ric waveguidesof differenttapers arises from the nonaxial rearrangement flowand may be understood in termsof theimaginary wave impedance of the locallyexcited evanescent modes. The casesconsidered consist of cy- 9.'• lindricalpipes with infinitely long conical terminations of differentangles. In thesecases, the terminal impedanceof the pipe can be written as S3. Acoustic scattering in a range-independent,shallow water waveguide with a penetrable bottom. Gary S. Sammclmann, D. H. Trivett, and Z, =jwM/q- Z•o,c,where Mj is thejunction inertance and Z•o,½ is the parallelcombination ofM o coni½ityinertartec of the cone,and Ro, the Roger H. Hackman (Naval CoastalSystems Center, PanamaCity, FL characteristicimpedance of thepipe. Experiments were performed over a 324O7 ) frequencyrange of 150 Hz-15 kHz and reflectioncoefficients were mea- At a previousmeeting of the AcousticalSociety of America,the analy- suredfor coneswith half-angie10, 32, and90 deg.The resultsshowed that sisof thelow-frequency, acoustic scattering from an elasticspherical shell at highfrequencies (above 8 kHz for piperadius a = 10ram), theeffect is in a homogeneous,range-independent waveguide with nn impenetrable negligiblefor all cases.For 10deg, Mj isO.03(a/c)R o in a rangeof 4-6 bottom was presented[G. S. Sammelmannand R. H. Hackman, J. kHz, wherec is thespeed of sound.At lowfrequencies ( below 3 kHz ), Zt Acoust.Soc. Am. Suppl.I 79, S76 (1986) ]. This previousinvestigation hasthe form ofjw(M 1 q-Me); to separateMj andM c becomesmore centeredon elucidatingthe underlyingdynamical picture leading to the complicated.Several cases will bediscussed. [Work supportedby NSF.]

S42 J. Acoust.Soc. Am. Suppl. 1, Vol.81, Spring1987 113thMeeting: Acoustical Society of America S42 10:15 fractionpattern described by n2 = 2A* sin0 a. Korpel[ OpticalImaging of UltrasunitFields by ,4cousticBragg Diffraction (Rotterdam, 1962)] S6. Analyticsolutions to the waveequation in a duetlined with axially studied,in detail,the condition n = I andthe imageproduced in thefirst nonuniformabsorbents. P. G. Vaidyaand D. G. Martin (Washington diffractionorder. Martin [J. Appl. Phys.43, 1480 (1972)] observed StateUniversity, Pullman, WA 99164-2920) Braggdiffraction with high-intensityultrasonic waves and notedthat for For circular ducts with axially uniform boundaryconditions, the n)2 oneobserves multiple images in the diffractionorders. A somewhat acousticfield can be expressedin termsof a set of eigenfunctions.The successfulmodification of the mappingtheory of Korpelwas developed, correspondingeigenfunctions depend on thecircumferential and the axial althoughit had distinctlimitations. The presentdiscussion is focusedon modenumber. In thispaper, a modificationof theanalysis, when the axial n)2 and the opticalconditions leading to multipleimages in the higher boundaryconditions are nonuniform,is presented.The firstpart of the diffractionorders. The existenceof two imagesis convenientlyexplained paper deals with an exponentialvariation in a semi-infiniteduct. It has on the basisof the theory of Biotaroeand Leroy [Acustica 59, 1821 beenshown that the field can be representedin termsof submodes.The (1986) ]. [Researchsupported by the U.S. Officeof Naval Researchand eigenvaluesof eachof thesesubmodes are distinctfrom eachother, how- by the UT-ORNL ScienceAlliance. ] ever,if theycan be readily calculated. This analysisthen is extendedto an arbitraryvariation of axial boundaryconditions for finitelength ducts. 11:15 Numericalcalculations are presentedfor the specialcase of circumferen- SI0. UltrasonicBragg imagingof flaws. JeongKwan Na, M. A. tially uniformfields (m = 0). It hasbeen noticed that the characterof the Breazeale(Department of Physics,University of Tennessee,Knoxville, multipleeigenvalues of the submodesundergoes a qualitativechange TN 37996-1200),and Oswald Leroy (KatholiekeUniversiteit Leuven, (akin to nonlinearbifurcation phenomenon) at the third radial mode B-8500Kortrijk, Belgium) (n = 3), for the specificcase studied. A superficialcrack on an aluminumplate becomesan internalflaw whencovered by a secondplate. Ultrasonicwaves are causedto resonate 10:30 betweenthe externalsnrfaces of the platesand producetransmission maximacharacteristic of Lamb modes in the plates. The transmitted wave S7. Analytical solutions to the wave equation in a duct lined with frontsin a liquid,modified by the presenceof the flaw,are now used to circumferentially nonuniform absorbents. D. G. Martin and P. G. diffractlight at the Braggangle. The Braggdiffraction orders contain Vaidya (WashingtonState University, Pullman, WA 99164-2920) imagesof theultrasonic wave fronts and, hence, can be used to imagethe Nonuniform boundaryconditions are of fundamentalinterest from internal flaws. Characteristic flaws are shown and resolution limits are discussed.[ Research supported by theU.S. Office of Naval Researchand @ the theoreticalpoint of view. They are alsoimportant from a practical ß pointof view becauseof the potentialof substantialenhancement of at- by the UT-ORNL ScienceAlliance. ] tenuation,which has been experimentally demonstrated. However, con- ventionaleigenfunction solutions cannot be usedto solvesuch problems. 11:30 Therefore,much of the work in thisarea has been of a purelynumerical nature.In thispaper, the recent work by Vaidya,which was restricted to a S11. Accurateand preciseassessment of puisatilevolume blood flow by singleterm in the exponentialexpansion, has been extended to any arbi- time domain correlation. Ilmar A. Hein and William D. O'Brien, Jr. trary circumferentialvariation. It hasbeen found in thisgeneral case that (Department of Electricaland Computer Engineering,University of theconcept ofsubmodes can still beused to constructthe solutions. How- Illinois, 1406 W. Green Street, Urbana, IL 61801 ) ever,the eigenvaluesof submodescan be altered, as opposed to theobser- An ultrasonicflow velocitymeasurement technique using time do- vationin the restrictedease. A modifiedprocedure to find the eigenvalues maincorrelation has been developed to accuratelyand preciselymeasure and the submodalcoefficients has been developed. Specific numerical cal- theaxial flow velocity of liquidin a circularvessel. This techniquecan be culationsare presentedto showthe alterationof the acousticfield and usedto estimatethe volumeflow in a circularvessel without any previous attenuation in hollow circular ducts. knowledgeof the vesselsize, flow velocityprofile, or transducermeasure- ment angle.Continuous flow has beenmeasured with an overalluncer- taintyof lessthan ! 5%. Pulsarlieflow hasbeen estimated by measuring 10:45 flow velocityat the centerof the vessel.Results indicate that the accurate S8. Modal propagationin ducts lined with elastic porousmaterials. J. and precisemeasurement of pulsatileflow of humanblood by time do- S. Bolton and N.M. Shiau (Ray W. Herrick Laboratories,School of main correlationis possible,and the applicationof this techniquein the MechanicalEngineering, Purdue University, West Lafayette, IN 47907) diagnosisof variousthrombosis in the lowerlimbs is beingstudied. The characteristicsof soundpropagation in ductslined with either 11:45 locally or hulk reactingmaterial are well known. The latter material is generallyassumed to be homogeneousand capableof supportingonly a S12. Measurementof coherencewith a vectoracoustic intensity probe. singlelongitudinal wave and is usually modeled as a rigid-framedporous Joseph A. Clark (Mechanical Engineering Department, Catholic material.It hasrecently been demonstrated both experimentally and the- University, Washington, DC 20064 and DTNSRDC, Bethesda,MD 20O84) oretica!iythat elasticporous materials of the type usedin noisecontrol (i.e., relativelystiff, partially rcticulated foam ) cansupport two longitu- Complexcoherence is usuallydefined in theacoustics literature as the dinalwaves: the framewave and the airbornewave. In thispaper, Scotts (ensemble-averaged)cross spectrum between pressure measurements treatmentof extendedreaction duct liningsis modifiedto allowfor this madesimultaneously at two pointsand normalizedwith respectto the observation.Equations govcroing the three-dimensionalpropagation of squareroot of the productof theautospectra at thesame two points.If the eachwave type within the material arc presented along with theappropri- two pointsare sufficientlyclose together, a considerablesimplification ate boundaryconditions at the duct/lininginterface. The effectsof finite occurswhich allowsthe complexcoherence to bemodeled as a functionof frameelasticity are demonstrated by a comparisonof the attenuationand one positionwith two parts.The real part correspondsto the classical phasespeed of the firstseveral duct modesfor elasticporous linings and definitionofplane-wave intensity. However, it is scalerin character(om- the equivalentrigid porouslinings. nidirectional).The imaginarypart correspondsto thedefinition of inten- sity assumedby acousticintensity measurement methods of more recent interest.This part exhibitsa vectorcharacter. Vector acousticintensity 11:00 probesconsisting of at leastfour elements arranged in closelyspaced pairs $9. Bragg imaging of high-intensity ultrasonic waves. M. A. Breazeale. alongthree orthogonal directions, can completelycharacterize complex Jeong Kwan Na (Department of Physics,University of Tennessee, coherence fields of the form described above. Ambient noise fields (and Knoxville, TN 37996-120O), and Oswald Leroy (Katholieke fieldscontaining both signalsand noise)can, in turn, be characterizedby UniversiteitLcuven, B-8500 Kortrijk, Belgium) complexcoherence measurements. These characterizations are of practi- cal importancein estimatingthe accuracyand array gain of acousticin- Lightincident on ultrasonicwaves at theBragg angle produces a dif- tensitymeasurements.

$43 J.Acoust. Soc. Am. Suppl. l, Vol.81, Spring 1987 113thMeeting: Acoustical Society of America S43 WEDNESDAY MORNING, 13 MAY 1987 CELEBRATION HALL, 9:30 A.M. TO 12:00 NOON

SessionT. ArchitecturalAcoustics lII, Psychologicaland Physiological Acoustics V, andSpeech CommunicationIV: SpeechIntelligibility in Lecture Halls and Classrooms

Richard M. Guernsey,Chairman CedarKnolls •4coustical Laboratories, 9 Saddle Road, Cedar Knolls, New Jersey 07927

Chairman's Introduction--9:30

Invited Papers

9:35

T1. Reviewof methodsof measuringrooms for speech.J. S. Bradley(Institute for Researchin Construction, National ResearchCouncil of Canada,Ottawa K IA 0R6, Canada) Measuresof theacoustical quality of rooms for speech should include both the signal-to-noise and the room acousticsaspects of theoverall problem. The classical approach was to includethese two aspects separately as backgroundnoise levels and reverberation times. Newer measures have combined both aspects into a single quantity.These more successful newer measures include an assessmentof the beneficialeffects of the directand earlyreflected sounds and the detrimentaleffects of laterarriving sounds. The predictionaccuracies of a numberof acoustical measures arecompared, and optimum values of each quantity are presented. Optimum valuesfor theclassical quantities, background noise levels, and reverberation times are derivedas a functionof roomvolume from the newerquantities. The relationshipsbetween various measures are discussed.

1o:oo

T2. Speechintelliglbility in classroomsusing RASTI. Klaus Hojbjerg(Briiel & Kjaer Instruments,185 Forest Street, Marlboro, MA 01752)

Speechintelligibility in classroomsisnormally not a problem.However, in certainsituations, when teach- inghearing-impaired children; the acoustics of theclassroom becomes important. Many old classrooms have insufficientacoustic design and therefore must be treated when hearing-impaired children are integrated with childrenwith normal hearing. A quickmethod of assessingspeech intelligibility is theRASTI system.This method,developed by Houtgastand Steenekenin The Netherlands,is basedon a measureof the modulation transferfunction in twooctave bands. These two bands are centered at 500Hz and2 kHz, wherea totalof nine modulationfrequencies are measured. This paper will describethe RASTI system,and actual measurements will be shown.

10:25

T3. Standardizationof speechlevel measurement. Karl S. Pearsons(BBN Laboratories,Inc., 21120Vanowen Street,Canoga Park, CA 91303) The levelof speechis measuredusing a varietyof instrumentationand techniques. Most methods serve the needsof the particular user. However, the many different schemes make it difficultto compare one set of speech levelswith another. In anattempt to providea standardmethod of measurement,a standards working group wasformed to developa simple,meaningful, repeatable method for quantifyingspeech. This paper discusses the difficultiesof providingsuch a measureand presents the philosophyof the workinggroup's proposed method.The proposed method will be described and relationships with other speech measurement techniques will be presented.

10:fi0

T4. Speechcommunication in lecturehalls and classroomsfor hearing-impaired.Anna K. Nabelek (Departmentof Audiologyand Speech Pathology, The Universityof Tennessee,Knoxville, TN 37996-0740) Roomswith good acoustics for normal-hearinglisteners might be inadequatefor peoplewith hearing impairments.To achievelistening conditions satisfactory for thehearing-impaired listeners, three conditions mustbe met: ( 1) Speechshould be delivered at highersound-pressure level than for normal-hearing listeners to oompensateforhearing loss; ( 2 ) backgroundnoise should be at least15 dB lower than the level of speech; and (3) thereverberation time of theroom should be as short as possible. Amplification through public address systemsis notpractical because hearing-impaired listeners would need levels not tolerated by thegeneral

S44 J. Acoust.Soc. Am. Suppl. 1, Vol. 81, Spring 1987 113thMeeting: Acoustical Society of America S44 public.Also, because there are limits to reductionin backgroundnoise and elimination of soundreflections, listeningconditions in lecture halls and in classroomsmight be less than ideal for thehearing-impaired. A solutionisthe use of assistire listening systems. In thesesystems, sounds which are picked up by microphones locatedclose to the talkers'mouths contain little noiseand reverberation.Then the soundsare transmittedon radioor infraredwaves throughout a wholeroom. The soundsare received by individuallyworn receivers whichare equippedwith gain controls. The benefitsand limitations of assistirelistening systems will be discussed.[Work supportedby NIH. ]

Cont•butedPaper

11:15 soundconsidered to bereverberant sound at the highestlevel return with- in thefirst 50 ms.This, in a majorityof eases,results in usingonly the first T$, Speechintelligibility measurements sing TEF analysis.Don Davis arrivaland nointegration of earlysound. Evidence will bepresented that (SynergeticAudio Concepts,P.O. Box !:239, Bedford, IN 474:21), indicatesthat the useof impulsesquared measurements that fail to process Don Keele (Crown International, 1718 W. Mishawaka Road, Elkhart, thesignal as a complexanalytic signal often fail to properlyrecord major IN 46517), and EugenePatronis { 1774 NorthridgeRoad, Dunwoody, reflectivesignals unless extensive spatial averagingis resortedto. The GA 30338) paperwill be supportedby actualpostprocessing of data takenwith a Recentinvestigations into the measurementof speechintelligibility TechronTEF analyzerusing the Heysettechnique for energytime curve usinglarge listener groups (three groups of 30 each) in a cathedral,a measurement.In such measurements,minor movemenlsof the micro- concerthall, and a classicmotion picture theater of the early 1930ssug- phonedramatically affect the impulseand doubletresponses while the gestthat a listener'ssubjective intelligibility score will bebest matched in samechange barely affects the energytime curvemeasurement, thus de- objectivetesting by dividing the sound considered to bedirect sound from monstratingthe needfor the complexanalytic signal in suchanalysis.

11:30-12:00

Panel Discussion

S45 J.Acoust. Soc. Am. Suppl. 1, Vo.I. 81, Spring 1987 113thMeeting: Acoustical Society of Amedca $45 WEDNESDAY AFTERNOON, 13 MAY 1987 MT. RUSHMORE, 1:00 TO 2:15 P.M.

SessionU. Bioresponseto Vibration I: Vibratory Sensitivity and Tactile SpeechAids

JanetM. Weisenberger,Chairman Central Institutefor the Deaf, 818 S. Euclid, St. Louis, Missouri63110

Contributed Papers

1:00 1:30

UI. Comparisonof two multichannel tactile aids for the hearing- U3. Psychophysicalevidence for a four-channelmodel of vibrotaction. impaired.Susan M. Pottsand Janet M. Weisenberger(Central Institute StanleyJ. Bolanowski,Jr. (Centerfor BrainResearch, University of for the Deaf, 818 S. Euclid, St. Louis, MO 63110) RochesterMedical School, Rochester,NY 14642), George A. Gescheider(Department of Psychology,Hamilton College, Clinton, Two multichanneltactile devices for the hearing-impairedwere com- NY 13323), Ronald T. Verrillo (Institute for SensoryResearch, paredin tasksusing acoustic stimuli of varyinglevels of complexity.One SyracuseUniversity, Syracuse, NY 13210),andChristineM.Checkosky device was a 16-clementlinear vibratory array worn on the forearm, (Centerfor Brain Research,University of RochesterMedical School, whichdisplayed activity in 16overlapping frequency channels. The other Rochester, NY 14642) deviceutilized 16 channelsin a similarstimulus processing strategy, but deliveredthe tactilestimulation to a linearclcctrocutaneous array worn Althoughprevious physiological experiments have identified four on the abdomen.Subjects were testedin tasksincluding phoneme dis- sensorychannels (Pacinian, RA I, SA!, andSAII) inglabrous skin of the criminationin pairsof rhymingsyllables, phoneinc identification in larger humansomatosensory periphery, only three (Pacinian, RA I, andSA I) setsof rhymingsyllables, learning of a list of words,and connecteddis- havebeen shown to mediatevibrotactile sensation. By usingstimuli to coursetracking. All stimuliwere presented live-voice by a femaletalker, selectivelymask thesevarious channels, it is demonstratedthat a fourth and lipreadingwas permittedonly in the trackingtask. Results showed channeldoes, indeed, participate in the perceptualprocess. The fourth both devicesto be goodtransmitters of mannerand voicingfeatures of channelis unaffectedby changesin skin-surfacetemperature (15 ø to articulation,but poortransmitters of placefeatures. Differences between 40'C) andstimulus area ( 0.008to 2.9 cm 2 ) orduration (700 to 2500 ms ). the two deviceswere found only at the levelof connecteddiscourse track- Adheringto previouspsychophysicai nomenclature, the fourth channel is ing. Resultsare discussedin termsof differencesbetween the two devices callednon-Pacinian IIl (NP III). Thefour psyehophysically measured in processingstrategy, location of stimulatorarray, and type of trans- channels(P, NP I, NP II, and NP III) combineat thresholdto createan ducer.[Work supportedby NSF and NIH. ] operatingrange for the perceptionof vibrationwhich extends f•om 0.4 to > 500 Hz. The four channelsmediate specific portions of the overall threshold-frequencycharacteristic, although their sensitivities partially overlap.Thus suprathresholdstimuli may activateseveral channels si- multaneously,suggesting that the perceptual qualities of touchmay be determinedby the combined inputs of all four channels. [ Work supported by NIH and NSF. ]

1:45 U2. Vibrotaetilemasking •s a functionof stimulus-onsct-•synchrony.G. A. Geseheider(Psychology Department, Hamilton College,Clinton, U4. Lingual wbrotaetile magnitude estimation and eross-modality NY 13323), R. T. Verril]o (Institutefor SensoryResearch, Syracuse matching:Aging effects. Elizabeth Randolph-Tyler (Ohio University, University,Syracuse, NY 13210),and S. J. Bolanowski,Jr. (Centerfor Athens, OH 45701}, Donald Fucei (Ohio University, Athens, OH BrainResearch, University of RocbesterMedical School, Rochester, NY 45701}, Linda Pettorino (Bowling Green State University,Bowling 14642) Green, OH 43403), and Daniel Harris (Healthcare Rehabilitation Center, Austin, TX 78745) Vibrotacti]ethresholds for thedetection of a 50-msvibratory stimulus on thethenar eminence of thehand were measured in the presenceof and Lingualvibrotaetile suprathreshold sensation magnitudes were inves- in the absenceof a 700-mssuprathreshold vibratory masking stimulus. tigated acrossfour age groups (mean ages= 7.8, 19.3, 45.2, and 57.0 Whenthresholds were measured in thepresence of themasking stimulus, years} by employingthe psychophysicalmethods of magnitudeestima- stimulus-onset~asynehronywasvaried so that hackward,simultaneous, tionand cross-modality matching. Lingual vibrotactile stimuli were pre- andforward masking could be measured.The amountof masking,ex- sentedin combinationwith auditory stimuli for the eroas-modality pressedas the differencebetween thresholds for detectingthe teststimu- matchingtask. For lingual vibrotaetilemagnitude estimation, both the lus in the presenceof and in the absenceof the maskingstimulus, was upperand lowerpower functions were steeper for the oldestage group. greatestwhen the test stimuluswas presentednear the onsetor offsetof Thepower functions for cross-modalitymatching in whichthe vibratory the maskingstimulus. For both backwardand forwardmasking, the stimuluswas the standardshowed asymptotic growth at about25-dB amountof maskingdecreased as a functionof increasingstimulus-onset- sensationlevel for thethree older age groups, but not for theyoungest age asynchronywith the decayrate being greater for backwardthan for for- group.Straight-line power functions were obtained for all agegroups on wardmasking. Comparisons were made of theamounts of maskingmea- the cross-modalitymatching task when the auditorystimulus was the suredwhen the testand maskingstimuli were both sinusolds,when the standard,with the olderaged subjects making larger lingual vibrotactile testand maskingstimuli were both noise,and whenthe teststimulus was a magnitude adjustmentsto the lower level auditory stimuli than the sinusoldand the maskingstimulus was noise. youngeraged subjects. In summary,age-related response differences did

S46 J. Acoust.Soc. Am. Suppl. 1, VoL81, Spring1987 113thMeeting: Acoustical Society of Amedca $46 occurat suprathresholdlevels of vibrotactile stimulation, and the psycho- neurologicaltests, and refinedmeasures of vibrotactileand gappercep- physicaltechniques employed appeared to bea noninvasiveway to make tion, Of 28 subjects,21 werejudged free of confoundingfactors (13 judgmentsabout suprathreshold functioning of thehuman tactile system forestryworkers exposed to chainsaw vibration, aged 28 years + 4 s.d., asit changeswith age. and 8 laboratoryworkers not exposedto vibration,for comparison,aged 34 + 3 years).The measurementsof vibrotactileperception were per- formedover a widefrequency range (2-400 Hz) to permitseparate assess- 2:00 mentof thethree different types of mechanoreceptors--Paciniancorpus- US. Tactile sensationin handsexposed to vibration: A pilot study. A. cles,Meissner corpuscles, and Merkel disks.The gap perceptionwas J. Brammer,J. E. Piercy (Division of Physics,National Research measuredwith a newlyimproved aesthesiometer. Preliminary analysis of Council of Canada,Ottawa, Ontario KIA 0R6, Canada), P. L. Auger the resultsindicates that measurementsof vibrotactileperception particu- (Centre HopitalierUniversit• Laval, Ste. Foy, QuebecGlV 2K8, larly can detectsensory changes in the fingersnot consistentlyfound by Canada), and S. Nohara (Department of Public Health, Schoolof conventional clinical tests. Medicine,Kanazawa University, Kanazawa, 920 Japan)

Three methodsare comparedfor assessingimpaired tactile sensationin vibration-exposedworkers: a medicalexamination including traditional

WEDNESDAY AFTERNOON, 13 MAY 1987 MT. RAINIER, 1:00 TO 2:30 P.M.

SessionV. Noise IV: Noise Control Methodsand Applicationsand Effectsof Noise (PosterSession)

AngeloCampanella, Chairman CampanellaAssociates, 3201 Ridgewood Drive, Columbus, Ohio 43220

All posterswill be displayed from 1:00-2:30 p.m., and contributors will be at theirposters the entire time.

ContributedPapers

V1. Noisecontrol case history: Cafeteria environment. Larry H. Royster ever,the task is made difficult by thefact that they are inevitably correlat- (DepartmentofMechanical and Aerospace Engineering, North Carolina ed and are oftenclosely spaced. Recently the newlydeveloped Briiel & StateUniversity, Raleigh, NC 27695-7910) Kjaerspatial transformation of sound fields (STSF) system was used to identifysources inthis situation. This system isa broadbandadaptation of Complaintsfrom employees at a localresearch institution about diffi- theacoustical holography technique; it makes use of sound-pressure mea- cultiesin communicating while eating lunch in theInstitute's cafeteria led surementsat a numberof referencelocations and at an arrayof fieldpoints theinstitution to requestrecommendations asto possiblefacility modifi- toidentify the wavenumber components of thefield. These may be used to cations.Premodification sound surveys were conducted with andwithout reconstructthe entiresound field exteriorto a planetangent with the the employeespresent. Recommendations were then made to manage- source.By examiningintensity maps on orthogonalplanes near the mentas to facilitymodifications that wouldbe expectedto significantly source,closely spaced individual surface sources may be identified. The lowerthe cafeteria'ssound level during the peaklunch period. After the applicationofthis technique toa completenoise control procedure will be recommendationswere implemented, sound surveys were conducted to illustratedin this paper. verifythe predicted levels of noisereduction. The facility modifications includedextensive use of sound-absorbingwall panels,a loweredand improvedacoustical ceiling, and the constructionof a partialbarrier betweenthe food-serving line and the eating area. At maximumusage, a V3. Determination of vehiclenoise source levels. Richard C. Smart and 12dB (A) ( A-weightedsound-pressure level) reductionin thecafeteria's StanleyE. Dunn(Department of OceanEngineering, Florida Atlantic soundlevel was achieved [from 75 to 63 dB(A)]. No additionalcom- University,Boca Raton, FL 33431) plaintshave been received from the Institute's employees regarding noise in the cafeteria. In 1974the FloridaDepartment of Transportationparticipated in a studysponsored by tbeFederal Highway Administration to determine vehiclesource levels. This paperreports the findingsof a secondstudy designedto extendthe range of theoperating speeds of thevehicles in V2. Applicationof the STSFsystem to noisesource identification in questiondown to 20 mph ( 32kph). A totalof I 1sites were included in the domesticappliances. U. D. Dietschiand J. S. Bolton(Ray W. Herrick studywith vehicles operating between 20 to 61 mph.The subsequent data Laboratories,School of MechanicalEngineering, Purdue University, wcrcanalyzed to providedistributions of maximum passby sound levels West Lafayette. IN 47907) andreference energy mcan emission levels as a functionof speed for auto- mobiles,medium trucks, and heavy trucks. The data were analyzedover Theacoustic energy produced by small appliances often originates at theentire speed range and on thebasis of 5 mphspeed band to provide onepoint within the device (e.g., an electric motor) but actually radiates empiricalrelations for use in predictivemodels. Of particularinterest was froma numberof points on the casing. It isuseful to identify these surface the extent to which the choiceof tbeseformats influencedthe noisesource sourcessince they may indicate internal energy transmission paths; how- relationshipsand, of moresignificance, the extent to whichthe introduc-

S47 d. Acoust.Soc. Am. Suppl.1, Vol. 81, Spring1987 113th Meeting:Acoustical Society of America S47 tionof low-speeddata which were not previouslyavailable influenced modeand SPLs were taken !.2 m from groundin front of the vehicles sourcelevel relationships. [Work supportedby the FloridaDepartment alonga 180' arc at pointsup to 30.5 m and in the vehicleat ear level of Transportation.] (referencedto driver, passenger,patient, etc. ). SPLs measuredoutside the vehicleat 30.5 m showedthe grill-mountedspeakers typically pro- duced14 dBA moreintensity than the conventionallylight-bar-mounted speakersat 0' azimuth.SPLs inside the vehicle were 11 to 16dBA quieter V4. A computer-basednoise measurementsystem. Patrick Luquet in condition2 dependingon positionmeasured. Efficacy of sirenitself for (Sceur-AnneCorporation, 43, Avenuede la Rrpublique,Villeurbanne, emergencyalerting was enhanced and occupantnoise exposure was re- France, 69100) ducedwhen sirens were grill mounted. Thispaper describes a computer-based measurement system that en- ablesthe operator to identifydifferent noise sources and to measuretheir separateacoustical contribution to noisebuildup. The principle is based V7. Effect of noise in ICU on heart rate and annoyance in adult uponthe storage of ! 31072 short-term L• 's(through asound level meter posto!•rativeImtients. Carol F. Baker (Collegeof Nursing,The Ohio with built-inmemory) that are processedby personalcomputer. The StateUniversity, Columbus, OH 43210) methodis illustratedby casestudies ranging from urban noise surveys to industrialnoise exposure monitoring, and includes environmental noise The relationshipsof environmentalnoise in a surgicalICU, measured mapping.It is shown that both the method and the instrument have made as soundpressure levels in dBA, to changesin heart rate and perceived it possibletoreduce study costs while increasing the number and duration annoyancewcrc determinedin 28 postoperativeadult patients.Levels of samplingmeasurements, improving reliability factor of analyzedre- were recordedfor a continuous6-h period on calibratedgraph paper. suits,and allowingfor the identificationand quantificationof multiple Heart rate wasrecorded simultaneously by convertingECG signalsfrom noisesources. The data-processingsoftware presented in thispaper pro- the bedsidemonitor. Data were sampledevery 12 s and a meanobtained videsthe means to speedup reportproduction while guaranteeing mini- within eachnoise episode. The graph patternswere classifiedinto four mum-errordata interpretation. typesof noise:talking inside the room,talking outside, nontalking, and ambient.The meanswithin eachtype were averaged. Annoyance to ICU noise, which included disturbance from sound, disturbanceto activities and to sleep,was measured by a questionnaire.Intervening variables of noisesensitivity and hearing acuity were also determined for eachsubject. VS. A method for presentingdynamic performancecharacteristics of Resultsshowed noise levels in patients'rooms ranged from 60-64 dBA. A highlydamped vibration isolators. Neil G. Piesher(E-A-R Division/ highambient level was created by theuse of oxygenwhich masked outside CabotCorporation, 7911 Zionsville Road, Indianapolis, IN 46268-0898) sounds.Sixty-eight percent of subjectsshowed a significant(p ----0.10) increasein heart rate with an increasein decibelfrom a previousnoise A methodfor presentingdynamic performance characteristics of level.Mean heartrate was greatest during talking inside the room. Heart highlydamped vibration isolators is discussed.The methodutilizes nor- rate wassecond highest during nontalking noise. Heart rate duringam- realizedstiffness versus load graphsobtained from laboratorytest data bientconditions was highly variable within subjects. The majorityof sub- andenables determination of dynamicstiffness and naturalfrequency as a jects reportedlittle annoyanceto ICU noise,except when it interfered functionofisolator load and temperature. Isolators examined were grom- with sleep.Noise sensitivityand mild hearingloss were not significant metsand bushings made from three PVC thermoplastics.Because similar factorsin annoyanceto ICU noise. typesof isolatorsshow similar isolation characteristics with respectto loadand temperature, they can be categorized into families based upon materialformulation and isolatorgeometry. This providesa meansfor presentinga large amount of performanceinformation in an abbreviated VS. Comparisonof hearing acuity of rural, urban, and industrial format.Methods of data acquisitionand reductionare discussedbriefly populations.S. Raja and K. Harjeet Singh (ErgonomicsDivision, with majoremphasis on the determinationof isolatoreffectiveness for National Institutefor Trainingin IndustrialEngineering, Vihar Lake basicnoise and v•brationcontrol problems. Road, Bombay-400087, India) Auditoryacuity of 104 rural individuals,126 urbanindividuals not exposedto occupationalnoise, and 118workers from a textilemill was examinedin orderto studythe influence of noiseexposure characteristics V6. Ambulance sirens and in-vehicle noise exposure:An investigation on hearinglevel of the threepopulations. Pure-tone audiometry in 5-dB into alternative siren speaker placement.Martin W. Van Buren stepsat selectedfrequencies was conducted with the helpof a portable (AmbulanceService, ADABEC 825,Hennepin County Medical Center, diagnosticaudiometer. Noise level recordings were made by a B&K im- 701 Park Avenue,Minneapolis, MN 55415)and Gary Caple(Federal pulseprecision sound level meter and an octave band analyzer. The differ- cncesin heatinglevel at 4 kHz betweenthe populationswere found to be Cartridge,Anoka, MN 553.03) statisticallysignificant, with the rural individualsexhibiting superior Two modularRoad Rescuetype Ill ambulanceson 1985Ford E350 heatingcapacity compared to othergroups, and urban individuals show- XL RV cutawayvans, cab headliners insulated with fiberglass,modules ing betterability compared to their industrialcounterparts. In the low with 1«in. of self-extinguishingpolyurethane foam planking, were, re- frequencies(0.5 and I kHz), however,significant differences were ob- spectively,outfitted with Southern D-50-C chrome bell 100-W speakers, servedonly betweenrural and industrialworkers. The comparison forwardfacing, light-bar mounted above cab at 15' off center,speakers betweenurban and industrial workers yielded only differences ina.bsolute approximately2.3 m from ground(condition i ) andwith WhelenSA- valueswhich were not significant. Some factors contributing to thepoorer 450G speakergtrobe 100-W apeakers, forward facing, flush-radiator-grill- heating capacity of urban individuals have been discussed.The signifi- mounted,0.94 m apart,speakers approximately 0.9 m from ground(con- cance of this evaluation in the context of a mass movement of individuals dition 2). Eachvehicle was placed on tarmacwith sirensset on "wail" from rural to urbanareas to seekemployment has been outlined.

S48 J. Acoust.Soc. Am. Suppl. 1, Vol.81, Spring 1987 113thMeeting: Acoustical Sociely of America S48 WEDNESDAY AFTERNOON, 13 MAY 1987 MT. McKINLEY, 1:00TO 3:05P.M.

Session W. Underwater Acoustics IV: Seabed Acoustics

Ian Roebuck, Chairman /ldmiraltyResearch Establishment, Portland, Dorset DTS-2JS, United Kingdom

Chairman's Introduction--l:00

ContributedPapers

1.-05 investigatedusing the resultsof at-seameasurements and predictions basedon geoacousticand numericalmodels of the testenvironment. The WI. Measurementof soundabsorption and soundspeed in terrigeneons experimentwas conductedby the Naval Ocean Researchand Develop- sediments.Marco M.P. Weydert, Nicholas Murray, and Marco mentActivity in a shallowwater region off the southeasterncoast of the D'Alessandro(Commission of the European Communities,Joint U.S. A verticalarray of hydrophonesin the watercolumn and a distribu- ResearchCentre--Ispra Establishment, 21020 Ispra (VA), Italy) tionoftri-axial geophoneson the oceanbottom were used to monitorthe The absorptionand speedof soundwere measuredbetween two bore responseto both cw and broadband(explosives) sound sources. Predic- holeseach 150 m deepand spaced 4 m apart.Sediment profile samples tionsof the propagationwere made using the SAFARI versionof FFP, havebeen obtained from the two wellsand the watercontent, porosity, thewide-angle version of theParabolic Equation Method, and the SNAP density,and mineralogy determined. Acoustic measurements were made normalmode model.Preliminary results of the •easurementsare dis- at selecteddepths in thewater saturated sediments down to a maximumof cussedand comparisons are madewith the predictionsbased on the nu- -- 83 m. The acousticfrequencies ranged from 7.5-18 kHz; at the lower merical models. frequency,the absorptionvaried from 0.3 dB/m in clay to 0.4 dB/m in sand.At 18kHz thecorresponding values were 2.0 and 4.5 dB/m, respec- tively.Measurements of soundspeeds for clay resultedin a velocityof 1480+ 15 m/s, 1540- i 820 + 15 m/s in silt, and 1540+ 15m/s for sand, 1:50 at a temperatureof 12øC. The absorption measurements compare well at W4. Laboratory measurementsof geo-aconstieproperties of the New 12kHz to thosemade in late 1986in deepocean sediments using penetra- Jersey Shelf sediments.Mohsen Badicy, Tokuo Yamamoto, and totsthat wereable to penetrateup to 55 m into the sediments. AItan Turgut (DivisionofApplied Marine Physics,RosensteilSchoolof Marine and Atmospheric Science, University of Miami, 4600 RickeabackerCauseway, Miami, FL 33149) Laboratorymeasurements of selected geo-acoustic properties of sedi- 1:20 ment samplescollected at the New JerseyShelf are presented.A high W2. Deep ocean/seabed-satelliterelay for long-term quasi-real-time precisiontorsional resonant column apparatus was usedto determine data transmissions.C. N. Murray and M. M.P. Weydert (Commission both the shearmodulus and the attenuationat differentconfining stress of the European Communities, Joint Research Centre---Ispra conditions.Porosity and permeabilityof thesesediments were also mea- Establishment,21020 Ispra (VA), Italy) sured.These measurements are comparedto boththe existinggeological data in this regionand the remotemeasurements of the shearmodulus During the last2 years,work hasbeen underway at theJoint Research usingthe BottomShear Modulus Profiler (BSMP). Finally,the quality Centreof the Commissionof the EuropeanCommunities on the useof factorand the attenuationare calculatedusing measured properties as satellite communications for the transmission of data from instrumenta- input to a numericalmodel for acousticwave propagation in shallow tion placedin the oceanbed. The setupof the transmissionlink has re- water.[Work sup_ported byONR. ] quiredthe developmentof severalnew systems. These include an under- water vehiclecapable of successfullyemplacing instrument packages within deepocean sediment formations, a transmitter-receiversystem whosecharacteristics are suchas to be able to sendacoustic signals 2:05 throughboth 50 m of sedimentsand a 6-kinwater column, sensots which will giveinformation on sedimentcharacteristics, and a satellitecommu- W5. Horizontally polarized shear waves in shallow marine sediments. nicationssystem for the automaticquasi-real-time relay of data from the George H. Sutton (Rondout Associates,Inc., P.O. Box 224, Stone eraplacedinstrumentation to the laboratoryin Ispra (Europe). The pres- Ridge, NY 12484), John I. Ewing-(Woods Hole Oceanographic ent paperwill discussthe acoustic!ink and the relay/buoysystem and its Institution, Woods Hole, MA 02543), Noifl Barstow, and Jerry applicationsto oceanographyand meteorology. A. Carter (RondoutAssociates, Inc., P.O. Box 224, StoneRidge, NY 12484 )

In June 1986 a seismicexperiment emphasizing the observationof shear waves in the bottom sediments was conducted off the southern New 1:35 Jerseycoast in waterdepths between about l0 and 56 m. This paperem- W3. Low-frequencyacoustic/seismic propagation in a slopingocean phasizesthe generationand detectionof horizontallypolarized shear environment: Comparison between measured results and numerical wavesSH producedby a pair of air (mud) guns,mounted to applyhori- predictions.Hassan B. All and Michael F. Werby (Naval Ocean zontal forces,on a sleddeployed from the ship and capableof being Researchand DevelopmentActivity. NSTL, MS 39529-5004) draggedalong the bottom. Signalswere digitally recordedfrom three- component geophonesand a hydrophone. Shear waves and boundary Thepropagation of low-frequencysignals and noise in shallowwater, waveswere recorded in the frequencyband 2 to 40-50 Hz havinggroup and more generallyin a bottom-limitedenvironment, is of considerable velocitiesranging from about 50 to 300 m/s. Both SH/Love waveand interestto the Navy.A particularaspect of thisproblem, namely the P/SV/Rayleigh-Stoneley-Scholte wave signalswere dearly recorded relativemerits of waterborneversus seismic propagation paths, has been and resolvedby combiningsums and differences of two properlyoriented

S49 J. Acoust.Soc. Am. Suppl. 1, VoL81, Spring 1987 113thMeeting: Acoustical Society of America S49 horizontalcomponents and comparing the resolved horizontal data with anadaptation of theGelfand-Levitan inversion procedure, originally de- verticaland pressure components. Full-waveform synthetic seismograms velopedin thecontext of quantummechanical potential scattering, to the arebeing used to aid inversionfor shearvelocity and attenuation models problemof determiningthe acousticproperties of the bottom.In this that are requiredto be consistentwith informationavailable from test approach,if the bottomplane-wave reflection coefficient at a fixedfre- boringsas well as the shear wave data. [Work supportedby ONR.] quencyis known for all anglesofiocidence, then the sound velocity versus depthcan be uniquely recovered. If thereflection coefficient at all anglesis knownat twofrequencies, then both the density and velocity profiles can 2:20 be uniquelyreconstructed. The inversionscheme consists of Fourier transformingthe reflectioncoefficient and solvingthe Gelfand-Levitan W6. The acousticsof "black smoker"hydrothermal plumes, David integralequation. This procedureis implementednumerically and ap- R. Palmer and Peter A. Rona (NOAA/AOML, 4301 Rickenbacker pliedsuccessfully to synthetic data for severaltypical profiles. The stabil- Causeway,Miami, FL 33149) ity of the methodin the presenceof noiseis alsodemonstrated. [Work High-temperature"black smoker" hydrothermal plumes occur when supportedby ONR.] seawaterthat haspenetrated into the oceaniccrust and assimilatedheat from magmais dischargedfrom ventslocated at the axisof a mid-ocean ridge. The acidic, metal-rich,discharge mixes with alkaline,oxidizing seawater,and a fine suspensionof sulfideparticles is precipitatedand conveeredby the flow. Ventsfields have now been found at both fastand slowseafloor spreading centers and may be a ubiquitousfeature of mid- oceanridges. A reviewof theprogress made in usingunderwater acoustics to studyblack smoker plumes is presented.Both active and passive tech- niquesare being investigated. Active techniques involve a high-frequency monostaticsonar mounted on a submersible.Analysis of the amplitude and phaseof the signalbackscattered from the plumeprovides informa- 2:50 tionabout the three-dimensional shape of theplume as well as estimates of the flow-velocityfield of the dischargingfluid. Passivetechniques use WS. Determination of modal attenuation coefficients and the attenuation bottom-mountedhydrophones to listento the verylow-frequency, hydro- profile of the bottomin shallowwater. SubramaniamD. Rajah, James dynamicnoise generated by a plume.These noise signatures have poten- F. Lynch, and George V. Frisk (Department of Ocean Engineering, tial use in locating,characterizing, and monitoringplume sitesand in WoodsHole OceanographicInstitution, Woods Hole, MA 02543) determiningthe contributionplume noise makes to the overallambient noise field in the ocean. Techniquesfor determiningmodal attenuation coefficients and the compressionalwave attenuation profile of thebottom in shallowwater are presented.The requiredinput data consistof measurementsof the pres- sure field versusrange due to a monochromaticpoint source.Several 2:35 methodsare describedfor obtainingmodal attenuation coefficients from W7. Exact reconstructionof ocean bottom velocity profiles from the pressurefield or its Hankeltransform (the depth-dependentGreen's function versushorizontal wavenumber}. These modal attenuation coef- monochromaticscattering data. Andre A. Merab (MIT/WHOI Joint Programin Oceanography/OceanographicEngineering, Woods Hole, ficientscan be relatedto the bottomattenuation profile through an inte- gralequation that can be solved using linear inverse theory. The methodis MA 02543) and GeorgeV. Frisk (Departmentof OceanEngineering, demonstratedusing synthetic noise-free and noisydata. The resultsof WoodsHole OceanographicInstitution, Woods Hole, MA 02543) invertingexperimental data from Nantucket Sound at 140and 220 Hz are A techniquefor exactlyreconstructing ocean bottom velocity profiles also described. Resolution and variance estimates for the bottom attenu- from monochromaticscattering data is presented.The methodinvolves ation profileare pr•'caented.[Work supportedby ONR.]

WEDNESDAY AFTERNOON, 13 MAY 1987 CANYON HALL, 1:15 P.M.

Meeting of Accredited Standards Committee S2 on Mechanical Shock and Vibration

to be held jointly with the

TechnicalAdvisory Group (TAG} Meeting for ISOfYC 108 MechanicalVibration and Shock

J. C. Barton, Chairman $2 CaterpillarTractor Company, Research Department, 100 N. E. •4dams,Peoria, Illinois 61629

G. Booth, Chairman, TechnicalAdvisory Group for ISO/TC 108 220 Clark Aoenue,Brandford, Connecticut 06405

StandardsCommittee S2 on MechanicalShock and %bratlon. Workinggroup chairs will presentreports of theirrecent progress on writingand processing various shock and vibration standards. There will bea reporton the interfaceof S2 activitieswith thoseof ISO/TC 108 (the TechnicalAdvisory Group for ISO/TC 108 consistsof membersof S2, S3,and other persons not necessarilymembers of thosecommittees) including a reporton the meetingof ISO/TC 108,held in Washington,DC from 30 March to 10 April 1987.

SS0 J. Acoust.Soc. Am. Suppl.1, VoL 81, Spring1987 113th Meeting:Acoustical Society of America SSO WEDNESDAY AFTERNOON, 13 MAY 1987 REGENCY BALLROOM D, 1:15 TO 3:15 P.M.

SessionX. Physical AcousticsIV: Special Sessionon Sonic Energy for Particle Processing

Osman K. Mawardi, Chairman ElectricalEngineering and AppliedPhysics Department, Case Western Reseroe University, Cleveland, Ohio 44106

Invited Papers

!:15

X1. Solid particles in sonic field. Osman K. Mawardi (Electrical Engineeringand Applied Physics Department,Case Western Reserve University, Cleveland, OH 44106) A reviewis presentedfor the dynamicsof solidparticles in suspensionin a fluid and subjectedto sonic energy.The controllingparameters associated with collectivebehavior of theparticles such as precipitation or coagulationare identified.A brief discussionis thengiven on a classificationof observedphenomena in the processingindustry and by meansof theseparameters.

1:35

X2. Aerosolagglomerationinhigh-lntensityacousticfidds.DavidT. Shawand Sushil Patel (Departmentof Electricaland ComputerEngineering, State University of New York at Buffalo,Amherst, NY 14260) The operationalconditions for theapplication of acousticagglomeration (AA) asa preconditionerfor the controlof particulatematter under high temperatureand pressureare discussedbased on recentdata on the acousticallyinduced turbulence. The AA kernelsin variousregimes are evaluatedfor variousperformance parameters,including acoustic intensity, frequency, residence time, gas temperature, and pressure.The turbu- lent interactionis foundto be the dominantprocess for particleagglomeration. Since AA is not particle-size dependent,it is ideallysuited for preconditioning,and subsequentremoval of the submicronparticles. A computermodel for the predictionof AA hasbeen developed and good agreements have been found between thetheory and experimental data. Based on a comprehensiveevaluation of thetechniques for the generationof high-intensitysonic field and problemsin their applications,a dirty-air chopperhas been built and testedwith very favorableresults.

2:05

X3. Acousticagglomeration of powerplant fly ashfor environmentaland hot gascleanup. Gerhard Reethof (Departmentof MechanicalEngineering, The PennsylvaniaState University, University Park, PA 16802) Emissionof smallparticulates from coal-fired power plants in therange of 0.5 to 5/t resultsin particularly seriousinjury to thehuman respiratory system. Currently used environmental cleanup devices in powerplants suchas bag houses, electrostatic precipitators, wet scrubbers, and others are very efficient in removingparticu- lateswhich are largerthan about 2/t in size,leaving by far the majorityof thesetiny particulatesto beemitted into the air environment.Current regulationsfor effluentcleanup emphasize the massremoval without any attentionto the particulatesize. Acoustic agglomeration isa meansof causingthese tiny particulates to collide with one another, adhere, and thereby result in the formation of larger particles,thus removingthe tiny particulatesfrom the aerosolstream. In this manner,the efficiencyof particleremoval of the conventional removaldevices can be substantiallyenhanced. This paper introducessome of the fundamentalaspects of acousticagglomeration theory and practiceand presentssome of the resultsof recentstudies.

2:35

X4. Removalof partieulatecontaminants from surfaees.K. W. Montz (Departmentof Chemicaland MaterialsEngineering, ! 153 EB, The University of Iowa,Iowa City, IA 52242),P. B. Butler(Department of MechanicalEngineering, The Universityof Iowa,Iowa City, IA 52242),and J. K. Beddow(Department of Chemicaland Materials Engineering, 1153 EB, The Universityof Iowa, Iowa City, IA 52242) An experimentalinvestigation was made on the interactionof an acousticfield with particulatematter adheredto a substrate.The particlesof interestare in the/t-sizerange. In the experimentaldesign, a combined acoustic/convectivefield is usedto overcomethe adhesiveforces of the contaminantmaterials. A key param- eterin thiswork is the removalefficiency (based on numbercounts} of contaminantparticles from the surface ofmaterials. An imageanalysis technique is used to determineparticle counts before and after the process. The

S51 J. Acoust.Soc. Am. Suppl. 1, Vol.81, Spring1987 113thMeeting: Acoustical Society of America S51 relativeadhesive and removalforces are a functionof particulatematerial and substrateproperties. Prelimi- nary resultsusing a factorialdesign illustrate the influenceof severalacoustic properties on the removal efficiencies.

ContributedPaper

3.q!O Separationand purificationof finesolids suspended in fluidsare in- volredin a varietyof technologies.A process utilizing high-energy acous- X$, Acousticsuspension processing. D. L. Feke (ChemicalEngineering tic planesthat are separatedby low-energyzones will be describedfor Department. Case WesternReserve University, Cleveland,OH 44106) thesepurposes. Results of theoreticaland experimentalstudies will be and D. Hazon¾ (Electrical Engineering and Applied Physics discussed. Departments,Case Western Reserve University, Cleveland, OH 44106)

WEDNESDAY AFTERNOON, 13 MAY 1987 CELEBRATION HALL, 1:30 TO 2:35 P.M.

SessionY. Musical AcousticsII, ArchitecturalAcoustics IV, and Shockand Vibration II: Distinguished Lecture on Early Lateral Reflections in Modern Concert Halls

ThomasD. Rossing,Chairman Departmentof Physics,Northern Illinois University,Dekalb, Illinois 60115

SinceProfessor Cremer will be unableto be present,his paperwill be read for him by TheodoreSchultz, Theodore J. Schultz Associates,Boston, MA 02118.

Chairman's Introduct'on-l:30

Invited Paper

1'.35

YL •rly lateralreflections in modernconcert halls. Lotbar Cremer(D-g 16Miesbach, Federal Republic of Germany) It isagreed that part of theacoustical qualities of the "shoebox" halls of the 19thcentury results from their nearlyparallel sidewalls and from "cueball" reflectionsbelow the soffitsof their balconies.This arrangement conflictswith the enlargementof the stageand audience capacity and with the modernexpectation of comfort- ableseating and full viewof the stagefrom eachlocation. Three possibilitiesfor overcomingthese difficulties, basedon the author'srecent consulting work, are discussed:(a) Placementof a largepart of the audience behind the stagebut not lateral to it (Madrid. under construction). This solution is unmatis/'actory/'orvisual performances;(b) providingstrong early reflectionsfrom prosceniumtowers which focusthe soundin the verticalplane but diffuseit in the horizontal.This solution,proved by echograms,can be usedin evena very broad (26-m) stage,such as the SalleApoiion, Nice, openedin 1985.Subdivision of the audienceby "vineyard" stepsproduces early lateral reflections; (c) theuse of vineyardsteps, allowing an optimaland simple "trapezi- urnterrace" system (Las Palmas, Gran Canaria, planned). Here, the visually preferred diverging fan-sbaped plan is compensatedacoustically by the convergingsteps of the trapeziumterraces, which could easily be inclinedso that they provideearly lateralreflections to the middleof the terraces.The limitsof this geometrical behaviorare quantitativelyinvestigated according to Fresncl'sformula. The morediffuse reflections at lower frequenciesare profitablefor the late reverberantsound.

S52 d. Acoust.Soc. Am. Suppl. 1, Vol.81, Spring1987 113thMeeting: Acoustical Society of America S52 WEDNESDAY AFTERNOON, 13 MAY 1987 REGENCY BALLROOM C, 1:30TO 3:15 P.M.

SessionZ. Psychologicaland Physiological Acoustics VI: Masking

Robert H. Gilkey, Chairman CentralInstitute for the Deaf 818 SouthEuclid, St. Louis,Missouri 63110

ContributedPapers

signalsat a far, unexpectedfrequency (probe). The presentexperiments test the hypothesisthat the internal filter is narrowestat the primary Zl. A modelof the effectsof signaldelay and maskerlevel on masked frequency,thereby admitting less external noise there. According to this measuresof frequency selectivity. Robert A. Lutfi (Waisman Center, hypothesis,the probeshould be as detectableas the primarywhen the University of Wisconsin,Madison, W[ 53705) external masker is narrower than the internal filter. Against wideband In a previouspaper [R. A. Lutfi,J. Acoust.Soc. Am. 76, 1045-1050 noise,subjects detected a I-kHz primaryon 90% of thetrials and a 2-kHz (1984) ], thefollowing relation was used to predictmeasures of frequency probeon 60% of the trials.Against two simultaneoussubcritical noises-- selectivityobtained in forwardmasking from measures obtained in simul- one at 1 kHz, the other at 2 kHz--results were similar. With the noiseat 2 tanenosmasking: F(g) --- G + H(g) - It(O), where,for a givenmasker kHz narrowedto 50 Hz, 6 of 12 subjectsdetected the probereliably, level,Fis theamount of forwardmasking (in dB) asa functionof signal- possiblybecause the strongpitch of the maskerdrew attentionto the 2- maskerfrequency separation (g), ltis the amountof simultaneousmask- kHz probe.Overall, these results suggest that attentiondoes not affectthe ing,and G is the amountof forwardmasking for g = 0. In the present width of the internalfilter. [Work supportedby NIH.] study, the relationwas testedfor a wider rangeof signaland masker frequencies,masker levels, and signaldelays. The relationdescribed thresholdsfrom all conditionswell with theinclusion of onefree param- eter •. correspondingto a constant frequency increment: 2:15 F(g) = G+H(g+/I) --H(,•). The parameter•. wasrequired to ac- countfor observedshifts in the frequencyof maximumforward masking. ZA. Psyehometriefunctions for multicomponentmaskers with spectral It issuggested that a singletuning mechanism can account for commonly uncertainty. Donna L. Neff and Brian P. Callaghan (Boys Town observed differences between simultaneous- and forward-masked mea- National Institute, 555 North 30th Street, Omaha, NE 68131 ) suresof frequencyselectivity. [Work supportedby NationalScience Previousexperiments used a two-alternative,forced-choice, adaptive FoundationGrant BNS 83-08498.1 procedureto measurethresholds for a 1000-Hzsignal in the presenceof maskerscomposed of multiplesinusoids. These sinusolds were drawn at randomfrom a 300-to 3000-Hzrange, excluding the signal frequency and frequencieswithin a criticalband around the signal.This experimentex- 1:45 aminedpsychometric functions for 50 of the original 200 maskerswith 10 components,using signal levels from 10--80dB SPL. The psychometrie Z2. Roving level tone in noise masking.Gerald Kidd, Jr., Christine functionswere well fitted in d' by signallevel coordinates, but individual R. Mason,Merry A. BrantIcy,and Orace A. Owen (Departmentof functionstypically spanned a 30-to 40-dBrange. Corresponding adaptive CommunicationDisorders, Boston University, 48 CummingtonStreet, thresholds did not differ from thresholds based on 200 maskeva and were Boston, MA 02215) in agreementwith the averageof the predictedthresholds across the 50 Theresults of tonein noisedetection experiments have long formed an maskeva.Although individual maskeva could differ in effectivenessby 10-- empiricalbasis for the notionof the "criticalband" and haveled to the 15dB, the majorityproduced similar masking. Overall, the adaptive pro- developmentof the "energydetection" model. In thisstudy, the detect- cedureadequately characterizes performance in theseconditions. [Work ability of tonesin bandsof randomnoise was measured for conditionsin supportedby NIH. ] whichthe overalllevel of the noisewas roved randomly from intervalto intervalof eachexperimental trial. The functionsrelating masked tone threshold to noise bandwidth for the roved conditions were identical to thoseobtained when no rove was employedat "supracritical"band- 2:30 widths.At "subcritical"bandwidths, the detection thresholds were high- er for theroved conditions, but werestill lower than would be predicted ZS. Exact jnd functionsfor a generalizedMcGill-Goldberg counting fromarguments based purely on energydetection. These results suggest model.William S. Hellman(Department of Physics,Boston University, thatthe traditional critical band and energy detection models should be Boston, MA 02215) and Rhona P. Hellman (Department of modifiedto accountfor discriminationbased on spectralshape or wave- Psychology,Northeastern University, Boston, MA 02115) shape.[Work supportedby NIH andNMRDC.] In an earlier work [W. S. Hellman and R. P. Hellman, $. Acoust.Soc. Am. Suppl. I 79, S34 ( ! 986) J, a generalizationof the McGill-Goldberg countingmodel waspresented. It was demonstratedthat loudnessfunc- tions,consistent with experiments,could be determinedfrom intensity jnd functionsthat obeyedboth the power-functionnear miss and Weber's 2:00 law. The central formula for the model is the integral relation Z3. ]•ffectof manlierbandwidth on the detection of signalsat unexpected N(I) j/: = (h /2).fall /lid(l) ] + a,wherehandaareconstants, andN(1) freqneneles. Huanping Dai, Bertram Scharf, and S•ren Buus andJ(1) are the neuralcount and inputjnd functions,respectively. Fol- (Auditory PerceptionLaboratory. Northeastern University, Boston, MA lowingMcGill andGoldberg, the modelwas developed using a first-order 02115) approximation for the jnd induced change AN. To determine just how appropriatethe first-orderapproximation might be, the resultsof boot- In widebandnoise, listeners tested with theprobe-signal method [G. strappingthe modelare shown.That is, giventhe derivedneural-count Z. Greenbergand W. D. Larkin, J. Acoust.Soc. Am. 44, 1513-1523 functions,the "exact" associatedjnd functionsare generated.For a pow- ( 1968) ] detecta signalat anexpected frequency (primary) while missing er-functionnear miss as original input, an "exact"jndfunction that exhib-

S53 J. Acoust.Soc. Am. Suppl. 1, VoL 81, Spring1987 113thMeeting: Acoustical Society of America $53 its a low-intensitydeviation from power-functionbehavior is obtained. varied,support this interpretation.The firstcomponent, which is prob- When the inputjnd functionobeys Weber's law, it is foundthat the boot- ablya "true" CMR, wasonly about 3 dB. [Work supportedby theMRC, strappedjnd functionis constantover a widerange of intensities.These U.K.] resultsare compatiblewith psyehophysiealdata. [Work partiallysup- portedby the RehabilitationResearch and DevelopmentService of the VA.]

3:00 2:4• Z?. CMR for complexsignsls. Joseph W. Hall, Ill, John H. Grose Zt. Comodulationmasking release (CMR) as a function of signal (Division of Otolacyngology,Department of Surgery,University of frequency,flanking-band frequency, masker bandwidth,and flanking- North Carolina, Chapel Hi!l, NC 27514), and Mark P. Haggard band level. Gregory P. Schooneveldt and Brian C. J. Moore (Institute of Hearing Research,University of Nottingham,Nottingham (Departmentof ExperimentalPsychology, University of Cambridge, NG7 2RD, England) DowningStreet, Cambridge CB2 3EB, England) PreviousCMR investigationshave examined the effectof across-fre- Thresholdsfor 400-mssignals were measuredin the presenceof a quencymasker envelope coherence on thedetection of a pure-tonesignal. continuousnarrow-band noise centered at signalfrequencies (rs) ranging The presentstudy extends this investigation to examinethe effect of the from 250--4000Hz in l-oct steps.The maskerwas presented either alone numberof componentscomprising the signal.The maskerwas composed or togetherwith a secondband of noise(the flankingband) whoseenve- of eitherone, two, or three 30-Hz-widenarrow-band noise components. lope was eithercorrelated with that of the on-frequencyband or was In multihand conditions, the bands had either correlated or uncorrelated uncorrelated;its frequency ranged from 0.5 to 1.5fs. CMR wasdefined as envelopes.For the one-componentmasker, the signalwas a puretone at the difference between thresholds for the correlated and uncorrelated con- the centerfrequency of the masker.For the two-componentmasker, the ditions.The CMR showedtwo components:a broadly tuned component signalwas either a one-componentor a two-componentsignal. For the occurringat all signalfrequencies and all flanking-bandfrequencies, and a three-componentmasker, the signalwas either a one-, two,- or three- componentrestricted to flanking-bandfrequencies close to fs, whichin- componentsignal. For the three-componentmasker, CMR wasgreatest creasedin magnitudewith increasingfs. The second component was prob- for thesingle-component signal. However, CMR wasappreciable for two- ably not a true CMR, but resultedfrom "beating"between the carrier and three-componentsignals. CMR generallyincreased as a functionof frequenciesof the two maskerhands. Additional experiments, in which increasingnumber of maskerbands. Results will bediscussed in termsof the bandwidthof the maskerand the level of the flankingband were modelsof CMR. [Work supportedby AFOSR.]

WEDNESDAY AFTERNOON, 13 MAY 1987 REGENCY BALLROOM A & B, 1:30 TO 2:50 P.M.

SessionAA. SpeechCommunication V: CommunicationDisorders (Poster Session}

Mary E. Beckman, Chairman Departmentof Linguistics,Ohio State University,Columbus, Ohio 43210

All posterswill bedisplayed from 1:30-2:50p.m. To allowall contributorsan opportunity to seeother posters, contributorsof odd-numberedpapers will be at their postersfrom 1:30--2:10p.m., and contributorsof even- numberedpapers will be at theirposters from 2:10-2:50p.m.

ContributedPapers

AAI. Developmentand testingof. artificial low-frequencyspeech codes. Hz. Identificationof C and V componentsin roving-contextCV syllables C.M. Reed, M. H. Power, K.K. Foss,N. 1. Durlach, and L.D. Braids was generallyinferior to that obtainedin the fixed-contextconditions. (Research Laboratory of Electronics, MassachusettsInstitute of [Work supportedby NIH. ] Technology,Cambridge, MA 02139) Previouswork on frequencylowered speech for listenerswhose hear- ing is confinedto low frequencieshas focused on signalprocessing of naturalspeech. In thepresent research, the use of artificiallow-frequency AA2. Spectral shapingoptions for personswith low- or high-frequency codesfor suchlisteners is explored.This researchwill helpseparate limi- s•nsorineural hearing loss. Donald I. Sehum and M. lane Collins tationsimposed by signalprocessing schemes from limitations impos•l by (Division of communicationDisorders, Louisiana State University, 163 the listener'sperceptual system. It will alsoprovide background for the M&DA, BatonRouge, LA 70803) designof newsystems based on the useof speech-recognitiondevices as front ends.Artificial frequency-loweringcodes were developedfor 24 Whenhearing loss is limitedto oneparticular frequency region, am- consonants(C) and 15 vowels(V} for two valuesof low-passcutoff plificationis traditionallyprovided in the regionof the poo•st audio- frequencyF (300 and 500 Hz). Individualphoneroes were coded by a metric thresholds. To the extent that audiometric data correlate with au- uniqueacoustic signal confined to frequenciesless than or equalto F. The ditory systemdamage, the usefulnessof informationprovided to these ability of normal-hearinglisteners to identifycoded C's and V's in fixed- regionsof greatestdamage is questionable.Optionally, gain may be pro- contextsyllables was compared to their performanceon single-tokensets videdto frequencyregions where thresholds are improvingtowards nor- of naturalspeech utterances low-pass filtered to equivalentvalues of F. real. To that end, continuousdiscourse intelligibility ratings and conso- Performanceon coded C's was superior to thaton low-passfiltered speech nant discrimination scores were obtained from individuals with either for bothvalues of F (by roughly20 percentagepoints ). An advantagefor low-frequencyor precipitouslysloping high-frequency sensorineural codedV's (of roughly15 percentage points ) wasobserved only at F = 300 hearingloss. During testing,spectral emphasis was variouslyplaced in

S54 J. Acoust.Soc. Am. Suppl.1, Vol. 81, Spring1987 113th Meeting:Acoustical Society of America S54 regionsofhea•i. 'ng impairment and/or improving thresholds. For the low- vocabularytraining protocol was modified from Brooksand Frost [P. L. frequencyimpaired subjects, consistently inferior subjective ratings and Brooksand B. J. Frost, J. Acoust.Soc. Am. 74, 34-39 { 1983) ]. Training discriminationscores were obtained when spectral emphasis was placed wordswere presented using only tactile stimulation with feedback.Train- solelyin theregion of hearingloss. For thehigh-frequency impaired sub- ing wasconducted a minimumof lb/day, 5 days/week.After approxi- jeers,no single spectral weighting scheme emerged as superior or inferior. mately88 h of trainingover 18 weeks,the subjectwas able to identify15 Thecurrent results are consistent with previous findings which have sug- words,yielding a word acquisitionrate of 0.17 words/h. This differscon- gestedthat pure-tone thresholds may underestimate the degree of apical siderablyfrom acquisitionrates previously reported of 2.7 words/h for regiondamage in low-frequencysensorineurai hearing loss. [ Work sup- normal-hearingsubjects [P. L. Brooksand B. I. Frost, J. Acoust.Soc. portedby DRF. ] Am. 74, 34-39 (1983) ] and 0.53 words/h for hearing-impairedsubjects [S. Englemannand R. Rosov,Except. Child. 41, 243-253 (1975) ].

AA3. A multichannel tactile aid reduces articulation errors during spontaneous and imitative speech. William J. Gavin, Melinda AA6. Auditory/phonetic categoriesin a patient using a multichannel K. Mathay, and Debra Harr (Institute of Logopedics,2400 Jardine cochlearimplant. M. F. Dorman (Departmentof Speechand Hearing Drive, Wichita, KS 67219) Science, Arizona State University, Tempe, AZ 85287} and Geary McCandless(Department of Otolaryngology,University of Utah Five tactuallyexperienced, hearing-impaired children were testedin Medical School,Salt Lake City, UT 84114) two sessionswearing the tactile aid during both sessionsbut activated duringonly one session.Subjects received auditory and visualinforma- Identificationfunctions in responseto stimulifrom severalacoustic tion throughout.Each session consisted of a spontaneousand an imitative continuafrom a patientusing a Symbionmultichannel cochlear implant speechtask, each eliciting six productionsof four monosyllableand four have beenobtained. Auditory/phonetic categories of normal configura- bisyllabicwords. Recorded responses were transcribed using broad IPA tion were obtained for stimuli which varied in event duration ("slit"- techniques.Four of the fivechildren produced fewer errors with the aid "split" and "ehop"-"shop"),in steady-statefrequency composition activecompared to the nonactivecondition during both the spontaneous (/I/-/E/and/s/-/f/, andin eventduration and low-frequency composi- and imitativetasks. The meanpercent of errorsin nonactiveand active tion (/ga/-/ka/). For the/ga/-/ka/contrast, F 1 onsetfrequency and conditionsfor spontaneoustask was 27% and 26%; for imitative task, VOT "trade" to determinecategorization. Abnormal categories were ob- 19% and 17%. A 2X2 randomized block analysis-of-variancetest tained for stimuli which variedin F2/F3 onsetfrequency (/ba/-/da/) showeda significantmain effect for task (p <0.001 }. The tactileaid con- and for stimuliwhich variedin signalamplitude (/s/-/o/). Thesedata ditionapproached but did not reachsignificance (p <0.10). The dataare indicatethat, in at leastsome instances, the implantcan provideauditory extremelyencouraging. While the act of producingspeech is largelya informationwith sufficientresolution to affordnormal phonetic categori- habitualmotor response, removal of the tactileinformation resulted in a zation. measurable increase in articulation errors.

AA7. Using cued speechto clarify speechreading.Kathy L. Tonry AA4. Vocabulary training via a tactile communication aid with a (University of Cincinnati, Communication Disorders, ML 379, 0relingual deaf child. Robert E. Woodard and William J. Gavin Cincinnati, OH 45221 <)379 ) (Instituteof Logopedics,2400 Jardine Drive, Wichita,KS 67219) Speechreadingfor hearing-impairedindividuals is a monumentaltask A wearable,self-contained 24-channel vibrotactile vocodcr was used dueto visualsimilarities of somespeech sounds and the lack of visibilityof to train receptivevocabulary. The subjectwas a 6-year-old,prolingual, others.Cued speech is a visualsupplement to speechreadingused to reme- profoundlyhearing-impaired female of averageintelligence. Receptive diatethis problem. It employsa systemof 12visual hand cues. Four hand vocabularytraining was conducted a minimum of • h/day,4 days/week, positionsare used to clarifyvowels and eight hand configurations are used with the subjectreceiving auditory, visual (speechreading),and tactile to differentiateconsonants which are visuallyunclear. Two previousstud- stimulationduring training. Assessments of vocabulary growth were con- iesby Ling and Clarke [D. Ling and B. R. Clarke, Am. Ann. Deaf 120, ductedevery fifth sessionvia a picturepointing task. Words for training 480-488 ( 1975); and B. R. Clarke and D. Ling, Volta Rev. 78, 23-34 wereselected from Benedict[H. E. Benedict,"Language comprehension (1976} ] evaluatedthe speechreadingcapabilities of hearing-impaired in 10- to 16-month-oldinfants," unpublisheddoctoral dissertion,Yale subjectsusing cued speech.Results from the first study (subjectsused University,New Haven,CT (1976) ] andclinieian suggestions. After ap- cuesfor I year)supported the use of cuesfor identifyingwords in phrases. proximately34 h of trainingover 13 weeks, the subject learned 60 words,a The follow-upstudy ( 1 yearlater) supportedthe ideathat cuedspeech learningrate of 1.79 words/h. This rate is slower than the rate of 2.7 facilitatesspeechreading for sentences,phrases, and words.The present words/h reportedfor normal-hearingsubjects [P. L. Brooksand B. J. informalstudy indicatesimproved language skills in nine hearing-im- Frost, J. Acoust. Soc. Am. 74, 34-39 (1983) ] but faster than the rate of pairedchildren using cued speech. 0.53 words/h reported for deaf subjects[S. Englemann and R. Rosov, Except.Child 41, 243-253 (1975) 1.

AAg. Performanceon SPIN as a function of subject age. Melanie L. Matthiesand RobertC. Bilger (Departmentof Speechand Hearing AAS. Assessmentof a tactile communicationaid with a post-lingual deaf Science,901 South Sixth Street, University of Illinois, Champaign,IL adult. Robert Rosov, Robert E. Woodard (Institute of Logopedics, 61820) 2400 Jardine Drive, Wichita, KS 67219), Dennis R. Ingrisano (University of Northern Colorado, Greeley, CO 80639), and The effectof agingon word-recognitionability typically has been con- Darlene Murrell (Humble I.S.D., Humble, TX 77338) foundedwith theeffect of hearingloss in studiesinvolving the analysis of age-groupmeans. A correlationalapproach allows for an efficientanalysis A casestudy was utilized to assessreceptive vocabulary training using of the increasingheterogeneity with agein word-recognitionperformance a wearable,self-contained 24-channel vibrotactile vocoder. The subject and the effectsof hearingimpairment. Correlational analyses of perfor- wasa 58-year-old,post-lingual, adventitiously deafened female of average manceon SPIN andsubject age are described for fourexperiments. The intelligenceand above-average skills in learningword meanings ( q- 2 s.d. data setsinclude subjects from the SPIN standardizationstudy ( 19-69 on vocabularysubtest of the WAIS). It waspredicted that assessingrate years},a hearing-aidfitting experiment (29-74 years), a studyof older of vocabularyacquisition with thistype of subjectwould be a morerigor- listeners(60-81 years),and subjects from a studyof word recognitionin oustest of usingtactile stimulation as a meansof sensorysubstitution for noise( 18-70 years).All subjectswere tested at a singlepresentation level thedeaf than could be achieved using a prelinguallydeafened subject. The calculationq- 50 dB re: babblethreshold but at a variety of signal-to-

S55 J. Acoust.Sec. Am. Suppl.1. Vol. 81. Spring1987 113th Meeting:Acoustical Society of America S55 babbleratios ( + 8 to -- 2 dB S/B). Correlationsbetween SPIN scores AAll. Recentprogress in computerrecognition of cerebralpalsy speech. andage were only occasionally significantly different from zero and were J. g. Deller, Jr. (Electricaland ComputerEngineering Department, foundto increaseslightly with thesignal-to-babble ratio used and to de- Northeastern University, Boston, MA 02115), C. G. Venkatesh creasewith the severityof hearingimpairment. [Work supportedby (MathematicsDepartment, NortheasternUniversity, Boston, MA NINCDS. ] 02115), D. Hsu (Electricaland ComputerEngineering Department, NortheasternUniversity, Boston, MA 02115), L. J. Ferrier(Speech and Language Pathology and Audiology Department, Northeastern University, Boston, MA 02115), and M. B. Cozzens (Mathematics AA9. Effects of contextualprosodlc patterns on the auditory Department,Northeastern University, Boston, MA 02115) comprehensionof normally stressedtargets. Mikael D. Z. Kimelman This paperis ultimatelyconcerned with the developmentof an AI (Departmentof Communication Disorders, L.S.U. Medical Center, 1900 communicationaid for thenonverbal, profoundly motor disabled. Part of Grnvier Street, New Orleans, LA 70112) and Malcolm R. McNeil thiseffort is aimedat automatedrecognition of speechof the nonverbal. (Departmentof CommunicativeDisorders, University of Wisconsin-- The speechstudy has focused on the cerebralpalsied (CP) population, Madison, Madison, WI 53706) and recentpapers have reported methodology and early experimental resultsconcerning the lower (acoustic and word) levelrecognition tasks Reportsindicate that neurologically normal subjects produce faster for CP speakers[Deller et al., Proceedingsof the .45SP Workshop on reactiontimes to phoneme targets when the context preceding the targets .4coustics,New Paltz, NY (1986) and Deller et al., Proceedingsof isproduced with a stressedversus normally stressed prosodic pattern. The IC.4SSP'87, Dallas, TX (in p•ss) ]. Thepurpose of this paper is twofold: effectsof contextualprosodic patterns on the auditory comprehension of ( 1) to presentfurther experimental data concerning the word level recog- normallystressed targets by aphasic listeners were investigated. Target nitionproblem, particularly with regardto vowelsand diphthongs in wordswere computer edited out of paragraph-lengthstimuli that had varyingconsonant contexts, and (2) to presenta graph-theoreticap- beenproduced with emphaticstress and with normalstress. The target proachto employingsentence level grammar. The graphsearch strategy, wordswere then replaced with normallystressed cognates. Analysis re- basedon the Planarseparator theorem [R. J. Liptonand R. E. Tarjan, vealedthat aphasic auditory comprehension was better when the context SIAM J. Appl. Math. 36, 177-189 (1979) and Venkateshet al., Proceed- surroundingthe target words had been produced with an emphatically ingsof the IEEE InternationalConference on Circuitsand $ysterns'87, stressedrather than a normallystressed prosodic pattern. Acoustic analy- Philadelphia(in p•ss ) ], isparticularly useful in thisproblem where iso- sesof the emphaticallystressed and normallystressed stimuli revealed latedregions of reliabilityin themessage may be surrounded by unrecog- differencesinduration but not peak fundamental frequency of wordspre- nizableacoustics. [Work supportedby theW. R. HearstFoundation, The cedingtarget words. [Work supportedby NICHD CoreGrant # 5 P30 UnitedCerebral Palsy Research and EducationFoundation, and by HD03352to WaismanCenter, University of Wisconsin--Madison.] N.I.H. under Grant No. IR03RR02630.]

AAI2. Tongue-jaw displacementvariability in the fluent speechof stutterersand control subjects. P.J. Alfonso(UniversityofConnecticut, AAI0. Anticipatorycoarticulation in aphasia:Acoustic and perceptual Storrs,CT 06268 and HaskinsLaboratories, 270 Crown Street, New evidence.William F. gatz (Departmentof Psychiatry,M-031P, Haven, CT06510), B.C. Watson (Universityof Texasat Dallas/Cailier Universityof California--SanDiego, La Jolla,CA 92093) Center, Dallas, TX 75200), and R. Story (Universityof Connecticut, Storrs, CT 06268 and Haskins Laboratories, 270 Crown Street, New Acousticanalyses of anticipatorycoartieulation were conductedfor Haven, CT 06510) the initialconsonants ofCV [si suti tu ki ku] andCCV [sti stuski sku] productionsby sixnormal and ten aphasic (five anterior, five posterior) The x-raymicrobeam installation at theUniversity of Tokyowas used subjects.For normalsubjects' productions, reliable coarticulatory shift to comparesupralaryngeal kinematic patterns of fluentutterances pro- wasfound for almostall measurements,indicating that acousticcorre- ducedby a controlsubject and two stutterers.For the controlsubject, latesfor anticipatory coarticulation obtain for [ s], [ t ], and[ k ] in a prevo- trial-to-trialvariability in individualand combined tongue-jaw peak dis- calic environmentas well as when Is] is the initial consonantofa CCV placementfor alveolarobstrnent closure and release was equivalent to the syllable.The data for theaphasic subjects were statistically indistinguish- variabilityin lip andjaw displacementfor bilabialstop closure and release ablefrom those of the normalgroup, with no differencesnoted as a func- by a largergroup of normalsubjects [V. L. Graecoand J. H. Abbs,Exp. tionof aphasiatype. In theperceptual experiment, a subset of theconso- Brain Res. (in press)]. The stutterersdemonstrated greater variability nantalstimuli produced by thenormal and aphasic subjects was presented thanthe control in individualtongue and jaw displacement,and the com- to a groupof ten naivelisteners for a vowelidentification task. Listeners binedtongue-jaw displacement variability was not lessthan the individ- wereable to identifythe productionsof all subjectsat a levelwell above ual articulator variability. In contrast to the control, the stutterers chance.In addition,small but statisticallysignificant group differences achievedclosure and releaseprimarily by jaw displacementwith little, wereobserved, with the [sV], [skV], and [tV] productionsby anterior andoccasionally paradoxical, tongue displacement. The lackofcovariabi- aphasicsshowing significantly lower perceptual scores than those of nor- lity in tongue-jawdisplacement, coupled with the dominanceof a single malsubjects. The results suggest a model of speech programming in which memberof an articulatorcomplex, suggests that stuttererslack the same coarticulatoryprocesses are largely preserved in aphasia.[ Work support- degreeof precisionand flexibility observed in normalspeech motor sys- ed in part by grant NS-22282to BrownUniversity Department of Lin- temsto efficientlymeet invariant object-level goals. [Work supportedby guistics.] NIH NS-13617.]

S56 J.Acoust. Soc. Am. Suppl. 1, Vol. 81, Spring 1987 113thMeeting: Acoustical Society ofAmerica $56 WEDNESDAY AFTERNOON, 13 MAY 1987 REGENCY BALLROOM A & B, 3:30 TO 5:00 P.M.

Plenary Session

Ira Dyer, Chairman President,Acoustical Society of America

BusinessMeeting

Presentation of Awards

Gold Medal to Cyril M. Harris R. BruceLindsay Award to IleneJ. Busch-Vishniac

Musical Entertainment TheCardinal Quartet, a stringquartet of precociousstudents from the Indiana University School of Music, willperform three pieces by Joseph Haydn: Quartet in D Major,Op. 50, No. 6, "TheFrog," Minvetto Alle- grettoand Finale Allegro con spirito. The quartet members are Anne Nagosky, violin; Marrie Arnold, violin; Ana Ruesink,viola; Kathy Cherbas,cello.

S57 J. Acoust.Soc. Am. Suppl. 1, Vol. 81, Spring 1087 113thMeeting: Acoustical Society of America S57 THURSDAY MORNING, 14 MAY 1987 REGENCY BALLROOM C & D, 8:15TO 11:30A.M.

SessionBB. EngineeringAcoustics I, Psychologicaland PhysiologicalAcoustics VII, and Speech CommunicationVI: EngineeringApproaches to Hearing Problems

Mead Killion, Chairman EtymoticResearch, Inc., 61 Martin Lane,Elk GroveVt71age, Illinois 60007

Chairman's Introduetion--8:15

Invited Papers

8'.2O

BBI. An overviewof the functionsoftbe ear. Murray B. Sachs(Department of BiomedicalEngineering and Centerfor HearingSciences, Johns Hopkins University School of Medicine,Baltimore, MD 21205) The functionof theperipheral auditory system (external, middle, and inner ears) is to producea represen- tationof soundacross the populationof auditory-nervefibers. This representationis processedby the brainto produceappropriate behaviors (e.g., perception, movement, etc. }. Thistalk will focuson therepresentation of the spectralfeatures of speechsounds in the auditorynerve. Emphasis will be placedon thoseaspects of the encodingin the auditorynerve that allowthe representationto be robustover a largerange of soundlevels and in the presenceof backgroundnoise. The transformationsof this representationby populationsof cochlear nucleuscells will bc discussed.[Work supportedby grantsfrom NINCDS. ]

8:42

BB2.Digltal hearingaids. Harry Levitt (GraduateSchool, City Universityof New York, 33 West42rid Street, New York, NY 10036)

Digital hearingaids offer many advantagesover conventionalhearing aids. These include programm- ability, communicationwith and controlby a hostcomputer, and the potentialfor implementingadvanced signalprocessing techniques for reducingbackground noise and for enhancingspeech intelligibility. Three typesof experimentaldigital hearing aids have been developed: ( 1 ) a quasidigitalsystem in whichthe audio signalsremain in analogform but arecontrolled by digitalmeans, { 2) a digitalfiltering system under micropro- cessorcontrol, and (3) real-timesimulation of a prescribedhearing aid on a high-specd,general-purpose computer.Recent experiments using digital hearing aids have evaluated new methods of hearing-aidprescrip- tion, techniquesfor processingspeech to improveintelligibility for thc hearingimpaired, methods of noise reduction,and new approaches to the measurementand specification of hearing-aidcharacteristics. Existing experimentaldigital hearingaids are relativelylarge in size,the smallestbeing a body-wornunit. Current engineeringefforts are directedtowards developing a unit smallenough to be worn on or in the ear.

BtL•. The middle ear from the standpointof the surgeonand the acoustician. Richard L. Goode (VA Medical Center,Palo Alto, CA 94304) andMead C. Killion (EtymotieResearch, 61 Martin Lane,Elk GroveVillage, IL 60007)

Recentdata obtained from fresh human temporal bones [Gyo etel., Ann.Otol. Rhinol.Laryngol. ( 1987} ] haveprovided previously unavailable information regarding the likely effecton the middleear transmission resultingfrom surgicalmodification. The possibilityof improvinga low-gradeear (from the middle ear transmissionstandpoint) into a "goldenear" will be discussed.Calculations based on modificationsto the analogexternal-plus-middle-ear model of Killion andClemis [J. Aeoust.Sac. Am. Suppl.1 69, S44 ( 1981} | will be presented.

9:26

BB4. Cooblearimplants: What are they and what do they accomplish?Donald K. Eddington(Research Laboratoryof Electronics,Massachusetts Institute of Technology,Cambridge, MA 02139) A largeportion of the profoundlydeaf are not ableto benefitsignificantly from conventionalhearing aids. Evenwith the tremendousgain provided by high-poweredaids, the peripheralauditory system of theseim- pairedindividuals is notable to transformthe intensesound input to patternsof neuralactivity that thebrain caninterpret. Cochlear implants are devicesthat convertsound to electricalstimuli and useelectrodes placed in the cochleato deliverthese stimuli to the auditorynerve. The neuralactivity elicited by thesestimuli is interpretedas sound percepts by thebrain. The goalof thesedevices is to ereatepatterns of neuralactivity that

S58 J. Acoust.Soc. Am. Suppl. 1, Vol.81, Spring1987 113thMeeting: Acoustical Society of America $58 thebrain can learn to interpretand thereby restore some measures of hearingto thedeaf. These devices are now commerciallyavailable in severalforms and can provide significant benefit to theprofoundly deaf individual. Thispresentation will describe the rationale of cochlearimplantation, the classes of devicesnow available, and the benefitsprovided to usersof thesedevices.

9:48

BBS.Tactile aids for thedeaf. Moise H. Goldstein,Jr. (JohnsHopkins University, Electrical Engineering Department, Baltimore, MD 21218) In a recentarticle [ C. E. Shetrick,J. Acoust.Soc. Am. 75, 1325-1342(1984) ], somenoteworthy questions abouttactile aids were posed. Among them were:" (i) Whatare the processing capacities of theskin?, (ii) what formof transducersystem will provide a reliableand efficient display to the skin?, (iii) if notall speechfeatures canbe handled by the substitute channel, which are the important ones to emphasize?,and (iv) howshould the targetpopulation be defined?"These questions will be consideredin contextof the presentday. Several companiesnow sell tactile aids for amountsclose to the costof a qualityhearing aid. The characteristicsand marketingof thesecommercial aids will be indicated.The targetpopulation of childrenversus adults and prelinguallydeaf versus postlingually deaf will receivespecial consideration. At present,one may question whethertactile aids are effective sensory substitutes for audition;nevertheless, it is becoming clear that they can haveimportant benefits. [Work supportedin part by NSF and NIH.]

10:10-10:15

Break

ContributedPapers

10:15 thecoupling diameter range between 1 and 2 ram,the maximal calibration error causedby the interactionof couplingmouth diameter and tube-neck BB6. Coupledpendulum model for the middle eat. Ahmed M. Nassef,R. lengthreached 0.4 ml for low frequencies;the maximalcalibration error D. Finch (Department of Mechanical Engineering,University of wasmuch larger for high frequencies.In addition,comparisons of five Houston, Houston, TX 77004), and L. Gray (Department of differentcalibration cavities were carried out on, for example,Madsen Otolaryngology--Headand Neck Surgery,University of TexasMedical and Chineselaboratory and clinical types. On the basisof thesemeasure- School,Houston, TX 77030) mentson differentcavities, it isproposed to takeas a standardthe valueof Modelsof the middleear givenin the literature(piston and lever, 2 mm for both the tube-necklength and the couplingdiameter. membraneand lever, two piston and lever) were studied by derivingtheir transferfunctions, and the values of theparameters best fitting an experi- mental transfer function were derived for each model. It was found that 10:45 noneof thesemodels could fit thedata with thesame physically realizable componentsover the wholeaudible frequency range. Consequently, a new BBS.Interpretation of amplitudecompression in termsof the modulation modelwas sought, based on an inspirationfrom B6k6sy'sobservation of transfer function. R. Plomp (Departmentof Otolaryngology,Free rotationalmotion of the tympanum.That the middleear actsas a two- University Hospital, P.O. Box 7057, 1007 MB Amsterdam, The degree-of-freedomsystem comprised of two coupledpendulums is sug- Netherlands) gested.Such systems have an inherentout-of-phase motion at high fre- quencies.That themalleus and part of thetympanum could comprise one .The successfulapplication of the speechtransmission index for pre- rotatingunit and that the incusand stapes could comprise the other is also dictingthe combined effects of reverberationand noise on the intelligibil- suggested.The incudo-malleoljointcould then be represented by thecou- ity of speech[e.g., T. Houtgastand H. J. M. Steeneken,J. Acoust.Soc. plingand fulcrum in themodel. Such a modelhas been found to meetthe Am. 77, 1069-1077 (1985)] demonstratesthat the modulation transfer objectiveof fitting the transfer function over the entire frequency range. It function(MTF } isan appropriate measure of theconsequences of tempo- is possiblethat suchmodels can haveapplication in prosthesisdesign. ral modificationsof thespeech signal on itsperception. In viewof this,it makessense to describealso the effectof amplitudecompression on speechintelligibility in termsof theMTF. A compressioncircuit, as ap- pliedin hearingaids, reduces the MTF fromzero up to a criticalmodula- tionfrequency of, typically,10 Hz. Thismeans that a substantialpart of 10:30 the rangeof modulationfrequencies present in thespeech signal and rel- evant for its intelligibility(0.4-20 Hz) is affectedby the compression BB7. On the measurementand calibrationof eat impedanceand its process.This can explain why amplitudecompression with short time relationto the frequencyof test signal.Yu-An Rao, Zhian Liang constantshas a negativeeffect on theintelligibility of speechin noise.The (Instituteof Physiology,Academy of Sciences,Shanghai, People's resultsof otherattempts to modifythe MTF for betterspeech understand- Republic of China), and Edward C. Carteterre (Department of ing will alsobe discussed. Psychology,University of California,Los Angeles, CA 90024) Experimentalmeasurements and comparison of calibratedequivalent volumesof acousticcompliance were carried out with a probeset under 11:00 differentlengths of tubeneck and diametersof couplingmouth. The rela- tionshipbetween equivalent volumes of acousticcompliance was a mono- BB9. Functional gain measurementof both amplitude and phase tonicfunction of frequency for test frequencies below 500 Hz, butchanged characteristics. Harry Levitt (Center for Research in Speech and to a V-shapedfunction of frequencyas testfrequency was raised higher Hearing Sciences,City University of New York, 33 West 42nd Street, than 800 Hz. In caseswhere neck length ranged between 0 to 5 mm and New York, NY 10036)

S59 J. Acoust.Soc. Am. Suppl. 1, Vol.81, Spring1987 113thMeeting: Acoustical Society of America S59 The principleunderlying the measurement of functionalgain in hear- Universityof Nottingham,University Park, NottinghamNG7 2RD, ing aidsis thatof comparingthe stimuluslevel at thresholdfor the test UnitedKingdom) condition(e.g., the aidedcondition) with the thresholdlevel for a refer- encecondition (e.g., the unaidedcondition). This techniqueis extremely Peoplewith sensorineuralhearing impairments find the taskof sep- usefulbut islimited, in itspresent form, to themeasurement of amplitude- aratingspeech from interferingnoises particularly difficult. For this rea- frequencycharacteristics only. The techniquehas been extended to the son,the idealhearing aid would•:lectively amplify a targetvoice while measurementof phase-frequencycharacteristics by introducing a second- attenuatingcompeting voices and other background noises. In exploring ary reference,a sinusoidalsignal delivered to the car by an alternateroute possiblenoise-reduction strategies for futureaids, two algorithms for se- (e.g.,by bone conduction). The signal generated by the system under test paratingthe voices of talkerswho are speaking simultaneously, with peri- isadjusted in amplitudeand phase so as to cancelthe secondary reference odicexcitation at similaroverall intensities, are evaluated.Both ap- signal.The cancellationis donesubjectively with the testsystem in situ. proachesare pitch basedand exploit the regularityin the harmonic The signalgenerated under the referencecondition is canceled in thesame structureof voicedspeech. The firstinvolves attenuating the harmonics of way. A comparisonof the two setsof adjustmentsneeded for caneelation thecompeting voice via a cepatrumlikerepresentation. The secondmeth- determinesthe functionalgain of the systemwith respectto bothampli- od isderived from the procedure for harmonic•election IT. W. Parsons,3. tudeand phase. Acoust.Soc. Am. 60, 9 i 1-9 i 8 ( i 976) ]. Perceptualevaluation of the two processingmethods, in a testinvolving the separation ofconcurrent vowel ' pairssynthesized on fixedfundamental frequencies, has demonstrated an 11:15 increasein performancefor both normal-hearingand hearing-impaired subjects.The resultsof experimentsinvolving the separationof simulta- BB10.Separation of simultaneous voices. Richard J. Stubbsand neoussentences containing a highproportion of voicedexcitation and QuentinSummerfield (M. R. C. Institute of Hearing Research, varyingfundamental frequencies will alsobe discusam.

THURSDAY MORNING, 14 MAY 1987 CANYON HALL, 8:30 A.M. TO 12:05 P.M.

Session CC. Musical Acoustics III: Acoustics of Pianos I

Gabriel Weinreich, Chairman Randall Laboratory,Unioersity of Michigan,Ann Arbor,Michigan 48109

Chairman's Introduction-=8:30

Inoited Papers

8:35

CCI. Pianodesign factors--Their influence on tone and acoustical performance. Harold A. Conkiln,Jr. (Box 1915, Dunedin, FL 34296)

Major designfactors that affectsignificantly the toneand acoustical performance of the modemmechano- acousticpiano are reviewed and the influence of eachon theperformance of theinstrument is briefly described or illustrated.Elements discussed include the string plate, the soundboard, the ribs, the bridges, the "scale," the strings,the hammers,the frame,the case,and the lid. Somedirections are suggestedfor future work to improve performance.The presentationis fromthe perspectiveof the instrumentdesigner.

9:05

CC2. Pianostringing-scale design. Albert E. Sanderson(lnventronics, Inc., 171Lincoln Street, Lowell, MA 01852)

Stringing-scaledesign in pianoscomprises the specification of thespeaking length of eachnote, the number of stringsper note(unichord, bichord, or trichord), the diametersfor all plain-wirenotes, and thediameter of the core and diameterand lengthof the copperwinding for all loadedstrings. These factors control the inharmonicityand tensionof eachstring, and control of bothis essential for excellentvolume, tone quality, and balanceof soundfrom baasto treblein a finegrand piano. While thereis no accountingfor taste,there is general agreementon whichpianos sound best. Design rules have been derived based on thesepianos, as well ason a large numberof poor pianos,that reliably predict what rangesof the abovedesign parameters will "sound good."In general,the largerthe piano,the moretension and the lessinharmonicity it musthave for excellent tonequality. lnharmonicity must also be carefully controlled to achieveperfect tunability. This is a rarequality that allowsan instrumentto betuned so well that everymusical interval (when played in ascendingsequential semitones)increases smoothly and evenlyin beat rate.

S60 J. Acoust.Soc. Am. Suppl. 1, Vol.81, Spring1987 113thMeeting: Acoustical Society of America S60 9:35

CC3. From touch to string vibrationsThe initial course of the piano tone. Andors Askcnfclt and Erik Jansson(Department of SpeechCommunication and Music Acoustics, Royal Institute of Technology KTH, P.O. Box 70014, S-10044 Stockholm,Sweden) In a pilotstudy [J. Acoust.Soc. Am. Suppl.I 71, S92 (1982)], measurementsof key velocity,hammer acceleration,and string vibrations were reported. The study also covered the timing of theparts in theaction andcontact durations between hammer and string. The project was now continued by verifying measurements of keymotion and string vibrations by means of a noveloptical detector. In addition,the motion of thehammer has beenrecorded simultaneously with key motion underdifferent playing conditions (pianist, nonpianist, pendulum).The effectsof adjustmentof theaction on timing,as well asthe effectsof weight,shape, and softness(intonation) of thehammer on thestring waveform and spectrum, have also been investigated. The methodsand the resultsof the measurementswill be presentedand discussed:

10:05

CC4. Input impedanceand soundradiation of the pianosound board. Klaus Wogram (Physikalisch- TechnischeBundesanstalt, 3300 Braunschweig, Federal Republic of Germany) Thesoundboard of thepiano acts as the signal converter from the string vibration to theairborne sound. Thetype of mounting of the soundboard onthe back, as well as the ribs, influences both the sound radiation and theinput impedance that acts as a loadfor thestrings as vibration generators. Furthermore, the iron plate affectsthe effectivenessof the soundboard.Extensive measurements have shown that massloading by the ribs isin general too large to compensate forthe unisotropism inits modulus ofelasticity. This causes an additional dampingand sometimes an increaseof thedecay rate of thepiano sound.

ContributedPapers

10:35 11:05

CC5. Longitudinalvibrations in piano strings. Michael Podlesakand CC7. Analysis and synthesis of piano tone. Astrid Reinholdt Anthony R. Lee (PhysicsDepartment, La Trobe University,Bundoora, (Laboratoryof Acoustics,Technical University of Trondheim,N-7034 Victoria-3083, Australia) Trondheim, Norway), Erik Jansson, and Anders Askenfelt (Departmentof SpeechCommunication and MusicAcoustics, Royal The percussiveexcitation of a pianostring by a hammeris expected to Instituteof TechnologyKTH, P.O. Box 70014, S-10044 Stockholm, producelongitudinal string vibration components in additionto the de- Sweden) siredtransverse ones [e.g., Yanagisawa etal., J. Acoust.Soc. Jpn. 33,412- 416 (1977) ]. However,so far little quantitativeinformation exists in cur- Signalsfrom a grandpiano, consisting of thestring velocity and the rent acousticsliterature on the contributionof suchlongitudinal compo- soundin theroom, were recorded. The signalswere analyzed with regard nentsto the radiatedsound of a piano.Our investigationsrevealed the to waveformand spectral development in time.The analysis,as well as a presenceofintial components of radiatedsound generated by thelongitu- listeningto therecording, revealed a prominentinitial thump in theroom dinal stringvibration mechanism. These components, coined as thepre- signalthat precededthe tonalstring sound. This attacksound was not cursivesound, appear distinctly ahead of the mainbody of soundthat is presentin the stringvelocity signal. Piano toneswere synthesizedby almostentirely due to transversestring vibration. Our experimentaldata modelingthe analysisresults in an additivecomputer synthesis. Impor- on thelongitudinal modes in pianostrings indicate that themost apparent tant featuresin the synthesizedpiano tone, suchas spectralenvelopes, contribution to the radiated sound occurs in the attack transient of tones initialthump, inharmonicity in strings,and multiple stringing, are illus- in thelow bass register. For thelowest bass tones, the sound-pressure level trated by soundexamples. (SPL) of theprecursivesound may be only 10to 20 dB belowthe overall peakSPL and the decay rate of theorder of 100dB/s. [Work supported by A.R.G.S. and C.T.E.C.] 11:20

CC8. Vocal register change: A study of perceptual and acoustic isomorphism. Anat Keidar (Department of Otolaryngology, 10:50 WashingtonUniversity Medical Center, JewishHospital, 4910 Forest Park Boulevard, Suite 212, St. Louis, MO 63108) CC6. Vibrations of a piano soundboard:Modal analysisand finite elementanalysis. Joseph Kindel and I-Chih Wang (3903 Hemphill This studyfocuses on the perceptualnature of chestand falsettoregis- Way, Cincinnati,OH 45236) ters,and on thedegree of correspondencebetween perception and several acousticmeasures. Fifteen target notes, ranging from G •3 to A#4, were Modal analysismeasurements have been made on two concertgrand sungby a male and a femalesubject in the contextof ascendingand pianosoundboards and a finiteelement model to describethe vibrational descendingsequences on the vowels/i/and/a/. Registertransitions were characteristicsof thesesoundboards has beendeveloped in order to ex- elicitedby settingstrict constraints on production,and by minimizing plorethe possibility of usingboth of thesetechniques in thedesigning of auditoryfeedback. Segments of l-s durationwere extracted from the tar- newsoundboards. To providean experimental basis for themodel, modal getnotes, digitized, acoustically analyzed, and perceptually judged by ten analysismeasurements were made on two piano soundboards,each trained listeners.Multidimensional scaling and hierarchicalclustering mounted in a rim. Then a finite element model of the soundboard was analyseswere utilizedto capturethe dimensionalityand the internal constructed.The resonantfrequencies and modeshapes of the first few structureof perceptualdata sets derived from pairwise similarity ratings. modes of the finite element model match very well with those found ex- Similar analysesof the acousticdata setsprovided a meansfor evaluating perimentallyusing modal analysis. The correspondence between the mod- thecongruence of eachacoustic variable and perception. Optimal spatial al analysisand finite element analysis results is verygood and these tech- representationof theperceptual data required no morethan two orthogo- niqueswill be of value in designingnew piano soundboards.[Work nal dimensions,with the quality attributerepresented by the dominant supportedin partby BaldwinPiano and Organ Co., Cincinnati, Ohio. ] dimension.The acousticvariables which exhibitedthe highestdegree of

561 J. Acoust.Soc. Am. Suppl.1, Vol. 81, Spring1987 113thMeeting: Acoustical Society of America S61 isomorphismwith perceivedregisters were characterized by differencesin iscurrently being done to calibrate feedback and envelope rate parameters frequencyspectra obtained from a setof l-oct bandpassfilters, and by andto developsoftware to goin theopposite direction, determining FM harmonicratio. The representationof pitchdifferences was reflected only parametersto approximatespectra with complicatedand time-varying in theinternal ordering of thestimuli within register, but did notaffect the shapes.Ultimately, such software should choose the configurationof os- perceptualdiscontinuity between registers. cillatorsas well as otherparameters to createthe perceptua!lyclosest approximationto the desiredspectral characteristics.

11:3•

CC9. Propresstoward more intuitive programming of FM synthesizers. 11:50 G. L. Gibian, D. R. Clements,E. N. Hamden (PhysicsDepartment, American University,Washington, DC 20016), and D. L. Bort (Johns CCi0. Absolute pitch: A methodologicalfallacy. Rudolf A. Rasch HopkinsApplied Physics Laboratory, Johns Hopkins Road, Laurel, MD (Departmentof Phonetics,Uniyersity of Utrecht, Trans 14, 3512 JK 20707) Utrecht, The Netherlands)

As wasreported last year, work has been done to makethe program- The researchon absolutepitch (AP) hasalready celebrated its first mingof newtone colors on FM synthesizersmore intuitive for composers centenary.So far, researchers(and the public) have divided listeners into andmusicians. The logarithmicrelations between modulator, carrier, and AP possessorsand non-AP possessors.Analyses of the tasksincluded in envelopelevel parameterson commerciallyavailable instruments and AP performancesshow that it is unsuitableto speakabout AP or RP correspondingindex of modulationand outputamplitudes in standard (relativepitch) without qualification. Certainly there are large individual FM synthesisequations have been empirically determined. The relations differencesin thecapacity of namingthe pitch of a tonalsound presented havebeen incorporated into a tutorialcomputer program that displaysthe withoutprior reference.But responsesare boundto be (more or less) waveformand corresponding spectrum after synthesis parameters are en- normallydivided, with the standard deviation as measure of performance. teredin eitherform. With theprogram, users can gain familiarity with the In sucha view,the decision of whetheror nota personis an AP possessor spectraof FM-synthesizedsounds, which can be quitecomplicated for dependson the categorywidth of the labels,which meansthat the distinc- synthesizersusing four or sixoscillators in variousconfigurations. Work tion betweenAP and non-AP is relative, not absolute.

THURSDAY MORNING, 14 MAY 1987 MT. McKINLEY, 8:30 TO 11:55 A.M.

SessionDD. UnderwaterAcoustics V: Matched Field Signal Processing--Part I

Orest Diachok, Chairman Naval ResearchLaboratory, Washington, DC20375

Chairman's Introduetion•g:30 InuitedPapers

8:35

DDI. Use of matched fields and other methods to locate sound souree• or reflectors in the ocean. Homer P. Bucker (Code 541B, Naval Ocean SystemsCenter, San Diego, CA 92152) and Philip W. Schey (ComputerSciences Corporation, 4045 HancockStreet, San Diego, CA 92110)

A fundamentaldifference in locatinga sound sourceunderwater and a visual sourcein our everyday experienceis thatthe sound waves are strongly bent by thevariation of soundspeed as a functionof depthand rangein theocean. With theadvent of inexpensivecomputing machines, it is nowpossible to beginto unscram- ble the refraction and reflectioneffects of underwatersound propagation to "see" the location of underwater sourcesand reflectors of sound.This paperreviews earlier theoretical and experimental work in matchedfield processingwhere the typical problem has been to determinethe range and depth of an underwatersource using narrow-bandsignals received at a verticalline array. In future years,it is clear that thesemethods will be expandedto coverwideband signals and reflective as well as active sources. A methodwill bediscussed where correlationsare made between calculated and measured plots of soundpressure as a functionof frequencyand time. [Work supportedby NOSC IR Program.]

9:00

DD2. An evaluationof matchedfield processorperformance with environmentalmismatch. Ronald L. Dicus (Code 5120, Naval ResearchLaboratory, Washington, DC 20375)

The matchedfield processoris enjoyinga technicalrenaissance because of increasedcomputer computa- tion speedsand environmentalmodeling capability. Its performance,however, is degradedby error or mis• matchin waveguidesteering vectors (theoretical fields) and by ambientnoise. The effectsof error in sound velocityprofile, water depth, array depth, and sensorpositions will be discussedin relation to their effecton sourcelocation bias, peak height, and peakwidth asa functionof mismatchstrength, frequency, range, and arraylength. Noise effects are not considered.To gaininsight, the processoroutput was investigated for a simplemultipgth signal environment inwhich acoustic energy travels along straight line trajectories but with

S62 J. Acoust.Soc. Am. Suppl.1, VoL81, Spring1987 113th Meeting:Acoustical Society of Amedca S62 allowancefor different effective wave speeds. At sufficientranges it canbe shown that the processor isequiva- lentto a linearsum of focusedbeamformers, each steered to a particularmultipath. Error in thewaveguide steeringvectors has the effect of differentially rotating theoretical beams relative to truefield beams, resulting in localizationbias and peak height reduction. Ambiguous peaks are caused by rotation of a theoreticalbeam forone multipath onto the true field beam of anothermultipath. These effects will bediscussed with numerical examples.

9:25

DD3. Matchedfield processing:A detectionand estimationtheory overview. A. B. Baggeroer(MIT, Cambridge,MA 02139),W. A. Kuperman(Naval ResearchLaboratory, Washington, DC 20375),and H. Schmidt(SACLANT ASW Centre,1-19026, La Spezia,Italy) Matchedfield processing in weak signal/noise situations requires maximum exploitation of thephysics of boththe signaland noisestructure as well as optimummethods for the signalprocessing. In recentyears, numericalmodels for the physicshave advanced to the point wheremany of the detectionand estimation theoryresults available in the signalprocessing literature can now be usedfor manyacoustic environments. Fundamentally,matched field processing isknown as the detection/estimation in colored, or correlated,noise problemin the signalprocessing literature. As such,ambiguity functions, Cramer-Rao bounds, and spectral measuresof performancecan be derived from a basic,well-known theory. Generalizations to high-resolution algorithmsand environmentswith partial coherenceare alsosuggested. Finally, resultsfor the lessstudied problemof matchedfield processing performance using estimated covariance matrices can be addressed.

9:50

DD4. Sourcelocation and identificationby backpropagationin the time domain.Robert P. Porter and Jei ShuanChcn (Electrical Engineering, FT-10, Universityof Washington,Seattle, WA 98195) Generalizedbackpropagation in the time domain has been applied to seismicinversion and is nowbeing extendedto thesource location and identification problem in underwateracoustics. The methodis basedon a discreteimplementation of the Huygens-Kirchhoffintegral and is applicableto a wide rangeof wave-front migrationproblems including underwater acoustics. The computationis simplifiedby usinga few nearest neighborstocalculate the field along a nearbycoplanar surface. A briefdiscussion ofgeneralized backpropaga- tionin boththe frequencyand the time domains will bepresented. The methodwill be illustratedby showing reconstructionsof someof the numerousspread-source geometries that havebeen studied. Some implications of the useof this methodfor locatingand identifyingsources in the oceanwill be discussed.

10:15

DDS. Signal field matchingin range,depth, and bearing.John M. Ozard (Defence ResearchEstablishment Pacific, FMO, Victoria, British Columbia V0S lB0, Canada)

Advancesin propagationmodeling have enabled increasingly accurate calculations of theacoustic field for situationswhere fairly complete knowledge of theacoustic environment isavailable. To takeadvantage of the improvedpropagation models, various matched field signal processing schemes have been developed. Because of thelarge number of possiblecombinations of range,depth, and bearing for a movingacoustic source, it is desirableto speedup the matchingprocess and reduce the searchregion. This canbe achievedby usingan initialcoarse global grid search followed by a fineoptimization of sourceposition to producefield matches. Further gainscan be obtainedby predictingthe next sourceposition so that subsequentsearches can be restrictedto smallregions around the predicted positions. In thispresentation, the essence of thenormal mode propagationmodel and suitable processing and predictionschemes are describedand appliedto a shallow waterenvironment. This is followedby illustrationsof performancefor a generalizedbeamformer and for an orthogonaltechnique under a varietyof environmentalconditions, source parameters, and array configura- tions.

ContributedPapers

10:40 searchover forward solutions, each of whichassumes a particularsource location.The sensitivityof the techniqueto errorsin the assumedsound DD6. Passiveranging as an inverseproblem. E.J. Sullivan (SACLANT velocityprofile and tilting of the 16Avertical receiving array is studied. ASW ResearchCentre, APO New York, NY 09019) Also, the effect of both white and colored noise is investigated.Results A passive ranging technique is presented which uses SNAP, the indicatethat, for the scenarioconsidered (Summer profile in the Mediter- SACLANT Centre'snormal-mode model. A set of linear equationsare raneanwith a water depth of 130 m and sourceranges of 10 and 25 kin), obtainedthat allow a maximumlikelihood estimate of the rangeof an the methodcan be quite robustto soundvelocity profile errors on the acousticsource to bedirectly computed using any desired combination of order of severalm/s and array tilts on the orderof 1.5ø. Solutions were modes.This is in contrastto the matched-fieldtechniques that use a obtainedwith input signal-to-noiseratios as low as - 17dB.

S63 J. Acoust.Soc. Am. Suppi. 1, Vol.81, Spring1987 113thMeeting: Acoustical Society of America S63 10:55 This paperdescribes an analyticalstudy of range-depthambiguity surfacesobtained on a verticalarray in shallowwater through the spatial DD?.Asimplemethodofrangeanddepthestimation.T.C. Yang(Naval correlationof the incidentacoustic field with a replicaof that field.The ResearchLaboratory, Washington, DC 20375) resultsindicate that a high-qualityambiguity surface (narrow main lobe- The rangeand depthof an acousticsource in the oceancan be deter- low sidelobelevels) can be obtainedprovided that the incidentacoustic minedby decomposing array data and beamforming on themode ampli- fieldis formed from a significantnumber of"effective" modes and that the tudes.In particular,because the modeamplitudes are proportional•to arrayspans a largefraction of the watercolumn. Changes in the acoustic exp( -- ik•rs) asa functionof sourcerange, the productof the modeam- environmentthat reduce the effective number of modes diminish the qual- plitudeswith the steering vector V [whereV,. = exp(ikir)] ismaximum ity of theambiguity surface. Thus the quality is reducedby eithera de- for thetrue source range (r = rs). Accuraterange and depth estimation creasein the waterdepth or the sourcefrequency or by an increasein with thisapproach, however, requires reliable estimates of the modeam- eitherthe sourcerange or the bottomloss. Furthermore, although the plitudes--oftendif•cult to obtain. In thispaper, an eigenvector decompo- array lengthis a key parameter,hydrophone spacings over twice that sitiontechnique is usedto extractthe mode amplitudes for datareceived requiredto satisfya Nyquistcriteria (water depth/number modes) can be on a long (l-km) verticalarray. Range and depth are successfullyesti- usedwithout substantial degradation. Finally, errors in thebottom pa- matedboth for simulated data and for data from the 1982 Fram IV Exper- rameters,which produce errors in the replicafield, shift the main-lobe iment in the Arctic Ocean. The effect of the number of modes on the peak,whereas errors in thesound-speed profile can degrade the ambiguity estimates is also illustrated. surfaceto thepoint where the main-lobe peak is indistinguishablefrom the sidelobepeaks.

11:10 11:40 DD8. Simulationof matchedfield processingfor convergencezones in a strongbottom field. David F. Gordon (Naval OceanSystems Center, DD10. Experimentaldetermination of modaldepth functionsfrom Code711, SanDiego, CA 92152-5000) covariancematrix eigenfunction analysis. Stephen N. Wolf (Code5160, Naval ResearchLaboratory, Washington, DC 20375 and Defence Below30 Hz, the convergencezone energy can be smallerthan the ResearchEstablishment Atlantic, P.O. Box 1012, Dartmouth, Nova bottomreflected energy. Matched field simulations using a normalmode ScotiaB2Y 3Z7, Canada) programgive narrow, irregular correlation peaks for targetvectors taken fromthe complete field. Target vectors computed using only modes repre- A low-frequencysound field in a shallow-waterduct is usually repre- sentingconvergence zone energy are then processed against the complete Sentedbya set of discrete normal modes, each of which ischaracterized by acoustic field. A much broader, smoother correlation function is ob- a uniquevertical pressure amplitude depth function. In manyapplica- tained.Target vectors are thenconstructed that are equivalentto delay tions,such as matched-fieldsignal processing, it .is important to have and sumbeamforming at specifiedangles. These vectors give correlation accuratedeterminations ofthese depth functions, which are usually calcu- functionsthat resemblethose for convergencezone energy, and illustrate latedfrom normal-mode models. By using.adensely populated vertical therelationship between matched field processing and beamforming. arrayspanning the water column and a largetime-bandwidth test signal, in somecircumstances thenormal-mode functions of theduct may easily be obtainedby diagonalizingthe cross-spectral density function of the receivedsignal. The condition required for using this technique is that, 11:25 overthe bandwidth used, the fields of individual modes must be mutually incoherentso that the cross-spectral density matrix is the sum of individ- DD9. Range-depthambiguity surfaces for verticalarrays in shallow- ualmodal diads, making the modal depth functions the same as the matrix water environments. Richard Heitmeyer and Rachel Hamson eigenfunctions.Experimentally determined mode functions of orders1 (SACLANT ASW ResearchCentre, APO, New York, NY 09019) through4 arecompared with theoreticalresults.

THURSDAY MORNING, 14MAY 1987 REGENCY BALLROOM A & B, 8:45 TO 11:45 A.M.

SessionEE. SpeechCommunication VII: Linguistics,Phonetics, and Women's and Children's Voices (PosterSession)

Paul A. Lute, Chairman Departmentof Psychology,Indiana University,Bloomington, Indiana 47405

All posterswill be displayed from 8:45 until I 1:45a.m. To allowall contributors anopportunity tosee other posters,contributors ofodd-numbered papers will be at their posters from 8:45-10:15 a.m., and contributors of even-numberedpapers will be at their postersfrom 10:15-11:45a.m.

ContributedPapers

EEl. The phoneticrelevance of temporal decomposition.Stephen speechsignal. Temporal decomposition isan acousticanalysis technique M. Marcus (AT&T Bell Laboratories,Murray Hill, NS 07974 and which,without using any detailedphonetic knowledge, decomposes a Institute for PerceptionRcscarch--IPO, Eindhoven,The Netherlands) speechsignal into a sequenceof spectraltarget vectors, each associated and Ann K. Syrdal(AT&T Bell Laboratories,Naperville, IL 60566) witha timevarying target function. [ B. S. Atal. Proc. IcAssP 83, 81-84 ( 1983};S.M. Marcusand R. A. J. M. vanLieshout, IPO AnnualProgress A simplifiedview of speechproducti6n considers it to bethe resultof a Report,19, 25-31 (1984) ]. Thisreport will furtherevaluate relationships sequenceof gesturestoward articulatory targets, these gestures overlap- betweenthe acoustic characteristics of phonetic units and the target vec- ping in time and thus resultingin spectraltransitions in the acoustic torsand functions resulting from temporal decomposition. Comparisons

S64 J.Acoust. Soc. Am. Suppl. 1, Vol. 81, Spring 1987 113thMeeting: Acoustical Society of America S64 will be madebetween the temporalalignment of phoneticsegments and EES. Effectsof voicing,place, and vowelcontext on VOT for Frenchand targetfunctions. The effecton targetfunction duration of systematiccon- English stops.Bernard L. Roebet, Terranee M. Nearey, and Murray textural effectsknown to affectsegment durations. such as final conso- J. Munro (Departments of Linguistics and Romance Languages, nantvoicing on preceding vowel duration, will beexplored. Spectral prop- University of Alberta, Edmonton, Alberta T6G 2E7, Canada) eftits characteristicof representativevowels and consonantswill be Preliminaryresults in a studyof VOT in the productionof French comparedwith thoseof the correspondingtarget vectors, and someesti- initial stops(recorded from eightnative speakers) indicate a significant matesof the stabilityof thesevalues will be given. interaction of voicing state, place of articulation, and vowel identity in /CVk/syllables. While someof the trendsobserved are similar (e.g., VOT for highvowels is generallylonger for thatof non-highvowels), the exact patternof interactionsdoes not agreewith that foundfor AmericanEng- EE2. Linguolabials.lan Maddieson(Phonetics Laboratory, Linguistics lish JR. F. Port and R. Rutonno, J. Acoust. Soc. Am. 66, 654-662 Department,UCLA, LosAngeles, CA 90024) (1979) ]. Resultsfrom a larger-scalemeasurement study comparing VOT A numberof Austronesianlanguages spoken in Vanuatuhave a series productionin Frenchand Canadian English will bediscussed. Interaction of linguolabialconsonants (i.e., stops,nasals, and fricatives produced by effectsthat dependexplicitly on categorical(as opposedto purelyacous- articulationof the tongueblade with the upperlip). This paperpresents tic) contexthave been shown to be reliablein VOT productionexperi- the firstdetailed study of the productionand acousticnature of linguola- ments[ Port andRutonno (1979) ]. Resultsof cross-languageperceptual bialsbased on data from threeof theselanguages. These sounds may be experiments(using VOT continuain whichvocalic context and placeof producedwith varyingdegrees of retractionof the upperlip andprotru- articulationcues are variedas parameters) designed to testthe perceptual sionof the tongue,but all involvea vocaltract configuration with a nar- reliablityof sucheffects will bediscussed. [ Work supportedby SSHRC.] row cross-sectionalarea in the front region.In linguolabialcontinuants the secondresonance of the vocaltract is higher than it is in labials,and the burstof the linguolabialstop has greater energy at highfrequency than a labialstop. These segments thus have some similarities with dentalseg- EE6. The "effective second formant" F•: A parameter for the ments.Linguolabials are perceptually difficult to distinguishfrom dental classification of French front vowels. Marins Mantakes, or labialsounds, depending on phoneticcontext. The occurrenceof con- Pierre Escudicr,andJcan-Luc Schwartz (InstitutdclaCommunication trast betweenlabials, linguolabials, and dentalsin theselanguages indi- Par16e,Unit6 associ6au C.N.R.S. No. 368, ENSERG, INPG, 46 avenue catesthat quite subtledetails in the spectrummust be adequateto signal F61ix-Viallet, 38031 Grenoble Cedex, France) differencesin placeof articulation.[Work sponsoredby NSF.] The "effectivesecond formant" F• wasanalytically tested as a cuefor roundingopposition in Frenchfront vowels(/i/-/y/and/e/-/o/oppo- sition).For thispurpose, a corpusof thesefour vowelsintroduced into EE3. Flappingof epicalstops in AmericanEnglish. Fares Mitleb contextsmaximizing and minimizing the roundingopposition [ C. Abry, (Departmentof English,Yarmouk University, lrbid, Jordan) L-J. BoG,P. Corsi, R. Descout, M. Gcntil, and P. Graillot, Labialit• et Phon•tique(Univcrsit6 dcs Langucsct dcs Lcttrcs,Grenoble, France, One fundamentalassumption in all theoriesof phonologyhas always 1980)] wasacoustically studied. The firstfour formantfrequencies and beenthat neutralizationrules have the power to obliteratethe contrast levelswere measured. TheF• of the analyzedvowels was next estimated betweensegments in certainenvironments. For example,American Eng- with a modelbased on psychophysicaland vowelperception hypotheses lish is well knownfor its neutralizationof intervocalic,poststressed/t/ andusing thc frequencies and levels ofF:, F 3,and Fn [M. Mantakas,J-L. and/d/to anapical "flap" [ r]. However,acoustic analysis of five pairs of Schwartz, and P. Escudicr, ,4ctesdes 15e Journ•esd 'gtudessur la Parole Englishwords produced by fivenative speakers of AmericanEnglish re- (GALF, Aix-en-Provence,France, 1996), pp. 157-161]. The effective- yealedthat flappingof epicalstops is a near-neutralizationprocess. Fur- thermore,in a listeningtest, American listeners were able to distinguish nessof F• as a classificationparameter was furthermore compared with underlying/t/and/d/with about69% accuracy--significantlybetter that of other acousticcues proposed for French. [Work supportedby thanchance. This suggeststhat segmentalfeature analysis oversimplifies CNET, France.] thespeech production and perception processes, since it statesin advance the factsto be accountedfor in phonology.Results of this studyseem to call into questionthe current formulationsof neutralizationrules and relatedconcepts. The findingswill be interpretedin termsof theirconse- EE7. Discrimination of duration ratios in Estonian and English. Robert quencesfor the presenceof temporalimplementation rules. [Research Allen Fox (Speechand HearingScience, Ohio StateUniversity, 324 supportedby YarmoukUniversity, Jordan. ] DerbyHall, Columbus,OH 43210) and Ilse Lchiste(Linguistics, Ohio StateUniversity, 204 Cunz Hall, Columbus,OH 43210)

Estonianhas beendescribed as havinga three-wayquantity distinc- EFA. Effects of pragmatics on phonetic variables. R. Port and tionamong disyllabic words based upon whether the ratio of thedurations P. Crawford(Indiana University,Bloomington, IN 47405) of syllableI to syllable2 is approximately2:3, 3:2,or 2:1.The present studywas designed to examinethe abilityof listenersto discriminate It hasbeen shown that the supposedneutralization of German mini- amongsuch duration ratios independent ofother phonetic factors, such as mal pairs like bunt and Bund is incomplete[J. Phonet. (1986)] since fundamentalfrequency or segmentalvariations. Pairs of noisebursts smallbut consistentdifferences can be foundin phoneticvariables. This (with 10ms rise/fall times) whose durations were in theratios of 1:2,2:3, permitslisteners to guesswith better-than-chanceaccuracy. But, since the 3:2, and 2:1, wereconstructed. In half of thesenoise sequences the com- distinctionis very small, a questionarose as to whether speakerscan binedduration of noise1 + noise2 was 350 ms; in the other half the controlthe amountof differencethey can producebetween the two cate- combinedduration was 450 ms. Subjectswere presented with two such gorics.In an experimentspeakers wcrc given a varietyof tasksinvolving sequencesand were required to respond whether the duration ratios in the pronunciationof a smallset of minimalpairs of thetype bunt-Bund. First, two sequenceswere the sameor different.Equal numbers of samesand they read the wordswithin a long list of sentencesso that their attention differentswere randomly presented to 56 nativelisteners (and five trained wasdiverted away from the test words.Then carrier sentenceswith the phoneticians).Twenty-eight listeners were native Estonians (whose data words in adjacentsentences were read, and finally German sentences werecollected in Tallinn, Estonia)and 28 listenerswere native American comparableto, "No, I didn't saybunt, I saidBund," wereread. Analysis Englishspeakers (whose data collectedin Columbus,OH). Obtained of temporalmeasurements from the wordsshowed that speakers did pro- resultsshow that both groupsof listenersclearly recognized only two duce more distinctive pronunciations in contexts where their attention contrastirepatterns: 1:2 and 2:3 vs 3:2 and 2:1. In addition. overall se- wasdrawn to the contrast,and evenmore when trying to distinguishthe quenceduration had a significanteffect upon duration ratio discrimina- pronunciationsfor a listener.This is evidenceof gradedphonetic control tions.These results will be discussedin light of possiblelanguage group even when speakershave faint awarenessat most that a distinctionis difference,phonetic training differences, and in termsof psychoaeoustic made.[Research supported by NIH, HDI2511 and NSF.] limits on the contrastireuse of duration in languages.

S65 J. Acoust.Soc. Am. Suppl.1, Vol. 81, Spring1987 113th Meeting:Acoustical Society of America S65 EES. Effects of consonantlength on vowel-to-vowelcoarticulation in VCV contextsby a nativespeaker of Farsiwere presented. Correct identi- Japanese.Caroline L. Smith (Haskins Laboratories,270 Crown Street, ficationof the medialconsonant varied systematically as a functionof New Haven, CT 06510) vowelcontext from very few errors to nearchange performance. Acoustic analysisrevealed systematic F2 and F3 formant transitiondifferences Vowel-to-vowel coarticulation across consonants can be seen as evi- betweenuvular and velar consonants produced in thesame vowel context. denceof overlapbetween the articulatorygestures of the vowels.Further Variationsin voicingoffset (murmur) werealso observed in severalvowel evidencefor the organizationof the gesturescan be foundin contextual contexts.These results further our understandingof the roleof linguistic variationin the durationsof the vowels.This acousticstudy of Japanese experiencein theperception of phoneticcategories. [Research supported examinesthe effectsof geminateconsonants on the durationsand the F 2 by NINCDS. ] valuesof thesurrounding vowels in VCV utterances.Because of the sylla- bicstructure of the language,geminatc consonants in Japanesemight be expectednot to closethe precedingsyllable, eliminating this potential sourceof vowelshortening. In agreementwith thishypothesis, vowels did EEl2. Vowelduration in Englishword and sentence patterns as spoken by not shortenbefore gcminate consonants (in fact theylengthened), and the non-nativespeakers. Joann Fokes (School of Hearing and Speech secondvowel affected the formantsof the firstvowel less across geminatc Sciences,Ohio University, Athens, OH 45701) and Zinny Bond than acrosssingle consonants. [Work supportedby NSF.] (Departmentof Linguistics,Ohio University,Athens, OH 45701) Non-nativespeakers from five different language backgrounds (Chin- ese,Hausa, Japanese, Persian, and Spanish)and threenative American EE9. The relationship between vowel variation and vowel-to-vowel Englishspeakers produced tokens of two-syllablewords (complete), coarticulationacross languages.Brian MeAdams (Department of three-syllablewords (completion), and four-syllablewords (competi- Linguistics,Ohio StateUniversity, Columbus, OH 43210) tion) in isolationand in sentencecontext. Vowel duration, a correlateof stress,was measured in thefirst two syllables in words from spectrograms. The amountof coarticulatoryvowel variation within a languagemay TheAmericans used very short vowels in thereduced syllables and short- be dependenton the sizeand distributionof the vowel inventorywithin the vowelformant space [P. A. Keatingand M. K. Huffman,Phonetica enedstressed vowels in suffixedwords and in sentencecontext. The pri- marydifficulties of the non-nativespeakers were vowel reduction in un- 41, 191-207 (1984) ]. Similarly,it hasbeen suggested that the extentof stressedsyllables and the stresspatterns of four-syllablewords. vowel-to-vowelcoarticulation in a languagevaries in proportionto the degreeof vowelvariation within the languageIS. Y. Manueland R. A. Krakow, HaskinsStatus Report No. 77/78, 69-78 (1984) ]. Manuel and Krakow supportedthis idea with evidencecomparing Swabill and Shone EEl3. Phoneticreality and phonologlcalprediction: Stress clash and ( 5-vowelsystems) to English( 12-vowelsystem ). The presentstudy com- rhythmin English.Keith Johnson(Department of Linguistics,Ohio paresvowel-to-vowel anticipatory and carryover coarticulation in Japa- State University, Columbus, OH 43210) and Dorothy Evans neseand Hausa ( 10-vowelsystems, with differentvowel distributions) to (Department of Linguistics,University of Illinois, Urbana, IL 61801) German ( 14-vowelsystem). Three speakersof eachlanguage read bVbV "words"in listsand in framesentences. The effectsof phoncmicvowel Cooperand Eady [J. Mere.Lung. 25, 369-384(1986) ] recentlytest- lengthand phrasalcontext on coarticulatoryvowel distributionarc also edsome predictions of metricalphonology only to finda lackof empirical considered. supportfor someimportant aspects oftbe theory. This report will present the resultsof a replicationand revision of oneof theirexperiments. The phonologicalprediction being tested in thisexperiment isthat the rhythm of an utterancewill beadjusted toward isochrony is casesof stressclash EEl0. A cross-languagestudy of •vowel spaces and interference. (adjacentstressed syllables). In a pilotstudy it wasfound that in normal Allard Jongmanand Marios Fourakis (Central Institute for the Deaf, productionsof testsentences the findings (or rathernonfindings) of Coo- 818 South Euclid, St. Louis, MO 63110) perand Eady were replicated. However, when subjects were instructed to "speakup," therewas a tendencytoward rhythmic adjustment of the This is a studyof the spectralcharacteristics of the vowdsof German durationof wordsinvolved in thestress clash. In thestudy to be reported andmodern Greek in relationto thoseof AmericanEnglish. Two native in thispaper, subjects produced stress-clash sentence pairs once normally speakersof Germanproduced 18 wordscontaining the shortand long vowelsof German,and two native speakers of Greekproduced five words and oncecarefully (the instructionswcrc "as if you weretalking to someonewho might have a hardtime understanding you"). The results of containingthe five pure vowels of Greek.All speakersalso produced nine the pilot experimentseem to indicatethat speakersdo in somecircum- Englishwords containing the nine simple vowels of English.Vowel target stancesadjust the rhythmof an utterancein responseto stressclash. This zonesfor German,Greek, and foreign-accentedEnglish are established withinthe auditoryperceptual theory [J. D. Miller, J. Acoust.Soc. Am. patternof resultsraises some questions about what linguistic"compe- tence"is beingdescribed by the phonologicaltheories tested. Suppl. I 76, S79 (1984)] and comparedto the targetzones of native speakersof English.A metricof the distance between the foreign, foreign- accentedEnglish, and native English target zones will bcdeveloped. Per- ccptionexperiments are plannedto obtainboth identification scores and EEl4. Usingmetrical phonology to synthesizespeech. William Reilly paired-comparisonratings of foreignaccentedness. The positionsof vow- (Department of Linguistics,Indiana University, Bloomington,IN elsin boththe nativeand acquired language will be correlatedwith these 47405 ) ratingsto determine if anobjective measure of foreign accent and phonetic interference can be derived. In thisexperiment synthesized reiterant speech is compared to natural reiterantspeech. Using multiple linear regression, equations are obtained whichtake grammatical information (e.g., syllable weight, word bound- ary, lexical•tre•) of natural gpeech•yllable• a• input and produceaa EEII. Perceptionof Persian uvular and velar stop consonantsby outputinformation sufficient to predictthe timingof the corresponding reiterantspeech in n0nphrasefinal position. A corpusof 35 phraseswas speakersofAmericanEnglish. Linda Polka(Department of Psychology, Universityof SouthFlorida, Tampa, FL 33620) spokenreiterantly by threespeakers, using the syllablesa asthe reiterant syllable.Measurements of the durationof the reiterantsegments were Recent cross-languagestudies by Werker and Tees [J. Acoust. Soc. madeautomatically from the digitizedspeech and constitutethe final Am. 75, 1866--1878(1984) ] describedifficulties in Englishspeakers' per- dependentvariable. Each syllable is grammatically described as a stringof ceptionof a Thompsonglottalized uvular-velar stop contrast. However, binary variablesdetermined from metrical phonology[Liberman and the acousticinformation that differentiatedthe contrastingphones was Prince(1977) ]. After calculatingthe predictedsegmental durations of a difficultto specify.The presentstudy extends the examinationof non- reiterantphrase, the originalspeech was modified to fit thesepredictions Englishplace contrasts by investigatingnative English speakers' ability to usingthe waveform editor of ILS. Theresulting synthesized speech is then perceivea nonglottalizeduvular-velar contrast in Persian(Farsi). Multi- judgedby comparingit to theoriginal reiterant speech of thethree speak- pie instancesof velar and uvularstop consonants produced in several ers.The successof thisexperiment suggests that the sametask might be

S66 J. Acoust.Soc. Am. Suppl. 1, Vol.81, Spring1987 113thMeeting: Acoustical Society of America S60 performedfor natural speech, and that the grammar is tied more closely to longstressed vowel (CVVC.). The durationof geminateswas studied in productionand perceptual mechanisms than previously shown. [Work four wordstructures, CVC.CV(V) and CVVC.CV(V), and theywere supportedby NSF. ] foundto belonger in theformer group than in thelatter.

EELS.The phonologicaldomains of final lengthening.Mary E. Beckman EELS. Metrical structure of initial syllables in English. Anne Cutler (Department of Linguistics,Ohio State University, Columbus,OH {MRC AppliedPsychology Unit, 15 ChaucerRoad, CambridgeCB2 43210) and Jan Edwards (Hunter School of Health Sciences,Hunter 2EF, United Kingdom) and David Carter (Computer Laboratory, College,425 East25th Street,New York, NY 10010) Universityof Cambridge,Corn ExchangeStreet, Cambridge CB2 3QG, United Kingdom) A syllableat theend of a phraseis considerably longer than it wouldbe phrase-internally.Similarly, a stressedmonosyllabic is generallylonger Cutler and Norris [J. Aconst.Soc. Am. Suppl.I 77, S39 (1985)] thanany identical syllable separated from the word's edge by one or more providedevidence for a segmentationstrategy in continuousspeech per- unstressedsyllables. Two setsof experimentshave been designed to deter- ception,whereby a wordboundary is postulated,and a lexicalaccess pro- minethe phonological domain of theseeffects. The first compared target cedureinitiated, at each metricallystrong syllable. In the presentstudy, syllablesat variousdistances from the ends of words( [ pt ] inpep, pepper, thelikely success of thisstrategy was estimated against the characteristics peppermint;[pal in popopposed, poppa posed) in sentenceswbere tbey of the Englishvocabulary. Two computerizeddictionaries and two fre- eitherdid or did not preccdcan obligatoryintonational phase break. quencycounts were consulted. The dictionarieslist approximatelythree Theseexperiments showed that ( I ) there is a smallerword-final effect timesas manywords beginning with strongsyllables (i.e., syllablescon- distinctfrom the substantialphrase-final lengthening at intonational taininga full vowel) as beginningwith weaksyllables (i.e., syllablescon- boundaries,and (2) the word-finaleffect must also be a boundaryeffect taininga reducedvowel }. Frequencycounts reveal that wordsbeginning ratherthan a resultof stresstiming, since it occurredeven in the pop with strongsyllables have a meanoccurrence frequency nearly twice that opposed-poppaposedutterances, where the target syllabic was always fol- of wordsbeginning with weaksyllables. These findings motivate an esti- lowedby exactlyone unstressed syllable. The secondset of experiments matefor everydayspeech recognition that approximately 85% of lexical testswhether word-final lengthening is affected by pitch-accent and stress words(i.e., excludingfunction words) will havestrong initial syllables. placement,or whetherit definesa phrasalunit independentof metrics. Thisestimate was tested against a corpusof 190000 wordsof spontaneous BritishEnglish conversation ]J. Svartvikand R. Quirk,/I Corpusof Eng- lish Conversation{Lund, Glecrup, 1980}]. Ninety percentof lexical wordsin thiscorpus were found to beginwith strongsyllables. [Research EEl6. Accents,focus distribution, and the perceiveddistribution of given supportedby the AIvey Directorate,United Kingdom.I and new information:An experiment.S. G. Nooteboom (Institute for PerceptionResearch, Eindhoven, The Netherlandsand the Department of GeneralLinguistics, Leyden University, Leyden, The Netherlands) and J. G. Kruyt (Iustitutc for Dutch Lcxicology, Leyden, The EEl9. On the resy!labificationof/1/in English. Richard Sproat and Netherlands) Toni Borowsky (AT&T Bell Laboratories,2D-443, 600 Mountain Avenue,Murray Hill, NJ 07974) This paperreports on an experimentexamining some perceptual con- sequencesof correspondencesbetween accent patterns, plus and minus English/1/is knownto be light {[I]) or dark (It]) whensyllable focus,and new and giveninformation in Dutch-spokensentences. The initial or syllablefinal, respectively.The acousticdifference is that Ills main questionexamined was to what extentplus focus (accented) con- havelower F I s andhigher F 2sthan [! ] s.The effectsof varyingstrengths stituentsare generally perceivedas conveyingrecently introduced of boundarieson Theresyllabification of/l/in Englishhave been exam- ("new") information,and minusfocus (unaceented) constituents as con- ined.Speakers were asked to producetwo sets of sentences,both of which veyingearlier introduced ("given") information.The linguisticmaterial included/1/s in the vowel contexts/i_if,/u_o/, and/o_•/: (i } The for the experimentwas formed by brief radionews items, each two sen- controlset had/1/s that wereeither necessarily syllable initial or syllable tenceslong. First sentences determined the distribution of newand given final;and {2) the testset had morphemefinal/l/s with a vowelinitial informationinsecond sentences. IThe accent patterns inthe second sen- morphemefollowing and boundaries of varyingstrengths [ +, •, • •: tenceswere varied systematically by manipulatingtheir syntheticpitch (compoundboundary), major phraseboundary, major intonational contoursaccording to therules for Dutchintonation. Subjects were asked boundary] intervening.The datawere analyzed by twotechniques, name- bothto finda fittingfirst sentence to eachsecond sentence, and to ratethe ly traditionalspectrograms, and by measuringthe frequencies of theLPC- acceptabilityof each possible combination of a firstwith a secondsentence polesfor the/I/s. It wasfound, for at leastsome speakers, that light/1/s on a scalefrom 1-10. Resultsshowed that the mostpreferred or accepta- are possiblebefore all boundariesexcept a majorintonational boundary. bledistribution of newand given information closely matches the distri- Theseresults support the positionthat resyllabifieationis generallyal- butionsof plusand minusfocus, as markedin the accentpatterns. New lowedacross any boundaryexcept a major intonationalone. We haveno informationcan hardlyever be acceptablyassociated with minusfocus, dataconfirming the claim of Halleand Mohanan ["Segmental phonology but giveninformation can, ratheroften, but not always,be acceptably of ModernEnglish," Linguistic Inquiry 16, 57-116 ( 1985) ] that speakers associatedwith plusfocus. resyllabifyacross compound boundaries but fail to do soacross word or phraseboundaries.

EEl7. Interacting effects of precedingstress and phonerolevowel quantity on consonantduration in Finnish. Riitta V'alimaa-Blum EE20. Acousticstudy of Russianvowel allophones. Patricia A. Keating (Departmentof Linguistics,Ohio StateUniversity, 1841 Millikin Road, (LinguisticsDepartment, UCLA, Los Angeles,CA 90024) Columbus, OH 43210) The five Russianvowels vary in auditoryquality depending on their Finnishhas a quantityopposition in bothvowels and consonants, and consonantcontexts; one traditional reference gives several major and mi- demarcativcstress on the initial syllable.Stressed vowels are longerthan nor impressionistieallophones for eachstressed vowel. The consonants correspondingunstressed ones. A peculiarfact about short and long vow- are reportedto be relatively unaffectedby their vowel contexts,and to els is that they are significantlylonger after a short initial syllable blockvowel-to-vowel interactions. This paperpresents a studyof Russian [ CV.CV ( V ) ] thanafter any kind of longinit ial syllable[ CVV.CV ( V ), vowelsin CV, VC, and CVC syllablesfor three speakers.Preliminary CVC. CV(V), CVVC.CV(V)]. A proposedexplanation is that duration resultsfor vowels/i/and/a/across a wide varietyof contextssuggest asa stresscue spills over to thesecond vowel in CV.CV (V) wordsin order that the allophonic variation is of thraa kinds. First, there is target vari- to avoidneutralizing the phonemie vowel quantity on the firstsyllable. If ation:Each of thesevowels has one target in somecontexts, and a second this indeedis the sourceof thesecond-vowel lengthening, then we would targetin othercontexts. Second, some additional vowel variation is due to expecta similareffect in syllablefinal consonants: The consonantafter a undershootof thosetargets after extensive F 2 andF3 transitions.Finally, shortstressed vowel (CVC.) shouldbe longerthan the consonantafter a however,in manycontexts the formantsdo reachtheir targets,despite the

S67 J. Acoust.Soc. Am. Suppl. 1, Vol.81, Spring1987' 113thMeeting: Acoustical Society of America S67 extensivetransitions. In thesecases, the perceivedvowel quality varia- and its relationshipto other,similar projects (e.g., Alvey) will be dis- tionsseem to arisefrom differencesin the transitionsalone. [Work sup- cussed. portedby NSF.]

EFAM. G!ottal source-vocal tract acoustic interaction. Gunnar Fant and EE21. Coartleulation in VCV •equeneesin Arabic. Lutfi Hussein Qi-guangLin (Departmentof SpeechCommunication and Music (Departmentof Linguistics,Ohio StateUniversity, Columbus, OH Acoustics,Royal Institute of Technology(KTH), S-100,44, Stockholm, 43210} Sweden)

Vowel-to-vowelcoarticulation in VCV utteranceshas been the subject Earlierwork reported in theSTL-QPSR (SpeechTransmission Labo- of severalstudies. Ohman [J. Aeoust.SOc. Am. 39, 151-168 (1966)] ratory,Quarterly Progress and StatusReport, KTH, Stockholm)each foundthat vowelsin VCV utterancesin Englishand Swedishhave some year since1979 has beenextended to the modelingof the supraglottai transconsonantaleffect on one another. He also found some evidence impedanceto includefive formants and a timespan of analysisto embrace suggestingthat secondary articulation features, like palatalization in Rus- severalsuccessive glottal periods. The acousticinteraction is highlynon- sian,block coarticulation. Action theorists, such as Fowler [J. Exp.Phon. linearand may give rise to spectralpeaks between formants. This is largely Gem112, 386-412 (1983)], explainV-to-V eoarticolationin termsof due to nonlinearsuperposition ripple originating from previousexcita- timing;that is, they claim that vowels in speechproduction are underly- tions.At a highF0, coincidingwith F 1,the air consumptionisminimized inglyoverlapping and consonants ride on top of thevowels. This sugges- as previouslyshown experimentally by Rothenberg.One aspectof the tion impliesthat intervocalicconsonants, whether they have secondary interactionis intraglottalvariations in formantbandwidths and frequen- featuresor not,do notblock coarticulation. Keating [UCLA WPP 62, 1- cies.The modeling of superpositionat increasing FO andconstant articu- 13 (1985)], on the other hand,explains it in termsof autosegmental lation showshow the formantamplitude range at in-phaseand out-of- phonology.She places the featuresfor vowelsand consonantson two phasesuperposition decreases due to intraglottallosses. In addition,there separatetiers, and leavesconsonants unspecified for vowelfeatroes, so appearnonlinear deviations such as a weak tendencyof synchrony that V-to-V eoarticulationaffects an interpolationbetween vowel targets. betweenthe secondand first formant amplitudedependency of FO. A Keating'smodel implies that consonants that have secondary articulation constantleak added to the normal glottalarea function has been modeled ( i.e.,vowel features ) mustblock coarticulation. A preliminaryanalysis of as a first steptoward the studyof leakyvoices. Here, the apparentlinear- VCV utterancesin Arabicshows that pharyngealizedconsonants indeed typeformant ripple in the maximallydosed phase is a mementofor in- tendto blockcoarticulation, a findingwhich supports Keating's predic- verse-filteringcriteria. Implications for femaleand child phonationsare tion over Fowlefts. discussed.

EE22. An acoustic study of the semivowels /w,y,r,I/ in American EE2$. Possibleproduction differences in children'sand adults'fricatives. Engl'sh.Carol Espy-Wilson(Room 36-545, Departmentof Electrical Richard S. McGowan (Haskins Laboratories,270 Crown Street, New Engineering and Computer Science, MassachusettsInstitute of Haven, CT 06511) and Susan Nittrouer (BoysTown National Institute, Technology,Cambridge, MA 02139) 555 N. 30th St., Omaha, NE 68131 ) The semivowelshave acoustic properties that aresimilar to bothvow- Most developmentalstudies of articulatoryability and phonological elsand other consonants. Ways to quantifyacoustic cues that distinguish organizationuse acoustic measurements to make inferencesabout pro- betweenthe semivowelsand separatethe semivowelsas a classfrom vow- ductiondifferences between children and adults.A commonassumption els and other consonantshave beenstudied. To make thesedistinctions, of thisapproach is that the only physical differences between children and the formantfrequencies within the semivowels,the formanttransitions adultsare the lengthsof variousvocal tract regions.Accordingly, any betweenthe semivowelsand adjacentvowels, and relativeenergy mea- acousticdifference not accounted for by thisscaling is attributed either to suresfelt to becorrelates of suchfeatures as voiced, sonGrant, nonsyllabic, a lack of articulatoryskill or to poorlydefined phonological categories. andstoplike have been looked at. Someresults of thisstudy agree with the This reportconsiders whether other physicaldifferences might account finding•of previousstudies. Namely, given minimal pair words, F I sepa- for someof the acousticdifferences between children and adults.Speech ratesthe glides/w/and/y/from theliquids/1/and/r/, F 2 separates/w/ samplesof 12speakers (8 childrenand 4 adults)producing the fricatives from/r/and/1/from/y/, andF3 separates/r/and/1/. In addition,it /s/ and/I/ followedby thevowels/i/and/u/were analyzedto locatethe wasnoted that the cuesusually separate the semivowelsfrom vowels and major spectralprominences. Acoustic measurements showed that the other consonants.In most caseswhere semivowelscannot be clearly dis- fricativelow-frequency prominences for children'ssamples differed from tinguishedon the basisof one or more features,considerable acoustic thoseof adultsin threeimportant ways. They: ( 1) weregenerally higher evidenceof featureassimilation between them and the adjacentsound(s) in frequency;(2) wererelatively greater in amplitude;and (3) showed exists.For example,often in wordslike "cartwheel"and "Norwegian," greatereffects of vowelcontext. The firstfinding can be explainedby a wherea vowelis followedby a postvocalic,but not word-final/r/, either simple scalingof adult modelsof fricative production to accommodate the lowestpoint of F 3 occurredat the beginningof the vowelor F 3 re- children'ssmaller vocal tracts.The last two findingssuggest, however, rosinedat the samelow frequencythroughout the vowel and/r/seg- that thereare other anatomicaland articulatorydifferences between chil- ments.That is, the featuresof the voweland following/r/overlapped. drenand adults affecting fricative production. The datasuggest the possi- Resultsare based on measurementsof 233polysyllabic words that contain bility thatone important difference may be that theratio of theglottal area the semivowelsin a varietyof phoneticenvironments. Each word was to frieative constriction area tends to be less for children than for adults. spokenby tw9 malesand twofemales. [Work supportedby a XeroxFel- [Work supportedby NIH Grants NS-07237 and NS-13617 to Haskins lowship.] Laboratories.]

EE23. PHONASCH: An ASCII-based system for detailed phonetic EE26. Sexdifferentiation cues in thevoices of youngchildren of different transcription.George D. Allen (Departmentof Audiologyand Speech language background. lnger Karlsson (Department of Speech Sciences;Purdue University, West Lafayette,IN 47907) Communication and Music Acoustics, Box 700 14, KTH, S-100, 44, Stockholm,Sweden) and Martin Rothenberg(Department of Eleetrical An ASCII-basedsystem is requiredin order to storephonetic tran- and Computer Engineering, Link Hall 111, SyracuseUniversity, scriptionsin computermemories. Although severalphoneme-level sys- Syracuse,NY 13210) tems(e.g., ARPABET) alreadyexist, none of thesepermits the levelof detailrequired for closetranscription. Under the partialsponsorship of Children,aged 3-8 years,speaking different native languages, were CHILDES (Child LanguageData ExchangeSystem, Carnegie-Mellon recordedand speechsamples from thesechildren were playedback to University),an IPA-to-ASCII systemhas been developed to permitthe adult listenergroups, also of differentlanguage background. The listeners archivingof highlydetailed transcriptions. This systemwill bedescribed, wereasked to judge the sexof the child.The childrenwere native speakers

S68 J. Acoust.Soc. Am. Suppl. 1, Vol.81, Spring1987 113thMeeting: Acoustical Society of America $68 of English,Finnish, or Swedishand the listenerswere native speakers of and analyzedfor meanintensity and intensitydistribution. The women Finnish,Swedish, English, or Chinese.Speakers and listenersfrom differ- alsorepeated a seriesofCV, VCV, andVC syllablesusing the consonants entlanguage backgrounds were used to findout if thedifferences in boys' /p/, /b/, /t/, /d/, /s/, and/z/combined with the vowel/a/, in the andgirls' voices were socially acquired or innate.The average right judg- carrierphrase "Speak again."Intraoral air pressureand the voicing mentwas 66% overall speakersand listeners, with nostrong tendency for signalwere recorded to providevowel and consonantdurations, voice a higherpercentage of rightanswers for childrenspeaking the listener's onsettimes, and peak intraoral air pressure.The F-maxtest for homogen- ownlanguage. The results from the listening tests have been compared to iety of variancewas used to comparethe variabilitybetween the two age differentacoustic measurements of F0, vowel formants,and speaking groups.The older speakers exhibited significantly greater variability than rate.No apparentcorrelation between perceived sex and these measure- theyounger speakers for the dependentvariables, peak intraoral air pres- ments has been found. sure, consonantduration, vowel duration, voice onsettime, and the mini- mumeffort level of speechintensity. The greatervariability of production exhibitedby theolder speakers could be a factorin theperception of older speakers. EE27. A multidimensionalscaling study of normal voice quality in females. Marylou PausewangGelfer (Department of Speechand HearingSciences, Indiana University, Bloomington, IN 47405) EE30. Acoustic-phoneticcorrelates of languagedevelopment. Harold Little is currently known about the perceptualdimensions listeners R. Bauerand Lauren Nelson (Speechand Hearing ScienceSection, usein discriminatingfemale voices and how thesedimensions relate to Departmentof Communication,Ohio State University, 324 Derby Hall, perceptualrating-scale judgements. The purposeof thisstudy was to ex- 154 North Oval Mall, Columbus, OH 43210) aminethese issues for normalfemale voices. In addition,the judgments of 20 naivelisteners and 20 experiencedlisteners (speech pathologists) were Phoneticcontrast has bccn suggested as a cognitiveoperating princi- compared.Listeners provided dissimilarity judgments of sentencespro- ple underlyingthe continuityof infantphonetic development [H. R. ducedby 20 females(24-25 years).The listeners also rated each voice on Bauer,J. Acoust.Soc. Am. Suppl.1 75, S45 (1984)]. Phoneticcontrast 17 perceptualrating scales (e.g., highpitch-low pitch, clear-hoarse). wasestimated in the currentstudy using the phoneticproduct (PP) esti- Resultsof themultidimensional scaling (MDS) analysisproduced a five- matorweighted to thesame eight American English sound-class frequen- dimensionalsolution (RSQ = 0.509). A stepwiselinear regression relat- cies.The PP was a resultof the multiplicationof the numberof eight edthe perceptual attributes of pitch,age, loudness, "liveliness," and pitch differentcontrasting sounds per minuteafter weighting and was summar- variability/qualityto the fiveMDS dimensions.When listener groups izedfrom recordings of mother-infantinteractions. The results from four werecompared, the experienced listeners relied on pitchsomewhat more childrenwere compared when each was 1 and 2 yearsold. Associated than the naivelisteners, while the naivelisteners utilized the pitch vari- measuresof languagedevelopment at 2 yearsof agewcrc also compared ability/qualitydimension to a greaterdegree. This studydemonstrates forpredicted order based upon the subjcct's 1-year data. As an estimator thatlisteners' perceptual ratings can be significantly correlated with per- of phoneticcontrast, PP andits acoustic correlates in l-year-oldinfants, ceptualdimensions derived from MDS analysis. [Research supported by werepredictive of mostof theirPP andassociated language variables at 2 BRSG Grant S07 RR07031, DRR, NIH.] yearsof age.

EE28. Age--sexvariations in maximumperformance measures of speech EE31. Vowel context effects in children's and adults' speech. production. Ray D. Kent and Jane F. Kent (Department of JoycePowers (Departmentof Linguistics,Ohio State University, Communicative Disorders, University of Wisconsin, Madison, WI Columbus, OH 43210) 53706) Recentstudies comparing coarticulation in adults'and children's The maximum performancemeasures of speechproduction include: speechhave yielded contradictory results; some have indicated that chil- phonationvolume, maximum phonation time, maximumcxpiratory pres- drencoarticulate more, and othersthat theycoarticulatc less. The studies sure,maximum vocal SPL, physiologicalvocal frequency range, maxi- whichfound more coarticulation in children'sspeech involved fricatives mum articulatoryforce, and maximumsyllable repetition rate. A survey and the vowels/i/ and /u/; thosefinding more coarticulationamong of the normatiredata seemedin order,given the frequentclinical use of adultsinvolved velar stops and the vowels/i/and/a/. It maybe that thesemeasures and the availabilityof a large,although scattered, archival coarticu]ationis not a unifiedphenomenon, and that the conflictingre- databasefor normalspeakers. This reportreviews published data for each suitsof earlierstudies were a consequenceof studyingdifferent kinds of measureand considers the adequacyof thesedata for clinicalapplication. coarticulation.The presentstudy, therefore, considers all of the things The data are foundto be deficientin severalrespects: ( 1) the effectsof that wereseparately investigated before. Adults and 3- and4-year olds subjectage and sexare incompletelydocumented; (2) testprocedures are wererecorded producing the syllables/si/,/su/,/sa/,/.[i/,/•u/,/j'a/, not standardized;(3) the validityof a maximumperformance estimate is /ki/,/ku/, and/ks/. The spectralpeak of the fricativeor stopwill be opento questionfor most,if not all, measures;(4) the variabilityof the determined,as will theF 2 values at theonset of voicingof thevowel. The datawithin and across studies is verylarge; and (5) a theoreticalframe- resultsof the studywill beconsidered in termsof whatthey imply about workfor the interpretation of the measures iseither lacking or deficient. howchildren acquire the phonologicalunits of theirlanguage. Recommendationsare offeredto correctsome of theseproblems, but the majorconclusion of thisreport is that measuresof maximumperformance lack validity and efficiencyfor generalclinical application. Summary ta- EE32. Cross-languagestudy of children'sprosodic development--IV: blesof the normatiredata are available upon request. [Work supported Comparisonof 4- and 5-year-oldFrench-, German-, and Swedish- by NIH. ] speakingchildren's TAKI productions,Denise Luczycki and George D. Allen (Departmentof Audiologyand SpeechSciences, Purdue University, West Lafayette, IN 47907) EE29. Variability differencesin the speechproduction in two age groups Six 4-year-oldand six 5-year-oldFrench-, (Austrian) German-,and of adult females.Richard J. Morris (Department of Communication Disorders,University of Utah, Salt Lake City, UT 84112) and W. Swedish-speakingchildren were engaged in an experimentaltask requir- S. Brown, Jr. (IASCP-ASB 63, University of Florida, Gainesville,FL ingthem to firstlearn and then produce the names of toys.Each pair of 32611) toyswas associated with a pairof names,which differed in prosodiccon- tour, onepair beingphonologically simple (/'taki/versus/ta'ki/), one The purposeof this study was to examinethe variability betweenthe slightly more complex (/'stoopill versus/smop'fi/), the third much speechproduced by twoage groups of adultfemales, a youngadult group morecomplex (/'gluvistrap/versus/gluvi'strap/). The children'sspon- anda geriatricgroup. The 25 womenin eachgroup phonated three pro- taneousproductions of thesenames were tape recordedand analyzed ductions of the vowel/a/for 5 s at three effort levels--maximum, com- auditorilyand spectrographicallyfor their prosodicfeatures (F0, dura- fortable,and minimum.Recordings of theseproductions were digitized tion, andintensity). Productions of the prosodicallysimpler forms were

S69 J. Acoust.Soc. Am. Suppl.1, Vol. 81, Spring1987 113th Meeting:Acoustical Society of America S69 morelikely to be prosodically correct than the more complex forms, for all tion data and the measurementsof the children'ssyntactic abilities is children.The patternof errorswas different. however, among the three evaluated.The resultsare discussedin terms of theoriesof motor pro- languagegroups. For example,the French children tended to dropfirm! gramming,the evolutionof the hominidbrain, and the relationshipof weaksyllables, whereas the Austrian children showed a reversetendency, speechmotor programming to thedevelopment of syntax. droppinginitial weaksyllables, and the Swedishchildren did neither. Eachof theseerror patterns conforms to thephonology of thechildren's targetlanguage. [Work supported in partby NSF.] EEM. The effect of speaker gender on word recognition. Jan M. Wasowicz and Lois L. Elliott (Department of Communication Sciencesand Disorders,Northwestern University, 2299 SheridanRoad, EF_33,Anticipatory eoarticulafion in children with good and poor Evanston, IL 60201 } syntaeticabilities. Philip Liehermanand Joan A. Sereno(Department The effectof speakergender on word recognitionwas investigated of Cognitiveand LinguisticSciences, Box 1978, Brown University, Providence, R102912) usinga forward-gatingparadigm [F. Grosjean,Percept. Psychophys. 28, 267-283 (1980}]. Stimuli varied in number of syllables (1 or 2) and The presentstudy investigates the relation between speech coarticula- genderspecificity (male-, female-, or neutral-oriented).The stimulicon- tion andsyntactic processing in children.Specifically, acoustic and per- stitutedthe final word ofa declarativesentence (e.g., "I recentlybought a ceptualmeasurements ofanticipatory labial and lingual coarticulation are newpipe/dress/bike"). Each sentence was spoken by botha maleand a comparedto thesyntactic abilities of children,as measured by the Rhode femaletalker, recorded and digitizedbefore the final wordswere gated. IslandTest of LanguageStructure. Two childrenwith good(greater than The shortestgate for eachword was the initial 30 ms. Successivegates 95% correct) and two childrenwith poor (lessthan 85% correct) syntac- were increasedin duration by 30 ms. The purposewas to determine tic comprehensionscores produced five tokens each of thefollowing CV whetherwords would be identifiedat shortergate durations when the syllables([si], [su], [zi], [zu], [ti], [tu], [di], [du], and [ki], and wordwas appropriate to thespeaker's gender, as compared to whenit was [ka] ). The effectsof the vowelon the precedingconsonant were acousti- not. The resultssuggested that speakergender facilitated the recognition callyassessed by measuringboth second formant and characteristic spec- of gender-appropriatewords and inhibitedthe recognitionof gender-in- tral prominenceregions in theconsonantal stimuli. Perceptual measure- appropriatewords. Results will bediscussed with respectto currentmod- ments were then performedby presentingthese excised consonantal els of word recognition.[Work supportedby DissertationYear Grant, segmentsfor vowel identification. The correlation between the coarticula- NorthwesternUniversity.]

THURSDAY MORNING, 14 MAY 1987 CELEBRATION HALL, 9:00 TO 11:30 A.M.

SessionFF. Bioresponseto Vibration II and PhysicalAcoustics V: BiophysicalAcoustics: Absorption in Biological Media I

Frederick Kremkau, Chairman BowmanGray School of Medicine,Center for Medical Ultrasound,300 S. HawthorneRoad, Winston-Salem, North Carolina 27103

Invited Papers

9:00

FFI. Theoreticalmodels of ultrasoundabsorption in t'ssues.James F. Greenleafand ChandraM. Sehgal (BiodynamicsResearch Unit, Mayo Clinic/Foundation,Rochester, MN 55905) On the basisof manymeasurements on attenuation,absorption, and speedof ultrasoundin biological materials,one can make the following generalizations: (a) Biologicaltissues have high attenuation coefficients, abouttwo to threeorders greater than their major component, water; (b) theamplitude attenuation coefficient increaseswith frequencynear-linearly in softtissues and near-quadraticallyin fluidswith frequencyin the rangeI to 10 MHz, and possiblyeven up to 100MHz; (c) speeddispea-sion isextremely small ( • 0.1 to I m/s/ MHz); (d) absorptionand attenuation coefficients either increase or decreasewith an increase in temperature, dependingon thenature of thetissue, and the frequency of irradiatiOn;(e) fluidscontaining proteins show a sharpincrease in excessabsorption in acidicand basicpH ranges, and finally; (f) at sufficientlyhigh intensity of irradiationthe absorptioncoefficient increases with intensity.Comprehensive models for the propagationof ultrasonicwaves through Iossy media should explain these experimental findings. We will reviewsome of the currentmodels and critically examine them in lightof thedefinition of absorptionin relationto attenuationand scattering.[Work supportedby NIH CA 24085,CA 41324,and NSF 8310626.]

9:30

FF2. Biomolecular ultrasoundabsorption. F. Dunn (BioacousticsResearch Laboratory, University of Illinois, 1406 W. Green Street, Urbana, IL 61801) Studiesof the bulk ultrasonicproperties of intacttissues reveal the importanceof biomacromolcculesin determinationof ultrasonicabsorption. The absorptioncoefficient of bloodhas been found to be proportional tothe weight percentage of theprotein content, which has encouraged studies of theabsorption by proteinsand their analogsin solution.Studies of aminoacids, polyamino acids, and solubleproteins in aqueoussolution

S70 J. Acoust.Soc. Am. Suppl.1, Vol. 81, Spring1987 113thMeeting: Acoustical Society of Amedca S70 havesuggested such mechanisms asrelaxation of proton-transferequilibria occurring at ionizableresidues and relaxationof solvent-soluteequilibria. Though other mechanisms have been proposed, no singlemechanism appearsto be predominantin beingresponsible for ultrasonicabsorption by proteins.

10:00

FF3, The contributionof absorptionto tissueattenuation. Kevin J. Parker (Department of Electrical Engineering,University of Rochester,Rochester, NY 14627) The relativecontributions of ultrasonicscattering and absorption to the overallattenuation coefficient of tissuesis an important issue in diagnosticand therapeutic ultrasound. This paper presents a range of experi- mentalevidence and case studies which support the postulatethat absorptiondominates attenuation in soft tissues.Comparisons of tissue absorption coefficients (using thermal pulse decay) and attenuation coefficients (usingradiation force insertion loss) are given, along with results of tissue homogenization experiments. Other evidenceis gainedfrom measurements of total scattered power, and clinical observations of backscatterand attenuationof focallesions. Finally, comparisons are made of theattenuation of diluteprotein solutions and wholeliver specimens, in order to establishthe role of multiplerelaxation mechanisms at the macromolecular level in the overall attenuation coefficient of mammalian liver tissue.

10:30

FF4. Calculationof temperatureelevation caused by ultrasoundabsorption. Wesley L. Nyborg (Physics Department,University of Vermont,Burlington, VT 05405) It hasbeen known for decades'thatultrasound is capableof producingphysiological change in man andin laboratoryanimals. A dominantmechanism for the changeis temperatureelevation resulting from sound absorption.It hasbeen shown for somesituations that the processesfor heatgeneration and transportare understoodwell enoughto makeit feasibleto predictthe temperaturethat resultsfrom specificacoustic exposures.Thus Pond, Robinson and Lele, Carstensen, Lizzi, andothers have successfully calculated intensi- ty-time combinationsrequired for productionof recognizablelesions in mammaliantissues and othermedia. Thereis now special interest in computationalmethods for applicationto ultrasonichyperthermia, and also to theformulation of safetycriteria for diagnosticultrasound. For thelatter purpose a simplifiedmethod has been developed,based on a Green'sfunction solution to thebio-heat transfer equation. In thispaper, previous work on temperaturecalculations is reviewed,and recentresults discussed.

11:00

FF5, Energytransmission into the human hand from vibrating tools. Douglas D. Reynolds(Department of Civil andMechanical Engineering, University of Nevada-LasVegas, Las Vegas, NV 89154) A methodfor calculatingpower transmitted to the handsof operatorswho usevibrating hand tools is presented.Results that relateto a comprehensivemultidisciplined NIOSH fieldstudy of severalhundred chipperand grinder workers who used pneumatic hand tools are discussed. These results indicated that the totalpower in thefrequency range of 6.3to 1000Hz transmittedto the hand ranged from 1080 to 7230J/s for thechisel and from 0.852 to 157J/s for the handleof chippinghammers. For pneumaticgrinders the power transmittedto thehands of thetool operators was in therange of 0.00658 to 0.235 J/s overthe same frequency range.

$71 d.Acoust. Soc. Am. Suppl. 1, Vol. 81, Spring 1987 113thMeeting: Acoustical Society of America S71 THURSDAY MORNING, 14 MAY 1987 MT. RAINIER, 9:00 TO 11:50 A.M.

SessionGG. Shockand Vibration IIl: Machinery Foundationsand the Transmission,Isolation, and Damping of Structural Vibrations

Louis A. Herstein, Chairman Naval SeaSystems Command, Ship Silencing Division: Code 55N, Washington,DC 20362

Chairman's Introduction--9:00

Invited Papers

9.'O5

GGI. A designoptimization for shipboardmachinery foundations subjected to noiseand shock requirements. RusselMiller, Ken Nuss,Peter Kasper,and George Amir (NKF Engineering,Inc., 12200Sunrise Valley Drive, Reston,VA 22091) The overallmethodology used to designfoundations are sometimesa compromisebetween the various conflictingrequirements of noise,shock, vibration, ship motion,thermal motion, and machineryimposed loads.The methodologydeveloped is based on iterativestructural design to achieveoptimum stiffness and the predominantnatural frequency that bestmitigate shock and vibrationmotions prescribed by realisticship- boardenvironment. Experimental data of testedfoundations in the prescribedshock environment is usedto verifythe validityof the structuraloptimization method developed. The paperdescribes the computercode developedfor thestructural optimization. Selection of variousfoundation categories are available for various locationsin theship and various installation configurations. Comparisons between structurally optimized and nonoptimizedfoundations are madedemonstrating substantial cost and weightsaving as well as improved hardnessand vibrationreduction. The iterarveprocess of structuraloptimization for shockand vibrationis linked to noiseattenuation performance. The analysisof noisetransmission through the foundationwas performedusing the direct dynamic stiffness method (DDSM). This approachprovides velocity, force, and powertransfer functions between input excitation positions and hull intersectionpositions.

9:35

GG2. Effectivenessof structurebornenoise isolation systems on a lightweightship foundation.G. L. Fox (Fox EngineeringAnalysis, 4455 TorranceBoulevard, Suite 196, Torrance,CA 90503) and Terry D. Scharton(ANCO Engineering,9937 Jefferson Boulevard, Culver City, CA 90230} Radiatedstrnctureborue noise from main propulsion machinery in a lightweight,high-performance craft is of concern.This isdue to theconflicting requirements of humanhabitability and ship weight. Efficient struc- tureboruenoise isolation of themain machinery will reducethe weightof theacoustical treatment required in receiverspaces. Main machineryisolation involves the consideration of themechanical vibratory interactions betweenthe machine,subbase, and foundationas well as the elasticmountings that connectthese components. Thispaper presents a method that allows an analystto calculatethe structureborne noise power transmitted into a structurecomposed of idealizedfinite length beams. Impedance relationships are developedfor the machine,subbase, foundation, ship hull, andthe intervening isolators. Idealized finite length beam impedances are derivedfor variousboundary conditions. The resultsof a parametricstudy to assessthe effectivenessof vibrationisolators, for varioussystem parameters, is presentedfor a shiphull of typicalaluminum construc- tion. ß

10:05

GG3. Selectionof resilient mountsfor protectionof fragile equipmentconsidering foundation and equipment structuraladmittances. Harry Himelblau(M.S. 301-456,Jet Propulsion Laboratory, Passadena, CA 91109) and Sheldon Rubin (M.S. M4/899, The AerospaceCorporation, P.O. Box 92957, Los Angeles,CA 90009) In 1962,a groupof structuraldynamicists under the auspices of SAE CommitteeG-5 on AerospaceShock andVibration developed a procedureon the abovesubject, which was published as SAE Doc. AE-3. This procedurewas restricted to the assumptionof rigidequipment structure under translational excitation and response.Five years later in an unpublishedreport, Rubin extended the procedure to permitthe consideration of arbitraryadmittances of bothequipment and foundation.This extensionis reviewedin this presentation, includinga simplecriterion for mountadequacy, a graphicalmethod for verifyingthat adequacy,and an overlayfor therapid selection of mountstiffness and damping. Mount restrictions to avoidbottoming under sinusoidal and random excitation are also discussed.

S72 J. Acoust.Soc. Am. Suppl.1, VoL81, Spdng1987 113th Meeting:Acoustical Society of America S72 ContributedPapers

10:35 wereweighted to producestanding wave patterns that were made up of left andright traveling waves, both of thesame wavenumber. The stand- GG4. Vibration dampingperformanee--What we shouldknow about it. ing wavepatternavoids the needto controlthe phasesbetween the drives Pranab Saha (Kolano and Saha Engineers,Inc., 1899 Orchard Lake that wouldhave been required for travelingsingle wavenumber drives. Road, Suite 105, Pontiac, MI 48053) The effectsof beamresonances are explored by comparingmeasured ad- The vibrationdamping performance of materialsthat are used in the mittancedata for beamswith freeends, with and withoutinternal damp- automotiveindustry are usually tested by either: ( i ) theGeiger Plate Test ingand for beams with heavily-damped ends. The wavenumber/frequen- Method,or (2) theComplex Modulus Test Method. The firsttest method cy transferfunctions of resilientlayers placed between the array of drives hassome advantages of testingmaterials that are unique to theautomotive and the beam are determined from admittance measurements made with industry.Both of thesemethods have certain limitations, though the sec- and without the resilient layer. ondmethod is a superiorone in thesense that it can measurethe damping performancewith temperatureand frequency.This paperdiscusses the limitationsof someof the waysthe data are typically presented using this 11:20 method.The paperalso discusses how design charts can be usedto over- come theselimitations and computethe dampingperformance of the GG7. Dynamics of piezoelectric rods under initial stresses. M. compositematerial (composite loss factor) for a givenapplication. Cengiz Drkmeci and E. E. nan!'D (Istanbul Technical University. P.K.9, istanbul 80191, Turkey)

The analysispresented is an extensionof our earliertreatment of rods 10:50 lint. J. SolidsStruct. 8, 1205-1222 ( 1972); and 10, 401-409 (1974) I in which the effectof initial stressesis neglected.In this study,this effectis GGS. Acoustic characterizationof some commerciallyavailable closed consideredon wavesand vibrationsof piezoelectricthin rods. First, a cell rubbors and co•rene. Gary Caiile, Jacck Jarzynski, and variationalprinciple due to theauthor [Proc. 39th Freq.Control Syrup., Peter Rogers (The George W. Woodruff School of Mechanical pp. 43 !-435 (1985) [ is reformulated,and the field quantitiesare expand- Engineering,Georgia Institute of Technology,Atlanta, GA 30332) ed in termsof Legendrepolynomials. Then, the expansionstogether with Three closedcell and two corprenerubbers (manufactured by Ruba- the variationalprinciple are usedso as to consistentlyestablish a hierar- texand Groendyk Corporations, respectively) with Neopreneand nitrile chicalsystem of one-dimensionalequations of crystalrods. The governing baseshave been experimentally investigated in the frequencyrange of 10 equationsmay incorporate the higher-ordereffects of piezoelectricrods to70 kHz. These matedills contain approximately 50% air and simulate a by a propertruncation of expansions.They accommodateall the typesof pressurerelease surface with reflectioncoefficients near --0.95. The extensional,flexural, and torsionalmotions of rods.Further, the resulting characterizationincludes longitudinal sound speed and transmission,re- equationsarc consideredfor specialmotions, and they are shownto agree fleetion,and absorptioncoefficients as functionsof incidentangles and with thoseof earlier ones.[Work supportedin part by the U.S. Army frequency.The dynamic(complex) Young's modulus and lossfactors throughits EuropeanResearch Office. ] havebeen determined by the longitudinalresonance method. Poisson's ratiois assumed to be0.499 which allows prediction of theshear modulus. A comparisonbetween the experimentallydetermined reflection and 11:35 transmissioncoefficients with theoretical values [D. L. Folds and C. D. GG8. A study of a parametrical system with a clearance type Loggins,J. Acoust.Soe. Am. 62, 1102-1109(1977) ] ispresented. Predic- nonlinearlty.R. Comparinand R. Singh (The Ohio State University, tion of the toodull usingcontemporary composite models will also be Department of Mechanical Engineering,206 West 18th Avenue, presented. Columbus, OH 43210- l 107)

Gearrattle is one of the majornoise and vibration problems affecting lightly loadeddrives. Gear rattle is a complicated,nonlinear vibration, 11:05 characterizedby backlashinduced vibro-impact between meshing gears. GG6. Wavenumber/frequency admittance of beams. Karl Grosh, W. For gearedsystems with a constantdriving torque, rattle is the resultof a Jack Hughes, and Courthey B. Burroughs (Applied Research parametricexcitation due to meshstiffness variation and transmission Laboratory, The PennsylvaniaState University, P.O. Box 30, State error.This work represents a fundamental study of thevibro-impact prob- College, PA 16804) lemin a parametricallyexcited mechanical system with clearance.Specifi- cally,this work describes the frequencydomain characteristics of a para- Using an array of point drives,the admittanceof finite beamswere metricallyexcited single degree of freedomsystem with a clearancetype measuredand compared to predictions.The predictionswere made using nonlineartry.The stabilityof steady-statesolutions are alsoconsidered. an analyticmodel ofthe beamresponse based on Timoshenkobeam the- An approximateanalytical technique is usedand resultsare compared ory.To drivethe desired wavenumbers, the amplitudes of thepoint drives with digital (numericalintegration) simulation results.

S73 J. Acoust.Soc. Am. Suppl.1, Vol. 81, Spring1987 113th Meeting:Acoustical Society of America S73 THURSDAY MORNING, 14 MAY 1987 MT. RUSHMORE, 9:00 A.M.

Meeting of AccreditedStandards Committee S12 on Noise

to be heldjointly with the

Technical Advisory Group for ISO/TC 43/SC1 Noise

K. M. Eldred, Chairman S12 P.O. Box 1037, Concord; Massachusetts01742

H. E. vonGierke, Chairman, Technical Advisory Group for ISOfrC 43/SC1 Biodynamics& BioengineeringDivision, AF/IMRL/BB U.S.Air Force,Wright-Patterson ,4FB, Dayton,Ohio 45433

StandardsCommittee S12 on Noise. Working group chairs will reporton theirprogress under the plan for the productionof noisestandards. The interaction with ISO/TC 43/SC1activities will bediscussed, with a report on themeeting of [SO/TC 43/SCI whichwas held in Copenhagen,Denmark from 4-7 May 1987.

S74 J. Acoust.Soc. Am. Suppl.1, VoL81, Spring1987 113th Meeting:Acoustical Society of America $74 THURSDAY AFTERNOON, 14 MAY 1987 REGENCY BALLROOM C & D, 1:00TO 4:30 P.M.

SessionHH. Psychologicaland Physiological Acoustics VIII: Ear CanalMeasures and Hearing Impairment

Honor O'Malley, Chairman AudiologyProgram, Teachers College, Columbia University, New York,New York10027

ContributedPapers

1:00 jcct scatterin hearingthreshold data at thesefrequencies. One of the main sourcesof scatteris the variationbetween subjects of sizeand shape of ear HH1. Auditory system impedance measurement using the two- canal.This factoris examinedby consideringa modelof an audiometric microphonewave-tube technique. Douglas H. Keefe (Schoolof Music headphonemounted over the ear of a subject.The ear canalis treatedin DN-10, University of Washington, Seattle, WA 98195), Edward detailusing a horn equationapproach to calculatethe pressuredistribu- M. Burns, and Robert Ling (Department of Speech and Hearing tion along its length, given its exact geometry;the calculationcan be ScienccJG- 15, Universityof Washington,Seattle, WA 98195) repeatedfor differentcanal geometries with everythingclsc (headphone, An impedancemeasurement tcchniquc suitable for middlecar investi- eardrumimpedance) unchanged. Above 8 kHz the transformationfrom gationshas been devised that hasthe advantagesof fastdata acquisition headphoneinput voltage to soundpressure at the eardrumis a function (lessthan 1 s) andlarge measurement bandwidth (200-6000 Hz). This which dependson frequency,showing peaks at frequenciesthat depend techniquedoes not require a transducerdelivering a constantvolume critically on the choiceof geometry.For a realisticrange of ear canal flow. The excitationused is a broadbandchirp whosespectral shape may lengthsand shapesthe cardrum pressure(and, hence, the apparent be varied to enhancesignal to noiseratio. The methoddepends upon threshold)can vary by as muchas 20 dB betweensubjects at a specific pressuremeasurements at two pointswithin a smooth,cylindrical tube frequency,for the sameinput voltage.Conventional audiometric tech- whosetransmission characteristics are well known. In our implementa- niquesmust be modifiedconsiderably if they are to be appliedabove 8 tion of this technique,the frequency-dependentviscous and thermal kHz. losses in the wave tube are accountcd for. The wave tube is inserted into the car canal,and the input impedanceat the tubetip is computedbased uponthe tubetransmission coefficients and the measuredtransfer func- tion betweenthe microphones.Measurements are presentedof the input 1:45 impedancein normaladult ears for comparisonwith the literature.Since thetcchniquc is fastand rclatively noninvasive, it appearswell-suited for HH4. Diffusefield responseof the ear. Mead C. Killion (Etymotic ourproject goal of measuring the middle ear impedance of infants.[Work Research,61 Martin Lane, Elk Grove Village, IL 60007), Elliott supportedby NINCDS.] H. Berger,and RichardA. Nuss (E-A-R Division,7911 Zionsville Road, P.O. Box 68898,Indianapolis, IN 46268-0898) Theear canal pressure developed in a diffuse-fieldfacility complying 1:15 with ANSI S12.6-1984was measured on 20 adultsubjects ( 11male and 9 female),with two replications on each ear for 19of the20 subjects. A soft HH2. Two-microphone measurement of aeonstie intensity in the ear 1-mm-o.d.silicone rubber probe tube was inserted until the subject report- canal as a calibration of high-frequencyhearing. William J. Murphy, ed the"thump" of thetube bumping the eardrum, and then withdrawn a Arnold Tubis (Department of Physics, Purdue University, West coupleof mm.Preliminary experiments indicated that this technique did Lafayette,IN 47907), and Glenis R. Long (Department of Audiology notalways produce the same results, with some curves on the same ear of andSpeech Sciences, Purdue University, West Lafayette, IN 47907) thesame subject showing substantially less "eardrum SPL" in the8- to20- As an alternativeto measuresof ear canal pressurein the vicinity of kHz regionthan others. It wassometimes (but not always)possible to the tympanicmembrane, we proposean acousticintensity measurement confirmwith otoscopicexamination that the 1ower-SPLcurves corre- slightlydownstream from thepoint of sounddelivery as a convenientand spondedto probe-tubelocations away from the eardrum. Based on the meaningfulcalibration of high-frequencyhearing. If soundabsorption in preliminaryexperiments, data from the "bestrun of the bestear" (i.e., the air mediumand at the wallsof the ear canalis neglected,the power highestlevel above 8 kHz) wereaveraged. The resulting curve was similar flow throughany crosssection of the ear canal would be equalto the to the curve obtained on a KEMAR manikin in the same sound field. powerflow into the middleear. A sounddelivery and intensitymeasure- ment systemhas beenbuilt usinga two-portearmold. The tube of an EtymoticResearch ER-2 sounddelivery system passes through one port and a pair of probe tubes (outer diameters= 1 ram, tip separation 2:00 • 3 ram) passthrough the other.The latter areconnected to ER-7 micro- phonesand usedfor acousticintensity measurements based on a cross- HHS. Referencethreshold levels for the ER-3A insert earphone.Laura spectrumalgorithm. Data are given on the sensitivityof measurement Ann Wilber (Program in Audiology, NorthwesternUniversity, resultswith respectto the relativepositions of the sounddelivery point Evanston, IL 60202), Barbara A. Kruger (Kruger Associates,37 andprobe tube tips. [Work supported bya grantfrom the Deafness Re- SomersetDrive, Cornmack, NY 11725),and Mead C. Killion (Etymotic searchFoundation. ] Research,61 Martin Lane, Elk Grove Village, IL 60007) Twosets of provisionalreference threshold sound pressure levels have beenprovided by the manufacturer for the calibration of the ER-3A insert 1:30 earphone.One set is for usewith the B&K DB-0138coupler (an HA-2 HH3. High-frequency audiometry and intersubject variations of ear 2-cccoupler that comes with a 5-mm-diamby 2-mm-long stainless steel canal geometry.Michael • R. Stinson(Division of Physics,National couplingnipple preceding the 18mm of 3-mm-diamearmold-simulation Research Council, Ottawa, Ontario K1A 0R6, Canada) portionspecified in S3.7-1973), andthe other set is for use with the HA-1 coupler( thestandard "In TheEar hearing aid" 2-cc coupler) with a foam An extcnsionof currentaudiometric techniques to frequenciesgreater eartipsealed directly to the top surfaceof the coupler.Several recent than $ kHz is highlydesirable but difficultbecause of the large intersub- studieshave demonstratedthat the ER-3A may be directly substituted,

S75 J. Acoust.Soc. Am. Suppl. 1, Vol.81, Spring1987 113thMeeting: Acoustical Society of America S75 withoutrecalibrating, for a TDH-39/MX-41AR earphonein somecases, high-frequencyexposure condition indicate that changesin GDT canbe but most available data have not been reduced to a form suitable for predictedfrom shifts in absolutethreshold. For thelow-frequency condi- establishinga revisedestimate of the referencethreshold levels. This pa- tion, differencesbetween the GDT and TTS recoveryfunctions and ele- per reportsthe resultsof sucha data analysis. vatedGDTs in theabsence of significantTTS requirean alternative expla- nation.[Work supportedby NIOSH.]

2:15 3.'OO HH6. The interaction of impulse and continuous noise: Energy and spectral considerations in the production of hearing loss. HH9. Temporal integrationin normal hearing,cochlear impairment, and Michele Roberto (Department of Bioacousties,University of Bari, Bari, impairmentsimulated by masking.Mary Florentine,Hugo Fastl, and Italy}, William A. Ahroon, Robert I. Davis, and Roger P. Hamernik S•ren Buus=• (CommunicationResearch Laboratory, 133 FR, (Auditory ResearchLaboratories, SUNY, Plattsburgh,NY 12901) NortheasternUniversity, Boston, MA 02115) Realisticindustrial noise environments containing impulsive and con- To assesstemparal integration in normaland impaired listeners, abso- tinuousnoise were modeledusing a 5-dayexposure paradigm that pro- lute thresholds for tones were measured as a function of duration. Dura- ducesan asymptoticthreshold shift (ATS). Pre-and postexposure mea- tionsranged from 500ms down to 15ms at 0.25 kHz, 8 msat I kHz, and2 suresof hearingthresholds were obtained on 96 chinchillasusing evoked msat 4 and 14kHz. An adaptive21, 2AFC procedurewith feedbackwas auditory responses(EAR). Six control groupswere exposedto octave used.On each trial, two 500-ms observationintervals, marked by lights, bandsof noiseat 0.5, 2.0, and4.0 kHz at 95, 90, and 86 dB SPL, respective- werepresented with an interstimulusinterval of 250 ms, The monaurai ly, or impactsof 113,119, or 125dB peakSPL presented once per 1,4, or signalwas presented in the temporalcenter of oneobservation interval. 16 s, respectively.Nine interactiongroups were exposed to combinations The resultsfor fournormal and six impaired listeners show ( I ) asexpect- ofan impulseand continuous noise. The greatestspectral overlap of ener- ed, thresholdsfor normal listenersdecrease about 8 dB per decadeof gy OCCursbetween the impulseand the 0.5 kHz octaveband of noise. duration, (2) for impairedlisteners, the decreaseusually is much less(2 Although eachof the differentimpulse noise exposures were balancedto to 6 dB) in the rangeof a hearingloss, but normal at frequencieswhere producean equalenergy exposure, an exacerbationof hearingloss was thresholdsare normal, (3) for listenerswith impairmentssimulated by producedin animalsexposed to the 119-and 125-dBimpacts in combina- masking,the slopcs are nearly the same as those for normallisteners and tionwith thelow-frequency (0.5-kHz) continuousnoise. This synergistic steeperthan those for the real impairments. These results indicate that the effectgradually disappears when the spectraloverlap between noises is shallowslopes observed for impairedlisteners probably are not-dueto reduced.[Research supported by NIOSH.] splatterof energyto frequencyregions where thresholds are low, but re- fleetdiminished temporal integration, per se. [Work supportedby NIH- NINCDS RO INS 18280.] '• Alsoat Dcpartmentof Electricaland Com- puter Engineering,Northeastern University. 2:30

HH7. Temporarythreshold shift after exposure to a narrow-bandnoi•e, frequency-modulatedtones, continuouslyvariable frequencytouea 3:15 and a pure tone. I. M. Young and L. D. Lowry (Department of Otolaryngoiogy,Jefferson Medical College of Thomas $cfferson HH10. Comparisonbetween loudness functions in noiseand in noise- University,Philadelphia, PA 19107) induced hearing Iosa. Rhona P. Hellman (Auditory Perception Laboratory,Northeastern University, Boston, MA 02115) Temporarythreshold shift after exposure to fourstimulating sounds weremeasured by automatic audiomerry for threesubjects with normal Pure-toneloudness functions were generated in a cochlear-impaired hearing.Stimulating sounds were ( 1) a puretone, (2) continuouslyvari- populationwith moderateIo severenoise-induced losses. Three proce- ablefrequency tones between 1250 and 1750 Hz, (3) frequency-modula- dureswere used: magnitude estimation, magnitude production, and cross. tedtones centered at i 500Hz witha frequencydeviation of + 250Hz and modality matching.The slopeof the loudnessfunction was determined a modulationrate of 25per s, (4) a narrow-bandnoise with a bandwidth overthe stimulus range where ouchlear impairment steepens the loudness of 1250-1750Hz. Subjectswere exposed to stimulatingsound through an function.Both the measuredand predictedslopes show that the steepen- earphoneat theintensity of 110dB SPL and duration of 10min. Tempo- ing of the loudnessfunction depends on the severityof the hearingloss; rarythreshold shift was measured for frequencies between 1000 and 8000 thatis, the higher the threshold the steeper the function. While this behav- Hz beginningat 5 safter cessation of the stimulating sound. Resulls indi- ior is also observedin partially maskednormal ears, the extent of the catedthat the greatest shift was observed at a frequency2000 Hz bya pure agreementbetween the partiallymasked and impaired loudness functions tonestimulation and the leastshift by a narrow-bandnoise. Effects of is determinedby thebandwidth of the maskingnoise. The impairedloud- continuouslyvariable frequency tones and frequency-modulatedtones nessfunctions closely agree with thoseobtained in wide-bandnoise, but were intermediate.These findings were comparedand discussedwith not with those obtained in narrow-band noise as wide as an octave. This temporarythreshold shift following exposure to whitenoise at equivalent findingimplies that theeffect of theeochlear impairment on theloudness intensityand duration. functionresembles that of an externalnoise with a broadfrequency spec- trum. [Work supportedby the RehabilitationResearch and Develop- ment Serviceof the VA.]

2:45

HHg. Effectsof brief, intensetones on auditory temporalscotty. Craig 3:30 A. Chainpith and Lawrence L. Feth (Department of Speech- Language-Hearing:Sciences and Disorders,University of Kansas, HHI 1. Loudnessjudgments in recruiting ears as influencedby intensity, Lawrence, KS 66045) and interspersed changes in intensity. Maureen A. Kurman, Ernest M. Weiler, and Angel Dcll'Aira {Communication Disorders, A gap detectionthreshold (GDT) procedurewas usedIo measure Universityof Cincinnati,Mail LocationNo. 379, Cincinnati,OH 45221) auditorytemporal acuity in humansbefore and after exposure to a brief, intense1ow-(0.4-kHz) or high-(1.7-kHz) frequencytone. The maximal It hasbeen found that loudnessjudgments adapt to mortauralstimulus temporarythreshold shift (TTS) producedby eachexposure was approx- increments[E. M. Weiler,D. E. Sandman,and L. M. Pederson,Brit. J. imately10 dB. GDT stimuliwere octave-band noises centered at oneof Audioi. 15, 201-204 ( 1981) ]. The presentstudy was undertaken to deter- threefrequencies: the exposurefrequency, 1/2 oc• abovethe exposure minewhether the changesin high-frequencyrecruiting ears measured at a frequency,or I octabove the exposure frequency. GDTs wereobtained at nonrecruitingfrequency ( 1000Hz), werethe same as in normallisteners. 35, 55, and 75 dB SPL at eachcenter frequency. GDT and TTS recovery Bothgroups showed a similardecline in judgmentto the baseline660-dB were monitoredfor 16 rain followingan exposure.The resultsfrom the tone.There was a significantinteraction between groups, intensity, pulsed

S76 J. Acoust.Sec. Am. Suppl. 1, VoL 81, Spring1987 113th Meeting:Acoustical Society of America S76 durationof aninterspersed 10-dB increment, and successive judgments of thoseobserved in normallisteners when masked by spectrallyshaped loudness. Similar interactions were seen at 20 dB above the baseline noise.For normallisteners with sucha simulatedhearing loss, perfor- intensity. manceon taskswith actualmasking noises thus involvesthe detectionof signalsin the presenceof two maskers.One maskeris usedto simulatethe hearingloss while the otheris incorporatedin the particularparadigm understudy. The maskedthresholds from eachmasker can be combined 3:45 usinga masking-additivityrule similarto that of Lutfi [J. Acoust.Soc. Am. 73, 262-267 (1983)]. This approachis usedto predictpublished HH12. Predicting masked thresholds in impaired listeners from data from impairedears on critical ratios,critical bandwidths,auditory combinationsof normal masked thresholds and hearing loss. Walt filter shapes,masking patterns, and psychophysicaltuning curves.For Jesteadt,Patricia G: Stelmachowicz,and Brian P. Callaghan (Boys Town National Institute, 555 N. 30th Street, Omaha, NE 68131 ) mostof the paradigmsstudied, the psychoacousticperformance of the hearingimpaired was predicted reasonably well with this approach. These Many studieshave simulated sensorineural hearing loss using maskers resultsseem to suggestthat the frequency-resolutiondeficits observed in that produceequivalent threshold elevations in normallisteners. This thehearing impaired are primarily a consequenceof alteredhearing sensi- suggeststhat maskedthresholds in impairedlisteners can be viewedas a tivity. [Work supportedby NINCDS.] combinationof themasking expected in normallisteners and the masking representedby thehearing loss. To testthis hypothesis, we fitted simulta- neous-maskingdata for five impairedlisteners using recent models of combinedmasking. The data were levels of narrow-bandnoise maskers at 4:15 severalfrequencies required to just mask 2000-Hz probes presented at 5 to HH14. Modeling sensorineuraihearing loss. II. Applicationto measures 25 dB SL. For maskerfrequencies in regionsof maximalabnormal up- of temporal resolution.Bias Espinoza-Varas,Larry E. Humes, and wardspread ot• masking, the model correctly predicts that: ( 1) growthof Charles S. Watson (Department of Speech and Hearing Sciences, maskingis moregradual in impairedlisteners, (2) the maximumdiffer- Indiana University,Bloomington, IN 47405) encein thresholdsfor normaland impairedlisteners occurs when the normallistener's masked threshold is equal to theimpaired listener's quiet Thresholdsof hearing-impairedlisteners in temporal-maskingtasks threshold,and (3) the sizeof this differenceincreases with the degreeof weremodeled by the performanceof normallisteners with a noise-simu- hearingloss. The last resultsuggests that sensorineuralhearing loss can latedhearing loss. This modelpredicts thresholds for suchtasks by assum- bestbe simulatedwith forwardmaskers. [Work supportedby NIH.] ing the presenceof two maskers;a spectrallyshaped continuous masker usedto simulatethe hearingloss and the maskerused in the temporal- maskingtask. The combinedeffect of thetwo maskerswas predicted using a masking-additivityrule similar to thatof Lutfi [ J. Acoust.Soc. Am. 72, 4:00 262-267 ( 1983) ]. Masked detectionthresholds from impairedlisteners and normal listenerswith simulatedhearing loss were examinedfor var- HH13. Modelingsensorineural hearing loss. I. Approachand application ioustemporal-masking paradigms. Data from the literaturewere exam- to frequency resolution.Larry E. Humes, Blas Espinoza-Varas,and inedfor eachof the following:( 1) detectionthresholds in continuousand Charles S. Watson (Department of Speech and Hearing Sciences, modulatedbroadband noise; (2) growthof forwardmasking with masker Indiana University, Bloomington,IN 47405 ) level; and (3) decay of forward maskingfollowing maskeroffset. The In the presentpaper we evaluatethe extentto which auditory-process- masking-additivityapproach predicted well the temporallymasked detec- ing deficitsobserved in listenerswith sensorineuralhearing loss can be tion thresholdsfor noise-maskednormal listeners with simulatedhearing predictedentirely on thebasis of lossof hearingsensitivity. In thismodel, loss,but underestimatedthe maskedthresholds of the hearingimpaired processingdeficits in the impairedear are consideredto be equivalentto by asmuch as 15dB. [ Work supportedby NINCDS. ]

THURSDAY AFTERNOON, 14 MAY 1987 REGENCY BALLROOM A & B, 1:00 TO 4:29 P.M.

SessionII. SpeechCommunication VIII: SpeechProcessing, Speech Synthesis, and Intelligibility

Mobart M. Sondhiand Shirley A. Steele,Co-Chairmen ,4T& T Bell Laboratories,Murray Hill, New Jersey07974

Chairmen's Introduction--l:00

ContributedPapers

1:05 powerfuldigital signalprocessing circuits, high-resolution graphic dis- playsand high-speed DMA capabilities.The digital signal processing chip II1. The designof a speechanalysis workstation. John M. Crump (Kay selectedwas the 32020from TexasInstruments. Special high-speed DMA ElemetricsCorporation, 12 Maple Avenue, Pine Brook, NJ 07058) chipswere used to facilitatehigh-speed data transfer between the different The recentavailability of generalpurpose digital signalprocessing systemmodules (A/D to memory,memory to DSP circuits,DSP circuits chips,inexpensive digital memories, and personalcomputers has opened to graphiccircuits, and DSP circuitsto printer). TheseDMA chipsallow the door to the developmentof a powerfulworkstation designed for the a 2-Mbyte/s transferrate. The systemmanagement is performedby a analysisof speech.A systemcan be developedwith the advantagesof a Motorola 68000 and the systemarchitecture has beendefined to include spectrograph(e.g., Sona-Graph),an oscillograph(e.g., Visicorder),a up to 8 Mbytesof RAM. This systemperforms all the desiredfunctions of featureextractor (e.g., Vlsi-Pitch), anda generalpurpose computer (e.g., a speechworkstation and could providea commonplatform for speech VAX with DSP software). This paper describesthe developmentand analysisresearch. capabilitiesof a standalonesystem based on a commonmicroprocessor,

S77 J. Acoust.Soc. Am. Suppl. 1, Vol.81, Spring 1987 113thMeeting: Acoustical Society of America S77 1:17 Theacoustical properties of a vocaltract depend on itsshape which, at frequenciesbelow about 4 kHz, isadequately described by thearea func- II2. Vocaljitter and shimmermeasurements with a personalcomputer. tion (i.e., cross-sectionalarea as a functionof positionfrom glottisto David G. Drumright (Department of Mechanical Engineering, 22 lips}. Obtainingeven this simplifieddescription of the tract is a difficult HammondBuilding, Pennsylvania State University, University Park, PA problem.The solutionthat is proposedis to constructa linkedcodebook 16802), J. Anthony Seikel, and Kim A. Wilcox (Department of of area functionsand correspondingLPC vectors.Then, a given LPC Speech-Language-Hearing,University of Kansas, 2101 Haworth, vectoris transformedto an areafunction by findingthe closest LPC vector Lawrence, KS 66045) in the codebookand accessingthe linkedarea function. The authorshave Vocal fundamentalfrequency is oneof the mostwidely analyzed com- constructedjust sucha codebook{to our knowledge,the first). At pres- ponentsin speechacoustics. As such,there is a needfor an efficientand ent, it hasabout 1500 shapes clustered from a trainingset ofabout 10 000 accuratemeans of producingfundamental frequency data. This paper shapesgenerated by a vocaltract model [P. Mermelstein,J. Acoost.Soc. describesa series of machinelanguage and basic routines that yieldaver- Am. 53, 1070--1082(1973) ]. Distance betweenarea functionsis defined agefundamental frequency, vocal jitter, and vocalshimmer measures asthe Itskuts distancebetween the correspondingLPC vectars.Handling with a resolutionsufficient for most researchpurposes. The algorithm theunique problems arising from thisdefinition of distanceand from the permitsthe userto determinemajor period divisions through an efficient largesize of the trainingset will be described.The plan for refiningand interactivegraphic process. The microcomputeris then responsiblefor enlargingthe codebookwill alsobe discussed. computingaccurate period and intensity data for eachcycle. In thepres- ent installation,the accuracyof theseprocedures is limited only by the 20 000-Hz maximumsampling rate of thehardware. In additionto thef0 2:05 analysisroutines, programs for high-speeddigital sampling,waveform editing,and waveformmanipulation have been developed for usewith 116. Statistical representation of word-initial obstruents: General PC-compatiblecomputers. Documentation of the installation,use, and considerations.Gary Weismet, Karen Forrest, and Paul Milenkovic accuracyof theroutines will be provided.[Work supportedby NINCDS (Speech Motor Control Laboratories, University of Wisconsin-- and U. of KengasGeneral Research Fund. ] Madison, Madison, WI 53705-2280)

The descriptionof obstruentspectra has typically been done in cate- goricalterms [e.g., S. E. Blumsteinand K. N. Stevens,J. Aeonst.SOC. 1:29 Am. 66, 1001-1017 (1979) ]. Whereasthis may be satisfactoryfor some 113. Some results of speechanalysis using a parallel image processor. purposes,the categorical approach is not helpfulin caseswhere obstruent JohnF. Hemdal(Department of ElectricalEngineering, The University soundsare produced that arenot easilydescribed according to the normal of Toledo, Toledo, OH 43606) set of segmentalcontrasts. In particular,many dysarthricand apraxic subjectsproduce stops and fricativesthat givethe perceptualimpression Specialpurpose parallel pipelined image processors arc not only f•ster of being"between" the normalsegmental categories. The purposeof this for imagesthan general purpose computers but also allow one to investi- paper is to describesome of the generalconsiderations that led us to gatethe applications of the latest image processing algorithms and tech- developmeasures capable of indexingspectra associated with suchinde- niquesto continuousspeech. This is particularly valuable when trying to terminateobstruent productions. A statisticalrepresentation ofobstruent automatethe spectrogram reading capabilities ofVictor Zue [Proc. IEEE spectrawill bedescribed that is similar to certainapproaches to describing 7:5, 1602-1615(1985) ]. Severalsentences of continuousspeech were a moregeneral class of impulsenoises [J. Erdreieh,J. Acoust.Soc. Am. sampledand converted to imagesusing the FFT. Theseimages were ana- 79, 990-998 (1986)]. [Work supportedby NIH AwardsNS13274 and lyzedon a parallelcellular image processor called the Cytocomputer TM. NS20976. ] Suitablestructuring elements were selectedto smooththe inherently bumpyFlY spectraand to removenoise. Several of thedistinctive fea- turesof speechare describedin mathematicalmorphology terms and thesefeatures were tracked. Specifically, stop consonants, fricatives, vow- 2:17 els,and nasals were located and labeled. Examples of intermediateimage 117. Statistical representationof word-initia! ohstruents:Adult data. transformationsand resultantlabeling were recorded by photographic Karen Forrest,Gary Weismer,and Paul Milenkovic(Speech Motor process.[Work supportedby OhioBoard of Regents.] ControlLaboratories, University of Wisconsin--Madison,Madison, WI 53705-2280)

1:41 The utility of a statisticalrepresentation of word-initial obstruents {Weisrueret el., previouspaper) was assessed for the speechof normal, II4. ARMA parameterestimation of speech.John J. Wygonskiand youngadults. Ten subjects repeated monosyllabic words, where the initial Guy SoMe (Department of Electrical and Computer Engineering, consonantwas a voicedor voicelessstop or fricative,in a carriersentence. Arizona State University. Tempe, AZ 85287) Each placeof obstruentarticulation was paired with at least two vowels andeach target word was repeated six times. The targetwords were digi- Autoregressivemoving average (ARMA) or pole-zeromodeling tized and the first four moments(mean, variance,skewhesS, and kurtosis) techniquesare knownto providebetter spectral estimation capabilities werecalculated for successive10-ms spectral slices, beginning with the than autoregressive(AR) or all-polemethods such as linea• prediction onsetofthe obstruentand continuingthrough the third cycleofthe vowel. for nasalizedspeech and speech corrupted by noise.This paperdescribes Moments were calculatedfrom linear madbark transformedspectra. the resultsof applyingtwo ARMA modelingtechniques to synthesized Three of the moments(mean, skewhess, and kurtosis)provide a good andnatural segments of noisyand clean speech. The overdeterminednor- descriptionof the shapeand centerof the spectralslices. These moments malequation (ODNE) andthe extended-order singular value decomposi- were plotted in three-dimensionalspace to determinewhether a unique, tion (SVD) methodsof ARMA parameterestimation are comparedto three-dimensionalpattern could be defined for eachplace of articulation. the covariancemethod of linearprediction and are evaluatedusing para- Discussionwill centeron the useof thesemoments, as they definea three- metricdistance measures in the ccpstraldomain. Use of the AR part of the dimensionalspace, to quantifyacoustic events associated with obstruent ARMA modelto estimatethe envelopeof noisyspeech is demonstrated. production.[Work supportedby NIH AwardsNSI3274 and NS20976.] Coefficienttransformations among ARMA, AR, andc•pstral parameters are also discussed.

2:29

1:53 II8. Graphics editor for speechsynthesis experiments. Andrew Helck, ian Coville, and Noriko Umeda (Institute for Speechand Language 115.A codebookof artieulatoryshapes. M. M. Sondhi,J. Schroeter,and Sciences,10 WashingtonPlace, New York University, New York, NY J.N. Larar (AT&T Bell LaboratoriesMurray Hill, NJ 07974) 10003)

S78 J. Acoust.Soc. Am. Suppl.1, Vol. 81, Sp•ing1987 113th Meeting:Acoustical Society of America S78 A graphicseditor of acousticparameters for a speechsynthesizer [an that includesnasal articulation effects and definesindependent acoustic assemblylanguage version of the softwaresynthesizer by D. Klatt, J. parameterswhich are the basis of perceptualstudies, has been obtained. A Acoust.Soc. Am. Suppl. I 68, S18 (1980)] has beenwritten. The pro- pole-zero-polestructure combined with a bankof formantsis proposed gramprovides an easyselection of variousediting functions on thescreen. asa high-qualitynasal vowel synthesizer. A setof perceptualtests is con- It givesusers visual patterns of time-varyingacoustic parameters and the ductedto test nasalityvariation with nasalsynthesis eigenparameters. time relationshipamong parameters (such as that amongfricative, hiss, The resultsof testsare used to establisha new model describing[ + and voice amplitude for stop consonants).Variable parametersare nasal].Based on thismodel, the natureof the Frenchnasal vowel and its groupedinto pagesaccording to function,and simplekey presseson the distributionalproperties are discussed. Finally, nasality variation is tested terminalallow users to selectpages, parameters, and editing functions for at the auditory-nervelevel with the help of a modelof the peripheral the parameter.Editing functions are: moving the cursor,inserting points auditorysystem. The neuralfiring pattern and the synchronization index for linear interpolation,changing parameter values on curves,setting a patternare discussedin termsof the nasalitymodel established. mark for playingthe designatedportion, etc. In addition,there are com- mandsto assigna setof parametervalues at a specifiedpoint of timefrom a tableof phonemedefinitions. The editorhas been used to synthesize 3:17 shortsentences and phrases of about Is and hasproven extremely useful. [Work supportedby NSA.] II12. Calibration and the comprehensionof syntheticand natural speech. BonnieL. Zeigler,George J. Boggs,and Leah S. Kaufman(Behavioral SciencesDepartment, GTE Laboratories,40 SylvanRoad, Waltham, 2:41 MA 02154)

II9. The shapeand alignmentof rising intonation. Shirley A. Steeleand Investigationsof "calibration"(the relationshipbetween knowledge Mark. Y. Liberman (AT&T Bell Laboratories, 2D 519, 600 Mountain and the self-assessmentof knowledge) have found that humansreading Avenue, Murray Hill, NJ 07974) expositorytext cannotaccurately judge their abilityto draw inferences from the material read. Whether low calibration was related to the infer- Factorsthat affectthe locationof the nuclearstress F0 peakin state- enceprocess or to theact of readingby presentingpassages aurally, as mentshave been described elsewhere, and the importanceof correctpeak eithernatural or phoneme-synthesizedspeech is examined.Sixty-four placementin text-to-speechsynthesis has beendemonstrated [Steele adults,divided into naturaland synthetic-speechgroups, heard 15 pas- ( 1986);Liberman and Steele (1986) ]. This paperdescribes the temporal sages,with half the subjects permitted to listentwice. After each passage, characteristicsof the risingintonation pattern at the end of yes/no ques- subjectsrated their comprehension, then judged the veracity of an infer- tions.In particular,certain questions of interestfor text-to-speechsynthe- encedrawn from thetext. Calibrationquotients, derived from the ratings sishave been asked: What parametersare needed to describethe shape of andperformance scores, were significant for bothsynthetic and natural thisF0 contourand its alignmentwith segmentsof the text?Specifically, groups.Performance, ratings, and calibration were slightly higher for howdo the shapeand alignment of the contourchange with variationsin naturalversus synthetic subjects, but the differencewas reliable only for thetype and timing of post-nuclearsegments and with changesin speech confidenceratings. Thus previous low calibration may be more related to rate and pitch range? presentationmode than to inferenceprocesses. Better calibration for lis- tenersmay be due to a closerrelationship between inferences and listen- ing,which encourages extraction of themesas opposed to detail,than betweeninference and reading. 2:53

II10. Implementingprosodic phrasing for anexperimental text-to-speech system.Joan Bachenko,Eileen Fitzpatrick,and John Lacy (AT&T 3:29 Bell Laboratories,Murray Hill, NJ 07974) II13. Children'sperception of syntheticspeech produced by rule. Beth While text-to-speechsystems tend to performwell on word pronun- G. Greene(Speech Research Laboratory, Department of Psychology, ciation,they fall shortwhen it comesto providinggood prosody for com- Indiana University,Bloomington, IN 47405) pletesentences. An experimentaltext-to-speech system that uses a natural languageparser and prosodyrules to determineprosodic phrasing for Severalexperiments examined the perceptionof syntheticspeech by Englishinput to text-to-speechsynthesis will be described.Building on school-agechildren ranging in agefrom 5- to 1l-years old. Thesetasks all informationfrom the syntaxtree, the prosodyrules specify the location usedsynthetic speech produced by commerciallyavailable text-to-speech andrelative strength of prosodicphrase boundaries; these specifications systems.In tasksinvolving free and ordered rgcall of lists of words, 8-year- are thenused to dictatemodulations in pitchand timingfor the Olive- old childrenrecalled naturally produced items better than synthetically Libermansynthesizer [J.P. Oliveand M. Y. Liberman,J. Acoust.Soc. produceditems even when the itemswere equated for familiarityand Am. Suppl.I 78, S6 (1985)]. Two importantassumptions motivate the intelligibility.Other tasksincluded children's responses to spokencom- prosodyrules. First, constituency below the level of thesentence is the mandsand sentence recall using meaningful and semantically anomalous crucialdeterminant for boundarylocation; i.e., boundarylocation is in- sentences.As in ourprevious studies, performance was better for natural flueneedby noun,prepositional, and adjective phrases, but not by clauses speechthan syntheticspeech, paralleling the generalfindings obtained or verbphrases. Second, the relative strength of boundaries isdetermined with adultsin our earlierstudies. Synthetic speech, even when the speech by balancingprosodic phrases around a verb(or predicate)according to is highlyintelligible, may interact with taskrequirements to producesig- length,adjacency to a syntactichead, and the subject-predicate relation. nificantdecrements in performancewhen children engage in complex The abilityto predictphrasing r.eliably allows the systemto usean ex- cognitivetasks. [ Supportedby NINCDS. ] pandedpitch range and insert pauses appropriately.

3:41 3:05 II14. Some relationshipsbetween preferenceand intelligibility among IIll. Nasal vowelstudy: Formant structure,perceptual evaluation, and synthetic voices. John S. Logan (Speech Research Laboratory, neuralrepresentation in a modelof the peripheralauditory system. Yan Departmentof Psychology,Indiana University, Bloomington, IN 47405) Ming Cheng and BernardGurrin (Institut de la Communication Parlre, UA 368 au CNRS, 46 avenue Frlix Viallet, 38031 Grenoble The relationshipbetween preference and intelligibilityamong syn- thetic voiceswas examined. Preferencesamong the speechproduced by Cedex, France) threetext-to-speech systems were assessed using an A/B pairedcompari- In thisstudy, the focus is on the searchfor a modelthat is articulatori- sonprocedure, and the intelligibility of thesynthetic voices was measured ly possibleand perceptually plausible. A high-qualitynasal sound synthe- using a transcriptiontask. The text-to-speechsystems tested were sisstructure in the acousticdomain, with a parallelformant synthesizer, DEC talk, Prose2000, and Infovox.Phoneme specific sentences served as

S79 J. Acoust.Soc. Am. Suppl. 1, Vol.81, Spring1987 113thMeeting: Acoustical Society of America S79 stimuli and enableda preliminaryexamination of the relationship Envelopemodification for the removalof room reverberationand noise betweenintelligibility and preference as a functionof specificphoneme from signalshas alreadybeen studied and foundto producesignal-to- categories.Results indicated a closerelationship between mean intelligi- noiseratio but not inteiligibility improvements. Theenvelope alone d.oes bilityand preference for a voice.In somecases, preference was found to not accountsufficiently for the detailedstructure of speech.A noisyin- varywith the intelligibility of individualclasses of phoneroes,accounting stantaneousphase has been found to havea perceptuallydegrading effect for someof the variabilityassociated with preferencedecisions. These evenwith a perfectlyrestored envelope. Thus it is proposedto enhance resultswill bediscussed in termsof previousresearch involving preference speechby alsoreplacing the measuredinstantaneous phase signal (in a andintelligibility. [Work supportedby NIH and USAF.[ numberof contiguousfrequency bands) by a modeledversion. To deter- mine the characteristicsof the instantaneousphase function both synthet- ic and recordedspeech have been studied. A simplemodel for the instan- taneousphase of speechis proposedand an analytical solution is 3:53 developedrelating the digitalmodel of speechproduction to an envelope 1115. Some measuresof intelligibiHtyof natural and codedspeech for and instantaneousphase model. Enhancement of a noisyinstantaneous nativeand non-nativespeakers of English.Kazunori Ozawa (Speech phasefunction can be achieved by usinga compensatingfrequency shift, ResearchLaboratory, Department of Psychology,Indiana University, low-passfiltering and linearprediction. Bloomington,IN 47405 and C&C InformationTechnology Research Laboratories,NEC Corporation,Kawasaki 215, Japan) and John S. Logan(Speech Research Laboratory, Department of Psychology, IndianaUniversity, Bloomington, IN 47405) 4:17

Segmentalintelligibility of bothnatural and coded speech was mea- II17. Adaptivespeech inteHilpbility testing for communicationsystems. suredusing the modified rhyme test (MRT). Pitchpredictive multipulse D. L. Hogan,C. C. Gumas,C. R. Moore (SPARTA, Inc., 7926 Jones excitedspeech coding (MPC) [K. Ozawa and T. Araseki, Proc. Branch Drive, McLean, VA 22102), B.T. Oshika (SPARTA, Inc., 2560 ICASSP8633.3, 1689-1692(1986)] wasused to producehigh-quality Ninth Street, Berkeley, CA 94710), S. L. Hamlet (Department of codedspeech at 8 kb/s. As a reference,p-law PCM wasalso used. To Hearingand Speech Sciences, University of-Maryland, College Park, MD investigatenot only perceptualdifferences between natural and coded 20742), and D. B. Pisoni (Speech Research Laboratory, Indiana speechbut also the differences due to linguisticknowledge and experience University,Bloomington, IN 47405) with English,both native and non-native speakers of Englishwere used as subjects.All of thestimuli were bandlimited through a low-passfilter with An automatedadaptive interactive speech intelligibility test was im- 4.5-kHz cutofffrequency and sampledat 10-kHz samplingfrequency. plementedon an IBM-PC. Subjects h.ear digitized short sentences such as Closedformat MRT scoreswere obtained to measurethe intelligibilityfor "grassis green" or "escalatorshave doors" over headphones and must key threeconditions, natural speech, p-law PCM and 8 kb/s MPC. Detailed in a T or F responsefor eachsentence. Quality of speechstimuli is con- analysisof the resultsof the intelligibilitytest will be presented.Differ- trolledby differentiterations of a degradingtransfer function before play. encesbetween the intelligibilityscores of nativeand non-nativesubjects back.The levelof degradationpresented to thelistener in successivetrials and the relationshipbetween these scores and their linguisticexperience is dependenton tbejust-previous pattern ofaecuracy in subjectresponse. will also be discussed. The testrun is programmedto convergeto that levelof stimulusdegrada- tion at which the subjectresponds at a selected% correctcriterion. The testis repeatedfor multiple% correctcriteria, to permitnot onlyassess- mentof a communicationsystem under good intelligibility conditions but 4:05 also measurementof sensitivityto reducedinte!ligibility. The approach 1116. Speech enhancement and the instantaneous phase signal. S. permitsflexible manipulation of parameterssuch as speechstimulus ma- J. Walsh and P.M. Clarkson (Institute of Sound and Vibration terial,type of stimulusdegradation, response time mcasurement,etc. The Research,University of Southampton,Southampton, England) testis undercomputer control from initial instructionsto the subjectsto finalsummary of responses.The automatedadaptive procedure has been An approachto speechenhancement based on a representationof the evaluatedfor 100normal hearing subjects. [ Work supportedby ESD, AF speechsignal by an envelopeand instantaneousphase model is proposed. SystemsCommand. ]

THURSDAY AFTERNOON, 14 MAY 1987 CELEBRATION HALL, 1:15 TO 4:45 P.M.

SessionJJ. Bioresponseto Vibration III and PhysicalAcoustics VI: BiophysicalAcoustics: Absorption in Biological Media II

William D. O'Brien, Jr., Chairman Departmentof Electricaland ComputerEngineering, University of Illinois, 1406 W. GreenStreet, Urbana,Illinois 61801

Contributed Papers

1:15 respectto molecularweight similar to that for dextran [Kremkau and Cowgill,J. Acoust.Soc. Am. 76, 1330-1335 (1984)1 was tested.If the JJ1. Absorption of ultrasound in denatured proteins. Frederick scatterin previousdata for nativeproteins is dueto structure,denaturing W. Kremkau (Ultrasound Center, Bowman (}ray School of Medicine, woulddraw the pointstoward the underlyingvalue. However, the scatter Wake ForestUniversity, Winston-Salem, NC 27103) existsin the denaturedprotein absorption values as well.Various solvent Absorptiondata havebeen obtained on nine globularproteins in contributionsto absorptionof thedenatured proteins may cause the seat- aqueoussolution denatured with 6M guanidinehydrochloride at neutral ter. A secondhypothesis was tested:secondary structure contributes to pH. The hypothesisthat there is an underlyingabsorption behavior with absorptionin globularproteins but tertiarystructure reduces this contrl-

S80 J. Acoust.Soc. Am. Suppl. 1, VoL81, Spring1987 113thMeeting: Acoustical Society of America S80 butionbecause of solventshielding [Kremkau and Cowgill,J. Acoust. for bothsafety and treatmentplanning. The ovaryis a dynamicorgan Soc.Am. 77, 1217-1221 (1985) ]. This hypothesispredicts that solvent exhibitinginterspecies variation as well as variationamong the intraovar- buffer ions would increaseabsorption to a greaterextent in denatured Janstructures, viz., the follicles,corpora lutea, etc. The in vitroultrasonic form (with many more sidechains exposed to the solvent) than in native absorptioncoefficient was determined,by the transientthermoelectric form. Suchbehavior was seen in some,but not all of the proteins.[ Work method,for ovariesof bovine, canine, feline, ovine, and murine species at supportedby NCI, DHHS.] 1 MHz. Similaritiesin valuesexist for intraovarianstructures among the speciesmeasured. For example,of the stromal tissues,the outer cortex layer exhibitsabsorption coefficients approximately 50% greaterthan that of the inner medulla.The follicleabsorption is the lowestand the 1:30 corporalutea values vary with thestage of development.These results are consistentwith the macromolecularcomposition of thesestructures. JJ2. Ultrasonic propagationproperties of excessivelyhigh fatty rat livers [Work supportedby the NIH. ] determined with the scanning laser acoustic microscope.William D. O'Brien, Jr. (Department of Electrical and ComputerEngineering, University of Illinois, 1406W. Green Street,Urbana, IL 61801) and John W. Erdman, Jr. (Food ScienceDepartment, University of Illinois, 506 S. 2:15 Goodwin, Urbana, IL 61801 ) JJS. Frequency spectrum shifts of ultrasound echoes as a function of The effectsof l% dietary orotic acid on the ultrasonicpropagation depth in a female breast. Elizabeth Kelly-Fry (Indiana University propertiesof rat liverswere examined. In rats,dietary orotic acid exerts School of Medicine, Wishard Memorial Hospital, Department of severaleffects on lipid metabolism;its overallconsequence is that exces- Radiology, Indianapolis, IN 46202), Steven T. Morris, Natentire sivelyhigh fat concentrationsare built up overa shortperiod of time, thus T. Sanghvi (Labsonics, Inc., Mooresville, IN 46158), and Ernest makingthis an ideal model to studythe ultrasonic propagation properties L. Madsen (Department of Medical Physics,University of Wisconsin, asa functionof fat in liver.Over a 16-dayperiod of timein whichthe rats Madison, WI 53706) wereon theorotic acid diet, lipid concentrationsincreased from a normal rangeof 2%-4% to the lower20's%. Additionally,water concentration Knowledgeof the changesin waveformcharacteristics as an ultra- decreasedfrom normalvalues of approximately70% to approximately soundwave penetrates multiple layers of softtissues within a breastcan be 50%. Total proteinconcentration decreased slightly from a normalof importantfor both detectionand diagnosisof breastpathologies by ultra- 17%-20% to 11%-16%. The rat liver weight increasedfrom approxi- soundmammography techniques. Using a spectrumanalyzer system in mately 11 g to around20 g. Ultrasonicattenuation coefficient and speed combinationwith an automatic,bi-plane scanning, B-mode breast imag- were assessedwith the scanninglaser acoustic microscope at 100 MHz. ing unit, techniqueswere developedfor recordingthe centerfrequency Strongcorrelates of ultrasonicspeed with both water concentrationand and bandwidthcharacteristics of signalsreceived from the subcutaneous fat concentrationin the liver wereobserved. Multivariant linearregres- fat, mid-breast,retromammary, and pectoralismuscle regions of the sionwas used in theanalysis of covarianceto fit theleast-squares estimates breastof a post-menopausalsubject. The sametechniques were applied to to the linear regressionmodel. a breastphantom that has internalarchitectural features and acoustic parameters(density, speed, attenuation coefficient) that are comparable to thoseof a normalbreast. A singlefocus, 7.5-MHz transducerwas used for most of the recordeddata. Lower frequencytransducers were also 1:45 used.Spectral analysis data accompanied by relevantbreast and phantom imageswill be presented.[Work supportedby IndianapolisCenter for JJ3. Ultrasound absorptionand attenuation loss in liver in the finite Advanced Researchand Labsonics,Inc. ] amplituderange. F. J. Fry (Labsonics,Inc., Mooresville,IN 46158), K. Dines (XData, Indianapolis,IN 46206), and M. Etchison(I. C. F. A. R., Indianapolis,IN 46204) 2:30 The ultrasoundabsorption coefficient in fresh excisedrat liver has beenobtained at 1-MHz fundamentalfrequency in the intensityrange JJ6. Intensefocused ultrasound for producingcomplex volume lesions in (SPTP) from low intensity(50 W cm 2) to high intensity(800 W brain. Francis Fry, N. T. Sanghvi, Rich Morris (Labsonics, Inc., cm 2). At atmosphericpressure the pressure absorption coefficient starts Mooresville,IN 46158), S. Griffith, and J. Hastings(I. C. F. A. R., at 0.035 (50 W cm 2} and risesto 0.090 (800 W cm-2). Theoretical Indianapolis,IN 46204) calculationsover this same intensity range show agreement in the shapeof the absorptioncoefficient curve as a function of intensity up to approxi- The ultrasounddosage for producingsingle site focallesions in the mately450 W cm 2.Above this intensity the experimentally derived val- experimentalanimal brain has been well documented. Complex sheet le- uesttatten off and slightlydecline with increasingintensity. The theory sionsin whitematter have been generated from a multiplicityof individ- showsno suchcharacteristic. The absorptioncoefficient was also mea- ual lesionsat I-MHz frequencywithout undesirable side effects in animal suredin the sameintensity range at a pressureof 350 lb in. 2. (This brains.At 4-MHz frequency,lesions in bothwhite and gray matter involv- pressureprovides a biasfor 193W cm 2 at 1 MHz.) Thereis a small ing a multiplicityof individuallesions have been generated without side ( 10% ) and statisticallysignificant reduction in the absorptioncoefficient effectsin the animal brain. At 1-MHz frequency,the productionof com- in theintensity range from 20•-500 W cm 2 but belowand above this plexlesion shapes from a multiplicityof individualsmall lesions in both rangethere is no statisticallysignificant difference in the absorptionval- whiteand gray matterrequired establishing the lesionsite intensity that uesfrom those obtained at atmosphericpressure. Attenuation losses show wouldnot initiateoff primary site undesirable side effects. Intensities be- thesame characteristic charges with intensityas does the absorption coef- low 300W cm--• at theprimary lesion site do notlead to sucheffects. A ficientbut the total attenuationloss is approximatelytwice that due to goodworking hypothesis for productionof sideeffects involves microbub- absorptionalone. [Work supported by NIH grant5ROl CA 41073-05.] ble formationat the primary lesionsite. These microbubbles can be car- riedthrough the vascular circulation providing sites for cavitationforma- tionoutside the primary lesion site. It isnow possible to prescribeprimary lesionsite intensities in brain in the frequencyrange from 1-4 MHz that 2:00 negatesthe possibilityof microbubbleformation. [Work supportedby Labsonics,Inc., Mooresville, IN. ] JJ4. Ultrasonic absorptionin mammalianovaries. K. I. Carnes and F. Dunn(Bioacoustics Research Laboratory, University of Illinois, 1406 W. Green Street, Urbana, IL 61801 ) 2:45 The humanovary, aswell as that of other mammalianSpecies, has the opportunityto receiveultrasonic exposure during diagnostic and thera- J J7. Human gallstonedissolution accelerated by ultrasoundapplication. peuticprocedures. However, the ultrasonicabsorption behavior seems Francis Fry, N. T. $anghvi(Labsonics, Inc., Mooresville,IN 46158), neverto havebeen investigated. Such information is consideredessential Bryan Burney (St. FrancisMedical Center,Beech Grove, IN 46107),

S81 J. Acoust.Soc. Am.Suppl. 1, Vol. 81, Spring1987 113thMeeting: Acoustical Society of America S81 S. Grif•th,J. Hastings,andT. D. Franklin(I. C. F. A. R., Indianapolis, transducerswith sensitivitythat couldbe routinely used in clinicalinstru- IN 46204) mentsfor ultrasoundimaging and diagnosis of tissue.Last year, we have takena novalapproach and developedelectronics to excitePVDF trans- Gallstonesin appropriatechemical species subject to ultrasoundexpo- ducerswith a sharpspike of voltagewith controlledenergy-frequency sureshow accelerated dissolution over that accruingto the chemical spectrumto generateand transmita selectedfrequency band with its alone.In vitrostudies using a humangallstone submerged with monooc- centerfrequency totally controlled by the excitationpulse and selected tanoin(a cholesterolstone solvent) in a latexenvelope show dissolution filter.With thisapproach four different center frequencies with approxi- ofa stonemass of 0.50 g with 6 minof totalultrasound exposure at a SPTP mateband width of 45%-50% isgenerated. This paper will describethe intensityof 15 W cm-2. Controlstones in the monooctanoinshow a analyticalmodel and compare theoretical data with the experimental re- weightloss of 0.05g in thesame overall treatment time. When a pressure sults.As a resultof thisdevelopment a prototype device is fabricatedto of 350lb in -2 isapplied the stone dissolution rate declines by a factorof 3 studyvarious breast tissue types and differentiatethem basedon their from that at atmosphericpressure. The primaryerosion mechanism is scatteringcharacteristics asa functionof different frequency bands. ["Bi- apparentlyof cavitationorigin but a smallerbut significant erosion accel- PlaneScanning with a High Frequency,Multi-Frequency Ultrasound erationoccurs in theapparent absence of cavitation.A uniquefeature of Instrumentfor ImprovedDifferentiation of Malignant and Benign Breast this type of gallstonedissolution is the conversionof solid stoneinto a Tumors,"E. Kelly-Fryet al. submittedfor publicationin Radiology.J. ] liquidstate providing for easeof passageof gallbladdercontent in the clinical situation. That this accelerateddissolution occurs in vitro has been demonstratedon a seriesof pigswith human gallstones implanted in their gallbladder.[Work supportedby IndianaCorporation for Scienceand Technology,I. C. F. A. R., and Labeco/Labsonics,Mooresville, IN. ] 3:15

JJ9. Acousticallyenhanced thermal diffusion. CharlesThompson 3:00 (University of Lowell, Departmentof Electrical Engineering,One UniversityAvenue, Lowell, MA 01854) JJS. A novelapproach of generatingvarious frequency bands using a The role of acoustic vibration in the enhancement of the thermal diffu- widebandPVDF ultrasoundtransducer and its applicationfor tissue characterization. N. T. Sanghvi, S. T. Morris, P. W. Wendt sionprocess near a solidboundary is discussed. Our purposeis to discuss (Labsonics,Inc., 236 E. WashingtonStreet, Mooresville, IN 46158), and thedegree with which flow unsteadiness can be exploited for thepurposes E. Kelly-Fry (Indiana University School of Medicine, Wishard of transportaugmentation. There are three factors that govern augmenta- MemorialHospital, 1001 West 10th Street, Indianapolis, IN 46202) tion:the behavior of theStokes layer; unsteady flow instabilities; and the geometryof the surfaceboundary. The interelationshipof thesethree The technologicaladvances in electronicsin recentyears have made it factorson theaugmentation process will be discussedand preliminary possibleto manufacturepolyvinylidene fluoride (PVDF) ultrasound resultsof our analysispresented.

3:30-4:45

Bull Session

THURSDAY AFTERNOON, 14 MAY 1987 CANYON IdALL, 1:30 TO 4:20 P.M.

Session KK. Musical Acoustics IV: Acoustics of Pianos II

Uwe J. Hansen, Chairman Departmentof Physics,Indiana State University,Terre Haute, Indiana 47809

Chairman's Introductionml:30

Invited Papers

1:35

KK1. Pianostring excitation: Theory and reality. Donald E. Hall (PhysicsDepartment, California State University, 6000 J Street, Sacramento,CA 95819) An idealizedmodel of pianostring excitation has been shown soluble by a combinationof analyticand computertechniques. It is also useful to stepaside from the mass of detailsthis model generates, and discuss generalphysical arguments about what overall envelopes should limit thestring vibration spectra produced. Thisalso provides a framework for more careful consideration of the limits of validity of thetheory. It isargued thatthe most important weakness is thenon-Hookean nature of thehammer compliance, followed by string stiffnesseffects; possible ways of including these effects will be considered. Further laboratory measurements of stringmotion will be presented, especially beating upon the question of whetherstriking the string a fraction I/N of its lengthfrom one end does or doesnot causemode number N to be missingfrom the spectrum. Measurementsof radiatedsound that wouldhelp clarify the roleof the soundboardwill alsobe considered.

S82 J.Acoust. Soc. Am. Suppl. 1, Vol. 81, Spring 1987 113thMeeting: Acoustical Society of America S82 2:05

KK2. Vibrationanalysis of a hammer-shanksystem. Hideo Suzuki (AcousticsLaboratory, Ono Sokki Company,Ltd., Shinjuku-ku,Tokyo, 163 Japan) The transientmotion of a hammer-shanksystem is mathematicallyanalyzed using a modifiedform of the Myklestadmethod. The hammer is modeled as a mass-springsystem with a nonconstantspring coefficient. The shank is divided into 13 elements,where each element is assumedto have a uniform crosssection. The effectof the shankstiffness, the hammervelocity, and the initial deformationof the shankin the force-time patternapplied by the hammerto an ideallyrigid stringare investigated.The resultsshow that the shank deformssignificantly during the hammer-string contact period. It isalso shown that the force-time pattern changessignificantly when an initial deformationof the shankis introduced.Some of the theoreticalresults are comparedwith experimentalresults. (This studywas conducted while the authorwas at CBSTechnology Center, Stamford, CT 06905, from 1981 to 1985.)

2:35

KK3. Piano hammer:A nonlinearmodel comparedto experiment.Xavier Boutilion (Laboratoire d'acoustique,Universit6 Paris VI, T66 5•me6tage, 4, placeJussieu, 75005 Paris, France) Thispaper presents a nonlinear model for thehammer, its experimentaldetermination, and comparisons betweensimulated and recorded movements of stringsand hammer during their interaction. It is firstshown howclosely the impact velocity of thehammer is the onlyinput parameter that governsthe collisionof the hammerwith the strings and therefore the quality of thesound. However, this quality is highly dependent on themagnitude of theimpact velocity. So, a nonlinearmodel is required to describethe hammer's behavior. It consistsof theassociation of a masswith a nonlinear,hysteretic spring whose characteristics are experimental- ly determinedunder realistic playing conditions. Both nonlinearity and hysteresis are fit by analyticalrelation- ships.This model, when associated with a simpleflexible string model, allows a numericalsimulation of the movementsof bothhammer and strings. These are compared to themeasured vibration of a stringand to the measuredacceleration of thehammer. In addition,results are presented regarding the efficiency of thehammer impact.

ContributedPapers

3:05 beinga significantincrease in the modaldamping as compared to thefree vibrationalresponse of the violin. The effectof the playeron the modal KK4. New method of measuring input admittance of stringed frequencieswas negligible. It wasalso found that restingthe instrument instruments. Gabriel Weinreich (Randall Laboratory, University of ona pieceof foamrubber or the useof sandbagsunder the neck and the tail Michigan,Ann Arbor, MI 48109) and Levon Yoder (Departmentof of the instrumentprovided a goodfirst approximationto the influenceof Physics,Adrian College,Adrian, MI 49221) the player.The otherboundary conditions that wereinvestigated caused Whena stringedinstrument, such as a violin,is subjected to anapplied significantdeviations from the normalresponse of the instrument,thus time-harmonicforce and the resultingvelocity of the bridgeis measured, indicatingthat thesemounting techniques should not be usedto measure the quantityusually referred to as the "inputadmittance" in factfunc- the vibrational behaviorof a violin or other stringedinstrument. tionsas an outputadmittance. Its valuecan be inferredby loadingthe bridgewith a knownexternal impedance and comparingthe velocities with and without this loading.In our experiment,the externalloading 3:35 impedanceis a knownmass, and the applied force results from an irradiat- ingacoustic field. By takingdata with twodifferent field configurations, KK6. Iranian scale of music can be considered as a universal scale. wecan independently determine the four elements of thetwo-dimensional M. Barkeshli (Department of Physics,Tehran University, Tehran inputadmittance matrix referred to thetwo possiblepolarization direc- 13887, Iran) tionsof the stringvibration. We utilizethe digitaldata acquisition and Iraniansdivide the major tone in two:Limma (L) anda comma(C). processingsystem that has been previously developed for radiativity mea- Safi-yud-din(the Iranian savant virtuoso from the 13th century) was the surements,in whichan appropriate broadband stimulating signal allows a pioneerof a schoolthat propagatedthe systematictheory, taking L as largespectrum of data to be obtained in a fewseconds. Some results will be unityfor intervals,and dividedthe tone9/8 into L L C. We seethis shown.[Work supportedby NSF.] divisionin the tablatureof tunburKhorasan, a typicalinstrument used in Iran and neighboringcountries (description by Farabi, the Iranian philosopherand musico]ogist from the 10thcentury). Our researcheson measuringthe intervals of contemporary Iranian scale ["La Gammede la 3:20 Musiquelranienne," T616communication, Paris 5, 5 (1950)] showedthat there are also other divisions L C L and C L L in Iranian music. With this KKS. Boundary conditions and violin vibrations. Kenneth D. Marshall arrangement,the octave is dividedinto 27 intervalsor 28 degrees.This {The Uniroyal Goodrich Tire Company,Research and Development scalecan be consideredas a universal scalebecause it contains all elements Center, Brecksville, OH 44141 ) of harmonic and melodic:scales. In fact the interval L + C, the character- In this paperthe vibrationalbehavior of a violin is examinedunder a isticof orientalmusic, is equalto 16/15 with the difference1.0011292, variety of boundary conditions;held by the player, freely suspended, being lessthan 1/50 of a semitone,a differencenondiseernable by the pinnedsupports, simple supports, clamps applied to theneck and corpus, normalear [V. O. Knudsen,ArchitecturalAcoustics]. Also with thesame and supportedby sandbags.It wasfound that threedifferent players im- difference10/9 = 2L, 5/4 = 4L + C, and so on. [Work supportedby posedvery similarconstraints on the instrument,with the principaleffect ASI and PSI.]

S83 J. Acoust.Soc. Am. Suppl.1, Vol. 81, Spring1987 113th Meeting:Acoustical Society of America S83 3:50 4:05

Kit?. An exploration of the Chinese pure-tunesystem. Hai-si Pan and KKS. A comparisonof the musical scalesof an ancient ChineseBronze Yu-An Rao (Instituteof Physiology,Academy of Sciences,Shanghai, bell ensembleand the modern bamboo flute. Yu-An Rao (Institute of People'sRepublic of Chinaand Department of Psychology,University of Physiology,Academy of Sciences,Shanghai, People's Republic of California,Los Angeles, Los Angeles, CA 90024) China), Edward C. Carterette(Department of Psychology,University of California, Los Angeles,CA 90024), and Ya-Kui Wu (Institute of After 300 yearsof effortin many countriesaimed at resolvingthe Acoustics,Nanjing University, People's Republic of China) inharmonicityof the 12-intervalequal-tempered scale, a purescale of 53 toneswas proposed in 1816-1890,but it cannot be applied usefully owing We compareover a two-octaverange the tonal, interval, and scale to its very greatcomplexity. A surveyof ancientChinese musical litera- relationshipsof an ancientChinese bell ensembleof the Zhou Dynasty tureand instruments and deductions from "$ing-Fang's60 Notes"of the and a modernbamboo flute. By usingsubjective pitches, a tonal system HahDynasty ( i•. , 209BC-220 AD) andEmperor Liang-Wu's "Four with simpleharmonic partials (the flute) couldbe compared with a tonal Pass"scale (502-519 AD), led us to proposea 23-tonescale. Its error systemhaving complex inharmonic partials ( thebell). We arguethat the curvecorresponds precisely with that of the53-tone pure scale. The prin- underlyingmusical scales of the bell ensembleand the fluteare closely ciple of Schismais usedfor solvingproblems such as (a) that of the relatedand lie betweenan unequal-intervalpure system scale and the just- inharmonicitybetween Gong (do) andJiao (mi), i.e., themajor third; intonation scale. There is some evidence that at least an interval of 60 or 66 and (b) that the major and minor chordscoexisted in an octave.We have centsfigures in the flute scale,that both flute and bell scalesinclude a 90- deriveda pure-temperamentscale of 23 tonesthat can be modulatedfor centinterval and a true (1200) cent octave,and that neitherscale includes everytonic and that is consistent with the modem pure scale of 53 tones. a 100-centinterval. Since there is a trueoctave the scale cannot be a cycle We showthat this23 unequal-intervalpure scale is consistentwith the of fifths,and sincethere is no equal-temperamenthalf-tone ( 100cents), intervalswhich were obtained by measurementfrom a stoneflute made in thescales cannot be of equaltemperament. We concludethat theflute and theQing Dynasty ( • , 1644-1908AD). Zhoubell scales are very similar if notthe same. Apparently strong cultur- al traditionsand humanperceptual constancies united to sustaina com- monflexible musical scale during twenty-four hundred years.

THURSDAY AFTERNOON, 14 MAY 1987 MT. McKINLEY 1:30 TO 4:35 P.M.

SessionLL. UnderwaterAcoustics VI: MatchedField SignalProcessingmPart II: GeneralSignal Processing

John M. Ozard, Chairman DefenceResearch Establishment Pacific, FMO, Victoria,British Columbia VOS1BO, Canada

Chairman's Introduction--l:30

ContributedPapers

1:35 Thispaper examines aspects of matchedfield processing for locatinga broadbandsource in deepwater. Concentrationis on nearbysources LL1. Bottomeffects on matched-fieldlocalization performance in the (within 5 km of a verticalreceiving array), on frequenciesfrom 100to 300 North Pacific. R. G. Fizell and M. B. Porter (Code 5120, Naval Hz, and on deterministic,simulation "data" only. The noisefield has been ResearchLaboratory, Washington, DC 20375) modeledas Gaussian,uncorrelated, white noise while the acousticfield PACIFIC ECHO wasan experimentconducted jointly by the Naval hasbeen modeled by thefast field program, with subsequent processing by ResearchLaboratory (NRL) and DefenceResearch Establishment, Pa- conventionaland maximum likelihood (ML) methodsto generaterange- cific (DREP) in May-June 1986.Vertical array measurements of a 15- depth ambiguitysurfaces (AMSs). The effectsof mismatchin the de- Hz cwsignal projected by theNRL MK-VI source,towed at a depthof scriptionof seasurface roughness have beenexamined and it has been 100m, weretaken on the675-m-long DREP arrayat boththinly ( < 50 foundthat it canlead to significanterrors in peaklocation on an AMS, m) and thickly ( > 500 m) sedimentedareas. The array waslocated in particularlyat the higherfrequencies. However, incoherent frequency separatecases in thedirect path and the shadow zone, and the top sensor averagingof AMSs can, in the presenceof relativelysmall mismatch, wasat a depthof approximately350 m. Matchedfield processing between overcometheeffect of such mismatch, even though almost all the compo- theoreticaland measuredfields was applied to thisdata set in orderto nent frequenciesshow errors in their predictions.Moreover, considera- performrange-depth localization. Both a linear(Bartlett) and a nonlin- tionof rangeaveraging plus frequency averaging can, under such condi- ear, minimum-variance(Capon) estimator were employed using theo- tions,improve those cases not resolved by frequency averaging alone. It is reticalfields generated by a normalmodes program. The bottommodel hypothesizedthat frequency and/or rangeaveraging will helponly when playsan importantrole in the shadowzone where acoustic energy is re- the mismatch is sufficiently small that the AM:Ss have at least local maxi- ceivedpredominantly via bottominteracting paths. The thin sediment ma near the true source location. site,in turn, is especiallyinteresting because of theinteraction with the elasticsubbottom. The effectof differencesin measurementsite (thin or thicksediment), source-received separation, and processor estimator on performanceof the matchedfield processor are discussed. 2:05 LL3. Sourcelocalization in almost-stratifiedwaveguides. E. C. Shang 1:50 (Departmentof ComputerScience, Yale University,New Haven,CT 06520) LL2. Broadbandacoustic source localization.A. Tolstoy and M. B. Porter (Code 5120, Naval ResearchLaboratory, Washington, DC In our previouspapers [E. C. Shang,C. $. Clay,and Y. Y. Wang,J. 20375-5000) Acoust.Soc. Am. 78, 172 ( 1985);J. Acoust.Soc. Am. 77, 1413(1985) ],

S84 J.Acoust. Soc. Am. Suppl. 1, Vol. 81, Spring 1987 113thMeeting: Acoustical Society of America S84 sourcelocalization techniques based on modefiltering have been devel- reviewsfundamental environmental effects and their influence on arrays opedfor stratifiedwaveguides. In thispaper, some problems of source in thedeep ocean sound channel. [Work performed while at NORDA.] localizationin almost-stratifiedwaveguides are discussed.Specifically, the Pronymethod is proposedfor sourcebearing in range-dependent waveguides.It is foundthat the Prony methodonly requiresa "local almost-stratified"condition, which means that within the data sampling 3:05 aperturelength the field can be treated as adiabatic modes. For mostof the LL7. Passive synthetic arrays. W. M. Carey (Naval Underwater practicalinteresting cases, this condition can be satisfied quite easy. SystemsCenter, New London,CT 06320)

Passive-syntheticapertures [W. Carey and N. Yen, J. Acoust.Soc. Am. Suppl. 1 75, S62 (1984)] were formed with experimentaltowed 2:20 hydrophonedata in a soundchannel that supportedRR andRSR trans- LIA. Extractionof averageunder-ice reflection amplitudes and phases mission.These apertures were formed with lengthsup to 952 with coher- with matchedfield processing.E. Livingstonand O. Diachok (Naval ent temporalprocessing gains approaching 0.75 of theoretical.These re- ResearchLaboratory, Code 5120, Washington, DC 20375-5000) sultsand thoseof previousinvestigators [R. Fitzgerald,J. Acoust.Soc. Am. 60, 752-753 (1976); R. Williams, J. Acoust. Soc. Am. 60, 60-73 Averagelow-frequency under-ice reflection amplitudes and phases in (1976) ] indicatethat syntheticapertures can be formedby the coherent thecentral Arctic were extracted from long-range (259 km) signalsfrom summationof the phase-correctedsummation of eitherhydrophone or fixedcw sources detected on a long( 1 km) verticalarray (the FRAM IV subaperturebeams over successive time samples when the synthetic aper- experiment)using conventional [ H. Bucker,J. Acoust.Soc. Am. 59, 368 ture lengthis lessthan the spatialcoherence length and the processing (1976) ] and maximumlikelihood JR. Fizell, J. Acoust.Soc. Am. (to be time isless than the temporalcoherence length. The evaluationof synthet- published)] matched field processing methods. Theoretical computation ic aperturesrequires comparisons with conventionaland other high-reso- ofamplitudes and phases for all assumedranges and depths were based on lution techniques.Comparisons between conventional array processing the Porter-Reiss[J. A½oust.Soc. Am. 77, 1760-1767(1985)] normal andhigh-resolution techniques [ maximum entropy (ME) andmaximum modecode. Under-ice reflection amplitudes and phases were incorporat- likelihood(ML) methods] are performed by useof theanalytical expres- edinto the propagation code and varied iteratively to achievemaximum sionsdeveloped by A. T. Parsons(AUWE, TN 700/83 ) for the determin- signalgain and minimum range and depth errors. The resultant best data- ation of the array, integration,and the net processinggains. Analytical fittingamplitudes and phases will becompared with expectationsbased comparisonsbetween conventional and syntheticaperture arrays formed on under-icescattering theories and laboratory-scale model experiments. with either the samenumber of hydrophonesor with the sameeffective lengthbut a differentnumber of hydrophones,show that, when the spatial processinggain exceedsthe lossin integrationgain, then the useof syn- theticapertures is advantageous.[Work performedwhile at NORDA.] 2:35

LLS. Ventriloquismand spurioussound sources in underwateracoustics. Ian Roebuck (Admiralty ResearchEstablishment, Portland, Dorset 3:20 DT5 2JS, England) LL8. Performance of sinusoidally deformed planar arrays. James With the increaseduse of active noise control has come wider aware- H. Leclcre,Donald R. Del Balzo,Deanna M. Cavcny(NORDA, Code nessthat the sourcedistributions generating prescribed sound fields are 244, NSTL, MS 39529), GeorgeE. Ioup (Universityof New Orleans, notunique. In particular,the possibility of preciselyreproducing the field New Orleans, LA 70148 and NORDA, NSTL, MS 39529), Jeffrey dueto a time-varyingmonopole by a multipolesource (of infiniteorder) L. Becklehimer,and Donald A. Murphy (NORDA, NSTL, MS 39529) locatedelsewhere, has been established. In thispaper, the fundamental physicallimitations of carryingout suchan "underwaterventriloquism The investigationsof Cavcnyet al. [J. Acoust.Soc. Am. Suppl.I g0, act" in practice•evelopinga "constructive"algorithm for the various S26 (1986)] are extendedfor the casesof horizontallyand vertically multipolecoefficients and criteriafor truncatingthe processare exam- towed planar arrays.Horizontal and verticalarrays of three lines (64 ined.It is shownthat this is closelyrelated to earlierideas on the effective hydrophoneseach) and nine lines (28 phoneseach) are included. In addi- sizeof"point" sources [I. Roebuck,J. Acoust.Soc. Am. Suppl.I 69, S87 tion, a nine-linearray with fivehorizontal and fivevertical lines (with the ( 1981) ] andfurther that acousticefficiency limits the extent to whichthe middle linc of each in common) is also examined. Horizontal sinusoidal transmittingmultipole elements can be compactedwithout destructive deformationsof one-halfcycle (and in somecases two and three half- mutualinteraction. The mannerin whichthe greatereffective size of the cycles)are applied to eachline. Complex pressure fields are modeled for "spurious"multipole source limits the potential for deception in thepres- varioussource directions for eacharray usingthe codeBEAMSTATPAK enceof varyingboundaries is alsoanalyzed. of Collier (privatecommunication). Beamforming is thendone with the knownarray configurationand with the assumptionthat the array is planar(for selectedcases). Degradations resulting from assuming plan- arity and the ability to removeleft/right ambiguityare summarizedas a 2:50 functionof the sourcelocation and the amountof array deformationin termsof reducedgain and angularresolution. Array performanceis also LL6. Space-time processing,environmental-acoustic effects. W. examinedin the presenceof a realisticvertical noise distribution. [Re- M. Carey(Naval Underwater Systems Center, New London,CT 06320) searchsponsored by NUSC. ] andW. B. Moseley(Naval Ocean Research and Development Activity, NSTL, MS 39529)

The processingof acousticwaveforms by arraysrequires an under- standingof the temporaland spatial characteristics of signaland noise 3:35 fields.Temporal and spatial processing schemes are analogous transforms LL9. Sidelobe suppressionin correlated multipath estimates. Peter thatcan employ a varietyof windows(such as Hann, Hamming, etc.). C. Mignercy (U.S. Naval Research Laboratory, Code 5122, However,the ocean environment isa filterthat introduces variability to a Washington,DC 20375-5000) signalin bothspatial and temporal domains. This randomness issuperim- posedon an ambient soundchannel characteristic.In the caseof static Someenvironments cause a propagatingsignal to splitalong several sourceand receiver combinations,the limits on horizontal broadsidear- differentpaths. When such multipath propagation occurs, the covariance ray resolutionare dueto volumescattering and surface scattering as long among signalstraveling along rays emanating from a common sourceis asthe time scaleis lessthan the signalcorrelation time. However,in the expectedto be larger than the covariancebetween signals generated by caseof a movingsource-receiver, the temporal and spatial scales are cou- independentsources. An estimateof thecovariance between signals arriv- pled throughthe soundchannel characteristic and the fluctuationeffects ingfrom two different directions isshown to bea bilinearform. The ability dueto multipathor modalvariations must also be considered. This paper of thebilinear form to distinguisha correlated arrival from an indepen-

S85 J. Acoust.Soc. Am. Suppl. 1, Vol.81, Spring1987 113thMeeting: Acoustical Society of America S85 dentsource is•tudied using asimulated acoustic field. Peaks associated thesesynthesizer techniques for trainingsonar operatom. [Work per- withthe correlated pair ofarrlvals are 24 dB above an uncorrelated back- formedin supportof NUWES,Keyport, WA.] ground,while no similar peaks occur for theindependent source. The 8- dB sidelobesare found to bea problem.An adaptiveset of filtervectors, obtainedfrom the classical minimum variance problem, produces a bilin- 4.•$ ear form which is found to minimize sidelobeinterference to 2 dB. How- ever,the peaks indicating a correlated arrival are reduced to 18-dBoutput LLII. Low-frequencymbient noisenear Bermuda: Filling in the notch. abovethe uncorrelated background. The constrainedminimum variance William A. Von Winkle, David G. Browning,Raymond J. Christian, estimateof thecovariance between two arrivals of a multipathis apparent- and A. Donn Cobb (Naval UnderwaterSystems Center, New London ly effectivein suppressing sidelobe interference at the cost of a lowermain Laboratory,New London,CT 06320) peak.[Work supportedby ONR.] Ambientnoise models which assume no significantwind-generated noisemechanism in the 5- to 100-Hz frequencyrange predict a notchin noiselevels, between shipping and microseismicnoise, at approximately 3:50 10 Hz. Data are presentedfor the frequencyrange 3-200 Hz that show thatthis notch fills in at increasingwind speeds and is entirely eliminated LLIO. The generationof propelk*?.modulation s•unds for sonartrainers. above 35 kn for a North Atlantic Ocean location near Bermuda. These Gary MCArthur, CharlesSchmid, Mike Warnecke (Honeywell resultsare consistent with thelow-frequency wind-generated noise mech- EngineeringServices Center, 1050 N.E. HostmarkStreet, Poulsbo, WA anismproposed by lsakovichand Kur'yanov [Sov. Phys. Acoust. 16, 49 98370), and Les Atlas (Department of Electrical Engineering, (1970) ]. [ Work supportedby NUSC.] Universityof Washington,Seattle, WA 98195) Soundsof propellermodulation were synthesized using linear predic- tive coding(LPC) techniquesresident in digitalsignal processing hard- warefor thepurpose of trainingsubmarine sonar operators. The combina- tion of LPC techniquesand digital soundgeneration produces realistic LLI2. Species and size-classdiscrimination of selected fish using propellermodulation sounds which can be convenientlyvaried by the broadbandsonar. Paul A. Skvore,II (Alaska Departmentof Fish and instructorto characterizethe type, speed, and depth of surfaceand under- Game, Cornre. Fish Div., P.O. Box 3-2000, Juneau,AK 99802) watervehicles. The synthesizedsounds were generated with digital LPC (all-pole) filterssimilar to thosecommonly used in speechsynthesizers. A sonarsystem was designed and built that could transmit and receive The coefficientsto drive the LPC filterswere calculatedfrom spectral a broadbandsignal. This transmission takes the form of a chirp,ranging in modelswhich were formulated from thecavitation index, KT• P . The cavi- frequencyfrom 50--150 kHz. Four speciesof fishrepresented by tensize tation index was calculated based on the instructor's commands of the classeswere used in a laboratoryenvironment as targets.An acoustic vehicletype, speed, and depth.Three differentLPC filter designswere signaturewas developed for each of the species and each of the size classes implementedto evaluatethe computationalefficiency and sound realism withineach species. Pattern analysis techniques were then employed to of each approach.The first designwas a standard12th-order LPC filter testunknowns against these signatures. The systemas a wholewas capa- whichwas not capableof changingthe spectrumover short time periods. bleof 95% accuracyin bothspecies and size class discrimination. (Those The seconddesign was a low orderLPC filter with coefficientswhich fishmisclassified to speciewere considered to bemiselassified to sizeirre- changedquickly with time. The last designwas a basebandLPC filter spectiveof the relativesizes of the signatureand unknown.)Size-class modulatedby a time-varyingsinusoidal carrier. Various propeller modu- accuracyis approximately+ 10% of the fork lengthof the fish.Hydro- lationsounds will be playedto demonstratethe qualityand flexibilityof acousticand pattern recognition techniques are presented.

S86 J. Acoust.Soc. Am. Suppl. 1, Vol.81, Spring1987 113thMeeting: Acoustical Society of America S86 THURSDAYAFTERNOON, 14 MAY 1987 MT. RUSHMORE,1:30 P.M.

Joint Meeting of AccreditedStandards Committees S3 and S1 Theactivities ofS3 will bc discussed first, procccciing tomatters ofinterest Ioboth S3 and S 1. and concluding with SI activities.

Meeting of Accredited StandardsCommittee S3 on Bioacoustics

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

StandardsCommittee S3 on Bioaeouatics. The current status of standards under preparation will be discussed. In additionto thosetopics of interestincluding hearing conservation, noise, dosimeters, hearing aids, etc., considerationwill begive• to newstandards which might be needed over the next few years.

Meeting of Accredited StandardsCommittee SI on Acoustics

D. Johnson,Chairman S 1 Larson-Davis Laboratories, 280 South Main, Pleasant Grove, Utah 84062

StandardsCommittee SI onAcoustics. Working group chairs will report on their progress inthe preparation of standards,methods of measurementand testing, and terminology in physicalacoustics, electroacoustics, son- ics,ultrasorties, and underwater sound. Work in progressincludes measurement of noise sources, noise dosi- meters,integrating sound-level meters, and revision and extension of soundlevel meter specifications. Open discussionof committeereports is encouraged. The internationalactivities in ISO/TC 43 Acousticsand IEC/TC 29 Electroacoustics,for whichSI and S3 serveas the IJ.S. Technical Advisory Groups, will bediscussed, with a reporton the meeting of ISO/TC 43, heldfrom 4--7 May 1987in Copenhagen,Denmark.

.S87 J.Acoust. Soc. Am. Suppl. 1, Vol. 81, Spdng 1987 113thMeeting: Acoustical Society of America S87 FRIDAY MORNING, 15 MAY 1987 MT. McKINLEY, 8:30 TO 11:50 A.M.

SessionMM. EngineeringAcoustics II: Transducersand Sampling

John C. Baumhauer, Jr., Chairman AT&T ConsumerProducts Laboratories, P.O. Box 1008, Indianapolis,Indiana 46206

Chairman's Introduction--8:30

ContributedPapers

8:35 solidblock, except in the neighborhoodof the lengthresonance of the solidb•ock; moreover, it is a smoothercurve. The open circuit receiving MML Nonuniformly poled piezoelectrictransducers. Dov Hazony responseof thecomposite is some10 to 20 dB lowerover this frequency (Electrical Engineeringand Applied Physics,Case Western Reserve intervalthat is attributedto the relativelylarge capacitance of the cables University, Cleveland,OH 44106) that wereused. Directivity patterns of the 1-3composite are betterthan A transducermodel similar to Mason'smodel [W. P. Mason,Elect•o- thoseof thesolid block and the availabilityof multipleoutputs makes it mechanicalTransducers and WaveFilters (Van Nestrand, New York, possibleto implementboth amplitude shading for patterncontrol, and 1948)] ispresented and discussed. Many exampleswill beshown includ- phasingor timedelays for beamtilting;both of thesefeatures were demon- ing the casewhen the mechanicalresponse of the transducerto an electri- stratcd.[ Work supportedby ONR. ] cal impulseis alsoan impulse.The presentationis basedon a forthcoming paper [D. Hazony, J. Acoust.Sec. Am. (to be published)]. Corrobora- tiveexperimental results will begiven. [Work supportedby Gould,Inc., and Tecsonics,Inc. ] 9:20

M'M4. Analysisof multilayeredwideband transducers. Hajimc Fujita (Mechanical Engineering Research Laboratory, Hitachi, Ltd., 502 8:50 Kandatsu, Tsuchiura, Ibaraki 300, Japan) and Kiyoshi Koyano (TotsukaWorks, Hitachi, Ltd., Japan) MM2, Determination of the mechanical limits of piezoelectric Singlepiezoelectric material used as a transducerelement usually transducersusing the finite element method. B. Dubus, J. C. Dcbus, J. givesa high Q resonancecharacteristic due to high acousticimpedance N. Decarpigny (Institut Sup•rieur d'Electroniquedu Nord, 41 relativeto that of water.Epoxy resins or similarmaterials are usedas BoulevardVauban, 59046 Lille Cedex,France), D. Morel (Sinaptec,41 impedancematching layers in order to obtaina low Q transducer.Al- BoulevardVauban, 59000 Lille, France), and D. Boucher (Groupe though analysisof a compositestructure element is traditionally made d'Etude et de Reeherchede D6tection Sous-Marine,Le Brusc, 83140 Six with an electromechanicalequivalent circuit, numericalanalysis is in- Foursles Plages, France) creasinglyin use.In this paper,a simpleand usefuldesign method for a The mechanical limit of ultrasonic transducers is associated with the multilayeredtransducer utilizing both an equivalentcircuit and a finite fracture,nonlinearities, and fatigue strength of thedifferent materials and elementmethod is described. Transducers with a half-wavelengthpiezoe- thus is directly related to the distribution of stressesover the structure. lectric material with one or two quarter wavelengthmatching layers are The staticcase corresponds generally to the designof depthtransducers analyzedfor transientresponse with pulsedsine wave input aswell asfor and prcstrcssedceramic stacks. The dynamiccase concerns high-power steady-stateresponse, and vibration,stress, and soundradiation charac- sonar transducers,as well as macrosonics.For severaltransducers, the teristicsare obtained.The resultsindicate that the bestmatching imped- stressfield has been computed with the helpera finiteelement modeling, anceis differentfrom the valueusually suggested lB. V. Smithand B. K. usingthe ATILA code[J. N. Decarpignyet al., J. Acoust.Sec. Am. 78, Gazey, IEE Proc. 113, 285-297 (1984)]. 1499 (1985)]. This paper describessuch an analysisin the caseof an axisymmetricallength expandertransducer and a flexural shell sonar transducerlB. Hamonic et al., J. Acoust.Sec. Am. Suppl. 1 80, S26 (1986) ]. The static stressesdistribution is found when a mechanicalbias 9:35 is applied and maximum dynamic stresszones are identifiedat several frequencies,using a classicalfatigue criterion. Measurements with strain MM5. Ultrasonic microprobe hydrophones.Mark B. Moffett, James gaugesdisplay a satisfactoryagreement with computedresults. M. Powers,and William L. Clay (Naval UnderwaterSystems Center, New LondonLaboratory, New London,CT 06320-5594) Miniature, bilaminarultrasonic hydrophones have been constructed with clementsof piezoelectriclead titanate (PbTiO3) , lead metaniobate 9:05 (PbNb206),and poly(vinylidenefluoride) (PVDF). The overallshape MM3. Electroacousticcharacteristics of a 1-3 compositetransducer. of the bilaminar element was cubical, with dimensionsof about 0.8 mm for William Thompson,Jr. (AppliedResearch Laboratory and Department thePbTiO 3 and PbNb206 probes and 1.3mm for the PVDF probe.When of EngineeringScience and Mechanics,The PennsylvaniaState usedwith a ] 9-dB-gain,100-pF-input capacitance preamplifier, the sensi- University,University Park, PA 16802) tivitiesranged from - 229 dB//IV/pPa for the PbTiO3to -- 236 dB// 1V/pPa forthe PVDF probe.The resonancefrequency of thePbTiO3 and A 1-3 compositetransducer was constructed by dicinga solidsquare PbNb206probes, about 0.9 MHz, waslower than expected;this is prob- blockof PZT-4 to createa largenumber of thin parallelpillars; the cuts ablydue to the relativelyhigh percentageof epoxyused in constructing wcrcthen backfilled with epoxy.The devicewas calibrated as both source the eicmcnts.If onedefines the usefulfrequency range as that for which and receiverand its responsewas comparedwith that of the samesize theresponse isfiat within ñ i dBand the beam pattern is omnidirectional solidblock. Over the frequency interval 10 to 300kHz, thetransmitting within ñ I dB, the usefulupper frequency limit extendsto 100kHz for voltageresponse of the 1-3composite is comparablein levelto that of the the (larger) PVDF probesand to 200 kHz for the PbTiO3and PbNb306

S88 J. Acoust.Sec. Am. Suppl. 1, Vol.81, Spring 1987 113thMeeting: Acoustical Society of America S88 microprobes.These upper frequency limits correspond to elementdimen- phonicprobe are compared. Sound source localizations are also investi- sionsabout one-tenth wavelength in water.[ Work supportedby NUSC's gated.The results are in goodagreement in spiteof thesmall bounded IndependentExploratory Development Program (funded by DNL) and watertank. This technique seems to bevery interesting to studymaterial by the TransducerTechnology Project (managedby NRL/USRD and characteristicslike transmissionor absorptionand sourcelocalization. fundedby ONT).]

9:50 10:35 MM6. Analysisof a magnetostrietiveTonpilz transducer.F. Claeyssen, D. Boucher, and C. Pohlenz (GERDSM, DCAN Toulon, DCN, Le MM9. Electroacousticmathematical model of a capacitive solid-state Brusc,83140 Six Foursles Plages, France) microphonestructure. John C. Baumhauer, Jr. (AT&T Consumer ProductsLaboratories, 6612 East 75th Street, Indianapolis,IN 46250) A rare-earthiron Tonpilz transducer has been developed in a compact size, low-frequency,high-power design. The main reasonfor this first A semiconductormicrophone structure is describedin terms of the transducerchoice is that its behavior is rather well understood,the rods optimizationof its micromachiningparameters. Microscaling of dimen- beingused on theirlongitudinal mode. The activeelements of theTonpilz sionsis subject to a minimumsignal-to-electrical noise ratio requirement, arefour rods of randomoriented TbO.3DyO.7 Fel.8alloy. They are mag- with an objectiveof smallsilicon diaphragm area. Side constraints include neticallycoupled through a laminatedflux return path. Force-cooled coils electrostaticstability, acceptable frequency response, and low-condenser providethe dynamicmagnetic field as well asthe polarizingbias. Data on biasvoltage. Relations on electrostatic biasing and acoustic sensitivity are electricalimpedance, transmitting current response, transmitting voltage presented.A lumpedparameter model of thesilicon diaphragm was justi- response,effective coupling coefficient, efficiency, and linearityversus the fiedfor theequivalent circuit. An electricalnoise model is described. Scal- biasare presented.The in-air and in-watermeasurements are compared ing to a submicronair film thicknesswas requiredto meet the above with the resultspredicted by a planewave model taking into account criteria.A novel(patented) acoustic hole array throughthe backplate leakageflux, reluctanceof thereturn path, eddy current losses in the rods overcomesthe resulting(excessive) air squeeze-filmdamping (i.e., resis- andin the returnpath, and mechanical damping. The materialconstants tance).The arrayof 2000holes, nevertheless, consumes a small fraction of of the magnetostrictivealloy usedin the modelare measuredindepen- thecapacitive area. Analyses for mechanicalvibration pickup sensitivity dently with a low-frequency,two-rods device under high-power condi- andperforated backplate mechanical stability are briefly discussed. tions.New developmentsin modelingand technologydesign will be pre- sentedin a subsequentpaper.

10:50

MMI0. The analysisof an opticalfiber microphonedesign. Andong Hu, 10:05 Frank W. Cuomo(Department of Physics,University of RhodeIsland, MM7. Bandwidth limitations of the mechanical impedanceof single Kingston,RI 02881), and Allan J. Zuckerwar (NASA Langley degree of freedom electromechanicalvibrators. Michael P. Johnson ResearchCenter, MS 238, Hampton,VA 23665) (Acousticsand SensorSystems Group, Gould, Inc., Ocean Systems The theoreticalresponse of a condensermicrophone [A. J. Zucker- Division, 18901 Euclid Avenue, Cleveland, OH 44117) war, J. Acoust.Soc. Am. 64, 1278-1285 (1978) ] and an electretmicro- All mechanically•resonanttransducer devices exhibit a minimum in phone[R. Zahn, Acoustica57, 200-204 (1985)] hasbeen developed their mechanicalimpedance at their fundamentalresonance. This mini- basedon the meandisplacement of a stretchedmembrane. Recent devel- mumin impedancecan result in deteriorationof electroacousticperfor- opmentshave produced an opticalfiber pressure sensor IF. W. Cuomo, mancewith possiblydisastrous results if left unchecked.The standard R. S. Kidwell, and A. Hu, SPIE 661, 234-239 (1986} ], whichutilizes a techniqueused to preventthis is attributedto Carson[J. Acoust.Soc. stretchedmetallized Mylar film with an opticalfiber probe acting at its Am. 34, 1191-1196(1962)] and essentiallyprovides an electricallyin- center.This paperderives the theoreticalexpressions representing the ducedantiresonance near the mechanicalresonance frequency. This tech- peakdisplacement at that point. In addition,the effects of damping due to niqueresults in two minima,one residingon eachside of the previous thebackchamber are investigated to showthe variations in amplitudeand minimum.The relativelocations of theseminima is dependentonly on frequencyresponse due to thedifferent design approaches. It is shown effectiveelectromechanical coupling coefficient and the ratio of the elec- that equivalentexpressions for the peakdisplacement can be obtained trical antiresonanceto mechanicalresonance frequencies. The bandwidth exactlyas well as by the lumpedelements approach. Comparisons are betweenthese minima appears to havea practicallimit of approximately madebetween the resultspreviously obtained for a l-in.-diamB&K mi- an octave. crophoneand the present analysis. [Work supported by NASA.]

11:05

10:20 MMll. Fiber opticsensor for measurementof pressurefluctuations in a turbulent boundarylayer. Part I: Constructionand calibration. Frank MM8. Hydrophonlc probe for underwater intensity measurements. W. Cuomo, Robert S. Kidwell, and Andong Hu (Department of S. Pauzin and D. Biron (ONERA/CERT/DERMES, 2 Avenue Physics,University of RhodeIsland, Kingston, RI 02881) Edouard Belin-B.P. 4025, 31055 ToulouseCedex, France) The measurementof mean velocities,forces, pressures, and shear Two hydrophonesare mounted side by sidewith a separationdistance stressescan provide useful information about transition, separation, and of 20 mm for thefrequency range 1-10 kHz. In an.anechoicchamber, the turbulentfriction in the studyof fluid flow. In mostcases, previous sen- probeis validatedwith a microphonicintensity probe for acousticpower sorshave lacked some of the featuresnecessary to satisfactorilyestablish measurementsof a referencesound source. The resultsare comparedand the flow properties.This paperdiscusses the developmentof an optical agreevery well. Directionalcharacteristics of the probeare carriedout. fiberpressure sensor whose active dimensions, sensitivity, and frequency Then,an experimentalsetup is developedin a smallcavity (2X 1X0.8 responsehave shown to improvethe measuringcapabilities presently m•) filledwith water.A hydrophoneas projectoris put in the middleof available.The deviceis designedfor flush mounting in a suitablealumi- the tank. The characterizationof this testfacility is donein termsof the num plate installedin the testsection of a wind tunnel.Details of the time responsebetween the differentboundaries and the receiver.The constructionwill be discussedand data, related to the dc and ac calibra- soundpower measurements obtained by anhydrophone associated with a tion methodsused, will be presented.[Work supportedby NASA and gatingsystem to simulatefree-field and thoseobtained by the hydro- NUSC.]

S89 J. Acoust.Soc. Am. Suppl.1, Vol. 81, Spring1987 113thMeeting: Acoustical Society of America S89 11:20 11:35

MM12. Fiber optic sensorfor measurementof pressurefluctuations in a MMI3. On multichannel sampling using only past samples. John turbulent boundary layer. Part II: Preliminary test results. Allan L. Brown,•'r. (Departmentof ElectricalEngineering, The Pennsylvania J. Zuckerwar,Ralph D. Watson (NASA LangleyResearch Center, StateUniversity, University Park, PA 16802) Mail Stop 238, Hampton, VA 23665), and Frank W. Cuomo (Departmentof Physics,University of Rhode Island, Kingston,RI 02881 ) A deterministicsignal bandlimited to the normalizedfrequency inter- val -- •r < •o< •r is completelydetermined by its samplevalues taken at The fiber-opticsensor described by Cuomoet al. (Part I ) wasused to the Nyquistrate of one sampleper second.It is well knownthat if the measurethe pressurefluctuations of a turbulentboundary layer in the 7- signalis processedin parallelby m "independent"linear time-invariant X 1l-in. low-speedwind tunnel at LangleyResearch Center. The sensor filters(channels), then the signal may be recovered from samples taken at wasflush mounted in thebottom plate ofthe test section at a distanceof 30 the m samplesper secondover all time.Here, the more realistic problem in. froma trip wire.The free-streamflow speed was varied from 0-140 ft/s of estimatingx (t) at a generictime t fromthe multichannel outputs sam- in fiveintervals. At eachflow conditionthe staticpressure in a plenum pledat only past sampling points {t - nT} isconsidered. It is shown that chambersurrounding the test section was adjusted to matchthe pressure if the rn channeloutputs are all sampledat the samerate of 1/T samples insideto eliminateinflow or outflow.At the sametime, the positionofone per second,where 0 < T< m, thenx(t) is uniquelydetermined from the wall was adjustedto providenegligible longitudinal pressure gradients channeloutput samples taken at thepast times {t - nT). Moreover,the dueto the growthof the boundarylayer at the tunnelwall. The nondimen- conditionrequired of the channeltransfer functions to assurethis result is sionalizedpower spectraldensity compares favorably with other mea- the sameas that requiredwhen the samplesare taken over the doubly surementsreported in the literature.[Work supportedby NASA.] infinite time interval.

FRIDAY MORNING, 15 MAY 1987 REGENCY BALLROOM C & D, 8:30 TO 11:50 A.M.

SessionNN. Musical AcousticsV and Psychologicaland PhysiologicalAcoustics IX: Rhythm and Timing

Punita Singh,Chairman CentralInstitute for the Deaf, 818 SouthEuclid, St. Louis,Missouri 63110

Chairman's Introduction---8:30

Invited PaPers

8:35

NN1. Timingin auditoryperception. IraL Hirsh (WashingtonUniversityandCentrallnstitutefortbeDeaf, 818 S. Euclid, St. Louis, MO 63110)

Recognitionof sequentialpatterns of sound is basic to speechrecognition, music perception, and identifica- tion of environmentalsounds from birdsong to thunderclaps.While we definethese sound patterns as se- quencesof briefsounds, the usual acoustical description has principally been the spectrum. For some30 years, workhas been reported on fusion and successivity, duration discrimination, perceived order, and the influence of temporalvariables on moretraditional psychoaeoustie dimensions. At CentralInstitute, with colleagues Divenyi,Lauter, Grant, Singh, and Monahun, our emphasishas been on listeners'sensitivity to changesin orderand timing,and influenceof nontemporalfeatures on suchperception. Here, someexperiments are describedthat addressinterval perception in a series.In an isochronousseries of three,six, or ten toneswith intertoneintervals of 200ms or more,listeners can detect a temporaloffset or "jitter" of between5% and 10%, irrespectiveof theposition of offset.For shorterintervals, performance is worseand there is a strongeffect of positionin the series,with offsetsmade late in the patternbeing more easily discriminated than thosemade earlier.When a singlepitch change is made in onetone in a seriesof six, detection of an offset is impaired when it coincideswith the differentpitch. Phrased patterns (do-re-mi-do-re-mi) on the otherhand, have not shown sucha strongposition effect. It is recognizedthat temporalpatterns influence, and are influenced by stimulus dimensionsaswell as by dimensions learned from formal systems like the rules of languageand music. Our searchcontinues to focuson an in-betweenperceptual territory, which lies beyond sensory processes, but yet is lessdependent on rule learning,[Work supportedby NINCDS and AFOSR,]

9:05 NN2.Timing inmusic: Performance andexperience. AllGabrielsson (Department ofPsychology, Uppsala University,Box 227, S-75104Uppsala, Sweden) The onlyvariable over which a musicperformer has practically complete control, regardless of which instrumenthe uses, is the duration of the sound events, as well as of"nonsound" events. Timing may therefore beconsidered as the most important tool available to theperformer. Generally seen, timing can be related to

890 J. Acoust.Soc. Am. Suppl. 1, Vol.81, Spring1987 113thMeeting: Acoustical Society of America S90 fourdifferent phenomena: tempo, different classes of durations,articulation, and deviations from mechanical regularity.The musical score provides only limited information about all theseaspects. Empirical studies of musicperformances reveal that the variations in thesevariables are much larger and much more frequently occurringthan what is usuallyrealized. They are used in orderto influencethe listener's experience of the musicwith regard to theperceived structure as well as regarding the motional-emotional qualities of the music. Thesystematic investigation ofthese questions isonly in its initial stage and faces many difficulties, not the least concerningthe proper ways of identifying and measuring the suggested experiential variables. Examples will be givenfrom ongoingresearch.

9:35

NN3. Determinantsof experiencedtension in timbresequences. Dirk-Jan Povel(Psychological Laboratory, Universityof Nijmegen,P.O. Box 9104, 6500 HE Nijmegen,The Netherlands) In listeningto rhythms,subjects may experience a sensationof tension.It is assumedthat thisimportant psychologicalattribute is directlyrelated to the processof perceivinga rhythm.In thisstudy, tension judg- mentsascribed to repetitivelypresented binary isochronic sequences (onset-interval 130 ms) are examined. One"period" of a samplesequence can be notsted as X X O X X O X O in whichX andO representtwo timbres producedby differentdrums. Subjects were asked to rate the experiencedtension of 16 sequenceson a five- point scale.Responses show consistent differences in judged tension.Tension judgments are explainedby supposingthat the sequencesare perceivedas composedof two separatesequences formed by the X and O events,respectively [ Garner, Tile Processing oflnformation and Structure (Erlbaum, Potomac, MD, 1974)], each contributingits own tensionto the compoundtension sensation. The tensionevoked by the separate sequencesis explainedby the displacedbeat hypothesis proposed by Povel[ "Time, Rhythmsand Tension: in Searchof the Determinants ofRhythmicity," in Time, Mind and Behavior, edited by J. Michon and J. Jackson (Springer,Berlin, 1985)].

10:05

NN4. The perceptionof metrical structure:Ex•rimental evidenceand a new model. ChristopherLee (Laboratoryof ExperimentalPsychology, University of Sussex,Brighton BN 1 9QG, England) Thispaper presents experimental results which are in conflictwith existing theories of metricalinterpreta- tion [H. C. Longuet-Higginsand C. S. Lee,Perception 11, 115-128( 1989);H. C. Longuet-Higginsand C. S. Lee,Music Perception 1, 42a. a.•. 1 ( 1984);F. Lerdahland R. Jackendoff,.4 GeneratireTheory of TonalMusic (MIT, Cambridge,MA, 1983);D. J. Poveland P. Essens,Music Perception 2, 411•A0 (1985)] anda new model,based on the algorithmin Longuet-Higginsand Lee (1982), whichaccounts for the mainfeatures of theseresults. Musically sophisticated subjects listened to sequencesof identicaltones in variousrhythmic arrangementsand transcribed them using standard musical notation. The results dlsconfirmed key predictions of all four theories,in that subjectsdisplayed a generalreluctance to chooseinterpretations containing an upbeat.However, the resultsdid showthat subjectswere more prepared to avoidsyncopated interpretations thanthose in whichlong notes occurred on weakbeats. These tendencies are accountedfor in themodel by the assumptionthat the listenerinitially takes the firstnote of a sequenceas the downbeatand is reluctantto abandonthis (or later) hypotheses.But theoccurrence of syncopationsconstitutes strong counterevidence and theoccurrence of longnotes on weak beats weak counterevidence, which can overcome the listener's conserva- tism. [Work supportedby NuffieldFoundation, Royal Societyand SERC.]

10:35

NNS. Rhythm perceptionand the perceptionof periodicity.Gerald J. Balzano(Department of Music, Universityof California at SanDiego, La Jolla, CA 92093) To hearsomething repeating is to hearsomething repeating, and this something must have a beginningand anend. Just where beginnings and ends are perceived in periodicduration patterns is the problem in rhythm perceptionwith which the present studies are concerned. More specifically, how does the metrical framework generatedby a periodicduration pattern map into the elementsof the pattern?Where is the "downbeat" perceivedto occur,and how is the time periodinitiated by that downbeatorganized into subperiods7These questionswere addressed using two distinctmethodologies. In one, listeners from an introductorymusical literacycourse transcribed simple patterns into musicalstaff notation. In the other,listeners from a wider populationresponded to similarpatterns by tappingalong in time with them.Both methods revealed pro- nouncedtendencies to hearpatterns in particularways. Some candidates for rhythmical"laws of organization" that accountfor thesetendencies are offered,along with a commentaryon the relationshipbetween the two methodsof measuringrhythmic interpretations.

ContributedPapers

11:05 Edward C. Carterette (Department of Psychology,University of California,Los Angeles,CA 90024) NN6. The influenceof temporalcontour and intervalinformation on the discriminationof rhythmic patterns.Caroline B. Monahan (Central Montonerhythmic patterns were constructed, each totaling 16 beats Institute for the Deaf, 818 S. Euclid Avenue, St. Louis, MO 63110) and apportionedamong 6 notes;we describethe rhythmsas ordered sequences

S91 J. Acoust.Soc. Am. Suppl. 1, Vol.81, Spring1987 113thMeeting: Acoustical Society of America S91 ofbeat interval values of 6 notes,e.g., 313144. Musicians judged similarity sizedwith eachcomposer's pulse plus a "neutral"version, were obtained of standard-comparisonpattern pairs. On targettrials, the comparison fromClynes and presented inrandom order to listeners of varying musical had the samerhythm as the standard;on relatedtrials, the compaxison sophisticationfor preferencejudgments. The results show reliable had the standard'stemporal contour, that is, the sameseries of longs, changesin listeners'pulse preferences across different composers' pieces, shorts,and sameswithout regard to intervalsize (as in the pair whichsupports one essential prerequisite of Clynes'theory. However, 313144--315133);on lure trials,the comparisonhad a differentcontour therewere some significant deviations from the predictedperference pat- andintervals. Twenty-four musicians were randomly assigned to oneof terns.Possible causes will be discussed.[Work supportedby NIH- threelistening conditions that differedin trial typespresented: (A) tar- BRSG. ] getsversus lures; (B) targestversus relateds, or (C) relatedsversus lures. Two otherfactors were tempo and metrical simplicity (i.e., the extent to whichgroups of intervalsformed simple submultiples of the 16 beats). 11:35 Discriminationwas better (1) in conditionA than in B or C, although NNS. Effects of interpretation on timing in piano performance. performancein bothB and C wasstill abovechance, demonstrating the CarolinePalmer (Psychology Department, Uris Hall, Cornell importanceof intervaland contour information, respectively;(2) when University,Ithaca, NY 14853) thecomparison tempo was the same as the standard's; (3) with metrically simplerstandards. Tempo interactedwith condition:discrimination of Threetiming methods in pianoperformance wcrc described in a pre- comparisonpatterns that werefaster or slowerwas poorer in B andC than viousreport [C. Palmer,J. Acoust.Soc. Am. Suppl.I 79, S75 (1986)]: in A. onsetasynchronies, rubato patterns, and legatoand staccatopatterns. The presentstudy examined the relation of thesetiming methods to per- formen'intended interpretations of an excerpt.Norated interpretations 11:20 includedindication of primarymelody, phrasing, dynamics, and tempo NN7. Expressive microstructure in music: A first assessmentof changes.Performances were recorded on a computer-monitored(MIDI "composers'pulses." Bruno H. Repp(Haskins Laboratories, 270Crown interface),velocity-sensitive, weighted keyboard. The performances Street, New Haven, CT 06511-6695) showedconsistent temporal patterns, directly related to thespecified in- terpretations.Onset asynchronies occurred within chords,such that the Accordingto a provocativetheory set forth by ManfredClynes [most primary melody (as noratedby each performer)preceded the other recentlyin Cognitionand Communication19, No. 2 (1986)], there are voices.Asynchronies wcrc generally largeit on the first beat of eachmea- composer-specificpatterns of (unnotated)musical microstructure that, sure,marking the excerpt'smetrical structure. Rubato patterns (devia- whendiscovered and realized by a performer,help to givethe musicits tions in tempofrom mechanicalregularity) showed larger changes characteristicexpressive quality. Clynes, relying on hisown judgment as between,than within performers' norated phrases. Legato and staccato an experiencedmusician, has derived such "pulses"for severalfamous patternswithin phrases were accurately predicted by a combinationof the composersby imposingtime-amplitude warping patterns on computer- durationsof successivenotes in the musicalscore, but only whenper- sythesizedclassical music. To conducta formalperceptual asessment of formers'intended phrasings were taken into account. Each of these timing foursuch pulses, two setsof pianopieces by Beethoven,Haydn, Mozart, patternsdecreased in degreewhen the pianists were asked to playunmusi- andSchubert, one in tripleand the other in quadruplemeter, each synthe- cally. [Work supportedby NSF and NIMH.]

FRIDAY MORNING, 15 MAY 1987 REGENCY BALLROOM A & B, 8:30 TO 11:45 A.M.

SessionOO. SpeechCommunication IX: SpeechRecognition

GeorgeD. Allen, Chairman Departmentof Audiologyand SpeechSciences, Purdue University, West Lafayette, Indiana 47907

Ch•drman's Introduction---8:30

ContributedPapers

8:35 fromtext sources. The set of sentencesisphonetically rich, balanced, and OO1. An acoustic-phoneticdata base. William M. Fisher (Texas deep.Although all recordingswere made in Dallas,we sampled as many Instruments, Inc., Dallas, TX 75266), Victor Zue (Massachusetts varietiesof AmericanEnglish as possible. Selection of volunteerspeakers Instituteof Technology,Cambridge, MA 02139), Jared Bernstein(SRI wasbased on their childhood locality to givea balancedrepresentation of International,Menlo Park, CA 94025), and David S. Pallett (National geographicalorigins. The subjectpopulation is adult;70% male;young Bureauof Standards,Gaithersburg, MD 20899) (63% in theirtwenties); well educated (78% with bachelor'sdegree); and predominantlywhite (96%). Recordingswere made in a noise-re- DARPA hassponsored the designand collection of a largespeech ducingsound booth using a Sennheiserheadset microphone and digitized database. Six hundred and thirty speakersread ten sentenceseach. Two at 20 kHz. A naturalreading style was encouraged. The recordingsare sentenceswere constant for all speakers;the remainingeight sentences complete,and time-registered phonetic transcriptions are being added to wereselected from a setof 450 designedat MIT and 1890selected at TI the6300 speech files at MIT. A versionof thecomplete data base ( 16-kHz

S92 J.Acoust. Soc. Am. Suppl. 1, Vol. 81, Spring 1987 113thMeeting: Acoustical Society of America S92 samplerate, with acoustic-phonetictranscriptions--approximately 50 mantratios or logformant distances; (4) a verysmall decrement in per- megabytesof data) will be madeavailable to researchersthrough the formartec (1.1%) was observedwhen MVD was tested under conditions NationalBureau of Standards.[ Work supported by DARPA.] of no overlapbetween the talkersused to train the systemand the talkers usedto testthe system; and (5 } MVD did notneed to be trained separately on maleand female talkers. [ Worksupported by theAir ForceSystems Command,Rome Air DevelopmentCenter, and the Air ForceOffice of ScientificResearch, Contract No. F30602-85-C-0008.] 8:47

002. Phoneticlabeling and acousticcorrelates for buildingJapanese speech data base. Yushinori Sagisaka, Shigeru Katagiri, and Kazuya Takeda (Advanced TelecommunicationsResearch Institute 9:23 International,Osaka, Japan) 005. Predicting stressand syllable boundariesfrom segmentaltiming. Finedescription of a largeamount of speechsignals is indispensable to Sven Anderson, Robert Port (Department of Linguistics,Indiana acquireeffective acoustic-phonetic rules in speechsynthesis and recogni- University,Bloomington, IN 47405), and Daniel Maki (Departmentof tion.To builda finelylabeled speech data base, manual labeling is carried Mathematics,Indiana University, Bloomington, IN 47405} out usingdigital sound spectrograms and additional acoustic parameters Recentstudies [Reilly andPort, J. Acoust.Soc. Am. Suppl.178, S21 that reflectpower and spectralcharacteristics. Through labeler training, (1985)] showthat timing measurementscan be usedto discriminate labelingitems are modified several times to decreasethe deviationof seg- amongitems in a smallvocabulary. Current efforts question the extentto ment boundariesand to hastenlabeling speed. As a result,not only the which timing measurementscan be used to augment basic segmental usualphonerole categories, but alsofiner phoneticevents (e.g., closure, knowledgein a continuous,real-time speechrecognition situation. These burst,and aspiration for plosiveconsonants) are labeled. Moreover, mul- experimentsexamine a singletemplate of segments(vowel-strong fries- tiplesegment boundaries (e.g., boundaries between vowels and following tire-stop-vowel) eachof which is embeddedin differentwords in 112 fricativeconsonants) and inseparable portions (e.g., aspiration followed differentsentences for fourEnglish speakers. Syllable and word boundar- bya alevocalizedvowel) are specially marked. To ensurelabeling quality, iesoccur between each of thefour segments. Discriminant analysis is used reliabilitytests and error analysis are carried out. Labelingcriteria using to predictthe stress patterns, possible syllabifications, and word boundar- theseresults will be usedfor a largescale data base construction. iesfrom timingmeasurements in the templatesof a fourthmale speaker aftertraining on threeothers. Results indicate that withinthe template a linearcombination of simpletiming measurements can be usedas predic- tors of lexical stress(95% correct). Word and syllableboundaries are 8:59 muchless reliably predicted (60%-75%) and apparentlybear no simple linear relationshipto timing measurements.[Research supported by 003. Evaluationof ASR front endsin speaker-dependentand speaker- NSF.] independentrecognition. Jean-Claude Junqua (SpeechTechnology Laboratory,3888 StateStreet, Santa Barbara, CA 93105) Thispaper extends previous experiments of Tsugaand He•nansky [J. 9:35 Acoust.Sec. Am. Suppl.1 80,Sl8 (1986) ]. Thoseexperiments evaluated the effectof spectralmodel order, in automaticspeech recognition 006. Acoustic phonetic representations for continuous speech (ASR), usinga smallalpha-numeric data base. PLP (pereeptuallybased recognition:Networks versushattiees. Robert A. Brennan and Michael linear predictive)and LP (linear predictive)analyses were compared, S. Phillips (Department of Computer Science, Carnegie-Mellon usinga ecpstraiand RPS (root powersums) metric. Those experiments University,Pittsburgh, PA 15213) dealingwith a biggerdata base were validated ( 104words, ten speakers). PLPRPS front end is compared with about ten other ASR front ends ( LP A latticehas been used to representthe acousticphonetic hypotheses cei•trom,LP RPS,critical band,...). Experiments were run at various in the CarnegieMellon speechrecognition system. This latticewas pro- differentanalysis model orders. Results of speaker-dependentASR show ducedby four separatemodules. Each module independently located and that the low-dimensionalPLP analysisis a goodalternative to high-di- classifieda setof targetsegments. A networkrepresentation is now being mensionalLP or filterbank analysis. The index-weighted metric improves usedthat explicitly defines allowable paths through the phoneme hypoth- the recognitionaccuracy, making the recognitionresults more uniform eses.The networkhas two advantagesover the lattice representation. acrossthe speakers. The speaker-independentexperiments (which use the First, acousticphonetic information can be usedto join segmenthypoth- templatesof onemale and one female speaker as references) confirm the eses.Second, a networkallows the useof context-specificphonetic classi- superiorperformance of thePLP method for extracting speaker-indepen- fication.Initially the networkhas been produced from the latticesusing dent information.Most of the errorsare on the consonants;some im- acousticrules and broad classificationinformation to connectsegments, provementson the recognitionprocess are being investigated. toadjust boundaries between segments, and to fill •n gaps between the segments.Context-specific classification is now being developedfor phonesthat are particularlysensitive to contexteffects. This network representationis beingevaluated in the frameworkof the overallCarne- gie-Meilonsystem. A comparisonof thenetwork representation with the 9:11 lattice representationwill also be presented.[Work supportedby 004. Speaker-independentvowel classificationbased on fundamental DARPA. ] frequency and formant frequcoeias. James Hillenbrand and Robert T. GayreFt (RIT Research Corporation, Rochester Institute of Technology,Rochester, NY 14623-3435)

A multivariate distance measure (MVD) was tested on a data base 9.'47 consistingof hand-measuredfundamental and formantfrequency values 007. Learning phonetic features using eonnectionist networks. from ten Englishvowels produaed by 29 male talkers and 27 female RaymondL. WatrousaodLokendra Shastri(Departmentof Computer talkers.The primarypurpose of the studywas to determinewhat set of and InformationScience, University of Pennsylvania,Philadelphia, PA parametersproduced the bestclassification performance. Results includ- 19104) ed: ( 1) classificationaccuracies as high as 90% were obtainedusing ex- clusivdy internal information (i.e., only acousticmeasurements of the A methodfor learningphonetic features from speechdata usingcon- unknowntoken); (2) classificationaccuracies as highas 95% wereob- nectionistnetworks is described.A temporalflow model is introducedin tained when internal information was combined with information de- whichsampled speech data flow through a parallelnetwork from input to scribingthe talker (e.g., average formant frequencies); (3) parameterse.•s outputunits. The networkuses hidden units with recurrentlinks to cap- usingabsolute formant frequencies performed better than sets using for- ture spectral/temporalcharacteristics of phoneticfeatures. A supervised

S93 J. Acoust.Soc. Am. Suppl.1, VoL81, Spdng1987 113thMeeting: Acoustical Society of Amedca S93 learningalgorithm is presentedwhich performsgradient descent in Rm. 6H-506, AT&T Bell Laboratories,600 MountainAvenue, Murray weightspace using a courseapproximation of the desiredoutput as an Hill. NJ 07974-2070) evaluationfunction. A simpleconnectionist network with recurrentlinks wastrained on a singleinstance of the work pair "no" and "go," and The applicationof hidden Markov modelsto text-independent successfullylearned a discriminatorymechanism. The trainednetwork speakerverification was studied. Linear predictive hidden Markov mod- alsocorrectly discriminated 98% of 25 othertokens of eachword by the els havebeen proved to be an efficientway for statisticalmodeling of samespeaker. The discriminatoryfeature was formed without segmenta- speechsignals in allthe .•.orms ofspeech recognition. As wasalready sug- tion of the input,and without a directcomparison of the two items.The gestedby Alan Poritz,such models can be usedfor statisticalcharacteri- networkformed an internalrepresentation of a single,integrated spectral zation of the talker himself.In our case,ergodie Markov modelswith featurewhich has a theoreticalbasis in humanacoustic-phonetic percep- four-sevenstates, are shownto discriminatebetween speakers, where the tion. spectraldensity of the statesis characterizedby eightorder LPC coeffi- cients.A largedata base of 100talkers with about20 000 isolateddigits wasused. The states,as well asthe optimal model dimensionality, tend to supplyenough information to verifythe talkerwith lessthan 3% error rate, on sufficientlylarge testingdata. The resultsshow, however, that mostof the speaker-dependentinformation is containedin the spectral COg. Text-independentspeaker verification using linear predictive densitiesand very little isleft in thetransition matrix. This may justify the hiddenMarkov models.Naftali Tishby(Speech Research Department, vectorquantization approach to the problem.

10:11-10:21

Break

10:21 10:45

009. Automarie speechrecognition in a noisy automotiveenvironment. OO11. Dynamic frequencywarping, the dual of dynamic time warping. J.O. Wilpon, L.R. Rabiner,D. DeMarco,and K. L. Shipley(AT&T Edward P. Neuburg (National Security Agency, Fort Meade, MD Bell Laboratories,Office 2C-573 Murray Hill, NJ 07974) 20755)

Recently,a greatdeal of interesthas been shown in performingreli- Comparisonof two tokensof the aameutterance is centralto many ablespeech recognition in an automotiveenvironment. in orderto deter- automaticspeech recognition systems. Matching is usuallydone in the mine the level of recognitionaccuracy to be expectedin sucha hostile frequency-timedomain; token matching is effectivelyspectrogram environment,a seriesof experimentswas performed. The data basefor matching.Dynamic time warping (DTW) overcomes,to someextent, the theseexperiments was createdby havingfour talkers (two male, two temporalvariability of speechtokens; spectrograms are time-alignedby female) speakten replications of an 11-digit vocabulary, zero-nine and oh calculatingsimilarity scores between segments of speech,now represented (in an isolatedformat), while drivingin an automobile.Five different as"columns" of theirspectrograms, and applying the mathematical tech- environmentalcdnditions were studied: ( i ) caroff, fan off; (2) earidling, niquecalled dynamic programming. DTW distortsthe time scalesof the fan on high;(3) cartraveling at 30 mph,fan on high;(4) car travelingat spectrogramsso that identicai speech events in thetwo spectrograms now 60 mph, fan on high;and (5) car travelingat 60 mph,fan off.Two differ- occurat identicaltimes. Variability in frequencyof theseevents is normal- ent recognitionalgorithms were tested,namely; ( 1) standardLPS-b•sed ly dealtwith onlyby usingrobust distance measures. There is a betterway. templaterecognition, using dynamic time warping;and (2) continuous After time alignment,frequency variability can be dealtwith specifically densityhidden Markov modelrecognition, using Viterbi scoringand cep- by doinga dynamicfrequency warp (DFW), a processstrictly analogous stralanalysis. Several different distance measures were also evaluated for to theDTW. The "rows"of thespeech spectrogram, which show the time eachof the recognitionsytems. Results from the template-basedalgor- behaviorof the spectral components, play the same role in theDFW asthe ithmsshowed speaker-dependent recognition accuracies from 96%-99% "columns" do in the DTW. Distances between the rows are calculated dependingon whichcondition was used for training.A five-stateHMM and passedto a dynamicprogram. The resultingDFW producesa distor- systemyielded recognition accuracies from 93%-98% dependingon the tion of the frequencyscales such that identicalspeech events in the two trainingcondition. tokensnow occur both at thesame time and at thesame frequency. Expe- riencewith distancemeasures between rows is limited,but early results are promising:(1) Tokensthat havebeen warped in both directions match better than tokenswarped only in time. (2) Redoingthe DTW aftera DFW resultsin improvedtime alignment. (3) Tokenssound more like eachother after DFW thanbefore. (4) Pain of speakersproduce OO10. Utilizingphase spectra for emulativespeech recognition (ESR). consistentfrequency warps. Results will bedemonstrated, and other ap- Nathan Cohen (Department of Natural Sciences,Bentley College, plicationssuggested. Waltham, MA 02254)

A newapproach is describedto machinespeech recognition that in- corporatesnonlinear spectral interferometry to modelthe binaural advan- 10:37 tagein human speechrecognition. This ESR schemeuses interharmonic OO12. On optimizing the innovation codebookof stocha.•i½coder. andinterear visibility observables from the spectra of phonemesto pro- Daniel Lin (Bell Communications Research, 435 South Street, videphoneme identification signatures. ln particular, the phase spectra of Morristown, NJ 07960) phoneroesare foundto be coupled,but not redundantto, the amplitude spectra.Use of amplitudeand phase spectra allows a criticalresolution of In stochasticcoding, the speechwaveform is representedas a nonsta- phonemeambiguities often present when derived from amplitudespectra tionaryGaussian random process and is reconstructed by filteringan i.i.d. alone.Interharmonic phase modulation appears to bea secondarymeans Gaussiansource (innovation) with a time-varyinglinear filter [M. R. of encodinghuman speech and is primarilyused to discernthe speaker's Schroederand B. S. Atal, Proc. ICASSP 85]. The designof optimum identification and mood. blockcodes for the whiteGaussian innovation using a "polar"product

$94 J. Acoust.Soc. Am. Suppl. 1, VoL81, Spring1987 113thMeeting: Acoustical Society of America $94 coderepresentation is considered.Each codeword in the productcode- HearingSciences and Mathematics,Indiana University, Bloomington, bookconsists of a gainand a vector's"orientation" (specified by a setof IN 47405) vectorson the unit hypersphere). The amplitude factors of thecodewords areencoded with a Max quantizer.The codeword"orientations" are iter- The IndianaSpeech Training Aid project(ISTRA) is evaluatingthe atively generatedfrom an ensembleof randomspherical vectors so as to useof speaker-dependentspeech recognition to providespeech-drill feed- maximizethe minimumspherical angle between the orientationvectors. backfor deafor misarticulatingchildren. The ISTRA systemsemploy The productcodes are jointly searched to determinethe optimumGaus- IBM PC's with Interstate Voice Products Vocalink SRB boards. The ba- sianinnovation. This approach is compared with probabilistically genera- sicapproach is to form templatesfrom thechild's best current produc- tedcodes as well asiteratively generated (cluster) codes for performance. tions.Feedback in drill sessionsis thenbased on a goodnessmetric. That Preliminarysimulation results have shown an improvementof nearly1 metricrepresents the "match"between 10-ms sampling of a newutter- dB in the averageSNR. anceand the correspondinginformation for the storedtemplate. The goodnessmetric hasbeen partially validatedas a substitutefor feedback judgmentsprovided by a humanteacher. In general,the methodcom- 11:09 paresvalues of thegoodness metric to actualratings by a jury of listeners. For wordsspoken by eithernormal speakers who intentionallyvary the OO13. Evaluatingspectral distance measures with referenceto human qualityof theirpronounciations, or by hearing-impairedspeakers, aver- perception.Y. Kane-Esrig (Cornell University, Ithaca, NY 14853), ageinter-listener correlations for ratingsof qualitydid not differfrom the L. A. Streeter, C. Karore, S. Devlin, and M. Macchi (Bell correlationsbetween the goodness metric and the average listener's judge- Communications Research,435 South Street, Morristown, NJ 07960) ments.Test-retest reliability is, of course,much higher for computerthan for the humanlistener. [Work supportedby NSF.] Two importantcriteria for spectraldistance measures in automatic speechrecognition are: ( 1) the varianceof distancesbetween different tokens of the same utterance should be small and variances of distances betweendifferent utterances large, and (2) thepattern of distancesacross 11:33 utterancesshould correlate with perceivedphonetic similarity of the ut- terances.These criteria were used to evaluateseveral spectral distance OO15. The Indiana SpeechTraining Aid (ISTRA): First year report. measures,including ( 1) Euclideandistance between two log formantra- D. Kewley-Port, C. S. Watson, M. Elbert, and G. DeVane tios, (2) LP-residual ("Itakura"} distance, (3) Manhattan distance (Departmentof Speechand Hearing Sciences,lndiana University, betweenlinearly spaced points on LP spectra,and (4) Manhattandis- Bloomington,IN 47405) tancebetween points on "perceptual"spectra (transforming the frequen- cy scaleto barksand convolvingwith an asymmetricfilter of critical The ISTRA systems[Watson et al., J. Acoust.Sac. Am. Suppl. 1 81, bandwidth).Distances were computed among synthetic utterances and AbstractOO14 (1987) ] areused to improvethe speech of deafor misarti- amongone speaker's natural utterances of 11Dutch vowels produced in culatingchildren, by providing unidimensional feedback based on acous- isolation.The perceptualsimilarity data were those reported by Pals,van tic information distributed over whole words or other utterances. This der Kamp,and Plomp [J'. Acoust. Sac. Am. 46, 458-467 (1969)]. Not approachdiffers from that of manyprevious aids in whichfeedback was surprisingly,Euclidean distances between log formant ratios predicted basedon measuresof singleacoustic dimensions, or othersthat provided perceivedsimilarity best, but thismeasure is of limitedpractical utility, spectragraphicdisplays. Using software developed over the first year of sinceformant tracking is problematic.The secondbest measure for both theproject, the clinical effectiveness of ISRA drill has been evaluated for evaluationcriteria was distance between "perceptual" spectra. Distance severaldeaf and one normal-hearing, misarticulating child. The research calculationsusing these "perceptual" spectra arc computationally feasi- emphasishas not been on comparisonsbetween the progress of training ble,produce the desired spread in intervoweldistance distribution, and with a teacherand that with the ISTRA system,but ratheron demonstra- mimic perceivedsimilarity. tionsthat 1STRAdrill is itselfan effectivetraining method. In thesestud- ies,listener juries rate the speechof wordscollected before, during, and

11:21 after training.Results show significant improvement of the qualityof wordstrained in the ISTRA drill, aswell as generalization to nontrained OO14. Evaluationof a speaker-dependentrecognition metric as a words.These and other results demonstrating the improvement of articu- substitutefor humanjudgments of speechquality. C. S. Watson, lationafter drill on the ISTRA systemswill bepresented. [Research sup- D. Kewley-Port,D. Maki,and D. Reed(Departments ofSpeech and portedby NSF. ]

$95 J. Acoust.Soc. Am. Suppl.1, Vol. 81, Spring1987 113thMeeting: Acoustical Society of America $95 FRIDAY MORNING, 15 MAY 1987 MT. RAINIER, 9:00 TO 11:45A.M.

SessionPP. NoiseV: Noisefrom Air Flowsand Transportation, Community Noise Modeling, and Propagationand Effects

Julia D. Royster,Chairman EnvironmentalNoise Consultants, Inc., P.O. Box 144, Cory, North Carolina27511-0144

Contributed Papers

9:00 A time-averagedsound intensity is calculated from the cross spectrum ofpressure outputsp• (t) andp2(t) oftwo closely located microphones. A PP1, Mechanismsof sound-producinginstabilities of chokedround jets majordrawback of thissound-intensity measurement technique isthat it impingingon smalland large fiat plates.Alan Powell(Department of isnot applicable to a transientsound. This problem may be solved by use MechanicalEngineering, University of Houston,Houston, TX 77004) of theWignet distribution that, roughly speaking, represents anenergy At the 112thMeeting certain characteristics of thediscrete tones emit- densityin thetime-frequency domain when it is appliedto properfunc- tedwhen a chokedround jet impingeson a normalfiat plate were reported tionsof time or frequency[T. A. C. M. Classenand W. F, G. Mecklen- [J.Acoust. Soc. Am. Suppl. 1 80, S9 (1986) ]. Theseare now shown to be br•iuker,Philips J. Res.35, 217-250 (1980) ]. Thecrnss-Wigner distribu- oneof two classes,dependent on whetherthe plate is smallor large.If tionof thepressurep(t) and the particle velocity u (t) (in thedirection of small ( •orificc diameterD), the actionoccurs when the stand-offshock- interest)is obtained from the cross-Wigner distribution ofpl (t) andp•(t) waveis in a pressurerecovery region of thespatially periodic jet structure, suchas Re [ Wp,(t,•o) ] = - Im[ Wplp2(t,o•) ] ffWpdl where d isthe mi- asin a Hartmannresonator, and the frequency overlaps those of a Hart- crophonedistance. Results of theapplication of thecrnss-Wigner distri- mannresonator, successively excited at highharmonics. If large ( > 4D), butionto severaltransient signals captured by a microphoneprobe used feedbacktothe orifice occurs, with up to seven frequency jumps not corre- forthe conventional sound-intensity measurement willbe reported. latedwith the periodicjet structure: Co N , 1•< N = integer•<8, f= (h+h')(1 +M•, •) 9:45 whereN_h/D + 3/2 (2

S96 J.Acoust. Soc. Am. Suppl. 1, Vol. 81, Spring 1987 113thMeeting: Acoustical Society of America S96 tural-intensitytransducers. In addition,the investigation points out the shadowthan measuredat higherfrequencies above the surfaceof finite carewhich must be takento makev•lid structural-intensitymeasure- impedance. ments.[ Worksupported by NASA LangleyResearch Center. ]

11:00 10:15 PP9.Ex•rimental investigation ofthe diffraction ofsound by a curved PP6. Reductionof wind noise usingeorrelatlon in outdoor acoustical surfaceof fmiteimpedance. Yves H. Berthelot,James A. Kearus,Allan measurements.3ohn Brunner,Richard Raspet,and Paul Schomer(U. D. Pierce,and Geoffrey L. Main (School ofMechanical Engineering, S.Army ConstructionEngineering Research Laboratory, P.O. Box4005, GeorgiaInstitute of Technology,Atlanta, OA 30332) Champaign,IL 61820-1305) Laboratoryscale experiments have been conducted tostudy the dif- Accurateoutdoor acoustical measurements are difficult underhigh fractionof sound by a singlecurved ridge on top of a fiattable. The sound wind conditions.Use of two microphonesand windscreensmay signifi- sourceisan electric spark that produces anN-wave type transient ofabout cantly reducewind noise.The basictechnique uses two facts.First, and 40-/zsduration. Two •-in. microphones capture the signal at a reference mostimportant, is that as the separationof the two microphonesin- position(before the ridge), and at a fieldpoint, respectively. Thesignals creases,the turbulence of thewind becomes largely uncorrelated. Second, aregated to eliminate undesirable reflections, digitized (250 kHz/chan- the turbulencecreated by placingthe microphonein a steadywind is nel),low-pass filtered (50-kHz cutoff frequency), and processed byan uncorrelated.A cross-multiplicationalgorithm on the data from the two IMB PC whichcomputes the Fourier transforms of bothreference and microphoneswill showthe effectivenessof this processas comparedto fieldpressure waveforms. Regardless ofthe spark variability, the ratio R usingjust a windscreen. ofthe Fourier transforms isconstant towithin 0.5 dB for the frequency rangeof interest(5-40 kHz). Consequently, R represents theinsertion 10:30 lossof the ridge as a functionoffrequency. Experimental results include, fortwo different surface impedances ( 1) theinsertion loss on the curved PP7. Echoesfrom hills. Allan D. Pierce and Pet-Tat Chen (School of surface,and (2) thediffraction pattern inthe transition region between MechanicalEngineering, Georgia Institute of Technology,Atlanta, GA theilluminated and shadow zones (penumbra), measured ata horizontal 30332) distanceof0, 0.71,and 2.09 m fromthe apex of theridge. Data will be comparedwith theoretical results presented earlier. [Work supported by The questionis raisedas to whetherechoes from hills are causedby NASA. ] reflection,scattering, or diffraction.In a typicalsituation when echoes are heardfrom a distanthill, it isimpossible to constructa geometricalacous- ticspath that connects source to hill tolistener and yet for which the angle 11:15 of reflectionequals the angle of incidenceat thehill's surface. If the hill is modeledas a trapezoid,then the echoes are diffracted waves that originate PPlO. Effectsof site geometryon noisecontrol investigated by a scale- at thebaseline (where hillside meets level ground) and at thehilltop edge modelexperiment. Selma Kurta ( Departmentof Architecture,Division (wherehillside meets hilltop). For hills with a continuouslycurved sur- of PhysicalEnvironment, Istanbul TechnicalUniversity, Istanbul, face,the curvatureradius is muchlarger than the wavelength,rigorous Turkey) wedgediffraction theory is inapplicableand, moreover,the previousfor- The geometricalparameters of a buildingand building groups were mulationsof the geometricaltheory of diffractionby curvedsurfaces also simulatedin a scale-modelstudy in whicha miniatureair-jet source mov- seeminapplicable because they accountfor diffractioneffects only on the ingalong a channelin a semianeehoieroom was used. The scalefactor was shadowside. Recent work by Medwin and othersalso suggests that the 20:! and the frequencyrange was chosenbetween 1.2-20 kHz, corre- validityof physicaloptics approximations isquestionable. In an attempt spondlngto 63-1000Hz of a trafficnoise spectra. The noise generated by to understandthe generalphysics of hill echoes,the classic rigorous solu- thesource pass-bys was recorded at 2.8-sintervals and analyzed with the tion for cw plane-waveincident on a hard paraboliccylinder has been aid of computerprograms to obtaintime/level distributionsin various studied.The contourintegral with Whittakerfunctions in theintegrand is pointsin thesite model, and to determinethe overall and spectrum levels approximatedin the high-frequencylimit for remotepoints back toward of theline source, by also taking into account the typical spectrums for the source.[Work supportedby NASA LangleyResearch Center.] light and heavyvehicles, air a•orption, and microphonedirectivity. After thevalidity tests of thetechnique, the effect of multiplereflections 10:45 from buildingsof differentheights, variation of gapsize between blocks, anddimensions of barrierbuildings and their location angles were stud- PPg. Propagationof soundabove a curved surface.Alain Berry ied.The correlationsand regressionsbetween the physicaldimensions (Universit•de Sherbrooke,Sherbrooke, Canada and Division of Physics, andthe noise levels were demonstrated. The results were confirmed by the National ResearchCouncil, Ottawa, Ontario K IA 0R6, Canada) and O. earlierresults of sometheoretical and experimental investigations. The A. Daigle (Divisionof Physics,National Research Council, Ottawa, furtherevaluations yielded some simple but usefulrelationships to esti- Ontario KIA 0R6, Canada) matethe noise propagation in urbanenvironments, for thedesigner's use Thereis a usefulanalogy between fiat ground and curved ray paths in especiallyin noisemapping, which requires a largenumber of noisedata. theatmosphere, and a curvedground surface above which there is no [Thescale-model study was carried out at PurdueUniversity, R. W. Her- refraction.Many features of thesound field in therefractive shadow can rickLaboratories, with the consultation of Dr. M. Crocker( 1981-82).] bestudied under controlled conditions indoors over a carefullyconstruct- edcurved surface. Preliminary measurements, and comparison with sim- pletheory restricted to theideal cases of rigidand pressure-release boun- 11:•0 daries,have been presented at an earliermeeting [J. Acoust.Soc. Am. PPI 1. Plans for a before and after studyon communityresponse to traffic Suppl.1 79, S20 (1986) ]. Themeasurements have been completed in the noise.Truls Gjestland(ELAB, The NorwegianInstitute of Technology, frequencyrange between 0.3-10 kHz, abovea rigidboundary and a sur- N-7034 Trondheim,NTH, Norway) andSigurd Solberg(KILDE, P.O. faceof finiteimpedance. Particular attention is given to theregion across Box 229, N-5701 Voss, Norway) the shadowboundary. In the shadow,the theoryhas been extended by removingrestrictive approximations and •y calculatingthe creeping wave Major changesin the roadtraffic pattern will beimplemented in Oslo to higher-orderterms. A numericalalgorithm allows the extension to the in the near future. A multidisciplinaryfield study has been plannedto caseof a finiteimpedance. Above the shadow boundary the sound field is assessthe impact on the community concerning social, medical, and beha- calculatedusing geometrical theory that accountsfor reflectionfrom a vioral effects.More than 1000 dwellingswill be affected.[n the test area curvedsurface. At the shadowboundary both theories typically agree to newby-passes/tunnels, traffic calming, and traffic management schemes, within0.5 dB. Goodagreement between measured results and theory is aswell asfacade insulation, will beintroduced. The plansfor describing obtainedin general,except across the shadow boundary where discrepan- changesin the noiseexposure situation and the communityresponse to ciesbetween 2 to 5 dB areobserved. The theorymay also predict a deel:•er thesechanges will be discussed.

S97 d. Acoust.Soc. Am. Suppl. 1, VoL81, Spring1987 113thMeeting: Acoustical Society o! America S97 FRIDAY MORNING, 15 MAY 1987 CELEBRATION HALL, 9:00TO 11:45A.M.

SessionQQ. Physical AcousticsVII: PropagationPhenomena

Leon A. Frizzell, Chairman DepartmentofElectrical and Computer Engineering, University ofIllinois, 1406 W. Green Street, Urbana, Illinois 61801

ContributedPapers

9:00 lemsare present for variationalformulations of thisproblem. The answer is ordinarily"yes," but properselection of the variatioualapproach can OO1. A general-purposeparabolic equat'on model for atmosphericand helpto circumventsuch difficulties. The variationalformulation based on ocean acoustics.Michael J. White and Kenneth F.. Gilbert (National the normalderivative of the Kirehhoff-Helmholtzintegral has a unique Centerfor PhysicalAcoustics, University of Mississippi,University, MS solutionfor vibratingdisks and platelike bodies. For bodiesof finitevol- 38677) ume,but for whicheach surface point is vibratingin phase,calculated A wide-angleparabolic equation model has beendeveloped that is totalradiated acoustic power is always unique, even though the pressure applicableto a varietyof propagationproblems in the atmosphereand may not be. Useof the Gerjuoy-Ran-Spruehtechnique and judicious ocean.Linear finite elementsare usedto discretizethe vertical depen- choiceof whatphysical quantity is stationaryunder variations leads to a dence of the acoustic field. This method of discretizatiun enables the mod- formulationsuch that the surfacepressure is uniquefor any specified el to efficientlyhandle both small-scale and large-scale vertical variations frequency.Similarities with the Burton-Millertechniques are discussed; in complexwavenumber and density.For example,the modelcan be an appropriatevariational formulation provides a methodfor choosing appliedto a turbulentatmosphere and to a randomlylayered ocean sedi- theweighting factor for the linear combination of the two surface relations ment.The computationalgrid is terminatedat the topand bottom with a (an integralequation and an integrodifferentialequation). [Work sup- compleximpedance condition so that a locallyreacting surface for atmo- portedby ONR. ] sphericproblems and a pressure-releasesurface for underwaterproblems caneasily be incorporated. Results from selected applications will bepre- sentedto demonstratethe capabilitiesof the model.

9:45

QQ4. Acousticinsertion loss from compliantplate gratings.C. George Ku (Martin Marietta BaltimoreAeruspace, Baltimore, MD 21220) 9:15 The insertionloss from multiple gratings of compliantplate immersed QQ2. Elastic wave propagationon a multilayer interface between two in wateris analyzed. The symmetrycondition of the geometricconfigura- solids.S. I. Rokhlin (Departmentof WeldingEngineering, Ohio State tionprovides the convenience of usingnormal mode solutions of theequa- University,Columbus, OH 43210) tion of motionfor plates.The structuralmotion of thecompliant plates is coupledwith the acousticpressure of the surroundingwater. Therefore, The propagationof waveson a multilayeredinterface is investigated themagnitude of the insertionloss is controlled by the structuralresonant by matrix method.The solutionis obtainedas a seriesexpansion with modesof the plates.Numerical results are presentedfor compliantplate respectto the thicknessof the interfacelayers. In the firstapproximation gratingswith simplysupported end conditions and clamped conditions. A the solutionis determinedby a simplecharacteristic equation for the ve- briefdiscussion about the dynamicbehavior of the gratingis alsopresent- locityof the interfacewave, where the interface layer is described by effec- ed. tiveelastic properties, depending mainly on shearmoduli. The resultsare comparedwith the caseof thin surfacelayers when the effectiveproperties dependon both elasticconstants. The theoreticalresults obtained can be usedfor calculationof the elasticproperties of interfacelayers based on experimentaldata on surface and interface wave velocity. Such applicabil- ity is demonstratedby severalexperimental examples. 10:00

QQS. Determination of Biot-Stoll pore-size parameter using high- frequencybackscattering. Kevin L. Williams, Roger H. Hackman, and D.H. Trivett (Naval CoastalSystems Center, Code 4120, PanamaCity, FL 32407)

9'.3O Calculationsutilizing a Biot-Stollmodel require knowledge of the QQ3. Nonuniquenessof solutionsto variationally formulated acoustic pore-sizeparameter of thesediment. This parameter is difficultto obtain radiation problems.Xiao-Feng Wu and Allan D. Pierce (School of evenfrom in situ measurements.Recent experiments using a broadband, MechanicalEngineering, Georgia Institute of Technology,Atlanta, GA high-frequency(0.5-2.5 MHz) pulseincident on a water-sedimentinter- 30332 ) faceat anglesfrom 15'-45' ( relativeto theinterface ) indicatethe possibil- ity of determiningthis parameterremotely. When the spectrumof the Determinationof surfaceacoustic pressure when the normalvelocity hackscatteredsignal is normalizedto that of the incidentpulse, an en- is prescribedover a vibratingbody's surface can be formulatedin various hancementcharacteristic of the pore-sizeparameter becomes apparent. ways,but for somesuch formulations the solutionis not uniqueat certain Thespectrum shows a gradualrise in amplitudewith increasing frequency discretefrequencies. The questionarises as to whetheruniqueness prob- followedby a declinewhose rate dependson the physicalparameters of

S98 J. Acoust.Soc. Am. Suppl. 1, Vol.81, Spring1987 113thMeeting: Acoustical Society of America S98 the sedimentbeing examined. Typical resultswill be shownfor several ary-integralequation formulation is used.It is shownthat the combined sediments,along with a phenomenologicalmodel that recaptures the gen- Helmholtzintegral equation formulation (CHIEF) methodworks even eralfeatures of theexperimental results. The modeldisplays the underly- whennumerous interior points lie exactlyon nodalsurfaces of a mode ingphysical effects that should be accounted for in a morecomprehensive correspondingto an eigenfrequencyof the related interior problem, when theory.Included in the modelare contributionsto scatteringfrom both at least one interior point does not lie on a nodal surface. The use of sedimentgrains and sediment channels. Also included is a "cutoff"of the CHIEF is illustratedwith numericalradiation experiments for the sphere channelcontributions due to the acousticscattering cross section of the and the finitecylinder. CHIEF is comparedto the Helmholtzgradient grainsexceeding their geometrical cross section. [Work supportedby formulation(HGF) for circumventingnonuniqueness and is found to ONR.] yielda moreaccurate solution, in at leastone published example. A proce- dure is usedto indicatethe solutionerror whenusing integral equation methods,with or withouta techniqueto circumventnonuniqueness. This procedureuses the velocity potential of an interiorpoint as an indicator of solutionerror. In all casesconsidered, the interiorpotential correctly indicateda goodor bad solution,whereas the matrix conditionnumber 10:15 falselyindicated a badsolution in severalinstances. [Work supportedin part by ONR. ] QQ6. Pore-fluidwave propagationconstants in stacksof low-flow resistivityglass beads. James M. Sabatierand Henry E. Bass(Physical AcousticsResearch Laboratory, University of Mississippi,University, MS 38677)

Measurementsof the attenuationand phasespeed of the pore-fluid wave were made in air-filled unconsolidatedstacks of glassbeads in the frequencyrange, 1-10 kHz. Glassbead sizes ranged from 1-10 min. The experimentalapparatus consisted of a 0.25-m-diamaluminum tube. A 0.25-m-diamcapacitance transducer was operated in a pulse-echomode at one end of the tube. At the other end, variousdepths of glassbeads couldbe supported by a rigidplate. Multiple echoes from within 10-30- 11:oo era-thickstacks of beadscould be observed.The measuredpropagation constantsare compared to thosepredicted by the rigidporous frame the- QQ9. Surfacegravity wave effects on soundbeams generated by a ory [K. Attenborogh,J. Acoust.Soc. Am. 81, 93-102 (1987)]. [Work transientcorrugated laser-deposited heat configuration moving at near supportedby WES.] sonic velocities. Allan D. Pierce and Hsiao-an Hsieh (School of MechanicalEngineering, Georgia Institute of Technology,Atlanta, GA 30332) Previousarticles suggest the use of a multiplysplit laser beam moving over the water surfaceat sonic velocitiesto create an underwatersound pulsebeamed at nearhorizontal directions. The moving corrugated wave- 10:30 trainof laser-inducedheating would systematically pump up the acoustic pressureand result in animproved optical-to-acoustic transduction effi- QQ7. Investigationof possibilityof damagefrom acousticallycoupled ciency,as well as yielding a controlledsound-radiation pattern. However, seismicwaveform from blast and artillery. JamesM. Sabaticr,Henry theextended nature of theeffective source allows the possibility that grav- E. Bass (Physical Acoustics Research Laboratory, University of itywaves on the water surface may upset the phase coherence. Considered Mississippi,University, MS 38677), and Richard Rasper(CERL-EN, adversemechanisms include the following:( 1) the refractionof light at Box 4005, Champaign,IL 61820) thetilted and curved rocking air-water interface causes the slabs of light Noise from artillary fire causescomplaints around military installa- penetratingto depthsbelow the surface not to beperfectly parallel; (2) tions.Cracked house foundations are oftenincluded in thesecomplaints. therippled water surface causes the energy being added to a givenmoving For the moderatesize explosivesinvolved and the minimumdistances (nearlyplanar) region of peakacoustic pressure to fluctuate;and (3) a ( > 2 kin) to homes,it is improbablethat directlyinduced seismic vibra- nearlyplane-acoustic wave propagating horizontally just below the sur- tionswould have high enoughamplitudes to causethis kind of damage.A faceis scatteredby thesurface ripples. Although the quantitativeassess- possibilitythat hasnot been previously investigated is that theacoustical- mentof suchmechanisms is still incomplete(and couldbe aidedby ly inducedseismic wave might have a high enoughamplitude to damage perimentalwork), a rudimentarymathematical theory is giventhat foundations.Measurements of the acousticwave and the acousticallyin- suggestscriteria for whengravity wave effects have minor influence. ducedseismic wave were made for 8-in. artilleryshells and 500-lbbombs [Work supportedby ONR. ] with peaklevels up to 145dB, and it wasfound that the inducedseismic wavewas much smallerthan the minimum criteria for damage.In addi- tion, an acoustic-to-seismicsteady-state plane-wave model wasmodified to predictthe acousticcoupled seismic wave. Comparison between pre- dictedand measured results will bepresented. [ Work supportedby WES, CERL.]

QQ10. Parametricstudy of a laser-generatedacoustic signal. Luis 1. Gonzalez and 11ene J. Busch-Vishniac (Applied Research Laboratories,University of Texas,P.O. Box 8029, Austin, TX 78713- 10:45 8029)

QQS.The use of CHIEF toobtain unique solutions for acousticradiation The generationof underwatersound by a movinghigh-power laser usingboundary-integral equations. A. F. Seybertand T. K. Rcngarajan sourceis numericallyinvestigated. 11:15In particular,properties of the re- (Departmentof MechanicalEngineering, University of Kentucky, ceivedacoustic signal, such as maximum and minimum periods and time- to-peakamplitude, are examined as a functionof thesource characteris- Lexington,KY 40506-0046) tics, such as velocity and source-receiverrange and angle. Signal Thisreport is concerned with the problem of obtaining a unique solu- propertiesthat are most and least stable to sourcegeometry variations are tionfor radiationproblems at characteristicwavenumbers when a bound- quantitativelydetermined. [Research supported by ONR.]

S99 d. Acoust.Soc. Am. Suppl. 1, Vol.81, Spring1987 113thMeeting: Acoustical Society of America S99 11:;30 varyingsinu. soidally along the axis. The analysisis an extensionof the work previouslyreported [M. Pierucci,J. Acoust.Soc. Am. Suppl.I 79, QQI1. Acousticradiation from a plate with s•n soldally varying S35 (1986) ]. The analysisconsists of solvingthe coupledfluid-structure properties.Mauro Pierucci(Department of AerospaceEngineering and equationswith the addeddifficulty of havingnonconstant coefficients. EngineeringMechanics, San Diego State University, San Diego, CA The systemreduces to a convolutedequation, which has been solved aua- 92182) lytically.The resultsindicate the presenceof acousticpressure compo- Theacoustic radiation produced by an infinite fiat plate with sinusoi- nentsradiating in directionsthat are relatedto the differencebetween the dallyvarying properties and driven by a distributedload is presented. The forcingfunction wavenumber and the wavenumberof the stiffnessvari- plateis assumedto bethin with constant thickness, but with stiffness ation. Acousticradiation patterns will be presented.

S100 J. Acoust.Soc. Am. Suppl.1, Vol. 81, Spring1987 113th Meeting:Acoustical Society of Amedca S100