PROGRAM OF The 118th Meeting of the AcousticalSociety of America Adam's Mark Hotel ß St. Louis, Missouri ß 27 November-1 December 1989 MONDAY EVENING, 27 NOVEMBER 1989 ST. LOUIS BALLROOM D, 7:00 TO 9:00 P.M. Tutorial on Architectural Acoustics Mauro Pierucci, Chairman Departmentof Aerospaceand EngineeringMechanics, San DiegoState University,San Diego, California 92182 TUI. Architecturalacoustics: The forgottendimension. Ewart A. Wetherill (Wilson, lhrig, and Associates, lnc., 5776 Broadway,Oakland, CA 94618) The basic considerationsof architeclural acouslics---isolation from unwanled noise and vibration, control of mechanicalsystem noise, and room acousticsdesign---are all clearly exemplifiedin Sabinc'sdesign for BostonSymphony Hall. Openedin ! 900,this hall isone of theoutstanding successes in musical acoustics. Yet, aswe approachthe hundredthanniversary of Sabine'sfirst experiments, acoustical characteristics remain one of the leastconsidered aspects of buildingdesign. This is due, in part, to the difficultyof visualizingthe acouslicaloutcome of designdecisions, complicated by individualjudgment as to whatconstitutes good acous- tics. However,the lack of a comprehensiveteaching program remains the dominantproblem. Significant advancesover the past 2 or 3 decadesin measurementand evaluationhave refinedthe ability to design predictabilityand to demonsIrateacoustical concerns to others. New techniquessuch as sound intensity measurements,new descriptors for roomacoustics phenomena, and the refinemen t of recording,analysis, and amplificationtechniques provide fresh insights into the behaviorof soundin air and other media.These topics are reviewedwith particularemphasis on the needfor a comparableadvance in translationof acousticprinci- plesinto buildingtechnologies. Sl J. Acoust.Soc. Am. Suppl. 1, VoL86, Fall1989 118thMeeting: Acoustical Society of America S1 TUESDAY MORNING, 28 NOVEMBER 1989 ST. LOUIS BALLROOM C, 8:00 A.M. TO 12:00 NOON SessionA. Architectural Acoustics I: Electronic Room Simulation for Production and Reproduction Elizabeth A. Cohen, Cochairman CharlesM. Salter Associates,Inc., 130 Sutter Street,San Francisco,California 94101 J. ChristopherJaffe, Cochairman JaffeAcoustics, Inc., 114A WashingtonStreet, Norwalk, Connecticut 06854 Chairman's Introduction4:00 SpecialTribute--8:05 Theodore John Schultz--A Tribute Presentedby:Ewart A. Wetherill ( Wilson, lhrig, and Associates, 5776 Broadway, Oakland, California 94618) Invited Papers 8:15 A1. Electroacousticalsimulation of listeningroom acousticsfor projectARCHIMEDES. S6rcn Bcch (The AcousticsLaboratory, Technical University of Denmark,Building 352, DK-2800 Lyngby,Denmark) ARCHIMEDES is a psychoacousticsresearch project, funded under the EuropeanEUREKA scheme. Threepartners share the workinvolved: The AcousticsLaboratory of The TechnicalUniversity of Denmark; Bangand Olufsen of Denmark;and KEF Electronicsof England.Its primaryobject is to quantifythe influence of listeningroom acoustics on the timbreof reproducedsound. For simulationof theacoustics of a standard listeningroom, an electroacousticsetup has been built in an anechoicchamber. The setupis basedon a computermodel of thelistening room, and it consistsofa nmnberof loudspeakerspositioned on an imaginary spheresurrounding the positionof the testsubject. The setuphas been designed for the highestdegree of flexibility.This includesthe possibilityof simulationof directivitycharacteristics of normaldomestic loud- speakersand absorption coefficients of thesurfaces of thelistening room. This paper is a presentationof the system,with special emphasis on the psychoacoustical background of thedesign. This will includea discussion of choiceof experimentalprocedure, test stimuli, and test subjects as well as purpose built loudspeakers and the DSP system. 8:45 A2. The psychoaeousticsof loudspeakersound reproduction--Past achievements and present problems. Floyd E. Toole (Division of Physics,National ResearchCouncil, Ottawa, Ontario K1A 0R6, Canada) The designof loudspeakersis graduallybeing put on a scientificbasis. Art and intuitionhave given way to engineeringguidelines as the relationshipsbetween perceptions and technicalmeasurements have been eluci- dated.Indeed, within limitedcircumstances, loudspeakers can be designedto meetspecific engineering design objectives,with considerable confidence in howthey will besubjectively evaluated. In practice,however, all of therelevant conditions are not controlled, and several factors conspire to precludeuniversal satisfaction among listeners.Most of the uncertaintyappears to bein the interactionsbetween loudspeakers, rooms, listeners, and programmaterial. This paperreviews the presentstate of knowledge,and outlinesthe areasmost in needof furtherwork. It isclear that additionalpsychoacoustical data and suitable technical innovations can alleviate someof the remainingproblems. Others, though, may be better treatedby standardization. 9:15 A3. RODS---An advanced approach to electronic reverberation enhancement. Peter W. Barnett (AMS Acoustics,Ltd., 52 ChaseSide Southgate, London N14 SPA, United Kingdom) This paperwill brieflyreview the recenthistory of reverberationenhancement and then examinethe processesinvolved in thedevelopment of theRODS ( Reverberation-on-DemandSystem) concept. The theory and implementationof the RODS conceptwill be explained,followed by examplesand resultsof recent installations. S2 J. Acoust.Soc. Am. Suppl.1, Vol. 86, Fall 1989 118th Meeting:Acoustical Society of America S2 9:45 A4. •plali•tion usingvoice and music •s the source.John Meyer (Meyer SoundLaboratories, 2832 San PabloAvenue. Berkeley, CA 94702) A source-independenttechnique to measureaccurately the amplitude and phase response of soundsystems in concerthalls is discussed. Measurements may be made during live performances or events,using music or voiceas the testsignals. Correlation is shownbetween the impulse•esponse and the resultsobtained using musicsignals. An equalizerthat corrects for manyroom resonances in both amplitude and phase simultaneous- ly hasbeen developed. The effectof thisequalizer on concertsystems in an existingvenue is shown. 10:15 A5. A spatial soundprocessor for headphoneand Ioudsl•eakerreproduction. William L. Martens, Gary S. Kendall,and Martin D. Wilde (SoundSphere,Inc., 1030Davis Street, Evanston, IL 60201) A spatialsound processor for stereohcadpbone and loudspeakerreproduction is describedthat can posi- tion soundelements within a threc-dimensionalreverberant space surrounding the listener.Spatial motion of soundsources in three dimensionsis createdby dynamicfiltering based on head-relatedtransfer functions. Additionalfilters and delaylines capture air absorptionand Dopplershifting as the propagationtime is manipulatedfor bothdirect and indirect sound. The spatiotemporaldistribution of earlyreflections is captured for a givensource/listener orientation: The gain,delay, and directionalfiltering of simulatedreflections are responsiveto changesin thespecified position and orientation of thesound source and the listener'shead in the simulatedenvironment. The spatialprocessor can be used for headphonereproduction using a head-tracking device,and can also be usedin moretypical reproduction settings such as living rooms with stereoloudspeak- ers.In the lattercase, additional processing is employedto stabilizethe stereoimage and produce a spatially diffusereverberant surround effect over a wide rangeof listeningpositions. 10:45-11.'00 Break Contributed Papers 11:00 11:15 A6. Binaural simulationtechnique for scale modeling.N. Xiang and J. Blauert(Lehrstuhl far AllgemeineElektroteehnik und Akustik, Ruhr A7. On the model order for the identification of acoustical systems. Universit•it,D-4630 Bochum 1, FederalRepublic of Germany) Nobuo Koizumi (NTT Human Interface Laboratories, Tokyo 180, Japan}and Richard H. Lyon (Departmentof MechanicalEngineering, Roomsimulation for thepurpose of predictingacoustic behavior and MIT, Cambridge,MA 02139) qualityhas recently become a populartopic in roomacoustics. At the Ruhr University,the experience of thebinaural human listener in a room simulationusing both physical and computer modeling has been authenti- The pole/zeromodel and the finite impulse response (FIR) modelare callyrecreated. This paper reports on thelatest stage of thepresent work usedas systemmodels for the identificationof unknownacoustical sys- in binauralroom simulation using a scaleddown physical model, where a tems.The size of the model is particularlyimportant in discrete-time sensitiveminiature dummy head with accuratclyscaled pinnae (scale implementationas it determinesthe convergencerate of adaptationand factor1:10) serves as a receiverto pickup themodel sound field. A versa- capacityof real-time processing. The order of the pole/zero model is relat- tile PC-basedsystem measures the binauralimpulse responses in model ed to modal distributionof systemswhile the order of the FIR model spaceaccording to the m-sequencetransform and alsoearfica out the dependson its dampingfactor. Effective orders of bothmodels are esti- convolutionof theroom-impulse responses with ancchoicspeech or music matedfrom the statisticalproperties of acousticalsystems. In a three- signals.An especiallywide broadbandultrasonic transmitter system is dimensionalenclosure, its volume and reverberationtime are used for necessaryto providethe desiredcomplex stimulation of the soundfield. estimation.It isshown that, whenmodal density of the systemis low, such After the necessarysignal processing, the