Comparisons of auditorium acoustics measurements as a function of location in halls

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Comparisons of auditorium acoustics measurements as a function of location in halls
(A)
Bradley, J. S.; Gade, Anders Christian; Siebein, G W
Published in:
Acoustical Society of America. Journal
Link to article, DOI:
10.1121/1.406637
Publication date:
1993
Document Version
Publisher's PDF, also known as Version of record
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Citation (APA):
Bradley, J. S., Gade, A. C., & Siebein, G. W. (1993). Comparisons of auditorium acoustics measurements as a
function of location in halls (A). Acoustical Society of America. Journal, 93(4), 2265-2266.
https://doi.org/10.1121/1.406637

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PROGRAM OF
The 125th Meeting of the AcousticalS ociety of America
Chfiteau Laurier Hotel ß Ottawa, Canada ß 17-21 May 199:3
NOTE: All Journal articlesa nd Letters to the Editor are peer reviewedb efore publication.P rogram
abstractsh, owevera, re not reviewedb eforep ublications, incew e are prohibitedb y time and schedule.
MONDAY MORNING, 17 MAY 1993 DRAWING ROOM, 9:00 A.M. TO 12:00 NOON
IaAA
Architectural Acoustics and Musical Acoustics: New Auditorium Acoustics
Measurements(cid:127)Results and ComparisonsI
Leo L. Beranek, Chair
975 MemorialD rive,S uite8 04, CambridgeM, assachuset0ts2 138
Ch(cid:127)ir's Introductions9:00
Invited Papers
9.(cid:127)$
IaAAI. The acoustics urveyo f Britiaha uditoria. MichaelB arron (Schoool f Architecturaen d Bldg.E ng.,U niv. of Bath,
Claverton Down, Bath BA2 7AY, UK)
By1 980th e ofa coustifcosrc oncehrta llsh adr eacheadn i nterestisntga geT.w oG ermasnt udieast G(cid:127)ttingen
andB erlinw ithd ummyh eadr ecordinghsa dg onea longw ayt o determininthge i mportanstu bjectivaen do bjectivdei mensions.
Howevetrh ei nfluencoef architecturfaolr mo n subjectivaec ousticco nditionwsa sm uchle ssw elle stablisheTdh.e rew eret wo
possibrloeu teste: stinagc oustsicc alme odeolsr f ull-sizaeu ditoriWa.i tha ccestoss ufficiefnutl l-sizaeu ditoritah,e l attewr asth e
obvioucsh oices ianlcseo a itll owedtr ues ubjectivaes sessmeTnht.e acoustiscu rveyo f Britisha uditoriain volvebdo tho bjective
measuremeanntdss ubjectiavses essmeinn otsv er4 0 auditoriian cludincgo ncerhta llsd, ramath eaterosp, erah ouseasn, dm ulti-
purpossep aceTsh. ew holee xercishea sn owb eenp ublishe[Md . BarronA, uditoriu(cid:127)4mc oustiacnsd (cid:127)4 rchitectuDrael sig(nC hap-
man& Hall,L ondon1, 993)]I.n concerhta llsa majorc onclusioonf t hes ubjectiveex erciswea st hath allsw ithg oodre putations
scorwe ellw ithr egartdo s everaalt tributessu, cha sr everberanecnev, elopmeanntd,i ntimacSy.e veranlo veol bservatioonnst h e
effecto f designd etailsw ill alsob e discussed.
9:30
laAA2.E ffectos f measuremepnrot ceduaren de quipmeonnt a veragreo oma coustmic easuremenAts.C. . Gade (AcoustL. ab.,
TechU. niv.o f DenmarkB,l dg3. 52,L yngbyD,K 28000D enmark)J, ohnS .B radley( Natl.R esC. ounciOl,t tawaK IA 0R6,
Canada)a, nd GaryW . Siebein (Univ. of Florida,G ainesvilleF,L 32611)
This preappoerrt sth er esultos f a measuremetonut ro f nineU .S. concerht allsT. hreem easuremetnetasm sf,r omt he
Universitoyf Floridat,h eN ationaRl esearcCho uncoilf Canadaa,n dt heT echnicUaln iversitoyf Denmarkm, adep arallesle ts
of measuremeunstsin gth eiro wne quipmenant dp rocedureIns .s omeo f the hallsm easuremewntesr er epeateuds ingth e
proceduroefts h eo thetre amtso m akeit possibtloes eparatthee e ffecotsfd iffereneqt uipmeanntd d ifferenptr ocedurTehse. p aper
willp resepnot sition-averraegseudltf sro mt het hreete amasn dw illd iscursesa sonfosr t hed ifferencoebss erve[Wd.o rkp artially
supportebdy theC oncerHt all ResearcGhr oup.]
9:55
IAAA3C. ompurisoofu asu ditoriuamco ustimcse asuremeansat s fu nctioonf ioc(cid:127)tionin h(cid:127)11s.J ohnS .B radley( M-27,I RC,
Natl.R esC. ounciOl, ttawaO, N KIA 0R6,C anada),A .C. Gade (TechU. niv.o f DenmarkL, yngbyD, K 28000D, enmark),
and GaryW . Siebein (Univ. of Florida,G ainesvilleF,L 32611)
In a measuremetnotu ro f nineU .S.c oncerht allsm easuremenwtse rem adea t 30 or morec ombinationosf sourcea ndr eceiver
positioinne achh allE. acho ft het hreem easuremteenamt (st heU niversiotyfF loridath, eD anisThe chnicUanl iversitayn, dt he
NationaRl esearcCho unciol f Canadam) adep aralleml easuremeonft sa numbeor f modemro oma cousticqsu antitieuss ing
2265 J. AcousSt.e c.A m.V, ol.9 3, No.4 , Pt.2 , Apri1l 903 125thM eetingA:c ousticSaol cietoyf America 2265
Downloaded 27 Jun 2010 to 192.38.67.112. Redistribution subject to ASA license or copyright; see http://asadl.org/journals/doc/ASALIB-home/info/terms.jsp
differenet quipmenatn d measuremepnrto cedureTsh. eser esultsa re compareodn a sot-by-seabt asisa nd the differenceasre
explainedin termso f earliers ystematisct udieos f thee ffectso f measuremepnrt ocedurdee tailsT. he measuremernets ultsw erea lso
usedt o examinet he influenceo f differentm easuremenetq uipmenat nd measuremenptr ocedureosn the within hall variationso f
the variousa cousticaqlu antities[.W ork partiallys upportebdy the ConcertH all ResearchG roup.]
10:20
laAA4. Effectso f measuremenetq uipmenta nd procedureo n IACC measurements.G ary W. Siebein,W ei-hwa Chiang,G ary
S. Madaras, Harold W. Doddington,W ilhelm K. Schwab (ArchitectureT echnol. Res. Ctr., Univ. of Florida, 231 ARCH,
Gainesville,F L 3261i -2004), and John S. Bradley (Natl. Res. Council,O ttawa, ON KIA 0R6, Canada)
A serieso f binaurala cousticaml easuremenwtse ret akena t severasl ourcelo cationsa nd multipler eceiverlo cationsin eight
concerth allsu singt he AcousticaRl esearchIn strumentationfo r ArchitecturaSl paces(A RIAS) systema nd manikind eveloped
at the Universityo f Floridaa nd the BRAM softwares ystemd evelopeadt NRC Canadaw ith a B&K dummyh eada nd torso.T his
paperw ill comparet he resultso f room averaged ata and severals pecifics eat locationso btainedf rom the two measurement
systemsw ith an analysiso f the similaritiesa nd differencesth at arose.C orrelationsa mongv ariousf orms of IACC including
IACC(cid:127)r¾ IACC(cid:127)a(cid:127) IACCvit,h d irescot unadn,d l ACCwi,ht oduir escotn dw eres tudiedA. comparisoonf binaurarle flectogramfosr
locationws ithine achr oomw erea lsom ade.S ummaryg raphss howingra ngeso f eachm easuremewnti thine acho f the roomsa nd
discussioonf similaritiesa nd differenceasm ongt he groupso f roomsw ill be presented[.W ork supportedb y the NationalS cience
Foundationa nd ConcertH all ResearchG roup.[
10.-45
IaAAS. Microphone placement in a binaural hearing manikin and its effects on IACC, reflectograms,a nd head-related
transfer functions. Gary S. Madaras,G ary W. Siebein,W ei-hwa Chiang, Harold W. Doddington,a nd Wilhelm K. Schwab
(Architecture Technoi. Res. Ctr., Univ. of Florida, 231 ARCH, Gainesville, FL 32611-2004)
A binauralh earingm anikin was constructeda nd then testedb y comparingi ts bead-relatedtr ansferf unctionst o thoseo f a
humans ubjectT. he manikinw asu sedt o recordi mpulser esponseins eightn ortheasterUn nitedS tatesc oncerth allsa sp art of the
recentC oncertH all ResearchG roup Study.T he placemenot f the manikin'sl /2-in. Bruel& Kjaer microphonevsa riedb etween
two locationsin: sidet he head( truncatingth e auditoryc anal)a ndo utsideth e head( 20 mm from thec analo pening)F. or most
measuremenntso, statisticallsyi gnificandti fferencewse ref oundb etweeno ctaveb andI ACC valuesf or the two microphone
locationsT.h em anikin'hs ead-relatetdra nsfefru nctionws erem easureidn an anechoicch ambeur singb othm icrophonpeo sitions
and3 24s ourcep ositionsC.o mparisonosf reflectogramasn dh ead-relatetdra nsfefru nctionssh owt hatt hem anikin'sh eada ndt he
human subject'sh ead affects oundi n similar ways. [Work supportedb y the National ScienceF oundationa nd Concert Hall
ResearchG roup.]
11:10
IAAA6. Acousticalm ensurementso n stageso f nine U.S. concert halIn. A.C. Gade (Acoustics Lab., Tech. Univ. of Denmark,
Bldg. 352, Lyngby,D K 28000, Denmark) and John S. Bradley (Natl. Res. Cauncil, Ottawa, ON KIA 0R6, Canada)
A measurementot ur of nineU .S. concerth allsi ncludeda cousticaml easuremenotsn the stageo f eachh all. Two teams( from
the National ResearchC ouncilo f Canada,a nd the TechnicalU niversityo f Denmark) made measurementosf the acoustical
quantitiess uggestebdy Gade:t he support familyo f measuredse scribintgh e acousticaclo nditionfso r the musicianosn stage.
This paperc omparetsh e resultsfr om the two measurementet amsa nd discusseths e influenceo f hall designs[.W ork partially
supportedb y the ConcertH all ResearchG roup.]
11:35
IAAA7. Statintiearle lationsa mongu rehiteeturafel aturesa ndo bjectivea cousticaml easuremenotfs c oncerht alls. Gary W.
SiebeinW, ei-hwaC hiang,G ary S. Madaras,H arold W. DoddingtonW, ilhelmK . Schwab (ArchitectureT eehnol.R es.C tr.,
Univ. of Florida,2 31 ARCH, GainesvilleF, L 32611-2004), /ohn(cid:127). Bfadlcy (i'.(cid:127)atf. Res.C ouncil,O ttawa,' ON KIA 0R6,
Canada), and A.C. Gadc (DanishT ech. Univ., Lyngby,D K 28000,D enmark)
A statisticaaln alysiosf architecturafel atureasn dd etailedo bjectivaec ousticaml easuremenmtsa dei n eightc oncerht ahsa nd
severaml ulti-usero omsin theirc oncerct onfiguratiowni ll be presentedA. methodfo r evaluatintgh e architecturafel atureso f
roomsth ata ffectt heira cousticpalr opertiewsa sd evelopeAd.r chitecturafel atureosf interesitn cludeb othr ooma veragvea lues
andm ore-detailesdu bdivisioonfs s urfaceins cludinsgh apev, olumeh, eightw, idth,a nds ounda bsorptiopnr opertieosf materials.
Regressionm odelingw asp erformedf or individuals ource-recovepr athsa s well as for entirer ooms.M easurementdsa ta from all
three teamsw ere usedi n the modelst o assessth e sensitivityo f the modelst o expectv ariationsi n measurementsT.h e resultsw ere
comparedto the previousw ork of Barron,G ade,a nd Honk amongo thers.[ Work supportedb y the NationalS cienceF oundation
and ConcertH all ResearchG roup.]
2266 J. AcousSt. oc.A m.V, oL9 3, No.4 , Pt.2 , Apri1l 993 125thM eetingA:c ousticSaol cietoyf America 2266
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MONDAY MORNING, 17 MAY 1993 BALLROOM, 8:00T O 11:30A .M.
Session laAO
Acoustical Oceanographya nd Underwater Acoustics:O cean Acoustics in Shallow Water: What are the
Issues? I
MohscnB adicy,*C ochair
Universitoyf Delaware,G raduateC ollegeo f Marine StudiesN, ewark,D elaware1 9716
*CurrenOt: fficoe fN avaRl esearcOhc, eaAn cousticCso,d e1 1250/810, 0N orthQ uincSyt reeAt, rlingtonV,i rgini2a2 217
Peter H. Rogers,C ochair
GeorgiIan stituteo f TechnologSyc, hoool f MechanicaEl ngineerinAg,t lanta,G eorgi3a0 332
Chalr's IntroductionS:00
Invited Papers
8:05
1aAO1C. riticapl ropagatiiosns ueisn shallow-waatecro usticsD. avidE . Weston( WhiteL aird,7 7 WykcR d.,W eymouth,
Dorset DT4 9ON, England)
Seversael tso fp ropagatiporno bleminss hallow-waatecro ustiacrse d iscussecdo,v erinogv erlappifnrgeq uencrayn geAs.t VLF
(sayb elow3 00H z) theb ottomm ateriails importanbt,e causeen ergytr avelsin theb ottomo r becausoef attenuatioans sociated
withs hear-wacvoeu plinAg.t LF (saya bov3e0 H z) thep resencoef g asin surficiasle dimenctasn c hangbeo undarcyo nditions
andb ottomlo sseasn, de vena llowa newt ypeo f interfacwe aveA. t MF (300H z to severaklH z) dispersefids hc anr aiseth e
attenuationty, picallyb y I dB/km. Fishh avea lsob eeno bservetdo dominateth ee chos tructureo r reverberatioonu, t to 100k m.
At HF (saya boves evera1l0 0H z) thes ound-speperdo fileb ecomeims portanpt,a rtlyb ecausoef channelinAgt. VHF (usually
aboves everaklH z) thep ropagatiomne chanismtesn dt o changfer omb oundarrye flectiotno boundarsyc atterinIgn. a dditioanl l
thesee ffectasr eg reatlyin fluencebdy distancaen db y waterd epth.
8:30
1aAO2. Shalloww ater actives onare nvironmentaalc ousticis sues. William M. Carey (DARPA, 3701 North Fairfax Dr.,
Arlington,V A 22203), PeterG . Cable (BBN SystemTse chnologyN, ew LondonC, T 06320), and HenryC ox (Orincon,
Arlington, VA 22202)
The propagatioann dr everberatioonf soundin shalloww ateru nderd ownwardre fractincgo nditioniss governebdy the
geoacousatincd s catterinpgr opertieosf theb ottomT. hea ctiveb istatics onaer quatiofno r thisc aseis developeadn di t is shown
that,w hent he transmissioton t he targeta ndt he bottoma re approximatetlhye samef or reverberation-limictoedn ditionas ,
simplepr arametrifco rmo f thise quationre sultsT. hat is, the signael xcesdse pendosn the effectivbeo ttomb ackscattering
strengtht,h e coherensti gnagl ain,a nda reverberatioanre af or a givent argets trengtha ndt hresholdA. parametriacn alysiiss
presentetdh atf ocuseosn the frequency-dependcehnatr acteristiocfs t heb ottomb ackscatterisntgr engthan dt hee ffecot f coher-
enceo n receivinagr raya pertureR. ecenrte verberatiaonnd signacl oherencmee asuremeanrtesr evieweadn dt he needsfo r
additionasl tudieds elineatedT.h e coherencies suefo r the waveguidies stresseadn dt he measuremepnrto blemo f coherencise
discusseadn dc omparedto the measuremenotf signalv ersusth e receivelre ngthi n wavelengths.
8:50
1aAO3.A mbientn oiseo ceanographAy :n ewr emotes ensingte chniqufeo r shalloww ater. MichaelJ . Buckinghaman d Grant
B. Deane (Marine Phys.L ab., ScrippsI nst. of OceanographyL,a Jolla, CA 92093-0213)
Ambientn oisec ontainbs roadbanidn formationab outt heo ceanice nvironmenItn. particulari,n shalloww ater,b ecausoef the
multipleb oundaryin teractionsa,m biennt oisec ontainsin formationab outt he geoacoustpica rameterosf the bottomT. o extract
thisi nformationi,t is necessartyo identifys tabler, eliablef eatureso f the noise.( Noisei ntensityis neithers tablen or reliables ince
it is influencebdy numerouhs ighlyv ariablef actors). An exampleo f a reliablef eatureo f thes hallow-watenro isef ieldi s its vertical
directionalityw, hichi s controlledb y the bottom.I n fact,i n an isovelocitcyh anneol f uniformd eptho verlyinga fastf luid bottom,
the verticasl tructureo f the noisec an be invertedt o obtaina n accuratee stimateo f the sounds peedin the bottoms ediment
[Buckinghaman dJ onesJ, . AcoustS oc.A m. 81, 938-946 (1987)]. Thus,i n thise xamplea, simplem easuremeonft the vertical
coherencoef the noisei n the waterc olumny ieldeda n importantg eoacoustpica rameteor f the sedimentS. imilarlyi,n shallow
watero verlyinga slopingp, enetrablbeo ttom( i.e.,a range-dependecnhta nnesl upportintgh ree-dimensionaaclo ustipc ropagation)
the noises howsa horizontaal nisotropyth at couldb e usedt o determineg eometrica ndg eoacoustpica rameterosf the channelI.n
sucha pplicationsa,m bient noiseo ceanographyp rovideas remotes ensingto ol for interrogatintgh e bottom,m ucha s seismic
reflectiona nd refractiont echniqueasr e useda t present[. Researchs upportedb y ONR.]
2267 J. AcoustS. oc.A m.,V ol. 93, No. 4, Pt. 2, April1 993 125thM eeting:A cousticaSl ocietyo f America 2267
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9:10
I(cid:127).AO4. Considerationsf or shallow water I(cid:127)ro!(cid:127)agation exl(cid:127)eriments. T. Ewart, F. Henyey, Darrell R. Jackson,a nd Eric I.
Thorsos (Appl. Phys.L ab., Univ. of WashingtonS, eattle,W A 98105)
Wheno nee xaminetsh ei ssueisn volvedin propagatioonf soundin shalloww ater,t hec onclusioins that thee ver-presenotc ean
bottom,w ith its inhomogeneitayn d anisotropyw, ill dominateA. singlem odelw ith a few parametersw ill not be appropriatefo r
all bottom types.T his is unlike studieso f scatteringin the randomo ceanv olumea nd from the sea surface,w here simply
parametrizedm odelsa re useful.T he presencoe f very largen umberso f multipathsb lurst he distinctionb etweens tochastiacn d
deterministici ssuesI.t is clear that one needst o understandt he angular and temporal behavioro f the acousticf ieldsi n order to
understandt he channel characteristicsf or given source(s)/reeeiver(s) combinations.T his implies that large aperture and
broadbande xperimentsw ill be required.S everali ssuesm ustb e addressedb efored esignings uche xperiments(. 1) Will the present
simulationc apabilitya llow one to designa goode xperimentf or the caseo f a reasonablyh omogeneoubso ttom?( 2) How many
multipaths are there, and can they be separated?( 3) If there are a large aperature and bandwidth, can matched field or
backpropagationm ethodso f sourcel ocalizationw ork? (4) What are the rest of the questions?T his group will conducta n
experimenitn Knight Inlet, BC, whichw ill includep reliminarys halloww aterm easurementasn, d the plansf or this experiment
will be discussed.
9:30
laAO$. An issue (sedimentv olume fluctuations)a nd a nonissue( shear wave propagation)i n shallow water acoustics.
FredrickD . Tapperta nd T. Yamamoto (Appl. Marine Phys.,U niv. Miami/RSMAS, 4600 RickenbackeCr swy.,M iami, FL
33149)
A two-wayf ull-waveP E reverberationm odelh asb eend evelopedth at providesp redictionso f meanr everberationle velsi n
shalloww ater to long ranges( hundredso f water depths)d ue to sedimentv olumef luctuationsa s well as bottom and basement
interfacero ughnesseUss. ingT . Yamamoto'tso mographicalmlye asuresde dimenvto lumefl uctuationsp ectraa so neo f the inputs,
the PE reverberationm odelh as beene xerciseda t severall ocationso n the shelfi n the East China Seao ver a broad rangeo f
frequencieIst .h asb eenf oundt hat predictedre verberatiolnev elsd uet o bothm echanismasr eg enerallyc omparablien magnitude,
and that absolutel evelsa re controlledm ainly by total field ensonificationo f the sedimentv olume and boundaries,i .e., forward
transmissiolno ssesT. he questionw hetheri t is necessartyo includes hearw avep ropagationin shalloww atera cousticm odelsh as
beenr esolvedt:h e answeris definitelyn egativea, nd thisi s no longera n issueM. easureds halloww atert ransmissiolno ssd atao ver
a broadr angeo f frequenciews ith sourcea nd receiverin the water columnh asb eens uccessfulmlyo deledu singa full-wave
range-dependePnEt modelt hat includesro ughb ottomf orwards cattering(n ecessarfyo r gooda greement)b, ut treatss hearw ave
effectsa sa n equivalenftl uidb y augmentingth e volumea ttenuationo f compressionwala vesin the sedimenlta yersT. he conclusion
that it is not necessartyo includes hearw ave propagationw hen sourcesa nd receiversa re in the water columnh as beenf urther
confirmedb y inter-modeal nd intra-modeci omparisonuss ingr ealisticg eoacoustisce dimenpt ropertiesa s measuredb y T. Ya-
mamoto'sB SMP system[ J. Acoust.S oc.A m. 90, 441-456 (1991)]. [Work supportedb y ONR, 1125OA.]
9:50-10:10 Break
10:10
laAO6. Predictabilityo f the acousticfi eld in a shalloww aterw avegulde.G eorgeV . Frisk and SubramaniamD . Rajan (Dept.
of Appl. OceanP hys.& Eng., WoodsH ole OceanographiIcn st., WoodsH ole, MA 02543)
The abilityt o predictt hes oundfi eldm agnitudaen dp hasein a shalloww aterw aveguidies criticallyd ependenutp ona ccurate
knowledgeo f the acousticp ropertieso f the environmentI.n this paper,a ttentioni s focusedo n the influenceo f the geoacoustic
propertieosf the seabedo n the predictabilitoyf the field.E mphasiiss placedo n the useo f geoacoustpica rameteer stimates
obtainedfr om modali nversionte chniquesS.o meo f the researchq uestiontso be addresseidn clude:( 1) What is the measureo f
predictability(?2 ) Vv(cid:127)at aret hee rrorsa ssociatewdi [h variousin versionm e[hodasn dh owd o theya ffectp redictability(?3 ) What
is the effecot f noisein the data?( 4) How usefual re geoacoustpica rameteers timateosb tainedo vera bando f frequencieins
predictintgh es oundfi eldo utsidteh atb and?E xampleuss ingb othr eala nds ynthetidca taw ill bed iscusse[dW. orks upportebdy
ONR.]
10:30
laAO?.G eoaconsmtieo delinogf thes eafloor--Receenxtp erimentwaol rk. R.D. Stoll (Lamont-DoherEtya rthO bservatory,
PalisadesN, Y 10964), J. Ewing (WoodsH ole OceanographIincs t., WoodsH ole, MA 02543), and T. Akal (SACLANT
UnderseaR es. Ctr., LaSpezia,I taly)
Overt hep astd ecadae numbeor f newt echniquehsa veb eend evelopefodr measurinthge g eoacousptirco pertieosf seafloor
sedimenStse. veraolf thesme ethodust ilizes ensotrhsa ta red eployeodn t hes eaflooarn dr espontdo seismiwca vegse neratebdy
differenkti ndso f sourcien cludinegx plosivaensd m echanicimal pacat sw ella st hea mbienptr essufrleu ctuatiognesn eratebdy
wavem otiona t thes eas urfaceS.i nceth em otionth ati ss enseadt thes eaflooisr a combinatioonf m anyd ifferenkti ndso f interface
andb odyw aves(i .e.,S eholtwe avesL, ovew avesp,, s(cid:127), ands Ar efractionasn dr eflectionest,c .),i nversiotno obtaina geoacoustic
modeils a completaxs kt hatm usbt et ailoretdo e achin dividueaxl perimetnatk ingin toa ccountht eb andwidothft hes ignaaln d
thei nteractiobne tweetnh ev arioutsy peso f waveT. hisp apesr ummarizseosm eo f ther ecenfti elde xperimenatnsd t hem ethods
thata reb eingu sedto interpretth ed ata.[ Works upportebdy ONR codes1 125OAa nd1 125GG.]
2268 J. AcousSt. oc.A m.,V ol.9 3, No.4 , Pt.2 , Apri1l 993 125thM eetingA:c ousticSaol cietoy f America 2268
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10:50
lsAOS. High-resolutiosnh alloww ater3 -D surveya ndi nversionfo r geophysicpaal rametersM. rinal K. Sen,P aulL . Stofa,
andJ amesA . AustinJ, r. (Inst.f or GeophysU.,n iv.o f Texasa t Austin8, 701N . MoPacE xpwy.A, ustinT, X ?8759)
In thes halloww atere nvironmeenvt enin subsurfadcee pthsle ssth an3 0 m, 3-D structurecsa na ffecwt avep ropagatioAn .
high-resolutio(5n0 0-3500H z) 3-D survey( 53 iines(cid:127) 5-kinl ength,1 0-ml ine spacing5, -m shots pacingu) singa Huntec
deep-towebdo omesr ourcaen dS TARNIXn avigatiowna sc arriedo uto ffshorNe ewJ erseyin 1989A. dditiona3l -D acquisition
alongw ithv ibrac oringw illb ec onducteind t hes amere gionin thes ummeorf 1993P. rocessianngd 3 -Di nterpretatioofn t hed ata
recordg eologifce aturehsu ndredosf metersa crosbsu to nlys everaml etersin totald epthi,. e.,g laciaml eltwatecrh annelpsr iort o
them ostr ecenWt isconsignl aciationR.e ducinsgp atiasl amplinegv ent o 100-mli nes pacinrge sultsin seversep atiaal liasingo f
thesefe aturesm, akingg eologiinc terpretatioernr oneouIsn. a dditionto 3-D structurleo, casl ubsurfaeclea stipc ropertiense edto
be estimateqdu antitativeblyy inversem ethodsT.h e globaol ptimizatiomn ethodcsa nb ee mployetdo derivee arthm odelsa nd
theiru ncertaintieAs m. ajorc hallengiset o combin3e- Da cquisitioinm, agingin, terpretatioann,d c ored ataw itht her equirements
of materiapl roperteys timatiosnu chth ata completuen derstandionfg p ropagatioinn s halloww atere nvironmecnat nb ea chieved.
11:10
19AO(cid:127). Influenceo f internals ofttonso n soundp ropagationin shalloww ater with a summers trongt hermocline,J i-Xun
Zhou, Xue-ZhenZ hang (Schoolo f Mech. Eng.,G eorgiaI nst. of Technol.,A tlanta,G A 30332a nd Inst. of Acoust.,A cad.
SinicaB, eijing1 00080P, eople'Rs epublico f China),a nd PeterH . Rogers (GeorgiaIn st.o f Technol.A, tlanta,G A 30332)
Analysiosf extensivdea tah ass hownth att hei nternawl avesin thec oastazlo nee xhibitth ep ropertieosf solitonsU.s ing
experimentdaal taa ndn umericasli mulatiorne sultsth, isp apers howws hath appentso soundp ropagatioifn i nternasl olitonasr e
presenitn shalloww aterw itha strongs ummetrh ermoclinTeh. e experimenwtse rec onducteind theY ellowS eao fft heC hina
coasdt uringth es ummerw, heres trongth ermoclinwesit hm oret han1 0' C temperatudreif ferencaer eo ftenp resenItn. ordert o
providea clearp hysicapl ictureo n the true problema, carefullyc hosens impleo ceanm odeli s usedt o showt he resonant
interactioonf soundw avesw ith internasl olitonsin, cludingsi gnaflr equencys,o lironw avelengthan, dp ackelte ngthr esonances.
Then,t he numericaml odeli s extendetdo includeth e classicc haracteristpicr opertieosf morer ealistico ceans olitonp ackets.
Undert he resonancceo nditiona coustimc odec ouplingtr ansferas significanatm ounot f energyfr oml owerm odesin to higher-
orderm odesth ath avem uchl argera ttenuatiorna tesT. hisb ecomeas n ewa ttenuatiomn echanismfo r shalloww aterw ith a strong
thermoclineT.h e resonancelikeb ehaviopr redictedb y the PE analysisis consistenwt ith modec ouplingth eory.[ Work sup-
ported by ONR and IAAS.]
MONDAY AFTERNOON, 17 MAY 1993 BALLROOM, 1:00 TO 5:15 P.M.
Sessionl pAO
Acoustical Oceanographya nd Underwater Acoustics:O cean Acoustics in Shallow Water: What are the
Issues? II
MohsenB adiey,*C oohair
Universityo f Delaware,G raduateC ollegeo f Marine Studies,N ewark, Delaware1 9716
*Current.O' fficeo f NavalR esearchO, cean(cid:127)4 cousticsC, ode1 1250(cid:127)4,8 00 NorthQ uincyS treet(cid:127)4, rlington,V irginia2 2217
Peter H. Rogers,C ochair
GeorgiaI nstitute of TechnologyS, choolo f MechanicalE ngineering(cid:127)4, tlanta, Georgia3 0332
Contributed Papers
1..oo water providess omeb enefits( essentially,b y taking advantageo f mul-
tiple imageso f the targetr eflectedin the boundaries)b, ut achievinga
lpAO1. Sinalloww ater acousticsr esearchi ssues. Hassan B. Ali,
positiven et gain is criticallyd ependenot n our basicu nderstandinogf
RobertL . Field, JeraldW . CaruthersR, . A. Wagstaffa, nd StanleyA .
the multiplicity of detrimentale ffects.T hese issuesa re discussedin
Chin-Bing (Naval Res. Lab., StennisS paceC enter, MS 39529)
terms of their relevancyt o acquiringt his understandingto support
Propagationo f soundi n shalloww ater is complicatedb y the prox- ongoingte chnologayn da dvancedde velopmenptr ogramsin the Navy.
imity of the boundarieasn d interferringn oises ourcesa nd by environ-
mentalv ariabilityM. oreoverg, eomorphiacn dg eoacoustpicr opertieos f
1:15
the seabedp lay a major role in the charactero f the propagatings ignal.
Propagationp redictionis complicatedb y the needt o usef ull wavef ield lpAO2. Issues in numerical modeling of shallow water
modelsv ersuss implerr ay models.R oughnessa nd inhomogeneitieosf seismoacoustics. Henrik Schmidt (Dept. of Ocean Eng., MIT,
the interfacesa nd seafloora re important to both forward and backscat- Cambrldse, MA 00139)
ter. Multiple interactionsw ith the interfacesc ause signal frequency,
angle,a nd time spreadsc, oherencelo ss,a nd out-of-planee ffectsa, nd Over the lastc oupleo f decadess ignificanpt rogressh asb eenm adei n
theye xacerbatseh eara nd interfacew avep roblemsT. he practicale ffects modelings eismoacoustpicro pagationin shalloww ater.T hus,f or exam-
of all this are complicationisn the reverberationa nd noisef ieldsa nd in ple, environmentafle aturess ucha s a stratifiede, lasticb ottomi s a stan-
signalc oherenceO. n the otherh and,m atch-fieldp rocessinign shallow dard featurei n severalp ropagationm odels,e ven range-dependenotn es
2269 J. Acoust.S oc. Am., VoL 93, No. 4, Pt. 2, April 1993 125th Meeting:A cousticalS ocietyo f America 2269
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with the developmenot f the elasticP E. The paste mphasiso n deter- Sonarso peratingi n shalloww ater usuallye ncounterw hat signal
ministicp ropagationm odelingh as beend rivenb y the primary interest processortse rm a reverberation-limiteedn vironmenth; ighers ignall ev-
in passives onars ystemfso r shalloww ater.H owever,w ith the increased els simply lead to higher reverberationa nd not to improvedp erfor-
importanceo f actives onars cenariosin shalloww ater, as well as the mance.C onsequentlyt,h e principalm eanso f improvings onarp erfor-
significancoef acousticfso r underwaterc ommunicationa, wide rangeo f mancei s to use signalsa ppropriatef or the task and environment.T his
new issuesf ace the acousticm odelersT. hus, at the higher frequencies impliest hat robuste nvironmentaml odelsa re imperativeI.n boths onar
involved,t he traditionalw avet heorym odelsa re not particularlye ffi- and radar, reverberationo,r scatteringi,s usuallym odeledt o be a ran-
cient, and classicaal pproachess ucha s ray tracings houldb e re-visited dom linears ystemc haracterizedb y a scatteringfu nction,o r someo ther
and modifiedt o properlya ccountf or bottomi nteractionin particular. secondm oments ucha sa two-frequenccyo rrelationfu nctionT. ypically,
In addition,t he spatiala nd temporalc oherenceb ecomesa n important an active sonar resolvesa target or an environmentalp arameter by
issue,i n particular in relation to the oceanographica nd geophysical either rangeo r time gating( high bandwidths ignals)o r Doppler gating
variabilityr, aisinga needf or stochastisce ismoacousmtico delsA. nother (long durations ignals).T he resolutionp ropertieso f a signala re spec-
importanti ssuei s reverberationfr om the rougha nd inhomogeneous, ified by its ambiguityf unctiona nd the interactionw ith the scattering
elasticb ottom. The variousi ssuesa re illustratedu sings imulateda nd functioni s the singlem osti mportantf actori n determinings ystemp er-
real data, and the associatedn eedsf or new mathematicala nd numerical formanceT. his talk will providea briefo verviewo f someo f the signal
models are discussed. processinigs suesfo r shalloww ater sonars.
1:30
2:15
lpAO3. Modeling acoustic propagation in shallow range-dependent
environments.R . A. Stephen (Dept. of Geol. and Geophys.,W oods lpAO6. Forward scatter and signal coherence in shallow water.
Hole OceanographicIn st., Woods Hole, MA 02543) $erald W. Caruthersa nd Michael F. Werby (Naval Res. Lab., Stennis
SpaceC enter, MS 39529)
Shallow water meansw ater depth less than an acousticw ave-
length and implies by definitions trong interactionw ith the bottom. In shalloww ater it is difficultt o separatet he effectso f propagation
However since most ocean bottomsa re rough and laterally heteroge- in a waveguidec omposedo f layeredm edia from thoseo f scattering
neousm any of the assumptionsu sed to simplify the elastodynamic producedb y roughnesast the layer interfacesM. oreover,t o properly
equationsa re invalid,O n the otherh and,s incet he depthsa nd rangeso f accounfto r thesec ombineedf fectst,h ree-dimensionfaull,l ye lasticp rop-
interesat rec onsiderabllye ss( in termso f wavelengthst)h and eepw ater agationa nd scatteringm odelsm ust be used,i f a fundamentalu nder-
problemsd, irect numericals olutionso f shalloww ater problemsa re standingo f shalloww aterp ropagatioins to be attainedV. ery few for-
quitet ractableF. inite differencea pproachesfo, r exampleh, avet he fol- ward propagations tudies include scatteringe ffects on forward
lowing advantageso ver alternativem ethods:( a) They includea ll shear propagatingsi gnalp ropertiess ucha s amplitudea nd coherenceIn. shal-
wave (rigidity) effectsi n the bottom including body and interface low waters uche ffectsa re criticalt o the conditiono f the signalw heni t
waves.( b) They can be appliedt o pulseb eamsa t low grazinga ngles reachesa target and when it returnst o the monostaticre ceiver.T he
(lesst han2 0') . (Methodsb asedo n infinite planew aves havec oncep- importanceo f thesee ffectso n the signalp ropertiesis magnifiedfo r
tual problemsa t low angles). (c) Both forwards cattera nd backscatter bistaticr eceiversB. oundarys catter,i ncludingo ut-of-planes catter,i n
are includedi n the solutions.( d) Multiple interactionsb etweens cat- shalloww aters ignificantlayf fectsti mea nda ngle( as wella sf requency)
terersa re included.( e) Arbitraryr ange-dependetnotp ographya ndv ol- spreadsth at leadt o degradationo f signalc oherenceT.h e requirements
ume heterogeneityc,a n be treateds imultaneousliyn the samef ormula- to dealw ith scatteringin threed imensionasn d to includef ull wavef ield
tion. (f) Problemsa re scaledt o wavelengthasn d periodss o that the physicsin propagationm odelsi ntroducet he needf or extensivec om-
resultsa re applicableto a wide rangeo f frequencies(.g ) The method puterc odea ndc omputationpaol wer.W hilet herea re no simples olu-
considerssc atteringfr om structuresw ith lengths caleso n the order of tionst o the problemsth eser equirementism poset,h e advanceo f com-
acousticw avelengths. putationatle chnologieasn d the developmenotf advancedp ropagation
and scatterincgo desw ill allowc omprehensiavned innovativea ppro-
achsT. heseis sueasr ea ddresseadn da n approactho solvingth iss ignif-
1:45
icant part of the shalloww ater acousticps roblemi s discussed.
lpAO4. Modeling issues for predicting sound propagation at
moderate frequencies in bottom-limited sound channels. Frederick
D. Tappert,M ichael G. Brown,H arry A. DeFerrari, CharlesM onjo,
2:30
and I_anN ghiem-Phu (Div. of Appl. Marine Phys.,R SMAS/U.M.,
4600 RickenbackerC swy., Miami, FL 33149-1098) lpAO7. Fluctuationsa nd predictabilityo f soundp ropagationa t
moderatefr equencieins bottom-limitesdo undc hannels.H arry A.
Considers ound propagationin the moderatef requencyr ange
DeFerrariM, ichaeGl . BrownF, redericDk . TappertC, harleMs onjo,
(deptht o wavelengthra tio,H /A, between2 0 and 100) in shalloww ater
andL an Nghiem-Phu( Div. of Appl.M arineP hys.,R SMAS/U.M.,
environmentws ith bottomr oughnessM. easurementisn the Straitso f
4600R ickenbackeCrs wy.,M iami, FL 33149-1098)
Florida have shownr emarkablep hases tabilityt ogetherw ith rapid
(minutes-to-hoursu) nstablea mplitudef luctuationsth at nevertheless Soundp ropagatioinn t hem oderatfere quencrya nge(d eptht o wave-
yields tablee nvelopews hena veragedo verm anyh ours.W hat physical lengthr atio, h/(cid:127)., between2 0 and 100) in shalloww ater environments
effectss houldb e containedin an acousticm odeli n ordert o predictt he with bottomr oughnesiss extremelyc omplicatedva, riablea, ndp oorly
observebde haviorI?t iss uggestethda ta full-wavem odetl hati sc apable understoodM. ultipaths are generallyn either resolvable( assuming
of multipler oughb ottomf orwards catteringa nd includest emporally Q> 1) nor stableF. luctuationsa re dominatedb y a combinationo f con-
slowlyv aryingr ange-dependesnotu nd-speepdro filesw ill yieldo bserved tinualf ormationan dd estructioonf multipathass w ella sb y perturba-
results,w hen usedt ogetherw ith coherents ignalp rocessingte chniques. tionst o otherwisset ablep aths--asis thec asein deepw ater.P ropaga-
A broadbandP E modelw ill illustratet he assertiona, t leastq ualita- tionc haracteristiocbss erveidn theS traitso f Floridaf or severarla nges
tively.A bsolutele velp redictionis quitea notherm attert hat requires havec onsistenfet aturesS. oundf ieldsa re slowlyv aryinga nd phase
more extensivee nvironmentailn puts. coherenLt.a rgef luctuationwsi thp eriodicitieosf a fewm inutesto a few
hoursc anb eq ualitativealyc countefdo r asa slowlym odulatecdo mpli-
2.'OO catedc austisct ructurTeh. eq uantitativdee scriptioonf t hesep henom-
enai s beyondth e domaino f validityo f existingth eoriebs ecausvea ri-
lpAOS. Souar sigmdp roemsinga nd shalloww ater acoustics. Arthur ablesd o not separataen d raysb ehavec haoticallyA. dvanceisn both
B. Baggeroer( Dept.o f OceanE ng.,R m. 5-204,M IT, CambridgeM, A theorya nde xperimenatrse r equiretdo improvuen derstandoinf tgh ese
02139) propagationi ssues.
2270 J.A cousSto. cA. m.V, ol9. 3,N o.4 , Pt.2 , Apd1l 993 125thM eetinAgc: oustiScaolc ieotyfA merica 2270
Downloaded 27 Jun 2010 to 192.38.67.112. Redistribution subject to ASA license or copyright; see http://asadl.org/journals/doc/ASALIB-home/info/terms.jsp
2:45 nally, the impacto f this forward modelings tudy on possiblein verse
problems tudiesf or the oceanographiys discussed.
lpAOS. Somef eatureso f ambientn oisei n shallowt ropicalw aters.
DouglasH . Cato (Maritime OperationsD iv., Mater. Res. Lab,,
DefenceS ci. & Technol.O rganisationP,. O. Box 44, Pyrmont,N SW, 3:45
2009, Australia)
lpAOll. Shalloww ater acousticc hannelm onitoringw ith selective
This paper discussetsh e main featureso f ambient noisei n shallow modee xcitation.J amesC . Preisiga ndl oskoA . Catipovic (Dept.o f
tropicalw atersn ear Australiaa nd the implicationfso r shalloww ater Appl. OceanP hys.& Eng.,W oodsH ole OceanographIincs t., Woods
acousticsN. oisef rom biologicasl ourcesis usuallyt he dominantc om- Hole, MA 02543)
ponento f the ambienti,n the absencoe f high windsa nd heavyr ain.
The shalloww atere nvironmenist characterizebdy multiplep ro-
Noisel evelsf luctuateb y moret han 30 dB (commonlyb y about2 0 dB)
cessetsh at covera wider angeo f temporaal nd spatials calesa nd that
as a resulto f biologicaal ctivity.D iurnallyv aryingb iologicacl horuses
havea significanetf fecot n thep ropagatioonf acoustisci gnals[{ 3. V.
produceth e highesnt oisel evelsa nda re evidentin the frequencrya nge
Frisk, Report on the Officeo f Naval ResearchS hallow Water Acous-
40 Hz to 5 kHz. Snappings hrimpn oisee, xtendingto frequenciebse -
tics Workshop,2 4-26 April 1991,W HOI-92-06].T he couplingb e-
yond 200 kHz, is the dominantc omponento f ultrasonicn oisew here
tweent he modeso f acoustics ignalsis potentiallya n effectivem eanso f
habitatsa re favorableB. iologicatlr ansients(s ignalsd etectablefr om
monitoringt hesep rocessesT.r aditionally,a signals ourcei s usedt o
individuaal nimalsu, suallyfi sha ndw hales)a re alsoi mportantT. raffic
excite the acousticm edium. A receivera rray is usedt o sort out the
noisev ariesf rom high levelsn ear ports to negligiblein areasr emote
modeso f the propagatinsgi gnala nd the couplingb etweenp articular
from portsa nd wherep ropagationis poor.
modesis inferredf rom travelt ime differenceTs.h is approachp rovides
relativelyli ttlec ontrool f the distributioonf transmitteedn ergya mong
the modesa nda ddsu ncertainttyo the estimatioonf the couplingb e-
3:00-3:15 Break
tweenp articularm odesA. n alternativea pproachis proposetdo usea n
array of sourcest o selectivelye xcite modeso f the medium. There are
3:15 severaal dvantageasn dc hallengeosf usings ucha n approachF. irst,t his
will improvet hea bilityt o estimateth ea ctualc ouplingb etweend ifferent
lpAO9. The issueo f time-varyingo ceanographcico nditionsa s related modesS. econdi,t is well knownt hat propagatioonf and couplingb e-
to acousticsin shalloww ater. PeterJ . Stein (ScientificS olutions,I nc., tweenp articularm odesis mosts ensitivteo environmentaple rturbations
47 Aster Ct., Nashua, NH 03062) and James K. Lewis (Atlantic havingp articulars patiasl cales[.B . Cornuellea ndB . M. Howe,H igh
AppliedR esearchC orp.,L ongbeachM, S 39560) SpatialR esolutionin VerticalS liceO ceanA cousticT omography,J .
GeophysR. es.9 2, No. CI 1 ( 15O ctober1 987)].T hereforeb,y exciting
Heree videncies shownth att ime-varyinogc eanographciocn ditions
particulamr odesa ndn ot excitingo therm odest,h e emitteds ignacl an
area n importanct onsideratioinn s halloww atera coustipcr opagation.
bet unedt o bem osts ensitivteo environmentfalul ctuationosn a partic-
In mosts halloww aterc onditiontsh erec anb e substantiatel mperature
ulars patiasl caleA. majorc hallengine thisa pproacihs t het uningo f the
and salinityv ariationsC. oastajle ts and freshwateor utflowsc an effect
sourcea rray to ensuret hat only the desiredm odesa re excited.
regionso ut to 40-50 km offshoreS. ound-speepdr ofilesa, nd thust he
acoustipc ropagatiocno nditionsc,a nb e highlyv ariablein boths pace
and time.T his is shownb y lookinga t a few examplesO. ceanographic 4:00
modelingw asc onductedu singa three-dimensionanlu mericalm odelf or
lpAO12. A two-wave-numberd escription of shallow water ocean
predictingt he time- and range-varyingco nditionsT. he resultsf rom the
acoustics. Robert M. Kennedy (Naval Undersea Warfare Ctr.
oceanographicm odel were input into the Navy standardP E model to
Detachment,A UTEC, West Palm Beach,F L 33402-7517)
predictt he acousticp ropagationth rought hesem odelt estr egionsT. he
results show substantial differences in the transmission loss over time Wave-numbesrp ectrumis a usefulm easureo f the spatialp roperties
changeosn the ordero f hoursO. theri ssuessu cha sb ottoma bsorption, of the underwater acoustic field. A basic tenet of the wave-number
surfacreo ughnesesff ectsa,n dr eflectionfrso ma slopingb ottomw ill also spectruma pproachis the spatialh omogeneitoyf the cross-correlation
be addressedF.u rtherm odelinge ffortst hat couplea dvancedo ceano- (or cross-spectrumfu) nction;a propertyt hat is frequentlys atisfiedin
graphicm odelsto advancerda nge-dependaecnot ustimc odelasr es ug- deepw atere nvironmentsS. halloww atera cousticc hannelso, n the other
gested. hand,a re basicallyn onhomogeneoiuns t he depthv ariablea sa resulto f
the additiono f numerousn ormalm odeso r multipathsT. wo-frequency
spectrumh aveb eenu sedt o analyze( temporal) nonstationaryv ariables
3:30
and to a lessere xtent two-wave-numbesrp ectrumh ave found use in-
lpAO10. How well do physical oceanographic(P .O.) models and vestigatingth e nonhomogeneounso isei n hydrophonea rray structures.
routine P.O. measuremenths elp predict acousticp ropagationi n For this paper,t wo-wave-numbe(rv ertical) spectrumw ere found for
shalloww ater? JamesF . Lynch and Timothy F. Duda (Dept. of severacl anonicaul nderwatear cousticw aveguidesT.h e physicasl ignif-
Appl. OceanP hys.& Eng., WoodsH ole OceanographiIcn st., Woods icanceo f the resultsa re identifiedb y comparingt hem with similar
Hole, MA 02543) spectrumfr om structuraal coustica nalysisP. articulara ttentionis paid
to the consequencoefs th e nonhomogeneosutrsu ctureto hydrophone
In trying to answert he questionp osedi n this title, the following arrayd esigna ndt hec hannepl arametertsh at emphasizteh e two-wave-
outlinei s followed.F irst, the dominanto ceanographpicr ocessetsh at number charactero f the spectrum.T he sensitivityo f the resultst o
effects halloww ater (coastal) acousticp ropagationin the 50-Hz to intermodacl orrelations uggestas m easuremenatp proachfo r determin-
2-kHz band is identified.N ext, how well theseo cean processesa re ing this basicc omponentc orrelation.
understooda nd modeled,a nd how the modelsa re constrainedb y stan-
dard input data is investigatedT. he limits of predictabilityo f the ocean
4:15-4:25 Break
field (spatiallya nd temporally) are then examined.T he issueo f the
sensitivityo f the acousticf ield to the particularo ceanp rocesseiss in-
vestigatedf,o llowedb y the predictabilityo f the acousticfi eld propagat- 4:25-5:15
ing through the oceanp rocessesT.h e variousm easureso f the acoustic
field (proploaa,c oherencee, tc.) one uacat o quantify the oc(cid:127)an/ac. oustlc PANEL DISCUSSION;
interactiona re consideredr,e flectingth e needso f variousa cousticsa p- Panel Moderator.P' eter H. Rogers
plicationsW. hicha cousticms odelsa re appropriatefo r describinpgr op- PanelM embers.D' . Weston,W . Carey, M. BuckinghamT, . Ewart,F.
agationt hroughp articularo ceanographifcie ldsi s alsoa ddressedF.i - Tappert,G . Frisk, J. Ewing,J . Austin,J . Zhou
2271 J. Acoust.S oc. Am., Vol. 93, No. 4, Pt. 2, April 1993 125th Meeting: AcousticalS ociety of America 2271
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MONDAY AFTERNOON, 17 MAY 1993 SALON MACDONALD, 1:45 TO 4:15 P.M.
Session1 pEA
Engineering Acoustics:S ound Intensity Measurement, Calibration, and Standards
GeorgeS . K. Wong, Chair
National ResearchC ouncil,I nstitutef or National MeasurementS tandards,O ttawa, Ontario K1A OR6, Canada
Chalr's Introduction(cid:127)l:4$
Invited Papers
l:S0
IpEAI. Intensity measuremenot n time-varyings ignals. Gunnar Rasmussen (Brfiel & Kj(cid:127)er, 2850 N(cid:127)erum, Denmark)
Intensity measurementsa re especiallyv aluablew hen used for the detectiono f phenomenao f a fast-varyingn ature. Sound
pressurele velsa re greatlyi nfluencedb y the charactero f the environmentt,h e reverberationti me, the locationo f acousticc enters,
and other reactivec onditionsT. he intensityd ata may be largelyi ndependenot f thesec onditionse speciallyw heno btainedi n very
shortp eriodso f time. Somes tandardrse quirea widef requencyra nge,w hicho ftenr equiresa t leastt wo spacingbse tweenth e
microphonaec ousticce ntersa ndt hust wo measuremenctasr riedo utw ith the samea cousticacle nterf or the probeM. any sources
are not stationarya ndw ill thereforen ot offert he repeatabilitrye quiredfo r two measurementtos b e carriedo ut with ther equired
accuracyE. xamplesa re vehiclep assbye, xplosionsn,o nlinears tructuralv ibration,r eciprocatinegn ginesa, nd measurements
duringb reakdownas w ella sr un up andd own.T echniqueisn volvingF 1TFt echniqume ayh aves eriouss hortcomingusn ders uch
conditionsT. hey will work extremelyw ell duringc alibrationa nd laboratoryc onditionsW. hen therei s a needf or actualt ests,
possiblee rrorsm ay be difficultt o assessS.p atialt ransformatiown ill alsor equires teadyc ontinuoussi gnalsT. he responsoef
transducersto very short durations ignals,t he influenceo f the transducers ize and configurationa, s well as wayso f assuringa
wide frequencyr angea s requiredf or standardizeds oundp owerm easuremenwt ill be reported.T he importanceo f the probe
configurationf or practical field measurementws ill be discussed.
2:10
lpEA2. Some recent developmentisn phasem atch of microphonesG. eorge S. K. Wong (Inst. for Natl. Measurement
Standards,N atl. Res. Council, Ottawa, ON KIA 0R6, Canada)
Phasem atchd ata for condensemr icrophoneosb tainedw ith a new couplera re discusseTdh. e protectiveg ridso f the
microphonehsa ves omei nfluenceo n the phasem atcha t frequencieasb oveI kHz. The phasem atcht heoryi s basedo n the
exchangme icrophonmee thod[J .A coustS. oc.A m. 90, 1253-1255(1 991)],w hichis alsoc apabloef discernintgh ep hasem atch
betweenth e amplifierso f the two measuringch annelsT. he performancoef the coupleri s verifiedw ith directe lectricaml easure-
mento f the phased ifferencbee tweenth et wo channelasn db y comparisown ith the correspondinmge asuremenptsro videdb y the
coupler.A comparisonis madeb etweent he data obtainedw ith the couplera nd thosea cquiredw ith the electrostatiacc tuator
method.S incet he electrostatiacc tuatorm ethodd oesn ot exposeth e microphonbe ackc avityp ressureeq ualizingv entt o the same
excitationt,h e phasem atchr eadingsp rovidedb y the electrostatiacc tuatorm ethoda rc confirmedto be not valid, particularlya t
low frequencies.
2:30
IpEA3. Progresso n the developmenotf nn instrumenst tandardfo r the measuremenotf soundin tensity. G. Krishnappa (Inst.
for Mech. Eng., Natl. Res. Council,M ontreal Rd., Ottawa, ON KIA 0R6, Canada)
ANSI and IEC workingg roupsh aveb eeni nvolvedi n the developmenot f instruments tandardsfo r the measuremenotf sound
intensityT. he primarya pplicationo f theses tandardsis to instrumentuss edf or determinings oundp owero f noises ourcesin
accordanwceit ht her equiremenotfs a pproveAdN SI andI SOs tandardTsh. ea pproactha kenb yb otht hew orkingg roupisn the
developmeonft thed ocumenitssv erys imilarw itho nlym inorv ariationsn,o tablyin thef requencrya nges, pecificatioonf p ressure
residuailn tensitrye quiremenatsn,d t estingd evicesR. equiremenatns dp erformancvee rificationasre s pecifiefdo r thec omplete
instruments ystemc omprisingp robea nd processora,n d separatelyfo r the probea nd processorP. erformancev erificationt(cid:127)t (cid:127) arc
writtenin termso f typeo f testsp, eriodivce rificatiotnes tsa, ndf ieldc hecksT.h ep apewr illd iscusisn detailt, hes copaen dp urpose
of the standardi,n strumenrte quirementasn, d methodsfo r performancvee rifications.
2:50
IpEA4. Standingw avet ubet estingo f soundin tensityp robes.R . W. Guy (Ctr. for BuildingS tudiesC, oncordiUa niv., 1455
de MaisonneuveB lvd. West, Montr6al, PQ H3G IM8, Canada)
To ensurceo rrecmt easuremoenf sto unidn tensitiyn highlyre activfeie ldsa ndl owerfr equenci(e(cid:127)4s0 0 Hz) a standinwga ve
fieldp erformanctee sth asb eens pecifiedin a draft standard( IEC 1043I nstrumentsfo r the measuremenotsf sound--instruments
whichm easuirnet ensitwyi thp airso fp ressusree nsinmgi crophonDesra, ftS tandar1d9 9)1. Thep urposaen dr equiremenotfs th e
2272 J. AcousSt. oc.A m.,V ol.9 3, No.4 , Pt.2 , Apri1l 993 125thM eetingA:c ousticSaol cietoyf America 2272
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testa ree xaminefrdo mt heoreticaanl de xperimenptaelr spectivaensd,s uggestiofonrsc hangaer em adeI.t iss howtnh atd iffering
tolerancliem itsa rer equireidf overa ndu nderestimaetrero rc aseasr et o bec onsidereAd w. idert olerancliem itm ayb es pecified
fort hes tandinwga vere quirebdy t het esta ndf ewemr easuremennetesd to bet aken( 2 in contrastot 15) . [Works upportebdy
theN ationaSl ciencaen dE ngineerinRge searcCho unciCl anada--IndividuOalp eratinGg rant.]
3:10
lpEAS. The standardizatioonf soundp owerd eterminatiouns ings oundi ntensitym easurementAsn: analysisb asedo n a
computesri mulationF. r(M(cid:127)ric Lavillca ndJ eanN icolas (Dept.o f Mech.E ng.,S herbrookUen iv.,S herbrookPeQ, JIK 2R1,
Canada)
The standardizatioonf soundp owerd eterminatiouns ings oundi ntensitym easuremenitss a muchm ored ifficultt askt han in
thec aseo f pressurme easuremenTtsh.e d ifficultyc omesfr omt hef actt hatb otht hep recisioonf eachin tensitmy easuremeannt d
of ther esultinsgo undp owerd epends trongloy n thea coustifcie ld.T hise ffecht asb eena nalyzedw itha computesri mulatiotnh at
hasa broadesr copeth anp reviouos nest hat werer estrictedto the evaluatioonf the samplinger rorf or the sourcefi eldo nly.
Becausteh e intensitye stimatedw ith two microphoneiss c omputedfo r sourcerse presentebdy monopolaer raysl ocatedin sidea s
wella so utsideth em easuremesnut rfacet,h ee ffectos f instrumentatioenrr ora ndb ackgrounndo isefi elda rei ncludedT. hed iscrete
pointm easuremesntta ndardpsr oposebdy ISO andA NSI arec riticallye xaminewd itht hec omputesri mulationA.m ongo ther
resultsit, is shownh owF 3 a sd efinedin thel SO standarids a goodin dicatoor f thep hasem ismatcehr rorb ut shouldn otb eu sed
in conjunctiownit hF 2 a ss uggestiend t hes tandaradt thisa pproaclhea dsto variableer rorl imits[. Works upportebdy IRSST.]
ContributedP apers
3:30 immunity,s malls ize,a nd robustnesasr e describedT. he interferometric
microphoneis a low-finessFea bry-Perots ensorin which interference
IpEA6. Field calibration and check-outo f an intensity measurement
occursb etweenth e light reflectedfr om the endf aceo f the fibera nd that
system using a simplified probe and a reference sound source.
reflectedf rom the membraneT. he return signali s directedt o a fast
AngeloJ . Campanella (CampanellaA ssociate&s ACCULAB, 3201
photodiodeT.h e sensohr asa flat frequencyre sponsfer om 50 Hz to 20
Ridgewood,D r., Columbus,O H 43026)
kHz. The phases hift is directlyp roportionatlo the amplitudeo f the
Therei s needf or a simplef ieldc heck-ouat nd calibrationm ethodf or diaphragmd isplacemenwti th a broadd ynamicr ange.T he sensitivitiys
intensitym easuremensyt stemsM. icrophonesp,r eampsa, ccompanying 2 rad/Pa and the minimumd etectablep ressureis lesst han 0.001 Pa
softwarea, nd data displayc onstantcsa n comei n questiona fter ship- whent he phases hifti s measureda t quadratureT. he intensity-reflection
ping, reassemblya, nd resetting.A simplifieda nd standardm ethodo f microphones implym easuresth e changeo f the intensityo f light that is
exercisingth e total measuremenst ystemi n a few minutesf rom micro- recapturedb y the fiber after reflectionf rom the diaphragm.I t has the
phonet o displayi s presentedM. icrophonesa re mountedi n the side-by- advantageo f low cost and easeo f soundr eproductionI.n a dynamic
sidec onfiguratiodne scribedb y Per Bruel[ 2nd ICA (Sept. 1985)].T he rangeo f more than 60 dB, it is lineara nd hasa flat frequencyr esponse
soundf ielda rounda n ACCULAB RSS-101[ Inter-Noise9 1,961-964] from 50 Hz to 20 kHz. The minimumd etectablep ressureis 0.1 Pa.
references ounds ource( RSS) is sweep-surveye[dT achibana,I nter- [This work is supportedi,n part, by NSF Grant No. MSS-9101514.]
Noise9 1, 1041-1044]o vert he fives ideso f an enclosingl- m cube.T his
intensitys urveym ethodt endst o cancele xternaln oisea nd reflectionsin
4:00
a wide varietyo f environment(ss hopso, fficeso, utdoorse, tc.). Instru-
ments oftwareis thens ett o displays oundp oweri n octaveb andst hat 1pEA8. Underwater PVDF acoustici ntensity probe. David Van Tol
can be directlyc omparedw ith the laboratoryc alibrationv aluesk nown andW . JackH ughes (Appl. Res.L ab., PennS tateU niv., P.O. Box3 0,
for the RSS-101S. oundp owera greemenwt ithin I to 2 dB will be found StateC ollege,P A 16804)
A-weighteda nd in the 250-Hz to 2-kHz octaveb andsw ith a nominal
The desiredc haracteristicasn dp ropertieosf an underwateirn tensity
l-in. (25-ram) microphones pacingS. ystemp erformancein lower and
probea re b(cid:127)t achievedb y constructingth e sensoro ut of the polymer
higherf requencyb andsm ay be verifiedb y repeatingth e test with ap-
polyvinylidenefl uoride( PVDF), which hast he propertieso f high sen-
propriatem icrophones pacing.
sitivity, small thicknessa, nd an impedancec loset o that of water. An
array is beingd esignedto measureth e acousticin tensityi n two dimen-
3:45 sionsa nd at severalc ollinearp oints.S incet he characteristicim pedance
of PVDF is close to that of water, the PVDF sensorsa re almost acous-
1pEA?. Fiber-optic interferometric and intensity microphones.
tically transparentT. his helpst o minimizet he scatteringa nd interfer-
ChonghuaZ hou, S. V. Letchef (Dept. of Phys., Univ. of Rhode
encec ausedb y the probe.T he probea rray is designedfo r use over a
Island,K ingston,R I 02881), A. Shukla,a nd RamanS ingh (Univ. of
frequencyra ngeo f 5130H z to 5 kHz. Designd ataw ill be presenteda,n d
RhodeI sland,K ingstonR, I 02881)
calibrationm easurementosf magnitudea nd phasew ill showh ow well
Bothi nterferometriacn dr eflective-intensiftiyb er-opticm icrophones thep robpe ei'formeSdo.m oef t hea dvantagdeiss,a dvantaagnedsc ,o n-
that exploitt he fiber-optica dvantageosf electromagnetic-interference structionp roblemsw ith PVDF sensorsw ill alsob e addressed.
2273 J. Acoust.S oc. Am., Vol. 93, No. 4, Pt. 2, April 1993 125th Meeting:A cousticalS ocietyo f America 2273
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