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256 Pages·2002·19.34 MB·English

by  Leo L. Beranek

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ACOUSTICS
LeoL .B eranek
195Ed4i tion
Acoustic Laboratory
MassachuIsnestttisot fTu etceh nology
BolBte ranaenkdN ewmanI,n c.
199Ed3i tion
MemoriaDlri veS,u ite
975 804
CambridgMeA,
02138
PREFACE
Acousitsim coass fta scinsautbijnegMc uts.i c, arcehnigtienceteurr­e,
ings,c iednrcaem,ma e,d icpisnyec,h olaongdly i,n guiaslstlei ecfksr oimt
answetrobs a sqiuce stiinot nhse fiierl dIsn.t hAec ousLtaibcosr atory
atM .LTs.t udemnatysb ef ounwdo rkionnsg u cdhi verspirfioebdl ems
asa uditoarnidsu tmu ddieos ign, loudspseuabkjeercp tedirevcseei pg­n,
tioonfc omplseoxu ndpsr,o ducotfis oynn thsepteiecpc rho,p agaotfi on
sounidnt haet mpohserdei,s perosfi osnoi unln idq urieddsu,c otfin ooni se
frojme t-aierncgrianafents du, l trasdoentiecco tfib oranti unm orTsh.e
annumaele tionftg hsA ec oustSiocicaelto yfA meriacrave e ritfiavbel­e
rinsgh owwsi,tp ha pearnsds ympoosnis au bjeicnat ltslh aeb ove-named
fieldOsp.p ortufnoiertm ipelso ymaernaetb undtaondtab ye caumsaen ­
agemeinnti ndushtarsry e cogntihzeie mdp toarncto ntributthiaotn s
acousmtaikcesbs o ttho t hiem proveomfet nhtep irro duacntdts o the
betteromfe netm plwooyrekeic nogn ditions.
Theriesn oe asryo atdo a n undersotfap nrdeisnegn ta-cdoauys tics.
Firtshtes tudemnuts atc quitrheev ocabutlhaaritysp ecultiota hre
subjeTchte.hn e m usats simitlhaleta ewg so vernisnogu npdr opagation
and soruanddi atrieosno,n aanncdte h,be e havoifot rra nsduicnae nr s
acousmteidci .u mLasbtu,tc ertanionotlf yl eaismtp ortahnemc ues,t
LibraorfyC ongreCsast alCoagr dNu mber8:6 -70671
leatronu nderstthaehn eda ricnhga racteorfpi esotpialcnesdt here ac­
InternatSitoannadlaB rodo Nku mber0:- 88318-494-X
tionlsi sotfe tnose orusn adnsdn oises.
Thibso oikst heo utgroowfat cho urisnae c oustthiacttsh ea uthor
Copyright©119958461,,9 901,9 931,9 96,
hast augthots eniaonrdst ofi rst-ygeraard usattued einnte sl ectrical
byt hAec oustiScoacli eotfAy m erica
engineaenrdic nogm municpahtyisoinTc hse.b aswiacv eeq uatainodn
somoef i tmso rien teressotliuntgai rodeni ss cuisnsd eedt aiintl h fier st
Allr ighrtess ervNeod p.a rotf t hipsu blicamtaiyob ne
parotf ttheex tT.h er adiaotfis oonu ncdo,m pnoenotfsa coustsiycsa­l
reproeddu,cs torienda r etriseyvsatle omrt, r ansmitted,
temmsi,c rophloonuedss,p eaankdhe orrsan,rs te r eaitnse udffi cideentta il
ina nyf ormo rb ya ny mea(neeslc tronmiecc,h anical,
toa lltohwse e risotuusd etnoet n tienrt eol eocatcrousdteisciagln .
phootcopyirnge,c oirndgo,r o therwiwsiet)h otuhte
Theriesa ne xtentsrievaet moefsn utc h impporrotbalnaetsms so und
priowrr ittpeenr miosnso ift hep ublisher.
ine nclosmuertehsof,do snr o irseed ucthieoanr,is npge,ei cnht elligibility,
andp sycahcoousctriict feorcrio am fofrotsr,a tisfascpteoercyh intelligi­
Publisbhyet dh eA coustiScoacli eotfAy m erica
biliatnydf, op rl easlainstt ecnoinndgi tions.
throutghhAe m ericIanns titofuP they siIcnsc,.
Theb oodki ffeirnos n ei mportraenstp fercotcm o nventtieoxnotansl
500S unnsyidBelv d WoodburNye,w Y ork1 1797
., acuostiicns thaetm pahisti ztehsep ractaipcpalli coafte iloencc tarli­
circtuhietoi rnty h es olutoifao wni de vaorfpi reotbyl eWmhse.r ever
Printientd h eU niteSdt atoefsA merica
possiblbea,c ktghreoo uftn hdee l ecternigcianlae nedr tchoem muan­ic
tiopnh yisciissut t iliinze exdp laiancionuigsc taclo ncepts.
v
vi PREFACE
Theh igh-fideexlpiewtriytlfi ln dt hceh aptoenlr osu dspeenackelro sures,
hornasn,dr oompsa rticuilnatrelryeb setcianugs e thheoywt hspehe orw­
formaonfcl eo udspeeaiktehiresnbr a ffleosra ttacthoeh do rnmsa yb e
accuraatnedls yi mpclayl culaTtheedsc.eh aptaelrsisol lustthrea te
necessofic toyn sideirndi ensgi tghneo ver-saylslt em, intchleu ding SUGGESTIOFNOSR I NSTRUCTORS
amplifitehrel, o udspetahkebe arffl,eo rh orann dc onsidaelrsitonh ge
rooimn w hicthh eayr teo b eo peratNeudm.e riecxaalm palnedss um­
marcyh aratrsge i vtenof acilaiptpaltiec oaftth iiosmn a tertioma uls ic­ Thist exitsd ividiedn ttoh irtcheaepnt ers, comtphriirstiyn-gpt awor. t ::;
reproduscytsitoenm s. Eacpha ritsi ntentdobe eda pproximatIew leyek s workalt,h ough thi::;
'
Inv iew tohfei ncreaisnetde rienns otsi ec ontrtohlea, u thhoars wilvla rya mong::; tudenotwsi lltgod ifTereinnet ehse pirervi uost raining.
keptth issu bjiecnmt i nid nw ritiCnhgap te1r,2,s a4n,d 1 0t o1 3. Ift hee ntirdea sesx pecttsot akae f ulyle aorfa coustthiec sp,a rts
Thesceh apst seerrvaesdt heb asiosfa specsiuamlm eprr ogroanm shoulbde t aughitls le quewnicteth,h eex cepotfiP aornt Mcas­
noirseed uctaitMo .nLT .i n1 953T.h em ateroifCa hla pt1e1ra sn d uremenotf A cousLteivce wlhsi,cm hay ber eferrteoid nXasX soVIcaItieId,l abo­
13i sn ewa,n di ti sh opetdh aittw ilbleo fv altuoet hoisnet ereisnt ed ratoerxyp erimanednd temso nstrattihornosu ghotuhtec ourseI.f o nly
noiasned i tesff ecotnh umabne ings. a parotft he assp latnosc ontitnhureo ubgohtt he rmtshf,eu nadmentl
Ins hortthe,en ginoerse cri enwthiows its hteops r actiintc hefie e lodf materisahlod ulbdet aughitnt hef irt::;etra mn dt hmeo raep plmiaeetdr aial
acousatnidcw sh od oenso t inttoec nodn fihniees ff orttost heeotrical int hes econdO.n e::; uggc::;tdcidv isiinto hnic,sa siesa, s f oolwl:s
mattemrussk tn otwh mea teroifta hlit se xt.
Problfeomersa cchh apatreiern cluadtte hde endt eoxfft ou trsh beey FirTsetr m SecoTnedr m
thset udeRnetf.e retnocc eosl larteeardaiilnn gE ngalrgieis vhie nnt he PartI . Introduction EnergDye nsity
texatl,t honuog ha ttempt mhaadset ogb ievaeeb n i bliogorfta hpeh y Part Va.n Id netnsity
PartI Terminology
primasroyu rocfem sa teriSaulg.g esttioio nnsst rufcotbroe rsusts e of
I. Part CircuiTth eorems,
thtee xatr gei viemnm ediaatfetlteyhr ip sr eface. Part. TllPW.a ve Equa­ IX. Energayn dP ower
Thea uthwoirs hteose xpress haipsp rdeeceitpao tF iroann cMi.s III . tioll
ParXtI . Dier ivity
Wienaenrd R udolHp.h NicJhrof.lo,sthr ,e iars sistiantn hcee detailed
tiOllltioofl ltSh e and etDiretviiItnyd ex
reviaenwd e ditoifnt gh et exatn dt hep reparaotfsi oomneo riginal e
PartI V. WaveE quation Factor
materiMaaln.y memobfet rhsAe c ouiscLtsa boraattoM r.yL T. have
reaodn eo rm orceh aptaenrdsh avgei vevna luaabslsei sttaotn hcee Part I. MechanicaCli r­ PartX IV . GenerChaala rdcr­
authoOrf.t hespea,r ticmuelnatrii osmn a deo fM aryA nneS umm­er V cuit::; istioefsM icro­
fieldW,a IteAr.R osenblKietnhn,e tNh.S teveJnesr,o mRe. C ox, phones
1'art A('ou::;ticai
JoTrhdeiJa l.Bnl a uurcsht,Jr aoaratdeniu Jnoet.eEn o t ns hg heli iagsnhhcdNl,a oy pr ambaaDlnnoedu e nltliireniffgno.gr o tfs V II. (: iurie,::;t Part XVMP.ri ::;ecsurrooep nshe
ClaTrwea rdziTkhe.a uthiosdr e epilnyd ebttohe idts y piEslti,z abeth I I' ['ran::;du('crs Part Gradieannt dCo m­
H.J onetsoh, i sse cretLayrdyiB,ao nazzaonldti oh, i wsi fPeh,y llwihso , PartV r. XVI.
Part [)ired.ivity binatiMoin<T o­
madiet p ossifbohlrie m t oc ompltehtteee xwti thair ne asonsahbolryt
X. PaLt,(�rns phoesn
spaonft ime.
LEOL .B ERANEK Part[ r. [{adiatIimopne d- PartX VIII.D esigFna etors Af­
X feetiDnigr ect-radi­
allees
atoLrou dspeakers
ParXt 1[I A.c oustic Part BasRse fleExn clo-
lements XX. �:illres
E
Part I 1.B a:;Tihee oryo f ParXtX I. HomD riving
X V J)rie el-radialor
ln.i:t :;
J.1 [ Ol'llS
Lou(L;pea ken; I'mtX XI
VII
viii SUGGESTIONS FOR INS TR lJCTORS
FirTsetr m SecoTnedr m
ParXtI X.S miplEen closurPeasr XtX V. SounTdr anissm­
siotnh rouWgahl ls
betweEennc losures
ParXtX III.S ounFdi elidns CONTENTS
ParXtX VI.N oise Control Pro­
SmalRle gularly
ceduraensdN oise
ShpaeEdn closures
Sources
ParXtX VII.A cousTtriacn smis­ PREFACE.
ParXtX IV.S oundF ielidns v
sioPna ths
LargIer regularly
ParXtX IX.R eciprocity SUGGESTIONFS OR INSTRUCTORS
ShapEendc losures Calibration vii
ofT ransducers CHAPTER1 .I NTRODUCTIONA ND TERMINOLOGY
ParXtX VIII.M eausremeonft ParXtX XI.S peech I Introduction 11
AcousLteivce ls Intelligibility PART II Termino.l ogy
PART 8
ParXtX XII.P syhcoacoustic
ParXtX X. Hearing Criteria CHAPTER2 .T HE WAVE EQUATIONA ND SOLUTIONS 16
A courisnae c oussthiocusbl eda ccopamnibeyda s eotf w ell-planned IIIT heW avEeq uat.i on 16
PART
lbaorateoxrpye rimeFnotres x.a mptlheme,a teroifta hlfie r sfte wc hap­ IV Solutoifot nhWsea vEeq uation. 23
PART
terwsi lblem orsei ngificainfat cc ompanbiyea dl aboratory experiment V EnerDgeyn siatnydI ntens.i ty 40
PART
onn oeim seasuremTehnits. fwaimlill itahrseit zued weinttth h mee as­
uremeonfst o unpdr essaunrdwe i tthh ues oef a f requeanncayl yzHeer . CHAPTER3 . ELECTRO-MECHANO-ACOUSTICAL CIRCUIT4S7.
wilalp precmioarfteue l tlhyme e anionfsg o unpdr esssuorueni,dn tensity, VI Mechanical Circuits. 47
PART
decibelse,n esrodgueynn ds iatnydp, o welre lv;ae ndh ew ill understand VII AcoustCiicraclu .i ts 62
PART
thaec caucrwyi th wnhoiiccshae nb em easured. VIIIT ransducers . 70
PART
A suggesmtiendi moufm1 0e xperimleinstbtsoe,tdn h u mericfaoalr l y IX CircTuhieto reEmnse,r gayn,dP owe.r 77
PART
yea'src ouer sabnydt ermi,sa sf ollows:
CHAPTER4 .R ADIATIONO F SOUND . 91
FirTsetr m SecoTnedr m
X DirectPiavtitteyr. n s 91
No.1 .N oiesm easurement No.3 .F ree-cfiealldi broaft ion PART
XI DirectIinvdieatxny dD irectFiavcittoyr 109
microphones PART
No.2. Measuremoeftn htec on­
stanotfas n e lectro­No.5 .D esign ando fat esting CHAPTER5 .A COUSTICC OMPONENTS 116
loupdesakbearffl e
mechalnt ircaansducer XII Radiation Impedances 116
No. Predicatnidco onn torfo l PART
Measuremoeffn rte e-field8 . XIIIA cousEtliecm ents 128
noiisnea v entilating PART
:\0.4. respoonfas l eo udspeaker
system CHAPTER MICROPHONES. 144
Studoyfs ounfide lidnsa No.9 .A udiomettersitcoi fn g 6.
:\0.6. XIV GenerCahla racteorfMi isctriocpsh ones. 144
smarlelc tangular hearing PART
XV PressMuircer ophones 150
enocslure No.1 0.A pplicoaftp isoync ho- PART
XVI GradiaenndCt o mbinaMtiicorno phones 178
No.7 .S tudoyfs ounfide lidnsa acousctriict ienrt ihae PART
larigrree guelnacrl osure desiogfn aaund itorium CHAPTER7 .D IRECT-RADIATOLRO UDSPEAKERS 183
Ana ssignmoeftn wtop roblepemrsw eeks houplrdo visdueffi cient XVII BasiTch eoorfDy i rect-rLaoduidastpoera kers. 183
PART
applicoaftt ihoemn a teroifat lh et extT.h es holritos ftp roblfeomrs XVIIID esigFna ctoArffse ctiDnigr ect-radiator Loudspeaker
PART
eacchh aptsehro ubleds upplemebnytt mieedl pyr obldeemrsi vferdo m Performance 195
.
thiesn trucetxopre'rsi ence.
ix
x c 0 I"� T' E I'"� T S PREFACE TO THE PAPERBACK EDITION
CHAPTER LOUDSPEAKER ENCLOSURES 208
8. Witht hea dventt hoecf o mpacdti swci,t mhi niatuhrieg h-fideslyisttye ms
XIX SimpElnec los.u res 208 ambulateivnegr ywhearnedw, i the mphasoinsc ombinatviooinca en d
PA RT
XX Bass-rEenfclleoxs ures 239 datian w orldweid digiatnadlt elephnoentew oreklse,c troacoiusas tics
PART
subjemcotr ev ittaold atyh aint w ast hredee cadaegso .
CHAPTER 9.H ORN LOUDSPEAKERS 259 Theh earotf thefi rstth ree-fooufrt thhets e xPta,r ts
Acoustics, l­
XXIV,i ss tivlall iTdh.e spea rtesn compafsusn damenatcaolu stpircisn,c i­
XXI Horn Drivi[nign ils 259
PART pleosf e lectro-mechano-caicrocuusritatidsci,aa lt oifso onu nda,c oustic
XXII Horns 268
PART elemnetsm,i cropholnoeusd,s peaaknedrt sh,e einrc losuarneds ,s ouinnd
rooms. Even ltsieor,a ttouhnrem e i cropholneuosds,p eakaenrdsr ooms
CHAPTER 10.S OUND IN ENCLOSURES 285
hasi ncreasseevde rtailm eosv esri ncpeu blicaotfti hoen orivgoilnuamle .
PART XXIII SounFdi elidnSs m alRle gulaSrhlayp Eendc losure2s8 5 InA ppendIiIxII h avaes semblfeodra lclh aptearr se presentsaetlievce­
PART XXIV SounFdi elidnLs a rgIer reguSlhaarplEeynd c losur2e9s8 tioonft extbooksa ratnidct lheahsta vaep pearseidn ce a1b9ou5wt0h ,ic h
PA RT XXV SounTdr ansmistshiroonuW gahl lbse tweEennc losur3e2s4. contaiantvs a,r iotuesc hcnaillv eeltsh,ea ccomipslhmenltesa ditnoag n d
thet renodfst odaIyh .a vceh osenno tt ol iesvte rayr tipculbel isnhoerdt ,o
CHAPTER 11.N OISE CONTROL 332 incluldtiee ratiunrf eo reilgnang uageTsh.e intiestn ost u ppsluyp plemen­
XXVI ProcedaunredSs o urces 332 tarrye adiinnEg n glish.
PART
XXVII AcousTtriacn smisPsaitohns . 345 Originaal plryi,m adreys iorfet hea uthowra st oh eltph es tudent,
PART
enginaenedra coustciocnaslu ltvainstlu iazbee ttheorw t od esiagnna udio
CHAPTER 12.A COUSTIC MEASUREMENTS 361 systetmoa chietvheee lusigvoeao lf " higfhi delistoyun"rd e production.
Them ediumI chosfeo ra chievtihnagrt e suilstt hes chematciicr cuit,
XXVIII MeasuremoefAn cto usLteivce ls 361
PART analogtoout sh at uisnee lde ctrobnuitdc isff,e rifnrgo pmr ilorie tratubrye
XXIX ReciprCoacliitbyr aotfTi roann sducers 377
PART combining indtioa gornatemh en ecessealreyc trmieccahla,n icaanld,
acoustciocmaplo nenitnsc,l udtihnetg r ansduction Apnr eoxcaemsisn.a ­
CHAPTER 13.H EARING, SPEECH INTELLIGIBILITY,A ND
tioonft helt ieratsuereem tsoi ndictahtaeot n er esuolftt h aetf fowratst o
PSYCHOACOUSTIC CRITERIA 388
stimultahtdeee velopmoefsn mta lllou dspeaeknecrl osuwrheisci,hn m ost
PA RT XXX Hearing. 388 locatiohnasv ree palcetdh eo ncee ver-expa"nwdoionfge r" boxes.
XXXI SpeeIcnht elligibility 406 A largper opoornto ift hel eadiwnrgi teornls o udspeaker dsey­stem
PART
XXXII PsychoacCoruistteirci a 417 siginnt hel satfi fteeyne arisn,c ludEi.n gM V.i lclhurA,.N .T hielRe.H, .
PART
Small,R .A shleAy.,D .B roadhurSs.Mt o,r itNa., K younoA,. L .
PROBLEMS 431 KarmiJn.s kyM,e rhauRt,.F .A llisRon.B, e rkoviatnzdo, t herhsa,v e
J.
usedt hem iddlceh apteorfts h ibso oka st heisrt artpionign t. In other
APPENDIX I. DECIBEL CONVERSIONT ABLES 455
wordsa, k nowledogfte h ep rincitpaluegshh te rhea sb eean p refatcoe
APPENDIX CONVERSION FACTORS 464 thepirro gress.
11.
Ih olndo p articburliaferof Cr h apterp arXtX V,t hrouCghha pter
APPENDIX Ill. 11,
469 13M.y latteerx t, (McGrawH-ilNle,w Y ork,
INDEX. treatthsNim osai tsaeenr diiV animl bo rraedt Ceiotonanbti erlno elf iftrionmgn eartlwye nty
1971),
479
yearosfi ntervenpirnogg reisnts h efi eldT.h ee ngineienrt ereisntn eodi se
contrsohlo ulpde,r hapcso,n sider and
asV olumeIs a nd ont hesA ucbojueTschttei.s c uNspo peilmsaeenn dtV ailrbiyrt aetCrioaoontnf­u re
trol 11
XI
"" PREFArE
thel asItSy earosnn oisceo ntrmoulc,h o fw hicihsl istienAd p pendIixI I
oft hirse priinsnt o,t t oof ormidatbolp ee rusFei.n alIlh ya,v mea dec or­
rectitoona sl tlh ek nowne rraitnat heb ook.
Iw istho t hantkh eA coustiScoacli eotfAy m ericfaot rh eiinrt eriens t
CHAPTE1R
reprinting I hopet heifra itihnt hipso rtioofnt hea coustical
Acoustics.
literaitssu urbes tantbiyat theead s sistiatmn caeyg ivset udeanntsde ngi­
neerisnl earnainndgp racticiintn hgefi elodf e lectroacoustics. INTRODUCTIAONND TERMINOLOGY
LeoL .B eranek
June1 986
PART
I nIl roduclion
1.1A. Li ttHlies tory.A cousitsie cnst erain negwe ra-tphree cisioll­
engineerinOgn eh eurnad.ry eeda rasg oa cosutiwcass a na rtF.o r
measuriinnsgt rumeenngtisn,ie net rhse fiuesletddh eeiarr psr imarily.
Theo nlcyo notlrlneodi se saovuariclewaseb rlweeh istgloensg,as n,d
sirenMsi.c rophcoonnessi sotfee idt hae dri aphrcaognmn ecttoae d
mechansiccraalt tchhaertre cortdhesedh apoeft hwea voen t hsem oked
surfoafca r eo tatingo rad fl raummwe h oshee igvhatr iweidtt hh e sound
pressuArbeo.ut th at tthigemr ee naatm eosfR ayleSitgoh,kT ehso,m ­
sonL,a mbH,e lmhoKlotnzi,Tg y,n daKluln,d atn,d otahpepresa orne d
importpaunbitls hepda perTsh.e icro ntributtoti hoenp sh ysiocfs
sounwde rfeo llobwyet dh ep ubilcatoifoL no rRda yleigth\'yso -veo lum
treat"iThseeo,r oyfS ound("81 77a nd1 887).A cousrteiscst ed
untWi.lC .S abiinnea ,s erioefps a pe(r91s0 -019)1a,5d vanacretc'dhh ciret ec­
turaaclo usttoit hcsest atoufas s cience.
Evetnh outghhce o ntribouftt ihoeensaesr lwioerrk ewresrg er eatth,e
greataecsceter latiofoi nn terients htefi elodf a coustics the
invenotfit orni ovdaec-uum-ctiurbce(u 1i9t0sa7 n)dt haed fvoelonlfotr,, a·dcid o­
broasdtcian(g91 20.) Withv acuum-taumbpel ifiaevrasi lalbolued,
sounodfs adneys ifrreedq uecnocuybl dep roducaenddt ,h ien tenosfi ty
verfya isnotu ncdosu lbdem easurAebdo.v ael iltb ecafmeea sitbol e
buimleda suriinnsgt rumtehnatts cwoemrpea rcutg,g aendd,i nsensitive
toa idrra fts.
Thep rogroefcs osm municaactoiuosnwt aisch sa stentehdr,o utghhe
efforotfts h Bee lTle lephLoanbeo rat(o91r2i0effbs)y t, h dee velopomf ent
thmeo detrenl ephsoynsetie nmt hUe nitSetda tes.
Architecatcuoruaslrt eiccesia vb eodo psrtci inpaflrlotymh teh eoarnyd
experimceonmtisno gu to fH arvartdh,eM assachuIsnestttist ute of
Techonlogayn,dt hUen iverosfCi atlyi foartLn oiAsan gel(e13s90- 1940,)
ands everreasle arch incE enngtleaarnnsddE urope, eGsepremcainayl.l y
1
I r� 'rl II\eT 0i r D�0A r�D TE Ri r l\r�0i L OG Y [Chap. I Part1 1 INTRODUCTION 3
Int hipse risoodu,nd de caiynr ectanrgouolmawsar s e xplaiinnd eedt ail, thed iaphragml ooupnde saak eorra, n ys urfafcoterh amta tter,
IS
thiem pedamnecteh oofds pecifaycionuigsc tamla terwiaassl hso wtnob e
vibraitnic nogn tact waiitrh. the
usefaunldt, h ceo mputaotfsi oounn adt tenuaitndi uocnwt ass p uton a .
A souinssd a itdoe xiisfat d isturbparpnoacgea ttehdr ouagneh l astlc
precbiassei Tsh.e a dvantoafgs ekse wweadl alnsd o fu siancg osutical
materciaaulsa enas l teraitnpi roens sourard ei splacoeftm hepena rtt icles
materiianpl ast chreast htehra onn e ntiwrael wlesr dee monstrated.
oft hmea terwihailcc ha nb ed etecbtyea dp ersoorn abnyi nsmternut.
Fucntioanbaslo rwbeerriesn trodtuotc hefiede ladn,da w idvearr ioeft y
Becautsheit se xdte aplrsi marwiiltdyhe vifcoehrsa ndlsipnege acnhd
acoustmiactaelrc iaamloesn tmhaer ket.
musigca,s (emso rpea rticualiarar)rlt eyh ,oe n ltyy poefse lasmtaitce rial
Thes cieonfpc sey choacwoaussa tlisdcoes v elopAitn gtB.he elT le le­
witwhh icwhes hacloln cern ouFrosretluvneastt.hep elh yy,s ipcraolp er­
phonLea boratuonrdieetrsh ,es plenldeiadd erosfHh airpv eFyl etcher, tioefsg asesr ealraet eiavsetyloe y x preasnsdw, ec adne scrriebaedt ihley
thceo nceopflt osu dnaensdms a skiwnegr qeu antiafinedmd a,n yo ft he natuorfse o unpdr opagaitnsi uocnmh e dia.
factgoorvse rning ssupceceeccsohsm fumunli catwieornde e termined Imagitnheaw tec oucludat t incyu b"ibco x"o ut aoiafrn dh olidti n
(1290-1490.) Acousttihcrso,ut ghhme e diuomfu ltraseonntiectrshe,ed ouhra ndassw ew oulabd loocfkw oodW.h atph ysipcraolp erwtoiuelsd
fielodfsm edicainndce h emistUrlyt.r asdoinaitch ewramsby e itnrgi ed, ite xhibiFitr?s ittw, o ulhda ve weaingdhh,et n cmea,s sI.n f acat ,
anda cosuticaaclcleyl ecrhaetmeidrc eaalc tiornesp woerrtee d. cubmiect eorfa ihra asm asosf a littloen kei olvoegrr Iafam f .o ricse
FinalWloyr,lW da rI I camei,t dswe imtahnf dot rh seu ccesdseftuelc ­ appltioei dtt ,h beo xw iltlh eanc cetleea rcoacrditnoNg e wtons'esc ond
tioonfs ubmerged suabnmdfa orhrii ngehrsle yl isapbeleecc ohm munica­ laww,h icsha ytsh afto recqeu amlass tsi maecsc eleration.
tioinnn oiesnyv ironsmuecnahtsas i rcarnadfa rtm orveedh iclGerse.a t If ewxee frotr cceosm prestswion goo spipsnigd oefts h lei tctulbete h,e
laboratwoerrfieoe rsm iend EngGlearnmda,nF yr,a nacneid, nt hUen ited fouort hseird weislb lu loguet warTdh.e rienmcenptraels spurroecd eud
StataetCs o lumbUinai verHsairtvya,ar nddt, h Uen iverosfCi atlyi fornia
int hgea bsy t hifso rwcielb let hsea mteh rougthhoisusmt a lvlo lume.
tod eawli tthh epsreo bleRmess.e airnca hc ousrteiaccsph reod portions Thiosb tabiencsa upsree ssiunar gea iss a s calia.rea,. n ,o ndcitrieonal
undreaomfea f de w ybeeafrosar nedh acso ntinuuneabda ted. quantity.
Todaayc,o usitspi acsss firnogbm e iant go oolft htee lephone industry, Imagitnheel itbtolxeo fa itro b eh eltdi ghbteltyw eyeonru h ands.
a fewe nlighatrecnheidt aencdtt hsme,i litianrtbyoe ianc go ncienr n the Stihloll dtihnbego xm,o veo ne hand sfooa rstw oad rids ttohrect u be
dailliyof fen earelvye rpye rsoInn.t erinoanmatolv emeanrtaesf otoot intao p aralleleYpoiufip neddt .h anto oppotsoit thideoi ns torotfi on
legisalnadtt oe providheo uqsuiinLegat.b oarn do fficweo rkearrse thbeo x maidsbe y t haei oru tstihdee dtiwsot osritdeeds . idnTihciast es
demandinagn dcs oamffeo rtaacboluese tnivci reonntimsnw hicthow ork. thaati dro enso stu ppoasr hte arfionrgtc e.
Architienrc atpsi idnlcyr eansuimnbgea rrshe i rinsge rtvhieoc fae cso us­ Furthiefwr e c onstfirvaesi ind oefst he caunbdae t temtpodt i splace
ticeanlg inaesea rr so utpianreot ft hdee siogfbn u ildingasd.d itIino n thse ix�tnhe w,e fi ndt hatth gea iss e lasit.ieac. f;,o ricsre e quitroe d
theirste h meo rgee nenreaeltd oa battehg er eat tnhoriefsareto amv ia­ comepsrtsh gea sT.h em agnitoufd et hei sf odricreep crto porttoi on
in
tion-paarrtlitych uafltr otmh eje etn giwnhei,c phr omitsoer su in the thedi splacoefmt ehnuetn cnostraisnideoedft hceo ntaiAn esri.m ple
comfoofro tu r homMeasn.u factaurruees risn g aicnosutsrtuimce ntation experiwmielnclto nviynocueo ft hisC.l osoefft heh osoef a na uto­
ont hepirro ducltiinoenAs c.o usitscio cmsi inngt ioto sw ni nt hlei ving mobile tisrote h apttuh mep i asci orn finientd h cey lindPeurs.dh o wn
roowmh,e rheig h-fidreelpirtoyd uocfmt uisohinac f so uanw di daeu dience. ont hpel uenrg.Y ouw ilfiln dt hat ctohnefi nebde haaivrae sas s imple
Thibso ocko vefirrsst th bea saiscp eocfta sc ous:wt aivcpesr poagation spring.
int haei trh,e themoercyh aonfai ncdaa lc otuisccailr cutihtresa ,d iation Thes pricnogn stoafnt th eg asv ariheosw,e vweirt,th h em ethoodf
ofs ounidn tfor esep acaen,dt hep rorpteioefsa cousctoimcp onents. comrpessiAo fno.r accet itnocg o mpraeg sassn ecesscaaruisleyds i s­
�
Thefno llcohwa pters wdietmahil cirnognp ehslo,o updesakeernsc,l osures placemoeftn htge a psa rticTlheeis n.ec mrentparle sspurroecd ed the
� 111
folro udspeaankdeh rosr,n sT.h eb asciocn ceopfst osu nidne nclosures gasw ilbled irecptrloyp orttioot hneia lnr cemencthaaln gev olume.
111
aret reatneedx atn,d p ractiincfaolr maotnin oonic sOe:1 tirsog li ven. If tdhiesp lacteamkepenlsta scleo wolnyec a nw rite
Thet exdte afilnsa lwliytm he asuremaennpdt ssy choacouTshtriocusg.h ­
outt het exwte s haslple atkoy ou-tshteu deonftt h imso derann d D.P= -K D.V slopwr ocess
interefisetlidn.g wherKe i sa constaInfto,.n t heo thehra ndt,h ed ispelmaecnatn,d
What IsS ound?I n reatdhimena gt ertihaaflto lloywosug,ro al
sh1.o2u.bl etd o f oramn dt ok eeipnm inadp ictoufwr hea ttr anisrpwehs en tT hisis o nlayp porxiamtely tarsut eh,ea irdo ehsa vev iscosbiuttyt ,h es hearing
forcaerse smalclo mparwcidt thh osien s olids.
vcry
I]
Part NTH( )
4 INTRODUCTION AND TERM!NOLOGY rChap.l 1 n 11 IeOTN
hencec htahneig nev olumtea,k pelsa ce raanpdfi udrltyih,fte .rgh aeis s themyo vfea stceorl,lw iidteh the cwoanlmtloasri fenr eerq tuleyan,n d,
airo,x ygehny,d rogoernn i,t rotgheenc ,ri enmenpt.raels spurroed uicse d havignrge amtoemre nttuhme mseltvreasns,mf oerrme o menmt uto the
equatol1 4.Kt imtehsie n rcemencthaaln ignev olume. waldlusir nega cihn divicdoulalli sion.
Fora givevno lumceh anAgV e, t hre atoefm omentcuhm angaen,d
AP= -1.4KA V faspt.r ocedsisa,t ogmaisc
theretfhoerp ree ssiunrcer eiasss ee,e n betg or eaitne r tahdei abatic
Not.teh atp oas it.iinvcer em(einnetca rsien)p resspurroed uacn eesg iavte proceIstsf .o lltohwaastg aisss tiffert-aikte s morteoe xfpoaroncrde
inecmren(td ecreianvs oel)u mPer.o cseeswsh ictha kpel aeaeti netr­ copmreists- itfh ael ternaitsia odni abaWtei sch.a slelle atienrt he
mediate arraemt oersed ifficutlodt e screivbeean,p proximaantde ly, textth asto unwda ves easrsee ntaidailalbyaa lttiecr nations.
fortunnaeteendlo ybt e c onsidheerreed.
Whati st hree asfoontr h dei fferebnectwee enp rtehsesa urriesf irnogm dLl��o�.:,:::!
changienvs o lumteh aotc curra pidalnydt hep ressaurries firnogm
. ......... ..................
changienvs o lutmhea otc cur slFoowsrll yov?wa riatiinvo onlsu tmhee
copmressairoien ss otahleB.ry ma ni sortmhaevla riawteim oena no ne 't·:::;·:;·:·: :; ·Dias"ppa lac:rteome·nfIt Cles· ·····················
thatta kepsl aactec onstant temTpheerraietst u irmfeeo. tr h eh eat R ,,+RW� Pressur.
I
generaitnte hdge a dsu rit.nhgce opmresstioflo onwt oo thpearr otfst he 1+0i....1LO � 2'a_I "65 'Dcstanct'4 a IfromI SOUIfCe Ilin I .8feJ eo;t61 {42 ]_0 1L1 0 _84f 1..1..1 1 ..4..,.�in1 fe6e.1t89 .2264
gaosr i,tf h gea issc onfinteofld o,w t o twhaelo lfts h ceo ntaiHneern.c e, (a) Staofrtc ycl0es ,e conds 0.007s5ec onds
thete mperaotftu hrege a sr emaicnosn staFnotrr. a pivda riatiino ns dO (dI)c ycle.
volume, htohwteee vmepre,r atuwrhee tnrh igesa eisss c omepsrsaendd
�· · �=:'::.: ..................... .
falwlhse tnh gea isse xpandeTdhe.r iesn oetn outgihm deu rianc gy cle
ofc omepsrsiaonnde xpansfiootrnh eh eatto fl owa way.S ucrha pid U;p�essur. Daiisparpl acerticmo.fnl t es
alternaatrsieao intdsob ea diabatic.
Ine ithiesro rtmhaeolr a diabpartoeicscs tehspe,r essiunar g ea s duise 5.6D8 ista.nce4 1f 1ro1sourc1m e 4 i.1fn0ee6 t. 189 .262 .4
toc olliosfit ohngesa mso leculecso nawtiintwehar l lYso.u w ilrle call cycl0e.,00 2s5e conds
(bi)
t.haptr essiusfr oer pceeur n iatr eoar,, from Nerwattooenfc , h atnigmee do
ofm omentpuemur n iatr eaL.e tu si nevstigtahtmeee chanoifst mh is l dloM. M..._. .......
momentcuhma nigne cao nfingeads T.h ec ontawianlelr chtahneg es .�...j� . ............................. ........�.... . .
Displacemoefn t
direcotfmi ootni oofnt hmeo lecuwlheiscs ht riiktae n ds oe hangtehse ir ai.rp articles Pressure Displaceomfe nt
Pressure .:�� �rt:�I
momentutmh;ic sh anagpep eaarsas p ressounrt eh gea sT. her ataet �-.I 5+ �Rl
which chtahneog fme o ment.oucmc uarnsds, ot hmea gnitouft.d hepe r es­ �� �K+_0 �csLR 0 DistUa ncelrom1SOU1f11cei 4n.f10ee6 t. 189 .262 .4 �.li E._0 C5I LO "'2s>i�;f.-��3�7tfs-�
surdee,p enodnts w oq uantitiiensec.ar soeIbstv iloyu sifn utmhbeeo fr
(, J seconds
Ic y0c.le00.5
collipseisroe ncso bnedt wetehnge a psa rtiacnldte hswe a lilnsc reaors es, FIG1.. 1P ressaunrded isplaceimnae nptl anseo unwda vep roducbeyda sinu­
if atmhoeu notfm omentturma nsfpeercrro eldl ibseicoonmg erse atoerr , sDo.i davlliyb ratwianlglD ., = onDe.- fowuarvtehl enDg,tD=h .o; n e-hwaalvfe length;
three-fowuarvtelhestnh g; onew avelength;t wow avelengths.
bothW.e n ows eteh atth ies othecrompmarle ssoifao g na rse suilnat ns R m=e ans disploaftc heeam ieprna tr =t ietioet sh er ighLtm ,e an= dsi splacemtehnet
inecarsoefp ressbuercea uags iev neunm beofrm olecaurlfeeo sr ciendta o lefatn,d meannso d isapclf'tncnCt.r owddeodt mse anp ositeixvceep srtose ssure
smallveorl umaen dw ilnle cesscaorlillwiyid teth h ec ontaimnoerre ands pr0e daodt mse ann egateixvcee psrse ssuTrheef. r equeonfvc iyb ratoifto hne
pistios1n 00 cyclpeessr e cond.
frequently.
Ont hoet hhearn da,l thotuhgaehd iabcaotmiepcsr sioofan g arse sults 1.3Pr.o pagatoifoS no undt hrougGha s. Thep ropagaotfsi oounn d
ina ni necarsient hneu mboefrc olliassdi eosnesr aibboevdie tc, a usaelss o throuagg ahcs a bne f ulplrye diacnt.dde eds criifb ewde i tnatkoe aeeount.
af urtihneecrar sient. hen umbeorfc ollisainodan gsr eamtoemre ntum thfea ctors just dtihsmeca usassns des dt,i ffnoefs stg haesa ,n di tf'
viz.,
transpfeercr o llisBiootnth.h esaed ditiionnecaarls aerse d uet ot he confmoanrcwei tbha spihcy silcaawlsS .u cahm athemadteicsaclr iptioll
temperaturew hcihcaahnc ogcmep anitehsea diabactoipmcr ession. wilbleg iviennd etaiinll a tcehra pteWresa .r e now cownictaeh r ned
Kinettihce otreyl ulsts hat vtehleo coifgt aysm olecuvlaersia ests h e qualitaptiicvteou frs eo unpdr opagation.
squarroeo otft hea bsoltuetmep eratureg asoI.fn t thheae d iabatic Ifw ep uats inusoivdiablrlaywt ailnilgna g as(s eFei g1.l. a ,i) tw ill
proctehsesn ,c onatsr awsitttehhd i es othetrhmmeao ll,e cguelhteo tst er; accelaetared jacaeinprta rtiacnldce osm pressp artothft a htge a nRe arest