Relationship between room shape and acoustics of rectangular

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Relationship between room shape and acoustics of rectangular concert halls
Klosak, Andrzej K.; Gade, Anders Christian
Published in:
Acoustical Society of America. Journal
Link to article, DOI:
10.1121/1.2933354
Publication date:
2008
Document Version
Publisher's PDF, also known as Version of record
Link back to DTU Orbit
Citation (APA):
Klosak, A. K., & Gade, A. C. (2008). Relationship between room shape and acoustics of rectangular concert
halls. Acoustical Society of America. Journal, 123(5), 3199-3199. https://doi.org/10.1121/1.2933354

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TUESDAY MORNING, 1 JULY 2008 ROOM 252B, 8:00 TO 10:00 A.M.
Session 2aAAa
Architectural Acoustics: Acoustics of Concert Halls II
Takayuki Hidaka, Cochair
Takenaka R&D Institute, 1-5-1, Otsuka, 270-1395 Inzai, Chiba, Japan
Daniel E. Commins, Cochair
Commins Acoustics Workshop, 15 rue Laurence Savart, Paris, 75020, France
Contributed Papers
8:00 8:40
2aAAa1. Acoustical design consideration for the new IFEZ concert 2aAAa3. Newdesigntendenciesinmodernconcerthalldesign. Alban
hall. JinYongJeon (cid:1)HanyangUniversity,DepartmentofArchitecturalEn- A. Bassuet (cid:1)ArupAcoustics, 155 avenue of the americas, NewYork, NY
gineering,133-791Seoul,RepublicofKorea,[email protected](cid:2), Yong 10013,USA,[email protected](cid:2)
Hee Kim (cid:1)Hanyang University, Department of Architectural Engineering,
133-791 Seoul, Republic of Korea, [email protected](cid:2), Shin-Ichi Newconcerthalldesigntrendsareemergingasseenfromrecentlycom-
Sato (cid:1)Hanyang University, Department ofArchitectural Engineering, 133- pleted halls around the world and recent international architectural
791Seoul,RepublicofKorea,[email protected](cid:2) competitions.Analyzingthecurrentsituation,thepaperstartsbydifferenti-
atingtheacousticalcharactersofmajortraditionalconcerthallformssuchas
ThedesignofanewconcerthallfortheIncheonFreeEconomicZone
(cid:1)IFEZ(cid:2)ArtsCenterinKoreaisinprogress.Thehallissupposedtobethe thelargeshoe-box,theVineyardandthesurroundhall.Itdiscussesinpar-
homeoftheAsiaPhilharmonicOrchestra.Ithasover1,700seats,including ticularthebalanceofacousticalenergythatcharacterizethesedifferentbasic
150 choirs.Avineyard seating arrangement will be applied, but the seats hallshapes,thesensationofintimacyinrelationtothelistener’sdistanceto
around the stage area will be minimized in order to form a solid stage theperformanceareaandthedifferentearlyreflectionpatternsinherentfrom
enclosure. Lateral walls are designed for each seating block to increase thesehallshapes.Asanexampleofmodernconcerthallsdesigntendencies,
acousticalintimacy.Averagewidthbetweenlateralwallshasbeendesigned thepaperthendescribesadesignoptionchosenbyArupAcousticsforthe
tobelessthan15m,andeveryseatisarrangedwithin7.5mtotheclosest Paris Concert Hall Architectural design competition with Zaha Hadid
lateralwall.Alllateralwallsaredesignedtobeinclinedtoleadfirstreflec-
architect.Thepaperdescribesthedevelopmentoftheformandshapeofthe
tionsandtoimprovespatialimpressionattheaudiencearea.Diffusersare
hall in response to the brief, the concept chosen for the design of sendin-
functionallyinstalledtotheeffectivereflectingsurfacesfromthesourceon
stage. The design considerations are investigated through both computer g”receivingsurfacestoimprovetheearlyreflection(cid:1)efficiency(cid:1)and(cid:1)stabil-
ity(cid:1) and the use of an overhead reflector to improve the balance between
simulationandscalemodelling.
soloistandorchestraandthebalancebetweentheorchestraandtherever-
berationinthehall.
8:20
2aAAa2. Objective and subjective analysis of acoustical response in
newlyrenovatedPalaisMoncalm,QuebecCity,Canada. Jean-Philippe 9:00
Migneron (cid:1)Lab.d’acoustique,Écoled’architecture,1,CôtedelaFabrique, 2aAAa4. Acoustic design and evaluation of a multi-purpose hall of a
Vieux Séminaire, Université Laval, Québec, QC G1K 7P4, Canada, newconferencecentre. AttilaBalázsNagy (cid:1)KotschyBt.,Álmosvezéru.
[email protected](cid:2), Jean-Gabriel Migneron (cid:1)Lab. 4, 2045 Törökbálint, Hungary, [email protected](cid:2), Ferenc
d’acoustique,Écoled’architecture,1,CôtedelaFabrique,VieuxSéminaire, Tamás (cid:1)Kotschy Bt., Álmos vezér u. 4, 2045 Törökbálint, Hungary,
Université Laval, Québec, QC G1K 7P4, Canada,
[email protected](cid:2), András Kotschy (cid:1)Kotschy Bt., Álmos vezér u.
[email protected](cid:2), Jean-FrançoisHardy (cid:1)Lab.d’acoustique,École
4,2045Törökbálint,Hungary,[email protected](cid:2)
d’architecture, 1, Côte de la Fabrique,Vieux Séminaire, Université Laval,
Québec,QCG1K7P4,Canada,[email protected](cid:2) AtForumAcusticum2005thebuildingandroomacousticdesignofa
Tocelebratethe75thanniversaryofPalaisMontcalm,thebuildinghas newConferenceCentrewaspresented.Sincethentheconstructionworkhas
beenalmostentirelyrebuilttoconvertitintotheHouseofMusic.Themain beenfinishedandtheCentreisnowopen.TheConferenceCentreitselfisa
room,namedSalleRaoul-Jobin,hasbeendesignedspecificallyfortheresi- multi-functional building, having three wings of different functions. The
dentchamberorchestra:LesViolonsduRoy.Collaborationbetweenacous- MainHalloftheCentreisaroomfor750peoplewhichcanbeextended
ticalconsultant,LarryS.King,andarchitectJacquesPlanteofMUSEcon- with adjacent section rooms for 1100 persons, giving a total volume of
sortium results in a 979 seats concert hall with variable acoustic to 14000m3.Itwasdesignedtohostconferences,lectures,and-mostofthe
accommodatedifferentkindsofmusicalevents.SincereopeninginMarch time-tobeusedasaconcerthall.Theextremelydifferentacousticalde-
2007, the general acoustic has been enthusiastically acclaimed by profes-
mands of being a concert hall and a lecture room had been fulfilled with
sionals,byworldknownmusicians,andbythepublic.Theprincipalobjec-
appropriateroomacousticdesignandwithvariableacousticsbyemploying
tive of this study is to characterize acoustical response of the room with
aDCR(cid:1)DigitalControlofReverberation(cid:2)system.Inthispaperwegivea
variousadjustmentsofwallcurtainsandmotorizedcanopy.Thisimportant
reportontheachievedacousticalperformanceoftheMainHalloftheCon-
reflective area is software-controlled in a range of 3 meters depending on
musicalneeds.Acousticalobjectiveparameters,suchasreverberationtime, ferenceCentre.Wehaveperformedextensiveroomacousticmeasurements
earlydecaytime,impulseresponseorC80factorwillbeanalyzedandcom- intheMainHall,theresultsofwhicharecomparedtothedesignedvalues
paredtomusicalsubjectiveperceptionofafewinstrumentsplayedatmul- andarepresentedinthispaper.ThedesignoftheDCRsystemisdiscussed
tiplepositionsonstageandfordifferentlisteninglocations. inadifferentpaper.
3088 J.Acoust.Soc.Am.,Vol.123,No.5,Pt.2,May2008 Acoustics’08Paris 3088
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9:20 were removed to get rid of unwanted reflections at the recording micro-
2aAAa5. RenovationoftheconcerthallTheDoelen:Acasestudyon phonespositionsjustbelowthecanopy.Sincethen,asignificantpercentage
theimpactofastagecanopyonstageandroomacoustics. MargrietR. oftheorchestraisunhappyabouttheacousticconditionsonstage.During
Lautenbach (cid:1)Peutz BV, PO Box 696, 2700 AR Zoetermeer, Netherlands, the design process of the renovation, possibilities to re-introduce a stage
[email protected](cid:2), Martijn Vercammen (cid:1)Peutz, De Grip- canopyareinvestigated.Objectiveacousticparametersobtainedbycarrying
pen 1124, 6605 TA Wijchen, Netherlands, m.vercammen@mook outmeasurementsinthehallaswellasina1:10scalemodelandbycal-
.peutz.nl(cid:2), Klaus-Hendrik Lorenz-Kierakiewitz (cid:1)Peutz BV, Kolberger culations with a ray-tracing computer model are examined. Parallel, three
Strasse19,D-40599Duesseldorf,Germany,[email protected](cid:2)
questionnaire rounds gave an impression about the musicians’ subjective
Whenopenedin1966,themainconcerthallinDeDoelen,Rotterdam, judgementaboutthestageacoustics.Inthispapertheacousticdifferencesof
theNetherlands,wasprovidedwithsixcanopiesabovethestageplatform. three situations (cid:1)without canopy, with original canopies and with new
Their function was twofold: to provide a large part of the audience with canopydesign(cid:2)andthesearchforanoptimalbalancebetweenimprovingthe
early reflections; to create good ensemble conditions for the musicians on stageacousticswithoutalteringroomacousticalconditionsintheaudience
stage.Despitegoodreviewsaftertheopening,afewyearslaterthecanopies arediscussed.
Invited Paper
9:40 M
A
2liacAhAScah6o.olEovfaMluuastiico,n5o5f5vSihrteurbarloaockoeuSsttirceesttaWgeests,uMppoonrtrtefaol,rQmCusHic3aAlp1Eer3f,oCrmanaandcae,[email protected].(cid:1)cMa(cid:2)c,GWillilUlianmiveLr.siMty,arStecnhsu- UE.
(cid:1)McGillUniversity,SchulichSchoolofMusic,555SherbrookeStreetWest,Montreal,QCH3A1E3,Canada,[email protected](cid:2) T
a
Theeffectsofperformancespaceacousticsonmusicalperformancecanbeevaluatedmosteffectivelybyeliminatingtheinfluence 2
ofpowerfulnon-auditoryfactors,suchasthevisualappearanceoftheperformancespace.Toallowforsuchrelativelyunbiasedevalu-
ations,avirtualacousticstagesupportsystemwassetupforalivemusicalperformance,andtheperformerwasaskedtomakeblind
comparisonsbetweenavarietyofarchitecturalacousticsimulations.Whileresultssupportthebroadgeneralizationthatthepreferred
reverberation time for acoustical stage support depends upon the piece of music to be performed, it was also clear that preferences
stronglydependeduponperformers’auralfamiliaritywitharchitecturalacousticspacesinwhichtheyhadconsiderableexperiencein
previousperformances.Aftersomeexposuretodescriptiveanalysistechniques,performerscouldexplaintheirpreferencesintermsof
theperceptualcharacteristicsthatdifferedbetweenpresentedauralarchitectures.
TUESDAY MORNING, 1 JULY 2008 ROOM 253, 8:00 TO 9:00 A.M.
Session 2aAAb
Architectural Acoustics and Noise: Low Frequency Absorption: Mechanisms, Measurement Methods and
Application II
Peter D’Antonio, Cochair
RPG Diffusor Systems, Inc., 651-C Commerce Drive, Upper Marlboro, MD 20774, USA
Christian Nocke, Cochair
Akustikbüro Oldenburg, Katharinenstr. 10, Oldenburg, 26121, Germany
Contributed Papers
8:00 thetightestbassimagerywasassociatedwithhighvaluesofinterauralco-
2aAAb1. EffectsofLow-frequencyAbsorptiononPerceivedTightness herence, with lower values producing more (cid:1)muddy(cid:1) bass imagery. (cid:3)Work
of Bass Imagery in Music Reproduction. William L. Martens (cid:1)McGill supportedbyCanadaFoundationforInnovation.(cid:4)
University,SchulichSchoolofMusic,555SherbrookeStreetWest,Mont-
real,QCH3A1E3,Canada,[email protected](cid:2)
8:20
Inordertoenableunbiasedobservationoftheeffectsoflow-frequency 2aAAb2. Acoustical tests of custom-made, low-cost bass absorptive
absorption on auditory imagery associated with multichannel loudspeaker treatment for small rooms. Ioana Pieleanu (cid:1)Acentech Incorporated, 33
reproduction, binaural recordings were made of surround sound program Moulton Street, Cambridge, MA 02138, USA, ipieleanu@acentech
materialthatwasreproducedoverfull-rangeloudspeakerslocatedinaroom .com(cid:2), JeffreyFullerton (cid:1)AcentechIncorporated,33MoultonStreet,Cam-
thatwasspeciallyconstructedtoallowforvariationinlow-frequencyacous- bridge, MA 02138, USA, [email protected](cid:2), Marc Choiniere
(cid:1)UniversityofNebraska,101APeterKiewitInstitute,Omaha,NE68182,
ticaltreatment.Theserecordingswerethenpresentedviaheadphonestoal-
USA,[email protected](cid:2)
lowfordouble-blindcomparisonofthevariationinauditoryimageryasso-
ciated with selected changes in room acoustics while holding listener and Smallmusicclassrooms,practiceroomsorsmallbudgetrecordingstu-
loudspeakerlocationsconstant.Severalperceptualattributeswereexamined, diosandcontrolroomsareafewofthenumerousapplicationswherelow
butthelistenerswereabletomakethemostcleardistinctionsbetweenau- frequencyabsorptionissoughtandnecessaryforawell-balancedacoustical
ditory spatial images in terms of the attribute identified as the (cid:1)perceived spectrum. Often, low frequency absorption is achieved by using pre-
tightnessofbassimagery.(cid:1)Analysisofthesignalspresentedtothelisteners’ engineeredproducts,suchastunedpanelresonators.Unfortunately,thecost
earsinthesebinaurally-reproducedmultichannelmusicsamplesshowedthat ofthesepre-engineeredproductscanbeexcessiveforsmallbudgetprojects,
3089 J.Acoust.Soc.Am.,Vol.123,No.5,Pt.2,May2008 Acoustics’08Paris 3089
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or projects that involve a large number of such spaces. For these applica- research,TechnicalUniversityofDenmark,DTU,Bygn.352,2800Lyngby,
tions, more affordable, custom-made low frequency absorbers are desired. Denmark,[email protected](cid:2)
Several types of custom-made treatments were physically tested, to deter-
Highlevelsofbasssoundhavebeenshowntostimulatethepartofthe
mine if the degree of low frequency absorption they provide would make brainthatcontrolssuchbasicinstinctsassexualdesireandhunger(cid:3)Todd,
themaneffectivereplacementforthepre-engineeredcounterparts.Thetest 2000(cid:4).Inrockandpopmusic,thebassfrequenciesfrom40-125Hzgetam-
samplesincludedglassfiberpanelsmountedascornertraps,custom-made
plifiedtoveryloudlevels.EasilyhalfoftheelectricalpowerofthePAand
plywoodpanelresonatorsandothers.Thetestingwasconductedinaspace monitorsystemgoestothese1.5octaves.Arecentsurvey(cid:3)Adelman-Larsen
comparableinsizetoasmallstudioroom”controlroom,oramediumprac- etal.,2007(cid:4)showedthatthemostimportantsubjectiveparameterforarock
tice room. This presentation describes the test method and measurement andpopmusichalltoscoreahighratingwas’bassclarity’whichcorrelated
results. withacoefficientof0.74to’overallimpression’.Informaldiscussionswith
audio engineers and bass players give the perspective that artificial rever-
beration is rarely, if ever, added to bass-frequencies. In fact the ideal hall
shouldbeasdryaspossibleatlow-frequencies.Inthemid-treblefrequency
range,soundabsorption,andthereby’clarity’,iseasilyobtainedthroughthe
8:40 presence of the audience that absorbs 4-6 times more mid”high frequency
2aAAb3. Theimportanceofbassclarityinpopandrockvenues. Niels soundenergythanbasssoundenergy.Inthelow-frequencyrange’clarity’is
W. Adelman-Larsen (cid:1)FlexAcoustics, Diplomvej 377, 2800 Lyngby, Den- notsoeasilyobtained.Thispaperdiscussesthechallengeindepthandpro-
mark, nwl@flexac.com(cid:2), Eric R. Thompson (cid:1)Centre for applied hearing posesdesignsolutions.
TUESDAY MORNING, 1 JULY 2008 ROOM 202 203, 8:20 A.M. TO 12:40 P.M.
”
Session 2aAAc
Architectural Acoustics and Engineering Acoustics: Acoustics and Electroacoustics of Small Rooms
Jiri Tichy, Cochair
Pennsylvania State University, 5552 N. Citation Road, Toledo, OH 43615, USA
Mendel Kleiner, Cochair
Chalmers Rm. Acoust. Group, Dept. of Appl. Acoust., Chalmers Univ. of Technology, Gothenburg, 41296, Sweden
Invited Papers
8:20
2aAAc1. InvestigationofBonellocriteriaasapracticaltoolinsmallroomacoustics. ToddWelti (cid:1)HarmanInternationalIndus-
tries,Inc.,R&DGroup,8500BalboaBlvd,Northridge,CA91329,USA,[email protected](cid:2)
TheBonellocriteriaareoftenusedasanobjectivemetricforassessingroomdimensionswithrespecttomodalresponse.Inreality,
themodalresponseisnotsimplyapropertyoftheroomdimensions,butisquitedependentonsource”receiverlocationsaswell.The
legitimacyofBonello’scriteriawhenusedinroomswithtypicalsubwooferandseatingconfigurationshasnotbeenwellinvestigated.
Inthisstudy,aroommodelisusedtocalculateroomresponsesforalargenumberofcombinationsofroomdimensions,subwoofer
positions,andseatinglocations.TheBonellocriteriaareevaluatedforeachcombinationandcomparedtoperceptuallyrelevantcriteria
suchasflatnessandseattoseatconsistencyofthecalculatedacousticalresponses.
8:40
2aAAc2. Regionofcontrolforlowfrequencymodalequalisationinsmalllisteningrooms. AkiMäkivirta (cid:1)GenelecOy,Olvitie
5,FIN-74100Iisalmi,Finland,[email protected](cid:2)
Small-sizelisteningroomsarecharacterizedbysparsemodaldensitywithpronouncedspectralcolourationwhenthedecaytimesat
lowfrequenciesarelarge.Variousactiveapproachesforreducingthemodaldecaytimehavebeensuggestedintheliterature.Areview
ofthesalientprinciplesoftheseapproachesisgiven.Activecontrolofthemodaldecaytimeattheprimarylisteningpositionbyusing
theprimaryradiatorforcontrolisdemonstratedandevaluatedforperformance.Thelocalityandsizeoftheregionofcontrol,andthe
amountofcontrolachieved,arestudiedinlightoftheexperiment.Effectofthemodalequalizerfiltertotheperceivedresponseflatness,
audibilityoflowfrequencyresonances,andtherequiredamountofmodalequalizationarediscussedinlightoftheexperiment.
3090 J.Acoust.Soc.Am.,Vol.123,No.5,Pt.2,May2008 Acoustics’08Paris 3090
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9:00
2aAAc3. Improving room acoustics at low frequencies with multiple loudspeakers and time based room correction. Sofus
BirkedalNielsen (cid:1)AalborgUniversity,FredrikBajersVej7B,9220AalborgØ,Denmark,[email protected](cid:2), AdrianCelestinos (cid:1)Oticon
A”S,Kongebakken9,2765Smørum,Denmark,[email protected](cid:2)
Smallandmediumsizerectangularroomsareoftenusedforsoundreproduction.Theseroomshavesubstantialacousticalproblems
atlowfrequenciesprimarilycausedbythereflectionsfromtheroomboundaries.Thespatialvariationinsoundpressurelevel(cid:1)SPL(cid:2)can
beupto30dBinaroomatlowfrequencies,andappearnotonlyatmodalfrequencies.Theproblemisanacousticalissueintime,and
shouldthereforebeanalyzedinthetime-domain,insteadofthetraditionalsteadystatefrequencydomain.Theconstructionofafinite-
differencetime-domainapproximationprogram(cid:1)FDTD(cid:2)hasleadtoasimpleanduntraditionalsolutioncalledCABS(cid:1)ControlledAcous-
ticalBassSystem(cid:2)thatmakesuseofmultipleloudspeakers.Withtheproperplacementoflowfrequencyloudspeakers,CABScancreate
aplanewavefromthefrontwallwhichwillbeabsorbedbyadditionallowfrequencyloudspeakersatthebackwall.Withthebackwall
reflectionremovedahomogeneoussoundfieldwillbecreatedinthewholeroomatlowfrequencies.Simulationsandmeasurementsof
normalsizelisteningroomsshowthat4loudspeakersareenoughtoeventhesoundfieldinaroom.TheCABSsystemiscontrolledby
adevelopedDSPsystem.
M
A
E.
9:20 U
T
2aAAc4. Applicationsofaplanewavebasedroomcorrectionsystemforlowfrequenciesusingmultipleloudspeakers. Adrian a
Celestinos (cid:1)OticonA”S, Kongebakken 9, 2765 Smørum, Denmark, [email protected](cid:2), Sofus Birkedal Nielsen (cid:1)Aalborg University, 2
FredrikBajersVej7B,9220AalborgØ,Denmark,[email protected](cid:2)
Whenlowfrequencysoundisradiatedinsidesmalllisteningspacesbyloudspeakers,largeuniformitiesoccuroverthesoundfield.
Thisisduetothemultiplereflectionanddiffractionofsoundonthewallsanddifferentobjectsintheroom.Adevelopedsystemnamed
ControlledAcousticallyBassSystem(cid:1)CABS(cid:2)producesuniformsoundfieldatlowfrequencies.Thisisperformedbyutilizingloud-
speakersatthefrontwallandextraloudspeakersattheoppositewall,processedtoremovetherear-wallreflectionofarectangularroom.
EffectivenessofCABSondifferentroomscenarioshasbeenevaluatedbyusingacomputersimulationprogrambasedontheFinite
DifferenceTimeDomainMethod(cid:1)FDTD(cid:2).CABShasbeensimulatedinasmallcarcabinandinanirregularroom.Non-idealplacement
ofloudspeakersinCABShavebeenevaluated.TheinfluenceofutilizingCABSwithdifferenttypesofloudspeakershasbeenevaluated
bysimulationsandmeasurements.
9:40
2aAAc5. Active Sound Field Equalization. Akira Omoto (cid:1)Kyushu University, 4-9-1, Shiobaru, Minamiku, 815-8540 Fukuoka,
Japan,[email protected](cid:2), HisaharuSuzuki (cid:1)KyushuUniversity,4-9-1,Shiobaru,Minamiku,815-8540Fukuoka,Japan,
[email protected](cid:2), Akihiro Kakiuchi (cid:1)Kyushu University, 4-9-1, Shiobaru, Minamiku, 815-8540 Fukuoka, Japan, kakirikakki
@hotmail.com(cid:2)
Dominantacousticmodesoftenresultintheinevitablenon-uniformdistributionoftheacousticquantitiessuchassoundpressure,
especiallyinthesmallsizedenclosure.Inourstudy,activecontroltechniqueisthusintroducedtoovercometheadverseeffectsofsuch
modes.Insteadofthesquaredsoundpressurewhichisnormallyadoptedinactivenoisecontrol,thequantitytobecontrolledisselected
astheweightedvaluesofacousticintensitiesortheacousticimpedancesinrectangulardirectionssuchasx,yandzmeasuredatplural
points.Thereasonablyselectedcombinationsofweightsyieldthecontroloutputswhichcanalterthedirectionsofpropagatingwaves
andresultinreducingthecomplicatedstandingwaves.Further,resultsofnumericalsimulationssuggestthatthewellbalancedarrange-
mentoftheprimaryandthesecondarysourcescan’rectify’thepropagatingdirectionandresultintheuniformdistributionsofsound
pressure.Thestrategiesusedinthisstudyhavepossibilitiesofrealizingusefulcontrollerforactivesoundfieldequalization.
10:00
2aAAc6. Differentapproachesforefficientfiniteelementmodellingofabsorbersinsmallrooms. MarcAretz (cid:1)RWTHAachen
University,InstituteforTechnicalAcoustics,Neustraße50,52066Aachen,Germany,[email protected](cid:2)
TheFEMisapowerfultoolforthenumericalsimulationofsoundfieldsinenclosures.Itaccountsforthemodalcharacteristicsof
thesoundfield,whicharedominantatfrequenciesbelowtheSchroederfrequencyanditisalsopossibletomodelthemutualcoupling
betweenairborneandstructurebornesoundfields,whenanappropriatestructuremodelisimplemented.WhenapplyingtheFEMto
complexroomacousticsapplications,likee.g.acontrolroominarecordingstudio,itisachallengingtasktospecifyrealisticboundary
conditions.DifferentkindsofacousticalabsorberslikeHelmholtzresonators,plateabsorbersandcomplexlayeredporousabsorbersare
foundintheseenvironments.Whileitispossibleinprincipletousecomplexandexhaustivemodelsfortheseacousticalabsorbers,it
is often computationally much more efficient to use acoustic impedances or two-port network FEM elements to represent the fluid
structureinteractions.InthecourseofthisstudywecomparedifferentapproachesforthemodellingofHelmholtzresonators(cid:1)without
andwithoutflowresistance(cid:2),sinceithasprovenverycostlyintermsofcomputationtimetoexplicitlymodeleverysingleholeinthe
resonatorboxes.Thesimulationresultsarecomparedwithresultsmeasuredinamodelroom.
3091 J.Acoust.Soc.Am.,Vol.123,No.5,Pt.2,May2008 Acoustics’08Paris 3091
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10:20-10:40Break
10:40
2aAAc7. Directandmodalfrequencyresponseanalysisofsoundfieldsinsmallroomsbyfiniteelementmethod. ReijiTomiku
(cid:1)FacultyofEngineering,OitaUniversity,Dannoharu700,870-1192Oita,Japan,[email protected](cid:2), ToruOtsuru (cid:1)Faculty
ofEngineering,OitaUniversity,Dannoharu700,870-1192Oita,Japan,[email protected](cid:2), NorikoOkamoto (cid:1)FacultyofEngi-
neering, Oita University, Dannoharu 700, 870-1192 Oita, Japan, [email protected](cid:2), Yuka Kurogi (cid:1)Faculty of Engineering,
OitaUniversity,Dannoharu700,870-1192Oita,Japan,[email protected](cid:2)
Inthispaper,soundpressuresarecomputedbytwotechniquesusingfiniteelementmethod.Oneisatechniquebysolvingthesystem
oflinearequationsdirectly(cid:1)directanalysis(cid:2)andtheotherisatechniquebymodalsuperposition(cid:1)modalanalysis(cid:2).Toconfirmtheac-
curacyofthedirectanalysis,soundpressuresobtainedbythetechniquearecomparedwiththoseobtainedbythemodalanalysisina
roomwiththevolumeof10m3.Then,asinthemodalanalysis,twomethodsareemployed:oneisasimplifiedmethodbasedonareal
eigenvalueproblemassumingthatthedampingmatrix,(cid:3)C(cid:4),hasorthogonality;andanotheristhemethodbasedoncomplexeigenvalue
problem.Thoseobtainedbythedirectanalysisareingoodagreementwiththoseobtainedbythetwokindsofmodalanalysesregardless
ofabsorptionconditions,eveniftheanalysisiscarriedoutatthefrequencyclosetoaneigenfrequency.Next,diffusenessofsoundfield
below315Hzinaroom,whichisusedinthemeasurementofISO140-3,isinvestigatedbythedirectanalysisfromtheviewpointof
meansoundpressurelevelmeasurements.
11:00
2aAAc8. Theeffectofdiffusersonlowfrequencymodes. JamieA.Angus (cid:1)UniversityofSalford,12ListerWay,YO306NLYork,
UK,[email protected](cid:2)
Smalllisteningroomsarebecomingprevalent,duetotheavailabilityofproductionfacilitiesonpersonalcomputers,andthefinan-
cialpressuresfacedbytheindustry.Intheserooms,modalbehaviouratlowfrequenciessignificantlyaffectsthequalityoftherever-
berantdecay,duetotheirnon-diffusenaturecomparedwithotherfrequencies.Diffusionandabsorptioncanhelpandmaybeauseful
wayofimprovingthelowfrequencyperformanceofsuchrooms.Thispaperdiscussesthepropertiesoftheseroomsatlowfrequencies,
inparticulartheeffectofdiffusingboundariesonthemodalbehaviourofsuchrooms.Thepaperwillfirstdiscusswhatismeantbya
modeandmodaldecay.Itwillthengoontoexaminetheeffectofdiffusingboundariesonthefrequencyanddensityofmodes.In
particular,itwillexaminetheeffectofthescaleofthediffuseronitsefficacyinthistask.Foreaseofvisualisationthiswillbedone
usingatwodimensionalmodeland,foraccuracyafiniteelement,elementsimulation.Theeffectofgoingtothreedimensionsonthe
resultswillalsobediscussed.Finally,theeffectofabsorptionbaseddiffusingboundarieswillbeexamined.
11:20
2aAAc9. Poweroutputregularizationintheactivereproductionofsoundfieldsinrooms. NickStefanakis (cid:1)NationalTechnical
University of Athens, School of Electrical and Computer Engineering, Heroon Polytechniou 9, 157 73 Athens, Greece,
[email protected](cid:2), SotirisDalianis (cid:1)NationalTechnicalUniversityofAthens,SchoolofElectricalandComputerEngineering,
HeroonPolytechniou9,15773Athens,Greece,[email protected](cid:2), TilemachosKaratzas (cid:1)NationalTechnicalUniversityofAth-
ens,SchoolofElectricalandComputerEngineering,HeroonPolytechniou9,15773Athens,Greece,[email protected](cid:2), George
Cambourakis (cid:1)NationalTechnicalUniversityofAthens,SchoolofElectricalandComputerEngineering,HeroonPolytechniou9,157
73Athens,Greece,[email protected](cid:2)
Inthispaperweaddresstheproblemofusingamulti-channelactivecontrolsysteminordertoreproduceaharmonicsoundfield
in a large part of the volume of a reverberant room.The problems associated with the calculation of the inverse system matrix are
confrontedbyintroducingatermthatisproportionaltothesoundpower-outputofthesysteminthecostfunctionthatisobtainedby
the multiple point method. Simulation results show that this technique results to a better conditioning of the system matrix at low
frequencies,comparingtoothertraditionalregularizationtechniques.Moreover,itisshownthatthismethodcanbeemployedtoin-
creasethespatialrobustnessofthecontrolsensorarrayinsidethelisteningroom.
11:40
2aAAc10. Low-frequency response in active acoustic practice rooms. Ronald Freiheit (cid:1)Wenger Corporation, 555 Park Drive,
Owatonna,MN55060,USA,[email protected](cid:2)
Integratingactive(cid:1)virtual(cid:2)acousticsintorelativelysmallpracticeroomstocreateasenseofenvelopmentiscriticaltothesatisfac-
tionofthemusiciansusingthesespacesforlearning.Thenumberofspeakersandtheirlocationsplayanimportantroleinminimizing
theabilitytolocalizetothesourcessupportingthissenseofenvelopment.Equallyimportantisthefrequencyresponserequiredforthe
speakersusedintheseapplications,tomoreaccuratelysimulatetheacousticsofaperformanceenvironment.Excessivehighfrequencies
increasetheabilitytolocalizeanddecreasethesensationofalargerspace,sincetheairinlargerspacesnaturallyabsorbsmanyhigh
frequencies.Anotherchallengeiscreatingthesenseofenvelopmentforinstrumentsinthebassregion(cid:1)125Hzoctavebandandbelow(cid:2)
byprovidingenoughlow-frequencyenergyresponse.Workwillbepresentedonlow-frequencyresponsedesiredtosatisfyasampling
3092 J.Acoust.Soc.Am.,Vol.123,No.5,Pt.2,May2008 Acoustics’08Paris 3092
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ofsolocelloplayersusingactiveacousticpracticerooms.Theoptimalsourcesfortheselowfrequencies-singleormultiple-willbe
discussed. Updated information will also be provided on the sound field coverage in active rooms with extended low-frequency
response.
Contributed Papers
12:00 explanationofthemodeltheory,theexperimentalapplicationtothesimplest
2aAAc11. Active playback of acoustic quadraphonic sound events. caseof1-Dconfinedfieldispresentedandsomeobtainedresultsareshown.
Domenico Stanzial (cid:1)Italian National Research Council, FSSG-CNR Lab
Acustica,c”oFondazioneCini,IsoladiSanGiorgioMaggiore,30124Ven-
ezia,Italy,[email protected](cid:2), GiorgioSacchi (cid:1)PhysicsDe- 12:20
partment - University of Ferrara, V. Saragat, 44100 Ferrara, Italy, 2aAAc12. Acoustics in a small control room. Sergio
[email protected](cid:2), Giuliano Schiffrer (cid:1)Physics Department - Beristain (cid:1)Mexican Institute of Acoustics, P.O. Box 12-1022, Narvarte,
UniversityofFerrara,V.Saragat,44100Ferrara,Italy,[email protected](cid:2) 03001Mexico,D.F.,Mexico,[email protected](cid:2)
Thereproductioninagivenconfinedspace-suchasacinemahallora Acousticsinsmallroomsisallwaysaproblem,particularlyatthelow
smallerroom-ofasoundeventpreviouslyrecordedinacompletelydiffer- frequencyrange,becauseoftheirsizeandthefactthatthereisverylimited
ent acoustical environment is an interesting and still open acoustical spacetoinstallalltheacousticmaterialsneededinordertoobtainthede- M
problem.Anewmethodforhi-fiaudioplaybackbasedonthegeneralsolu- siredacousticresponse,butwhenanelectroacousticsystemhastobeem- A
tionoftheacousticinverseproblemisherepourposed.Afeed-forwardcon- ployedasitisthecaseinasmallControlRoomforasmallrecordingstudio, E.
trolbasedonoverdeterminationofconditionsatactivecontours-i.e.loud- mattersbecomeevenworse.Firstofall,thespaceisfurtherreducedinorder U
speakers - in order to obtain an optimal stable solution via least square toaccomodatetherequiredsoundsystem,andwiththepresenceofhardto T
approach is here proposed. This is easily possible even for complex con- controllowresonantfrecuencies,whichcanbeexcitedatanymomentdur- a
2
figurationsthankstoacousticquadraphony,theapplicationofsoundinten- inganyrecordingsession,itcanbeproducedhighlydifferentsoundpresure
simetry to audio technology developed in the last years within the IST-2- levelsatthosefrequencies,changingthetimbreofsounds.Somemeasure-
511316-IP European project denominated IP-RACINE. After a short mentresultsarepresented.
TUESDAY MORNING, 1 JULY 2008 ROOM 253, 9:20 A.M. TO 1:00 P.M.
Session 2aAAd
ArchitecturalAcousticsandNoise:AcousticsandPrivacyinHealthcareFacilitiesI:EmergingPolicyAround
the World
David M. Sykes, Cochair
ANSI S12 Workgroup 44 and the Joint ASA INCE NCAC Subcommittee on Healthcare Acoustics & Speech Privacy, 23
” ”
Buckingham Street, Cambridge, MA 02138, USA
Kerstin Persson Waye, Cochair
Dept. of Environ. Medicine, The Sahlgrenska Acad. of Gothenburg Univ., Box 414, Gothenburg, 405 30, Sweden
Invited Papers
9:20
2aAAd1. Wavesofchange:globalpolicies&theirimpactsontheacousticsprofession. DavidM.Sykes (cid:1)ANSIS12Workgroup
44andtheJointASA”INCE”NCACSubcommitteeonHealthcareAcoustics&SpeechPrivacy,23BuckinghamStreet,Cambridge,MA
02138,USA,[email protected](cid:2)
Inadecade,fivewavesofchangesweptacrosstheglobestimulatingnewinterestinacoustics.Thissessionexaminestheireffects
ontheEU,NorthAmericaandJapan.TheInternetcausedthefirstwave-theEU’sprivacyDirective9546ECdrovenationseverywhere
to develop privacy laws, many covering (cid:1)Speech Privacy.(cid:1)Asecond wave, in 2000 when the (cid:1)tech bubble(cid:1) burst, produced laws to
improve financial accountability and forcing organizations to find ways to shield their leaders.Athird wave arose in 2001 with the
increaseinterrorism,producingasurgeinsecuritylawsthatchallengetherighttoprivacyenshrinedinthe1948DeclarationofHuman
Rights.Thefourthwaveisdemographic:racingtobuildhealthcarefacilitiesfor(cid:1)boomers,(cid:1)thisgiantindustryisnowwrestlingwitha
(cid:1)noiseepidemic(cid:1)resultingfromdecadesofneglectingthehealtheffectsofnoise.Thefifthwavecamefromthe(cid:1)green(cid:1)movement-the
conceptof(cid:1)indoorenvironmentalquality(cid:1)hasrenewedinterestinnoiseasapollutant.Howcountriesbalancesuchconcernsasstate
security,citizenprivacyandhumanhealthwillbedecidedbycourtsbutthesefivewaveshavecatalyzeddemandforunderstanding,
insight,expertise,standards,codes,manpowerandsolutionsfromtheacousticalprofession.
3093 J.Acoust.Soc.Am.,Vol.123,No.5,Pt.2,May2008 Acoustics’08Paris 3093
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9:40
2aAAd2. DevelopingacousticalpoliciesaroundinEUcountries. KatrinBergmark (cid:1)Saint-GobainEcophonAB,Box500,26061
Hyllinge,Sweden,[email protected](cid:2), MarcR.Janssen (cid:1)Saint-GobainEcophonAB,Box500,26061Hyllinge,Sweden,
[email protected](cid:2)
Accordingtoresearch,noiselevelsinhospitalsworldwidehaveincreased.Atthesametime,theawarenessofthenegativeeffects
ofnoiseonpatientsandhealthcarestaffhasgrown.Tomanageoreliminatenoiseinhospitals,standardsandpoliciesareagreathelp.
Anoverviewofinternationalstandardswillbepresented,showingvariousparametersanddifferencesinvaluesandanglesofapproach,
e.gbasedonactivityorroomtype.Tofurtheroptimizethecontent,andstimulatetheuseofthestandards,somecountrieshaveeven
definedhealthcarespecificstandards.Thesecansupporttheplanningandtheevaluationofthesoundenvironmentinthosepremises.
Newinsightsfromresearchandcasestudies,aswellasemerginglaws,provideopportunitiesorevenforceustoextendtheexisting
contentofstandardstomeetfuturedemands.Suggestionsforthatincludeextensionoftheamountofparameters,suchasdecreaseof
soundpressurelevel(cid:1)∆SPL(cid:2)andparametersaddressingprivacy(cid:1)PI,AC(cid:2).Finally,revisionofstandardsprovidesopportunitiesforend
users to increase their understanding and interest in acoustic and to supply possibilities to define the desired quality of the sound
environment.
10:00
2aAAd3. Effectsofhealthcareacousticsonmedicaloutcomes. RogerUlrich (cid:1)TexasA&MUniversity,DepartmentofArchitec-
ture,3137TAMU,CollegeStation,TX77843,USA,[email protected](cid:2)
Althoughconsiderableresearchhasexamineddetrimentaleffectsofnoiseonpatientsleepqualityinhealthcarebuildings,fewstud-
ieshaveinvestigatedtheextenttowhichnoisemayworsenothertypesofpatientclinicaloutcomes.Studiesarealsoscarceconcerning
theeffectsofnoiseandpooracousticsonhealthcarestaff.Thepresentationdescribesaprospectivecontrolledstudyconductedwith
colleaguesinSwedenthatexaminedtheimpactofhigherversuslowernoiselevels,andlongerincontrasttoshorterreverberationtimes,
onseveralpatientandstaffoutcomesinahospitalcoronarycriticalcareunit(cid:1)CCU(cid:2).Acousticswerealteredduringthestudyperiodby
changing the ceiling tiles throughout the CCU from sound-reflecting tiles to sound-absorbing tiles of similar appearance. Regarding
patients,animprovedacousticsenvironmentsignificantlyreducedphysiologicalstress,increasedsatisfactionwithqualityofcare,im-
provedsleepquality,andlessenedincidenceofcostlyre-hospitalizationsfollowingdischarge.Betteracousticsalsoimprovedspeech
intelligibility,andhealthcarestaffexperiencedreducedworkdemandsandlesspressureandstrain.Thediscussionconcludesbyout-
lining research directions, including the need for more outcomes studies to enable development of a strong business case for better
healthcareacoustics.
Contributed Papers
10:20 higher for the bad acoustics group. During the good acoustics period pa-
2aAAd4. Influenceofintenesivecoronarycareacousticsonthequality tientsconsideredthestaffattitudemuchbetterthanduringthebadacoustics
ofcareandphyiologicalstateofpatients. IngerHagerman (cid:1)DeptofCar- period. Conclusion, bad acoustics environment during acute illness may
diology, Karolinska University Hospital, M52, Huddinge, 141 86 Stock- haveimportantphysiologicaleffectsofimportanceforrehabilitation.
holm, Sweden, [email protected](cid:2), Gundars Rasmanis (cid:1)Dept
of Cardiology, Karolinska University Hospital, M52, Huddinge, 141 86 10:40
Stockholm, Sweden, [email protected](cid:2), Vanja 2aAAd5. ThefutureofUKhospitaldesign. AdrianPopplewell (cid:1)Arup
Blomkvist (cid:1)DeptofCardiology,KarolinskaUniversityHospital,M52,Hud- Acoustics, St Giles Hall, Pound Hill, CB3 0AE Cambridge, UK, adrian
dinge,14186Stockholm,Sweden,[email protected](cid:2), Roger [email protected](cid:2)
Ulrich (cid:1)TexasA&MUniversity,DepartmentofArchitecture,3137TAMU,
College Station, TX 77843, USA, [email protected](cid:2), Töres Theimportanceofacousticconditionswithinhospitalsishighlightedby
Theorell (cid:1)DeptofCardiology,KarolinskaUniversityHospital,M52,Hud- recentresearchindicatingthatpatientrecoverytimesaresignificantlyinflu-
dinge,14186Stockholm,Sweden,[email protected](cid:2) enced by the noise levels within wards.Added to this are concerns about
speechprivacyandconfidentiality,patientandstaffcomfort,communication
Backgroundunstablecoronarydiseaseisastressfulsituationandenvi- betweenpatientanddoctor,andtheeffectsofvibrationonsensitivemedical
ronmentalinfluencesmayincreasestressmechanismsimportantforthecar- equipment,allofwhichmakestheacousticdesignakeyparameterinany
diovascularstatus.Aimtoevaluateacousticinfluenceonpatientswithcoro- hospitaldevelopment.Thispaperwilldiscussthepracticalissuesassociated
nary artery disease and to test if the effects of poor sound absorption on withtheimplementationofthecurrentnationalguidanceonhospitalacous-
work environment affects quality of care and medical status of patients. tics (cid:1)Health Technical Memorandum 2045(cid:2) and the new, currently unpub-
Methods94patientsadmittedtotheintensivecoronaryheartunitforchest lishedreplacement,HealthTechnicalMemorandum08-01.Theexperiences
pain evaluation participated. Patient groups were recruited during bad and oftheauthorwithseverallargePrivateFinanceInitiativeprojects,designed
good acoustic conditions respectively. Blood pressure, pulse amplitude, to the current standard, have illustrated the practical difficulties of fully
heartrateandheartratevariabilityweremonitored.Patientswereaskedto complyingwithallitsrequirementsandthedesignsolutionswhichcanbe
fill in a questionnaire about the quality of the care and a follow up of re- adopted.Speechprivacyandconfidentialityhasbeenacriticalissueinde-
hospitalisationandmortalitywasmadeat1and3months.Resultsgoodand velopingthenewdesignstandard.WithArupAcousticsaskeycontributors
badacousticsdifferedsignificantlywithrespecttopulseamplitudeinacute tothisdocument,andacousticdesignersofoneofthefirstmajorprojectsin
myocardialinfarctionandunstableanginapectorisgroups,withlowerval- theUKtocomplywiththisstandard,theauthorisinaprimepositiontobe
ues at night during the good acoustics period. Re-hospitalisations were abletoassessthepracticalandtechnicalimplicationsofthefutureguidance.
11:00-11:20Break
3094 J.Acoust.Soc.Am.,Vol.123,No.5,Pt.2,May2008 Acoustics’08Paris 3094
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Invited Papers
11:20
2aAAd6. Developmentof’soundandvibrationdesignguidelinesforhealthcarefacilities’. KurtRockstroh (cid:1)SteffianBradley
Architects,100SummerStreet,Boston,MA02110,USA,kurtr@steffian.com(cid:2)
(cid:1)TheGuidelinesforDesign&ConstructionofHealthcareFacilities(cid:1)isutilizedbythemajorityoftheUnitedStatesanditsfederal
agencies involved in funding health care projects.As part of the development of the 2010 Edition of (cid:1)The Guidelines(cid:1) a joint sub-
committee of ASA, INCE, NCAC and the Health Guidelines Revision Committee was formed to develop sound and vibration
guidelines.Thispresentationwillexplainthecollaborativeprocessusedtodevelop,publicize,reviewandformallyvoteacceptanceof
thesoundandvibrationguidelines.Thepresentationwillalsooutlinethemajorcomponentsofthenewguidelines.
M
11:40 A
E.
2aAAd7. Acousticsingreenbuildings:refiningtheconceptofenvironmentallyqualitywhileimprovingoccupanthealthand
U
productivitysynergistically. SholemPrasow (cid:1)TeknionFurnitureSystems,1150FlintRd.,Thornhill,ONL3T4M9,Canada,sholem T
[email protected](cid:2) a
2
Environmental Quality has always been a keystone of the green building movement.The concept has evolved from (cid:1)IndoorAir
Quality(cid:1), for example, in the first version of LEED seven years ago to a much broader and enriched concept - a concept that fully
embracesAcoustics-today.ThispaperexplorestheevolutionofEnvironmentalQualityinbothgeneralandhealthcareenvironments,
anddemonstratestheemergingroleofAcousticsasanequalpartnerwithAirQualityandLightingasdeterminantsofbothhealthand
productivity in the built environment. Specific references will be made to LEED rating systems and to emerging acoustical design
requirementswithinLEED.
12:00
2aAAd8. Gettingnoiseandspeechprivacyissuesheardindesignofhealthcarefacilities. AnjaliJoseph (cid:1)TheCenterforHealth
Design,1850GatewayBlvd.,Suite1083,Concord,CA94520,USA,[email protected](cid:2)
Hospitalsareextremelynoisy,andnoiselevelsinmosthospitalsfarexceedrecommendedguidelines.Thehighambientnoiselevels,
aswellaspeaknoiselevelsinhospitals,haveseriousimpactsonpatientandstaffoutcomesrangingfromsleeplossandelevatedblood
pressureamongpatientstoemotionalexhaustionandburnoutamongstaff.Poorlydesignedacousticalenvironmentscanposeaserious
threattopatientconfidentialityifprivateconversationsbetweenpatientsandstafforbetweenstaffmemberscanbeoverheardbyun-
intendedlisteners.Atthesametime,apooracousticalenvironmentimpedeseffectivecommunicationbetweenpatientsandstaffand
betweenstaffmembersbyrenderingspeechandauditorysignalslessintelligibleordetectable.Thishasseriousimplicationsforpatient
safety. A well-designed acoustical environment is critical in addressing these problems related to noise and communication of
information.Thepurposeofthispresentationistoexaminehowdifferentaspectsofsound-noise,speechprivacy,speechintelligibility,
andmusic-impactpatientandstaffoutcomesinhealthcaresettingsandthespecificenvironmentaldesignstrategiesthatcanbeused
toimprovetheacousticalenvironmentofhealthcaresettings.
12:20
2aAAd9. NoiseconfoundsinfunctionalMRIresearchandpotentialsolutions. MarcJ.Kaufman (cid:1)McLeanHospital,115Mill
St.,BrainImagingCenter,Belmont,MA02478,USA,[email protected](cid:2), BlaiseD.Frederick (cid:1)McLeanHospital,115
Mill St., Brain Imaging Center, Belmont, MA02478, USA, [email protected](cid:2), Eric E. Ungar (cid:1)Acentech Inc, 33
Moulton St., Cambridge, MA02138, USA, [email protected](cid:2), Jonathan D. Kemp (cid:1)Acentech Inc, 33 Moulton St., Cam-
bridge,MA02138,USA,[email protected](cid:2), DavidM.Sykes (cid:1)ANSIS12Workgroup44andtheJointASA”INCE”NCACSub-
committeeonHealthcareAcoustics&SpeechPrivacy,23BuckinghamStreet,Cambridge,MA02138,USA,david.sykes@remington-
partners.com(cid:2)
HighfieldfunctionalMRI(cid:1)fMRI(cid:2)isbecominganeuroscienceresearchtechniqueofchoicebecauseitisnoninvasiveandcanreveal
braincircuitryregulatingsensory,motor,andcognitivefunctions.Unfortunately,rapidscanfMRIresultsinhighnoiselevels(cid:1)100-140
dB(cid:2) that can alter auditory, visual, and pain system function, and also can induce stress, which itself modulates brain responses to
variousstimuli.TheseeffectscanconfoundfMRIdatainterpretation.Anumberofsolutionsforthisproblemhavebeenproposedin-
cludingmodifyingMRIscannerhardwaretoreducenoiseoutput,anexpensivepropositionlimitedtowillingmanufacturers,andmodi-
fyingfMRIpulsesequencestoreducenoiseoutput,whichiseffectivewithincertainlimitations.Anotherapproachistodevelopacous-
ticnoiseisolatingequipmentthatseparatessubjectsfromnoise.Thispassiveapproachconfersmaximumflexibilitybecauseitisboth
hardware-andfMRIscansequence-independent.Wepresentinitialdatadocumentingefficacyoffirstgenerationacousticnoiseisolating
equipmentforanimalfMRIstudies.Asnearly25%ofpatientsreferredforclinicalMRIsrefusescansbecausetheyarestressful,acous-
ticnoiseisolatingequipmentscaledforclinicalMRIscannerusemaydecreasestressandincreasepatientcompliance,therebydecreas-
ingmorbidityandmortality,andimproveMRIcenterworkflow.
3095 J.Acoust.Soc.Am.,Vol.123,No.5,Pt.2,May2008 Acoustics’08Paris 3095
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12:40
2aAAd10. Experimental study on applicability of sound masking system in medical examination room. Kanako Ueno
(cid:1)Institute of Industrial Science, University of Tokyo, Komaba 4-6-1, Meguro-ku, 153-8505 Tokyo, Japan,
[email protected](cid:2), HyojinLee (cid:1)InstituteofIndustrialScience,UniversityofTokyo,Komaba4-6-1,Meguro-ku,153-8505To-
kyo,Japan,[email protected](cid:2), ShinichiSakamoto (cid:1)InstituteofIndustrialScience,UniversityofTokyo,Komaba4-6-1,Meguro-
ku, 153-8505 Tokyo, Japan, [email protected](cid:2), Atsuko Ito (cid:1)Center forAdvanced Sound Technologies,Yamaha, 203 Mat-
sunokijima, 4380192 Iwata, Shizuoka, Japan, [email protected](cid:2), Mai Fujiwara (cid:1)Center for Advanced Sound
Technologies, Yamaha, 203 Matsunokijima, 4380192 Iwata, Shizuoka, Japan, [email protected](cid:2), Yasushi Shimizu
(cid:1)Center for Advanced Sound Technologies, Yamaha, 203 Matsunokijima, 4380192 Iwata, Shizuoka, Japan, yasushi_shimizu@gmx
.yamaha.com(cid:2)
Recently,speechprivacytoavoidoralinformationleakageinhealthcarefacilitieshasbecomeanimportantissue.Thisstudyin-
vestigatedeffectivenessofsoundmaskingsysteminregardtomaskingefficiency,annoyanceanditsinfluenceonspeechconversation
formedicalexaminationroomsinanexperimentalapproach.Consideringactualapplication,twoadjacentmedicalexaminationrooms
partitionedbyalowsoundinsulationwallinatypicalhealthcarefacilitywereselectedasanexperimentalfieldandsoundmasking
systemwastemporallyinstalled.Intherooms,acousticenvironmentwasmeasuredandreproducedinananechoicroomwitha3-D
soundfieldsimulationsystemusinga6-chsoundrecording”reproductiontechnique.Inthesimulatedacousticcondition,subjectivetests
weredesignedtoquantifythemaskingefficiencyandannoyancecausedbythemaskingsound.Theannoyancetestwasconductedin
listeningcondition(cid:1)withhighattentiontothesound(cid:2)andintalkingcondition(cid:1)withlowattention(cid:2).Asaresult,mixedmaskerscomposed
bywaterstream,synthesizedspeechsignals,andsteadystatenoiseshowedhighperformanceinbothaspectofmaskingefficiencyand
annoyance.
TUESDAY MORNING, 1 JULY 2008 ROOM 252B, 10:20 A.M. TO 1:00 P.M.
Session 2aAAe
Architectural Acoustics, Musical Acoustics, Physical Acoustics, and Noise: Acoustics of Opera Houses I
Robin Glosemeyer Petrone, Cochair
918 16th St., Apt 3, Santa Monica, CA 90403, USA
Roberto Pompoli, Cochair
Engineering Dept. - Univ. of Ferrara, Via Saragat, 1, Ferrara, 44100, Italy
Invited Papers
10:20
2aAAe1. Generous opera house acoustics for lyric and symphonic performances. Daniel E. Commins (cid:1)ComminsAcoustics
Workshop,15rueLaurenceSavart,75020Paris,France,[email protected](cid:2)
Itisbelievedthatashortacousticresponseisneededinanoperahousetoguaranteegoodintelligibilityoflyrics.Someofthebest
operahouseshavearelativelylongreverberationtimeassociatedtogoodclarity.Theyaremoresuitabletosymphonicconcertsthan
(cid:1)damped(cid:1)rooms.Therecentlyopened1350-seatGrandThéâtredeProvenceinAix-en-Provence,France,isanexampleofanopera
housewithalongresponseandgoodclarity.Anadequateorchestrashellandproperpermanentacousticaltreatmentofthestagetower
leadtosuitableacousticalparametersinthesymphonyconfiguration.Themeasurementsshowthatinanoperahouseofthiscapacity,
itispossibletocreateconditionscompatiblewithopera,symphony,chambermusicandrecitals.Therichoperaconfigurationsound
generates mostly positive reactions. Most concert goers consider that this room is now the reference for the region. One must note
howeverthatthisapproachisriskysincethevaluesthatareconsideredidealforoperamustbestretchedfar.Itmayleadtoexcessive
reverberationandeventounwantedreflections.Thistargetrequiresgenuineinvestigations,fromearlyconcepttofinaldesign,usingthe
mostadvancedpredictionandmodelingtechniques.Thedesignoflargerroomsunderthesameprinciplerequiresevenmorecare.
10:40
2aAAe2. OperaHouseReverberationTimes-DesignConsiderations. EckhardKahle (cid:1)KahleAcoustics,188avenueMolière,
1050 Brussels, Belgium, [email protected](cid:2), Thomas Wulfrank (cid:1)Kahle Acoustics, 188 avenue Molière, 1050 Brussels, Belgium,
[email protected](cid:2), YannJurkiewicz (cid:1)KahleAcoustics,188avenueMolière,1050Brussels,Belgium,[email protected](cid:2), Brian
F.Katz (cid:1)LIMSI-CNRS,B.P.133,91403Orsay,France,[email protected](cid:2)
TheintimacyofmanyhistoricEuropeanOperaHouses,especiallyofthetraditionalItalianstyle,ishighlycherishedandmanyof
thesehallsareconsideredtobeamongthebesthallsacoustically.Fromanacousticalpointofviewthegenerallysmalldimensions-
oftencombinedwithamoderateseatcount-provideexcellentsourcepresenceandclarity.Ontheotherhand,thecorrespondingsmall
volumeleadstoshortreverberationtimes,andinrecentdecadeshigherreverberationtimeshavebeenpreferredandaskedforbyclients
andaudiencesinmanycountries.Ideaswillbepresentedonhowthisapparentdilemmabetweenthepreferenceforsmalldimensions
(cid:1)forintimacy,sourcepresenceanddefinition(cid:2)andincreasedvolume(cid:1)inordertocreatelongerreverberationtimes(cid:2)canbeaddressed.
3096 J.Acoust.Soc.Am.,Vol.123,No.5,Pt.2,May2008 Acoustics’08Paris 3096
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