千米小说网

Chapter 8 Sound out of place（第1页）

Chapter8Soundoutofplace

&ureofnoise

Whatishisisohosequestioistime?’，towhiightanswer:‘Iklywhatitisuntilsomeo’sworsethanthat，for‘woquitedifierentthings。Forastist，raneousacousticiergy。Whenusedforunioiseiswhateverisnotthesignal，inotherwordsdoesnotatioheinformationisavoiawire，orastructuralelementinanultrasonihelargertheamountofhemorediffcultitbeestouhesignalfromit—heofsignaltoio。

Onoisehasbeeifled，itbefairlyeasytoremove。Noiseinacircuitthatoccursatparticularfrequenfromamaiysupply，forexample）bedealtwithbyfllters，sothatonlyfrequeerestremain。Unfortunately，ironics，averyofenoise，asignalthatflllsallfrequeerestandsoundslikeahisswhehroughaloudspeaker。Thisotbefllteredoutsoeasily，butoeadfllterallbutthefrequendsthatcarrythesigillbewhitehosebands，butthenaltoiowillimprove。

Formostofusmostofthetimethough，‘noise’isanysoundwhiwahepersooit。Atrumpetermaybeverypleasedwithhisoutputaainlynotthinkofitasaneighbhtwelldisagree，howeverteicallyextitmaybe。Andbht—oneperson’smusiother’shisdisagreemeheveryheartofwhynoiseissodiffculttoquash。Butfortunately，whilealmosteverysoundhasatleastafewpeoplewholoveit，ahosetowhomalmostanythingbutsilehema，itisalsotruethatsoundswhiyofusthinkofasendtosharethreecharacteristiness，louduoflndoutwhythisisso，weosiderwhywehearanythingatall。

&rallegacies

Wehearbecauseouraorsdid，andtheyheardbecausetheirdeafrelativesdied。Amongthemanysoundswithwhichtheywouldhavebeensurrounded，afewweremattersoflifeah。Asuddenroar，thetwangofab，thesnapoftwigsuhecraderoverheadwerealldangersigns，andwhattheyhaveinonissuddeodayouriosuddennoise。Suddehehushredathted，meantasmuchassuddensoundahefamiliardeafeningsilenaclockstopstiairerswitchesofi，orpersistentrainsuddenlyfaexpegetothesoundsaroundusannoyingnoise:everydriverkionandcausedbyanewaiflableenginenoise，athetigermayopickoutatall，howeverwellthedriverimitatesit。

Butwhyareweahosesoundswhirelatedtoaralsoundthatmightsignaldaalkioutsideatmidnight?MP3playersyoujusthearacrossatraincarriage?

Theanswerliesinakeysoofsouepower，inparticularbygownershipofspace。Weareusedtotheideathateachofushasapersonalbubbleofspacethatwed，towhiinvitedareunweleonewhoispacewiththeirsoundsbeasannoyirudingintoitphysidthemainpointinbothexamplesisi。Howmunoyingisthepersonsittioyouiftheyphoalkhaniftheyreceiveacallofreal?

&herpersardedasnoisyoroooiohemaeoriansShaneandGrahamWhite，foriheirstudiesofslaveryintheUS，foundthatthesermonsofAfriAmerigelistpreachers，reciatedbygregations，werereferredtosimplyasnoisybywhiteAmeriswhowereedbecausethesounds，aheirmessagestoo，spreadfarbeyondtheesoftheirveuralanttoo:acceptablesoundlevelsinlibraries，duriimes，andatfuneralsvarygreatlyiries。

Theseaofotherpeople’snoiseinwhieisoftensubmergedonpublisport，inpublicspaces，oropen-planoffbeadisturbingeheindividualsouheridentifledheheariaodoboth，makingthemashardtoigoeswhenonedoesmaoignoresudsonasciouslevel，thementalprogues，asdoesthestressthatsometimesresults—andthehighbloodpressurethatthisstresscause。

&heonlywaytoree’sprivatesouoflllitwithasoundfleldofone’sownmaking，byuseofanMP3playerorsmartphtoMichaelBull，ProfessorofMediaandFilmattheUyofSussex（UK）:‘iPoduseusefullybeiedasaformofpleasurabletoxicitywithinwhiediated”worldofusersliesadreamofuedexperience—ofdirectaccesstotheworldaions’。

Therearesomesoundswhiotbeighoughtheydonotreallyexist。Theseso-calledearwormsareusuallybriefsnatusibanalones，whisistthemselvesinthemiisingjinglesareespeingtheirwayin。Thoughsowidespreadandseeminglysimple，earwormsareactuallyveryhardtoexplaiOliverSackssuggeststhattheunusualwaymusicisrememberedmaybesigniflt。Regaseoreverugit，whimeansthattheresultmaybeverydifierenti‘replays’。Inregapieusic，however，somethingmuchclosertoadirectcopyinalispreserved，an‘almostdefengravingofmusithebrain’，

asSacksputsit，overwhichwehaverelativelylittletrol。Perhapsthefactthattunes，ahis‘engraving’process，arrivedsolateiionofthemindisareasonwhysuchmemoriesarehardtotrol。

Musihaveevenmoreprofouhemind—icauseepilepticseizures，whileihaveasignifltlygefiedalleviatepainandhighbloodpressure。Itbeespeciallyefiethetreatmealproblems，andhasbeehiswaysinceWorldWarII。MusichasalsobeenshowrelieftosomewhosufierfromParkinson’sdisease。

Deafening

Theproblem—iragedy—ofnoise-induglossisthatitmayilyearsafterthedamagehasbeendone。Also，whilewereactimmediatelythtemperaturesori，ourdefeonoisearefarpoorer。

Oureyesareequippedrotectiveadaptations，mostobviouslyeyelidsaingpupil（orexpandingiris）。Whydoestheearhavehereasonforthelackofearlidsisthatwhiledeafnessmayshortenananimal’slife，itwohinglikeasmugsuccessfullycreptuponbyahungrytiger。Andwedohaveahepupil，thoughit’snotparticularlyefiective:theacousticrefflexisprovidedbytwomuseachearcalledthestapediusaympani。Whenaloudsouapediuspullstheossiclecalledthestapes（‘stirrup’，sshape）awayfromtheovalhilethetensortympanipullsonthemalleus（hammer）ossicle，whichisattachedtotheeardrumaifieer。Asaresult，soundsaremufied。Thestapediususuallytenseswheopusannoyihourowensortympahesamejobpressourownoises。

&icrefflexisoemporarythresholdshift（TTS），inwhidswhichareusuallyquietbeeiuimetherefflextakestowork（calleditslatency）isusuallyaround45milliseds，whichisfarlotakesanimpulsesound，likeagunshotorexplosion，todosiderabledamage。TherefflexisoributortoTTS;theothermeismsarestillunknown。

&heoverburdenedeardifiersfromotherabusedmeasuringis（biologidteological）isthatitisnotonlytheSPLofters:estoo。Aalevelwhichwouldorethanirritatiooforaseleadtosigniflthearinglossifituesforanhour。TheamountofTTSisproportiohmofthetimeforwhioisehasbeeis，doubliimemorethaheamount。

However，veryloudimpulsesous，willalsostantdamage，evealenergyislow。（Reputedly，atrainedaudiologisttifythepermadamagecausedbyasiflredbyapatientrote。）Reesiheamountofshift;aTTSof40dBtakeweekstoreountofTTSredusiderablyifthereisapauseinthenoise，soifexposuretonperiodsisuafootballmatch，say），thereisverysigniflefltinremovihenoisyarea，ifonlyforflfteenminutes。

Itisontheevidenanycarefulexperimesofnoisethations，nowstatutoryinworkpladelsewhereinmanytries，havebeeheyplacelimitsbothonpeaknoiselevelsandduratioospecifledlowerlevels。

Ohidentifyingholehavenoiseinduglossisthateveryoythfrequendsdeeswithage:newborn，to20kHz，bytheageofaboutfortythishasfallentoaround16kHz，

andto10kHzbyagesixty。Agedeighty，mostofusaredeaftosouheefiectiscalledpresbyacusis（literally‘oldmanhearing’）。Sinoise-induglossusuallyalsoimpactshigherfrequend，beingcumulative，beonwithage，wedon’treallyknowhowmuchlossisavoidable。

Iftherehasbeenadowheoftenlaudableprogressmadeintagerouslyhighlevelsofhasbeeiveofnoisewhily’loudenoughtoanetheirvasthe2008IpsosMORI（UK）NationalNoiseSurveyfoundthat26pertofresposwereannoyedbyneighbournoise，forexample。Thoseafiectedlosesleep，theylosetration，theylosepatiehejoyfromtheirlives（39pertsaidtheirqualityoflifewasadverselyafiected）。Suoisealsoexacerbatesmehproblems，unitytensions，andsocialisolation。

Therearefeoulddenythatthebestapproachwouldbetoremoveheeheflrstplace。Howthise，aively，dependscruthesourostinhabitantsofthedevelopedworldandmahefollowingsourcesarelikelytobethemainones:

·Airtraffc

·Industrial

·Neighbour

·Neighbourhood

·Rail

·Roadtraffc

Inaddition，shippingnoiseandwind-farmsnifltly，whilemostareasareblightedbystrutimetotime。

Ofthesegroups，neighbhbourhoodicularlydiffculttodealwith，partlybecausethemakerdoesnotclassthemashelistehisdiffcultyhasledsoundhistorianKariocludethatementisinthegripofa‘paradoxoftrol’，inwhiisesofexpertsandpolitistooiseactuallyamounttopassioneighbourstodoso，ordevelopingsuplexformulaefotherformsofnoise，suchasthatfromaircraft，thatfewderstah，orcritiquethem。

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