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INTERAURALCROSSCORRELATION: SOURCESOFVARIABILITYINCONCERTHALLS By GARYS.MADARAS ADISSERTATIONPRESENTEDTOTHEGRADUATESCHOOL OFTHEUNIVERSITYOFFLORIDAINPARTIALFULFILLMENT OFTHEREQUIREMENTSFORTHEDEGREEOF DOCTOROFPHILOSOPHY UNIVERSITYOFFLORIDA 1996 ACKNOWLEDGMENTS Iwanttothankeachofmycommitteemembersfortheirguidance. Dr.EarlM.Starnes (Chairperson)(ProfessorEmeritus,DepartmentofArchitecture)wasthedirectorofdoctoral studiesattheonsetoftheresearch. Despitehisretirement,hecaredenoughtocontinuehis involvement. Dr.Starnesalsohelpedtomakethetransitionintodoctoralstudiessurprisingly easy. GaryW.Siebein(Cochairperson)(Professor,DepartmentofArchitecture)providedover fouryearsofcontinualguidance,support,andfriendship. Therearenowordsmeaningful enoughtoexpressthetruegratitudethathedeserves. Heisoneofonlyfourpeopleinmylife thathavetrulyraisedmyacademic,professional,andpersonalstandards. Dr.DavidM.Green(GraduateResearchProfessor,Psychology),WillisR.BodineJr. (Professor,Music),andBertramY.KinzeyJr.(ProfessorEmeritus,Departmentof Architecture)completedthesupervisorycommittee. Theirinterdisciplinarycontributions helpedtomaketheresearchprojectandmyeducationingeneralmorewell-roundedand complete. 1wouldliketothankthefollowingstudentsfortheirideas,encouragement,andfriendship: AvrahamBortnick,RichCervone,Wei-HwaChiang,MartinGold,ChrisHerr,JohnKidwell, RobLilkendey,LorenRaia,andMitchellSpolan. Dr.HaroldDoddingtonandDr.Bill Schwab(DepartmentofAerospaceEngineering,Mechanics,andEngineeringSciences) developedmuchofthemeasurementinstrumentationandanalysissoftware. 11 Mr.ArtAlvarez(VisualArtsDirector,BelkLindsey,Gainesville)donatedadepartment storemanikinformodificationsanduseduringdatacollection. Dr.EverettScroggie (ConsultingClinicalAudiologist,Gainesville)donatedhistimeandadvice,makingthedesign ofthefullscalemanikinaccurate. Dr.GlennE.TurnerandMr.LeeD.Mintzinthe DepartmentofProsthodontics(CollegeofDentistry,UniversityofFlorida)generouslydonated theirtimeandmaterialstocastsiliconpinnaeforthefullscalemanikin. Dr.JohnC. MiddlebrooksintheDepartmentsofNeuroscienceandSurgery(UniversityofFlorida) measuredthefullscalemanikin’sheadrelatedtransferfunctions,suppliedhumansubjectdata forcomparison,anddiscussedtheresultsofthedataanalysis. TheConcertHallResearchGroup,anorganizationofprofessionalacousticalconsulting firms,researchers,andscholars,fundedandsupportedatriptocollectacousticaldatain multipleNortheasternUnitedStatesconcerthalls. Thedatacollectedduringthattripwerealso usedforthisresearchproject. Drawingsoftheconcerthallswhichwereusedforreference duringthisresearchprojectwerecopiedfromoriginalsthatwerepreparedforandfundedby theConcertHallResearchGroup. Dr.JohnBradley(NationalResearchCouncilofCanada)generouslygaveaccesstodata collectedduringtheConcertHallResearchGrouptrip. Theabilitytoanalyzeanadditionalset ofdatawasbeneficialandhelpedtoestablishevenfurtherconfidenceintheresultsand conclusions. JaffeHoldenScarbroughAcousticsInc.(Norwalk,CT)generouslyprovidedaccessto equipmentforthephysicaldocumentpreparation,printing,andcopying. Finally,1wanttothankmyfamilyforbelievinginme,andprovidingmewithloveand support. PREFACE Whenlisteningtomusicsomelistenersmaypreferanexperiencethatmakesthemfeel closetotheperformance(intimacy)withtheabilitytodistinguisheachnoteinthestaccato passages(clarity). Othersmaypreferadifferentexperience,perhapsonethatreinforcesthe naturalsoundfromtheperformers(loudness)andcausesittopersistthroughouttheroom decayingslowly(reverberance). Therelativeimportanceofthesepreferencesvariesfromone listenertoanother,onemusicalstyletoanother,andperhapsevenfromoneperformanceto another. Researchersinthefieldofarchitecturalacousticsattempttorelatelistenerpreferenceand thearchitecturaldesignofenclosures. Onecommonlyusedmethodofrelatingpreferenceto quantitativeaspectsofarchitecturaldesignsuchasroomvolumeorseatingareainvolvesan intermediatestep,onethattriestorepresentthebehaviorofsoundenergywithinanenclosure withquantitativeparameters. Thisapproachrequiresadualunderstanding. Thefirstpartisto knowhowlistenerpreferenceforanactualperformancecanbepredictedusingquantitative acousticparameters. Thesecondpartistoknowhowtheseparametersareinfluencedbythe architecturaldesignoftheenclosure. Thisresearchinvestigatesthesourcesofvariabilityof oneparticularacousticparameter,interauralcrosscorrelation,andidentifieshowthismeasure canbeinfluencedbyarchitecturaldesign. IV 1 TABLEOFCONTENTS Page ACKNOWLEDGMENTS ii PREFACE iv LISTOFTABLES vii LISTOFFIGURES viii ABSTRACT xi INTERAURALCROSSCORRELATION 1 RELATIONSHIPBETWEENINTERAURALCROSSCORRELATION ANDLISTENINGPREFERENCE 8 GottingenStudies 8 Ando’sStudies 1 RecentStudies 22 MEASUREMENTMETHOD 24 Introduction 24 SoundSource 24 BinauralReceiver 28 Instrumentation,Filtering,andProcessing 36 MeasurementMethodTest 37 MicrophoneLocationExperiment 38 LevelofDetailExperiment 43 INTERAURALCROSSCORRELATION: SOURCESOFVARIABILITYINCONCERTHALLS 46 DataCollection 46 PreliminaryDataAnalysis 47 DirecttoReflectedEnergyRatio 51 ExcludingtheDirectSound 57 UnexplainedVariation 57 Discussion 62 V Page INTERAURALCROSSCORRELATIONEXPERIMENTSINSCALEMODELS 63 Introduction 63 MeasurementMethod 63 DirecttoReflectedEnergyRatio 71 EffectofReflectionsfromtheSidesonInterauralCrossCorrelation 72 EffectofOtherArchitecturalChangesonInterauralCrossCorrelation 73 CONCLUSIONS 76 MeasurementofInterauralCrossCorrelation 76 InterauralCrossCorrelation:SourcesofVariabilityinConcertHalls 77 FutureResearch 83 APPENDIXA PLANSANDSECTIONSOFCONCERTHALLS 86 APPENDIXB PLANSANDSECTIONSOFSCALEMODELCONFIGURATIONS . 95 LISTOFREFERENCES 98 BIOGRAPHICALSKETCH 101 VI LISTOFTABLES Table Page 1 Preferencescoresforvariousspeakersystemsandlisteninglevels 20 2 Receivercharacteristics 44 3 Measuredconcerthalls 46 4 Correlationsbetweeninterauralcrosscorrelationand directtoreflectedenergyratios(subgroupedbyfrequency) 52 5 Correlationsbetweeninterauralcrosscorrelationanddirecttoreflected energyratios(subgroupedbyhallwithvariousfrequencysubsets) 54 6 Correlationsbetweeninterauralcrosscorrelationand directtoreflectedenergyratios(subgroupedbyhallandfrequency) 54 7 Correlationsbetweeninterauralcrosscorrelationand directtoreflectedenergyratios(subgroupedbyhall) 56 8 Scalemanikincharacteristics 65 9 Concerthall/modeledroomsizecomparison 68 vii LISTOFFIGURES Figure Page 1 Quantitativeparameterscorrelatedwithpreference 9 2 Quantitativeparameterscorrelatedwithpreference 10 3 Preferenceandinterauralcrosscorrelationversusreflectionazimuthangle ... 12 4 Preferenceandinterauralcrosscorrelationversusreflectionazimuthangle ... 13 5 Speakersystemsaand 14 6 Levelandtimepatterns/andII 15 7 Preferencerelatedtointerauralcrosscorrelation 15 8 Levelandtimepatternofreflectionsandreverberation 16 9 Preferencerelatedtoreflectiondelayandinterauralcrosscorrelation 17 10 Speakerconfigurationsa,b,andc 19 11 Levelandtimepatternofreflectionsandreverberation 20 12 Revolverfrequencyresponsecurve 25 13 Systemvariabilitymeasuredusing95%confidenceintervals 27 14 Fullscalemanikindesignandinstrumentationdetail 28 15 Spatialcoordinatesystemofsource 30 16 Manikin/manikinheadrelatedtransferfunctioncomparison 32 17 Manikin/humansubjectheadrelatedtransferfunctioncomparison 32 18 Intersubjectvariabilitybetweentenhumanheadrelatedtransferfunctions .... 33 19 Variabilitybetweenmanikinandhumansubjectheadrelatedtransferfunctions 33 viii Page Humansubjectdirectionalsensitivityplots 35 21 Interauralcrosscorrelationmeasurementmethodcomparison 38 22 Microphonelocationcomparison 40 23 Correlationofsignalsmeasuredinsideandoutsidethemanikinhead 41 24 Signalcomparison-500Hzoctaveband 42 25 Signalcomparison-4kHzoctaveband 42 26 Manikinmeasurementmethod 44 27 Effectofreceiverconfigurationoninterauralcrosscorrelation 45 28 Averageinterauralcrosscorrelationvalues 47 29 Standarddeviationofinterauralcrosscorrelationvalues 47 30 Comparisonofstandarddeviationsmeasuredusingdifferentsets ofinterauralcrosscorrelationvalues 49 31 Decreaseofinterauralcrosscorrelationvalueswithdistancefromthesource.. 49 32 InterauralcrosscorrelationvaluesmeasuredinsidetheKennedyCenter correlatedwithdirecttoreflectedenergyratios 56 33 Decreaseinstandarddeviationduetoexcludingthedirectsound 58 34 Decreaseinstandarddeviationduetoexcludingthedirectsound 58 35 Interauralcrosscorrelationvaluesversusdirecttoreflectedenergyratios .... 60 36 Scale(1:10)manikindesign 64 37 Scale(1:10)manikin 65 38 Frequencyresponseofscalemeasurementsystem 67 39 Basicscalemodeldesign 68 40 Relationshipbetweeninterauralcrosscorrelationandinitialtimedelaygap ... 69 IX Figure Page 41 Standarddeviationofinterauralcrosscorrelationvalues measuredinsidefourconcerthalls 70 42 Relationshipbetweenmodelinterauralcrosscorrelationvalues anddirecttoreflectedenergyratios 71 43 Interauralcrosscorrelationvaluesplottedversusdirecttoreflectedenergy ratiosfortwomodelconfigurations 73 44 Comparisonofinterauralcrosscorrelationvaluesmeasuredinside sixdifferentmodelconfigurations 74 45 BostonSymphonyHallfloorplanandsection 87 46 J.F.KennedyCenterfloorplanandsection 88 47 KleinhansMusicHallfloorplanandsection 89 48 MeyerhoffConcertHallfloorplanandsection 90 49 OrchestraHallfloorplanandsection 91 50 PhiladelphiaAcademyofMusicfloorplanandsection 92 51 SeveranceHallfloorplanandsection 93 52 TroyMusicHallfloorplanandsection 94 53 Nohallmodelconfiguration 96 54 Specularmodelconfiguration 96 55 Diffusivemodelconfiguration 96 56 Standardmodelconfiguration 97 57 Sidemodelconfiguration 97 58 Top/front/backmodelconfiguration 97 X