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GlossaryofTerms Term Definition 802.11 3Dpass-through A/Dconverter (ADC) AnindustrystandardforatypeofwirelesscomputerLAN. TechnologyinAVreceiverthatallows3DsignaltopassinandoutoftheHDMiinputs Analog-to-digitalconverter,adevicethattransformsincominganalogsignalsintodigitalform. AnacronymforAdvancedAudioCodec.AACisthedefaultaudiocodecformatusedbyApple's AAC iTunesMusicStore. Supportingdevices(suchasuniversalremotecontrols,touchpads,ordigitalmediaadapters) Accessories thatmakethecontentinyourhometheateraccessiblefromanotherlocation. AnacronymforAContrivedReductionOfNomenclatureYieldingMnemonics. Acronym Higherresolution3DTVperformancethatrequires'active'3Dglasses Active3D Aloudspeakerwithbuilt-inamplificationforallthedrivers.Somespeakershaveanamplifier Activeloudspeaker built-inforbassonly,butthesearenotregardedasactive.Mostloudspeakersarepassive,not active. Literally,itmeans"nottopassthrough."Indescribingthehigh-densityfoamusedinsidetheHR Seriesstudiomonitors,itmeansthatinternalreflectionswithinthecabinetareabsorbedbythe Adiabatic foam.Inphysicalterms,itmeansthemechanicalenergyofthesoundwaveisconvertedinto heatenergy. AESistheacronymforAdvancedEncryptionStandard-theUSspecificationforencryptionof AES electronicdata AudioEngineeringSociety/EuropeanBroadcastingUnion.Adigitalaudiocommunication standardmostcommonlyseeninprofessionalaudioapplications.Electricallyitisonlysubtly differenttotheconsumer-orientedS/PDIFstandard,themainvariationbeingadifferent AES/EBU methodofhandlingtheclocking signal,anditgenerallybeingcarriedbybalancedconnections.Neverthelessimplementations areseenthatseemtobefullycompatiblewithunbalancedS/PDIF. AnacronymforAfterFadeListen,whichisanotherwayofsayingpost-fadersolofunction. AFL AirPlayisanApple-designedwarlessstreamingformatthatallowsaudio,videoandphoto AirPlay informationtobetransferredbetweendevices Thisisatypeofdistortioncausedduringtheanalog-to-digitalconversionprocess.Ifthe frequencyoftheanalogsignalexceedsone-halfthesamplingrate,spurioussignalsand Aliasing harmonicsnotpresentontheoriginalsignalmaybecreated(seeNyquistTheorem).Careful designandfilteringbeforethesamplingstagecanreducethisaliasingtoaminimum. Anelectronicdevicethatincreases(or'amplifies')thepowerofanelectricalinputsignal. Amplifier Atypeoftelecommunicationssignal(audioorvideo)thatistranslatedintoelectronicpulses Analog withvaryingstrengthorfrequency. Adeviceonaturntable'stonearmtocounteractskating.Thissometimesconsistsofan AntiSkate adjustablespring-loadeddevicenearthetonearm'spivot,orweightonastring(wherethe torqueappliedbythisarrangementremainsconstantthroughouttherangeoftravel). aptXhasrevolutionisedtheBluetooth®Stereolisteningexperiencebysignificantlyreducingthe Aptx bitratewithoutaffectingaudioqualityorintroducinglatencyissues Aspectration ATSC Attenuation Audiosources Audiophile Azimuth Balancedinput Balancedoutput Bananaplugs Bandwidth BASS BassExtension Thewidthofavideodisplaycomparedtoitsheightanddefinedasaratio,suchas16:9for widescreenand4:3foratraditionalTV. AtechnicalstandarddevelopedbytheAdvancedTelevisionSystemsCommitteethatis synonymouswithdigitalTV,orDTV.HDTVisasubsetofATSC. Theweakeningofanaudiosignalasittravelsoveracable.Usetheshortestcablespossibleto lessensounddegradationinahometheater. Devicesinahometheatersystemthatprovideaudio-onlyplayback,suchasCD players/recorders,AM/FMtuners,satelliteradiotuners,audiocassetteplayers,andturntables. Apersonwhoplaces(orwouldliketoplaceifcircumstancespermitted)ahighpriorityon havingahomeaudiosystemthatperformsverywell,offeringalevelofreproductionthat soundsliketheoriginalrecordedeventtothem.Aswealllistenindifferentwaysandcan indeedtrainourselvestohearfordifferent‘cues’inmusic,itisaverysubjectiveissueastothe ‘best’system;indeedthereisno‘best’,justeachlistenerssenseofbest. Becausethemusicrecordedinthetwowallsofa‘V’-shapedrecordgroove,itisobviously essentialthatthestylusofthepick-upcartridgesitsperfectlyverticalinthegroove,ratherthan leaningintooneorotherofthegroovewalls.ThisadjustmentiscalledtheAzimuthAdjustment anditcanbecheckedinafairlysimpleway.Takeasmall,thinmirror(somemanufacturerssell mirror-platedalignmentgauges)andplaceitontherecordplatter.Putthecartridgeontothe mirror’ssurfaceandrotateitbylooseningoffthesmallscrewsatthebearingendofatonearm. Whenthealignmentiscorrect,thecartridgeanditsreflectionwillbeperfectlyinlinewitheach other Aninputconsistsoftwoleads,neitherofwhichiscommontothecircuitground.Thisisa “differentialpair”,wherethesignalconsistsofthedifferenceinvoltagebetweenthetwoleads. Balancedinputcircuitscanofferexcellentrejectionofcommon-modenoiseinducedintothe line. Inaclassicbalancedaudiocircuit,theoutputiscarriedontwoleads(highor+andlowor-) whichareisolatedfromthecircuitgroundbyexactlythesameimpedance.Asymmetrical balancedoutputcarriesthesamesignalatexactlythesamelevelbutofoppositepolaritywith respecttoground.Aspecialcaseofabalancedoutputcarriesthesignalononlyonelead,with theotherleadbeingatzerovoltagewithrespecttoground,butatthesameimpedanceasthe signal-carryinglead.Thisissometimescalledimpedancebalanced. Speakercableconnectorsresemblingapinconnectorthatbowsoutinthemiddle.Comesin bothsingleanddualconfigurations. Eithertherangeoffrequencieswhichacomponentcandealwithcompetently(oftenspecified astherangeacrosswhichtheattenuationisnomorethan3dB),orthefrequencyrange requiredtocarryasignal.Forexample,thebandwidthrequiredforacompositevideosignalis somewhatmorethan5MHz. Lowfrequencysounds,typicallybelowaround150hertz,althoughthedividinglinebetween bassandmidrangeisoneofopinion.Thehumanearislesssensitivetobassthantomidrange, particularlywithregardstolocationofsource. Animprecisetermconcerninghowlowinfrequencyaloudspeakerorsubwoofercanstill operatetoproduceusableoutput.Atypicalbookshelf-sizedspeakermaymanageabass extensionof80hertz(say,at-10dB),agoodfloorstandingspeakermaymanage30or40hertz, aninexpensivesubwoofer40hertz,amiddlingone25to30hertz,anexpensiveone16hertz. BassReflex BD-Live Bipole Bit BitDepth BitRate Bitstream Bluetooth Blu-raydiscs Bluetooth BonusView Bridgedmono Brightness Adesignfortheenclosureofaloudspeaker.Withbassreflexspeakerstheenclosurehasaport thatpermitsairtoflowbetweentheinteriorandexteriorofthecabinet.Theportisahole, usuallybackedbyatube.Thedimensionsoftheportarecarefullycalculatedsothatitpermits bassataselectedfrequencytobeproducedfromtheinterioroftheenclosure(drivenbythe backofthewoofer'scone).Thisarrangementpermitsabassreflexspeakertogenerallyachieve greaterefficiencythananacousticsuspensionspeaker,anditextendsthedepthatwhichbass maybeproducedwithoutsignificantattenuation.Howeverforfrequenciesbelowtheband producedbytheport,theoutputdropsoffrapidly. AnInternet-relatedfeaturesetincludedwithsomeBlu-raydiscplayers.Providesaccessto Internetsitessupplyinginformationrelatedtothemovieorprogramyouarewatching,aswell asotherfeaturessuchasonlinechat. Apolepositionofspeakersinwhichthedriversareontwofaces,oppositeeachother.Bipole speakersaredesignedforsideorrearsurroundsoundinahometheater.Theyfiretheircones atthesametime,inphase. Thesmallestcomponentofadigitalword,representedbyeitheraoneorazero. Thesizeofthenumberthatrecordseachdigitalsample.Sincethesystemisdigital,thenumber relatestopowersoftwo.Thecompactdiscusesabitdepthof16,whichallows65,536 differentlevelstobeusedtotracktheanaloguesourcesignal.DVDsusuallyalsouse16,but mayalsouse20bits(whichgivesoveramillionlevels)or24bits(whichgivesmorethan16.7 millionlevels).Thegreaterthebitdepth,thelowertheharmonicdistortionandquantization noise,andthemorestoragespacerequiredforthesignal.Audiorecordingstudiosuse20bit and24bit,whichisreduceddownto16bitforcompactdisc.Specialistaudiocompaniesare nowoffering20or24bitaudiofordownload,thisofferssuperaudioCDqualityandabove. Thenumberofdigitalbitsasystemtransferspersecond.Ingeneral,thehigherthebitrate,the higherthequalityofthesignal.Ineverycase,thehigherthebitrate,themoredataspace required.Withaudiobitratesaremeasuredinthehundredsofkilobitspersecond(kb/s).With DVDvideo,theyaremeasuredinmegabitspersecond(mb/s). Acontinuousstreamofbits(binarydigits)transmittedoveracommunicationspath,suchasa cableconnectingcomponentsinahometheatersystem. Bluetoothisawirelesstechnologyforexchangingdata(includingvideoandaudio)overshort distances. Ahigh-definitionopticalmediastoragealternativetoDVDs,developedbySonyCorporation. ThenameBlu-rayisderivedfromtheblue-coloredlaserthatreadsthediscinsideaBlu-raydisc player. Bluetoothisawirelesstechnologystandardforexchangingdataovershortdistances(using short-wavelengthUHFradiowavesintheISMbandfrom2.4to2.485GHz[4])fromfixedand mobiledevices,andbuildingpersonalareanetworks(PANs).Inventedbytelecom vendorEricssonin1994,[5]itwasoriginallyconceivedasawirelessalternativetoRS-232data cables.Itcanconnectseveraldevices,overcomingproblemsofsynchronization. AfeaturesetthatprovidesenhancedmenusandotherextrasforsomeBlu-raydiscplayers. Includessecondaryaudioandvideocircuitrythatallowspicture-in-pictureandaudio voiceovers. Amodeofoperationforastereoamplifierthatroutesasingleinputtobothchannels,but invertsthesignalonchannel2,therebyprovidingtwicethevoltageofanindividualoutputby connectingthespeakerbetweenthetwopositiveoutputterminals(thenegativeoutput terminalsarenotused). Thelevelofblackthatyouseeonavideodisplay.Thebrightnesscontrolonadisplayenables youtoadjustthissetting. Bypass CableCARD Cantilever Cardioid Termusedtowhenconvertinganintegratedamplifierintoapoweramplifieri.e.bypassingthe per-ampstage. Asmartcardwithanembeddedchipthatdescramblespremiumchannels.Yourenta CableCARD—whichplugsintoaslotonyourHDTV—fromyourcableserviceprovider. Thethinrodwithinaturntable'scartridgethattransmitsthemovementofthestylusin responsetoarecord'sgroovetotheinteriorcomponentsofthecartridgethatgeneratethe electricalsignal. Heart-shaped.Insoundwork,cardioidreferstotheshapeofthesensitivityvs.directionplotfor aparticularstyleofdirectionalmicrophone.Acardioidmicrejectssoundarrivingfromtherear. ThedevicethatconvertsthemovementsofastylusinthegroovesofanLPrecordtoelectrical signals.Thecartridgeisasmall,light-weightdevice,securedtotheendofaturntable's tonearmbymeansoftwoscrewsmounted12.5mmapart.Themovementsofthestylusare Cartridge transmittedthroughacantilevertosomeformofelectricalgeneratingdevice.Thetwomain typesofcartridgeareceramicandmagnetic.Thelatterisfurthersubdividedintomoving magnetandmovingcoiltypes. Along-runEthernetcablingsystemmostcommonlyusedinhomestocarryaudioandvideo CAT-5e signalsforcomputernetworksandawhole-hometheaternetwork. Along-runEthernetcablingsystemusedtocarryaudioandvideosignalsforcomputer CAT-6 networksandawhole-hometheaternetwork;suitableforveryfastcomputernetworks. Aplaceinyourhomewhereyoulocatetheinfrastructuredevicesthatenableyoutoconnect Centralwiringpanel yourhometheatertootherpartsofthehouseinawhole-hometheatersystem. Acentrespeakeristhecentrallyplaceunitineithera5.1or7.1surroundsystemandisplaced CentreSpeaker directlyinfrontoftheviewerorlistenerasclosetothevideosourceaspossible.Itismainly speechinformationthatisprocessedthroughacentrespeaker. Atime-basedeffectavailableinsomedigitaldelayeffectsunitsandreverbs.Chorusinginvolves Chorusing anumberofmovingdelaysandpitchshifting,usuallypannedacrossastereofield.Depending onhowused,itcanbelovelyorgrotesque. Thecolorportionofthetwo-componentvideosignalthatrunsthroughavideocable(theother Chrominance componentisluminance). ApoweramplifierinwhichasufficientDCbiasvoltageisappliedtothepowertransistorsso thattheoutputsignalalwaysoperatesentirelyinthepositiveornegativepartofthecycle, entirelyavoidingcrossoverdistortion.Thismakesthemquitewastefulofpowersinceevenat ClassA idleaconsiderablevoltageisbeinggenerated.TheDCbiasisfilteredoutbeforebeingfedto thespeakers.Therealbenefitofthisdesignisinthesoundqualities.ClassAdesignshaveno crossoverdistortion,whichisaudible. ApoweramplifierinwhichacertainamountofDCbiasvoltageisappliedtothepower transistorssothat,atlowpoweroutputs,theoutputsignaloperatesentirelyinthepositiveor negativepartofthecycle,avoidingcrossover distortion.Thus,atlowoutputs,aClassA/BamplifieroperatesinClassAmode.Athigher ClassAB outputsthesignaldoescrossoverthezeropoint,effectivelyenteringClassBterritory.This designisacompromisebetweentheefficiencyofClassBamplifiers(inwhichthereisnoDC bias)andtheeliminationofcrossoverdistortioninClassAdesigns.TheDCbiasisfilteredout beforebeingfedtothespeakers. Averyefficientamplifierdesign.Digitalamplifiersuseaformofpulsewidthmodulation(with lowpassfilteringtoreduceultrasonicnoise)todrivetheloudspeakers.Therearesome ClassD interestingamplifierproductsappearingthat incorporateclassDdesigns.Thejuryisoutonwhethertheyultimatelyofferthesamefidelityas moreconventionalclassA/Bdesigns. Aformofsevereaudiodistortionthatresultsfrompeaksoftheaudiosignalattemptingtorise abovethecapabilitiesoftheamplifiercircuit.Seenonanoscilloscope,theaudiopeaksappear Clipping clippedoff.Toavoidclipping,reducethesystemgaininorbeforethegainstageinwhichthe clippingoccurs.Alsoseeheadroom. Signalusedtosynchroniseitemsofequipmentwhicharecommunicatingdigitalaudioorvideo signalstoeachother.Thelackofasuitableclockingsignalwouldallowtheirtimingtodrift apartfromeachother,sincetheir internalclockingsignalswouldnotbeidentical,sodigitalsampleswouldbelost.Theeffect Clocksignal whenusingaveryhighqualityclockinaudiocomponentssuchasCDplayers,istoproducea highqualitysound.TheadditionalcostsassociatedwiththismeansthatonlythebestCD players(andusuallythemostexpensive)implementthisintheirproducts. 1.(noun)AdigitalaudiointerconnectcablewithRCAjacksoneachend,usedtoconnecthome Coaxial theatercomponentstotheA/Vreceiver.2.(noun)Acable(alsocalledcoax)withanF connector,usedtoconnectacableTVfeed,antenna,orsatellitedishtoahometheater. ThedigitalaudiooutputsignalofaDVDplayerinanelectricalformat,ratherthanoptical.The CoaxialDigital dataformataccordswiththeS/PDIFspecification. Acoaxialinputsocketreceivesdatafromanelectricalcomponentwhichcanbeeitheraudioor Co-axialin videoinformation Acoaxialoutputsocketsendsdatafromanelectricalcomponentwhichcanbeeitheraudioor Co-axialout videoinformation Asystemwhichcompressesasignalinsomewayforstorageortransportationandthen decompressesitatthepointofdelivery.ExamplesareMPEG,DolbyDigitalandDTS.These systemsuseacodec toreducetheamountofdatainthesignal.Otherformsofcodec,particularlyinthedaysof Codec analogueaudiosystems,compressedandthendecompressedthedynamicrangeofthesignal, Compression/Deco nottoreducethesizeofthesignalbuttoreduce mpression noiselevels.Oneconsumersystemwascalled'dbx'.Digitaldatastorageforaudiouseseveral softwaresystemstotakecomplete16bit(orhigher)filesinWAVandcompresstonearlyhalf theirsize.Whenuncompressed,thefilesareagainidenticalWAVfiles.Onecommon compressionprogramisknownasFLAC. Programsthatcancompress(forefficientstorageanddistribution)anddecompress(for Codecs playback)musicandotherfiletypesintoeitherlosslessorlossydigitalfiles. Ameasureofthenumberofdigitalbitsusedtostorethecolorinformationforahigh-definition Colordepth TVsource. Anunwantedalterationinthecharacterofaudio.Significantcolourationofsoundcanmake instrumentsandvoicessoundunrealistic.Itmaybecausedbyharmonicdistortion,vibrations Colouration ofcomponentparts(forexample,thepanelsofaninadequatelybracedloudspeakerenclosure) or,mostcommonly,throughanunevenfrequencyresponse. Separatesthecolorandbrightnesspartsofavideosignalintotheircomponentpartsandsends Combfilter themtotheappropriateinternalcircuitry.Combfiltersaremoreeffectivethannotchfilters, andincludethesetypes:2-D,3-D,anddigital. Asignalwhichisreferencedtothecircuitcommonpoint,usuallychassisground. Commonmode Atypeofshort-runanalogvideoconnectionthatprovidesonepathforbrightnessinformation Componentvideo andtwoseparatepathsforcolorinformation.Thesecablestypicallyhavered,green,andblue connectors;abetteralternativetocompositevideoorS-video. Atypeofshort-runanalogvideoconnectioninwhichbothcolorandbrightness(thetwo Compositevideo componentstoavideosignal)arecombinedintoasinglesignal.Thecombfilterinsideadisplay thenseparatesthesesignals.Thesecablesareusuallycolor-codedyellow. Thisisadynamicsprocessorusedtosmoothoutanylargetransientpeaksinanaudiosignal Compressor thatmightotherwiseoverloadyoursystemorcausedistortion.Theamplitudethresholdand otherparameterssuchasattacktime,releasetime,andtirepressureareadjustable. Anothertermfortheelectroniccomponentgenerallyknownasacapacitor.Inaudio, condenseroftenreferstoatypeofmicrophonethatusesacapacitorasthesoundpickup Condenser element.Condensermicrophonesrequireelectricalpowertoruninternalamplifiersand maintainanelectricalchargeonthecapacitor.Theyaretypicallypoweredbyinternalbatteries or“phantompower”suppliedbyanexternalsource,suchasamixingconsole. Thelevelofwhitethatyouseeonavideodisplay.Thecontrastcontrolonadisplayenablesyou Contrast toadjustthissetting. Anumericratio(suchas800:1)thatmeasureshowwelladisplaycanshowbrightcomparedto Contrastratio nuanceddarks.Ahigherratioisbetter,butthismeasurementisn'tstandardizedsoyoucan't easilycomparenumbersbetweenmanufacturers. ShortforA/Vcontroller.Adevicethatperformsswitching(betweenaudioandvideosources) Controller andpre-amplificationtasksinahometheater.Oneofthreeseparatecomponents(alongwitha poweramplifierandradiotuner)thatcanbeusedinplaceofanall-in-oneA/Vreceiver. TheratioofthepeakvaluetotheRMSvalue.Musicalsignalscanhavepeaksmanytimeshigher Crestfactor thantheRMSvalue.Thelargerthetransientpeaks,thelargerthecrestfactor. Whereasignal(particularlyaudio)leaksfromonechanneltoanother.Thusavoicemaybe intendedtobeentirelyintheleftchannelofastereorecording,butsomeportionofitappears CrossTalk intheright,draggingtheapparentpositionofthevoicesomewhattowardsthecentreofthe soundstage.Normallyspecifiedbytheinverseofcrosstalk:separation. Asmalldiscontinuity(or,atleast,nonlinearity)inasignalwhenatransistor-basedamplifier Crossover circuitswitchesfrompositivetonegativeoperation.ThisisaddressedbyClassAandClassA/B designs.Sometimescalled'zerocrossdistortion'. Asmalldiscontinuity(or,atleast,nonlinearity)inasignalwhenatransistor-basedamplifier Crossoverdistortion circuitswitchesfrompositivetonegativeoperation.ThisisaddressedbyClassAandClassA/B designs.Sometimescalled'zerocrossdistortion'. Thefrequencyatwhichasignalishandedfromonecomponenttoanother.Thisappliesin Crossover loudspeakercrossovernetworksandbasemanagementsystems. frequency Thesetofcomponentsinaloudspeakerthatdividesuptheincomingsignal,sendingthebass tothewoofer,thetrebletothetweeterand,sometimes,themiddlefrequenciestoamidrange Crossovernetwork driver.Thecrossovernetworkusesresisters,capacitorsandinductors(coils)todivideupthe signal.Somesystemsuseactivecrossovernetworks.Insuchcases,thedivisionismadebefore thesignalisamplified,soaseparateamplifierisrequiredforeachdriver. Thequantityofelectricalchargemovingthroughacircuitoveragiventime.Theunitfor Current currentisampsoramperes. D/Aconverter Digital-to-analogconverter,adevicethattransformsincomingdigitalsignalsintoanalogform. (DAC) DABstandsforDigitalAudioBroadcasting.Itisadigitalbroadcastingstandardusedmostly withinEuropetoeventuallyreplacethetraditionalFM.Theaudioqualitycandifferbetween DAB broadcastsandtheaudilmaterial,worthmoststationsusingthe128or160kbits/s(MP2)bit rate. AnacronymforDigitalAnalogConverter.OneoftwochipsinanA/Vreceiverthatdecodes DAC surround-soundformats.TheDACconvertsdigitallyencodedmusicsignalsintoanalogsignals thatareceiver’samplifierandthesurroundspeakerscanunderstand. Damping Dampingfactor DAT DAW dB dBA dBm dBu dBv dBV Decibel(dB) Deepcolor Dampingfactorisanumberthatrepresentstheratiooftheimpedanceoftheloadtothe outputimpedanceoftheamplifier.Inpracticalterms,itisameasureofhowwelltheamplifier cancontrolthemovementofaspeaker'scone.Thegreaterthedampingfactor,thebetterits abilitytocontrolthecone'smovement.Alowdampingfactor(highamplifieroutput impedance)allowsawoofertocontinuetomoveafterthesignalstops,resultinginanindistinct andmushylowfrequencyresponse.Ahighdampingfactor(200orabove)providesexcellent controloverlowfrequencywoofersandproducesatight,cleanbass. Aspecificationforpoweramplifierswhichsuggeststhedegreeofcontrolthattheamplifier exercisesoveraconnectedloudspeaker.Itistheratioofthenominalimpedanceofthespeaker (andistypicallyquotedforeightohms)totheinternalimpedanceoftheoutputstageofthe amplifier.Ahighinternalimpedancefortheamplifiermeansthatitsfrequencyresponsewill varywithreal-worldspeakerssincetheirimpedancevariesacrosstheirfrequencyrange.Italso meansthatthedriver,whichwantstodoitsownthingundertheinfluenceofair,its suspensionandsoforth,ratherthanwhatthesignalistellingittodo,willfacearelativelyhigh impedancetothevoltageitisgeneratingbackintotheamplifier.Consequentlyitwillbefreer todoitsownthing,ratherthanwhattheamplifieristellingittodo.Howeverthedamping factorquotedforamplifiersdoesnottakeintoaccounttheimpedanceofthewiringbetween amplifierandloudspeakers,northeimpedanceofthespeakers'ownvoicecoils.Consequently thereisonlyamodestperformancegainbetweenadampingfactorof,say,60andoneof600. DigitalAudioTapeisarecording/playbacksystemwhereanalogsignalsareconvertedtodigital formandstoredonmagnetictape.Itoffersallthebenefitsofdigitalaudioincludinglownoise andwidedynamicrange. DigitalAudioWorkstationisadedicatedrecording/editingsoftwareapplicationandhardware system,usedforharddisk(non-linear)randomaccessrecordingandplayback.ManyDAWsare usedwithpersonalcomputersusingWindows®orMacintosh®operatingsystems,thoughsome usetheirownproprietarycomputers. Seedecibel. SoundPressureLevel(SPL)measuredwithan"A"weightingfilter. Aunitofmeasurementofpowerinanelectricalcircuit,expressedindecibelsreferencedto1 milliwatt.The“m”indBmstandsfor“milliwatt.”Inacircuitwithanimpedanceof600ohms, thisreference(0dBm)correspondstoasignalvoltageof0.775VRMS(because0.775Vacross 600ohmsequals1mw). Aunitofmeasurementofaudiosignalvoltageinanelectricalcircuit,expressedindecibels referencedto0.775VRMSintoanyimpedance.Commonlyusedtodescribesignallevelswithin amodernaudiosystem.Nobodyisreallysureif“u”standsforanything. AunitofmeasurementequaltothedBunolongerinuseintheUS,butsometimesstillinGreat Britain.ItwastooeasytoconfuseadBvwithadBV,towhichitisnotequivalent. Aunitofmeasurementofaudiosignalvoltageinanelectricalcircuit,expressedindecibels referencedto1VRMSacrossanyimpedance.Commonlyusedtodescribesignallevelsin consumerequipment.ToconvertdBVtodBu,add2.2dB. ThedBisaratioofquantitiesmeasuredinsimilartermsusingalogarithmicscale.Manyaudio systemparametersmeasureoversuchalargerangeofvaluesthatthedBisusedtosimplify thenumbers.Aratioof1000:1=60dB.SincedBisaunitlessquantity,itdoesn’tmatterifit’s voltsordollars.(justtryaskingthechiefengineerfora3dBraise)Whenoneofthetermsinthe ratioisanagreeduponstandardvaluesuchas1.23V,1Vor1mw,theratiobecomesan absolutevalue,i.e.,+4dBu,-10dBVor0dBm. Asystemsupportedbyhigh-endHDTVsthatprovideshigher(thantypical)levelsofcolordepth, capableofsupportingmillionsofcolors. Insoundwork,delayusuallyreferstoanelectroniccircuitoreffectsunitwhosepurposeitisto delaytheaudiosignalforsomeshortperiodoftime.Delaycanrefertooneshortrepeat,a seriesofrepeatsorthecomplexinteractionsofdelayusedinchorusingorreverb.When delayedsignalsaremixedbackwiththeoriginalsound,agreatnumberofaudioeffectscanbe Delay generated,includingphasingandflanging,doubling,Haasprecedence-effectpanning,slapor slapback,echo,regenerativeecho,chorusingandhall-likereverberation.Signaltimedelayis centraltomanyaudioeffectsunits. Thebendingofsoundwavesaroundanobstacle(HuygensPrinciple).Thelongerthewave- Diffraction lengthincomparisontotheobstacle,themorethewavewilldiffractaroundit. Justlikeanyotherfileonyourcomputer,excepttheycontaindigitallyencodedmusicfilesthat Digitalaudiofile youcanplaybackonyourcomputer,onaportabledevice,orinyourhometheater. AfeatureofmostHDTVsthatenablesyoutoconnectacoaxialcablefromthewalldirectlyto Digitalcable-ready theTV,skippingaset-topbox(fornonscrambledchannels). Digitalrights Amusicorvideosystemthatplacesrestrictionsoncopyingorrecordingdigitalassets.Protects management;DRM thecopyrightinterestsofmusic,movie,andothercontentowners. DTSisacompanythathasinventedanddevelopedseveralsurround-soundencodingschemes, DigitalTheater includingthelosslesssurround-soundformatknownasDTS-HD. Systems Apolepositionofspeakersinwhichthedriversareontwofaces,oppositeeachother.Dipole Dipole speakersaredesignedforsideorrearsurroundsoundinahometheater.Theyfiretheircones atdifferenttimes,outofphase. Theoppositeofpeaking,ofcourse,usedinaudiotodescribetheshapeofafrequency Dipping responsecurve.AdipinanEQcurvelookslikeavalley,oradip.Dippingwithanequalizer reducesarangeoffrequencies. Atypeofdisplayinwhichtheimageiscreateddirectlyonthescreenyouarewatching. Direct-viewdisplay Includesold-fashionedtubeTVs,plasmadisplays,andLCDTVs. Asoundsignalcontainedineachoftheavailableaudiochannelsthatisdistinctand Discrete independentfromeachoftheothers. Thedeviceinahometheaterthatshowsthepicture.Includesdirect-viewdisplays(tube, Display plasma,orLCDTVs)andtheseparatescreeninafront-projectionsystem. Aninaccuracyinthereproductionofasignal.Inthecaseofaudio,itisnormallyregardedas beingcomposedofharmonicdistortionandintermodulationdistortion.Butusedmorebroadly, itcanalsoencompassfrequencyresponsevariationsandnoise.Inthecaseoflossy Distortion compressiontechnologies,somedistortionconsistsofspuriousnoise(notharmonically related)surroundingthesignal.When'distortion'isquotedasaspecificationwithout qualification,itnormallyrefersonlytoharmonicdistortion. Thisisaninterestingtechniquetoreducetheaudibilityoflowlevelnoiseinadigitalrecording. Dither Lowlevelrandomnoiseisaddedtotheanalogsignalbeforethesamplingstage,reducingan effectcalledquantizationerror. AnacronymforDigitalLightProcessor.DLPisamethodofprojectingvideoinprojector DLP systems,developedbyTexasInstruments.Usesaspecialvideochipwithmillionsof microscopicmirrorsthataremovedbycomputercommandtocreateimages. Anall-digitalsurround-soundformatdevelopedbyDolbyLaboratories(in1997)thathandles DolbyDigital audiocompression,availableonlyfordigitalcontent. Anall-digitalsurround-soundformatdevelopedbyDolbyLaboratoriesthatisanimprovement ontheolderDolbyDigitalandDolbyDigitalSurroundEXsystems.Enhancementsincludean DolbyDigitalPlus increasedbitrate,improvedsoundencoding,morediscretechannelsofsound,andbackward compatibility. DolbyDigital SurroundEX DolbyProLogic DolbySurround Sound DolbyTrueHD Doubling Driver Drivers Dry DSD DSP DSS Anall-digitalsurround-soundformatdevelopedbyDolbyLaboratoriesthatimprovesonthe olderDolbyDigitalsystem.Includesanadditionalrear(center)surroundspeakerwitha matrixed(intermixed)signalfromtheleftandrightsurroundchannels. Anoldersurround-soundformatdevelopedbyDolbyLaboratoriesthatincludesfourchannels andfivespeakersofmatrixed(intermixed)multichannelsurroundsound.Animprovementon theDolbySurroundSoundformat.NewerenhancedversionsincludeDolbyProLogicIIand DolbyProLogicII.x. Theoriginalsurround-soundformatdevelopedbyDolbyLaboratoriesthatencodesfouranalog audiochannelsintotwochannels. Anall-digitallosslesssurround-soundformatdevelopedbyDolbyLaboratoriesthatsupportsup to13.1channelsofsurround-sound. Adelayeffect,wheretheoriginalsignalismixedwithamedium(20to50ms)delayedcopyof itself.Whenusedcarefully,thiseffectcansimulatedouble-tracking(recordingavoiceor instrumenttwice). Themovingpart,orparts,ofaloudspeaker.Theseareusuallywoofers(bassdrivers),midrange driversandtweeters(highfrequencies).Therearea numberofdifferentdriverdesigns.Virtuallyallwoofersusethetraditionalspeakercone(some lightmaterial,oftenpaperpulporpolypropylene)heldinplacebyasuspensionandbackedby acoilinsertedintothemagneticfieldofastrongpermanentmagnet.Theamplifier'ssignalis fedintothecoil,generatingitsownmagneticfield,causingthecoilandtheattachedconeto move.Midrangedrivers,whicharerelativelyrarethesedays,usuallyuseeitherconesordomes (oftenpolypropyleneoralightmetalsuchasmagnesium),althoughtherearesomeribbon midrangedrivers.Tweetersaremostcommonlydomes(oftenpolypropylene,silkorsome othertextile,oralightmetalsuchasaluminiumortitanium),butcheaperonesusecones. Someuseinverteddomes(thatis,theyareconcaveratherthanconvex),whilesomeexpensive speakersuseribbontweeters.Therewaseven,forawhile,a'plasma'tweeterwherethehigh frequenciesweregeneratedbyapulsatingballofsuperheatedair.Somespeakersdonotuse whatcouldbeconventionallycalleddrivers,forexampleelectrostaticspeakers. 1.(noun)Theroundelementsinsideaspeakerenclosurethatmovebackandforthandcreate changesintheairpressure(soundwaves).2.(noun)Softwarefilesthatintegratehardware deviceswithaPC'soperatingsystem. Usuallymeanswithoutreverberation,orwithoutsomeotherappliedeffectlikedelayor chorusing.Dryisnotwet,i.e.,totallyunaffected. DirectStreamDigital.ThedigitalaudioformatusedintheSACD.UnlikethePCMsystem normallyused,DSDusesastreamofsinglebitsofinformation.Themomentarylevelofthe analoguewaveformbeingrepresentedbythebitstreamisdeterminedbythedensitywith whichthebitsare'on'ratherthan'off'.Itismodifiedbyusingnoiseshapingtoincreasethe effectivedynamicrangeinthemainaudibleband.DSDusesforeachchannelabitrateof 2,822,400bitspersecond. DigitalSignalProcessingcanaccomplishthesamefunctionsfoundinanalogsignalprocessors, butperformsthemmathematicallyinthedigitaldomain,withmoreprecisionandaccuracy thanitsanalogcounterpart.SinceDSPisasoftware-basedprocess,parametersandprocessing functionsareeasilychangedandupdatedbyrevisingthesoftware,ratherthanredesigningthe hardware.DSPcanbefoundinanoutboardeffectsdevice,suchasareverbordelayunit,orit canbeintegratedintoaDAWordigitalmixingconsole. AnacronymforDigitalSatelliteService.DSSisaTVsourcethatreceivesasignalfromasatellite dish.ThetwomainDSSservicesintheU.S.areDirecTVandDISHNetwork. AdevicethatdecodestelevisionsignalsfeedinginfromasatellitedishsothatyourTVcan displaytheprogramming. DirectStreamTransfer.LosslesscompressedDSD. DST Alosslesssurround-soundformatonBlu-raydiscsandplayersthatcanprovideupto7.1 DTS-HD channelsofsurroundsound.Therearetwovariants:DTS-HDHigh-ResolutionAudio(similarto DolbyDigitalPlus)andDTS-HDMasterAudio(similartoDolbyTrueHD). Amodeofoperationforastereoamplifierthatroutesasingleinputtobothchannels,butstill Dualmono allowsindependentlevelcontrolovereachamplifieroutput. ADVDorBlu-raydiscinwhichyoucanstoremediaonbothsidesofthedisc,doublingthe Dual-layerdisc capacityofasingle-layerdisc. 1.(noun)Ahigh-capacityopticaldiscresemblingaCD,usedprimarilyforstoringvideo(suchas DVD movies)anddata.2.(noun)OtherformsofthetermDVDindicateastandardforthewaydata isstoredonthedisc,suchasDVD+RWforarewriteablediscformat. Adevicethatperformshardware-baseddecodingoftheMPEGvideoonDVDs.Thisfreesup DVDdecoder yourcomputer’smainprocessorforothertasks(recommendedifyouhaveaslowerPCthat youwanttouseinyourhometheater). DVD-Audio.AnewerdigitalaudioformatonDVDthatoffershigher-qualitysoundandgreater DVD-A capacitythanaCD.TheDVD-Audioformatisnotintendedforvideo. AnacronymforDigitalVisualInterface.DVIisadigitalvideotechnologythatwasdevelopedas DVI ameanstoconnectcomputerstodigitalLCDscreensandprojectors. Digitalvideorecorder.Ahometheaterdevicethatrecordsvideoontoastandardcomputer DVR harddrive.DVRs(alsocalledPVRs)connecttoaprogramservice,usuallyviaatelephoneline. TiVoisamajormanufacturerofDVRs. Theclassofmicrophonesthatgenerateelectricalsignalsbythemovementofacoilina Dynamic magneticfield.Dynamicmicrophonesarerugged,relativelyinexpensive,capableofverygood microphone performanceanddonotrequireexternalpower. WhenpertainingtoaudioCDs,thedifferencebetweenthesoftestandloudestmusical passagesonacompactdisc.Therangebetweenthemaximumandminimumsoundlevelsthat Dynamicrange asoundsystemcanhandle.Itisusuallyexpressedindecibelsasthedifferencebetweenthe levelatpeakclippingandthelevelofthenoisefloor. Atypeofprocessorthatonlyaffectstheoverallamplitudelevelofthesignal(sometimesasa Dynamicsprocessor functionofitsfrequencycontent),suchasacompressor,expander,limiter,orgate. EBUstandsfortheEuropeanBroadcastingUnion,analliancefoundedin1950andbest-known EBU forproducingthemusicallydubiousEurovisionSongContest! Anexternalsignalprocessorusedtoaddreverb,delay,spatialorpsychoacousticeffectstoan Effectsdeviceor audiosignal.Aneffectsprocessormaybeusedasaninsertprocessor(serial)onaparticular effectprocessor inputorsubgroup,oritmaybeusedviatheauxsend/returnsystem(parallel).Seealsoecho, reverb. EquivalentInputNoise.Aspecificationthathelpsmeasurethe“quietness”ofagainstageby derivingtheequivalentinputnoisevoltagenecessarytoobtainagivenpreamp’soutputnoise. EIN Numerically,it’stheoutputnoiseatagivengainsettingminusthegain.EINisusuallymeasured atmaximumgainandtypicallyrangesfrom-125to-130dBm. Electro-MagneticInterference.Thisreferstocurrentinducedintothesignalpathasaresultof anexternalmagneticfield.Inaudiosystems,thisisusuallymanifestedasa60Hzor120Hz EMI humorbuzz(50Hzor100Hzin50Hzsystems).Thesourceofthisnoisecanbefromaground looporfromthesignalwirecomingtooclosetoastrongmagneticfieldsuchasatransformer orhighcurrentlinecord DSSreceiver Enclosure Encodingformats Enclosure EQ EQcurve Equalization Fader Familyofcurves FCC Filter FireWire Flanging Flutter FM FOH Theboxofaloudspeaker.Inanyhalfdecentspeaker,thisisnotmerelyadevicetokeepthe driversoffthefloor,butanintegralpartofthedesignofthewholeloudspeaker,contributing greatlyto--or,ifdonebadly,detractingfrom--itsperformance.Themostcommonenclosure designsarebassreflexandacousticsuspension.Goodqualityenclosuresincludestrongbracing toresistsympatheticvibrationsintheirpanels,whichcanleadtosoundcolouration Fileformatsusedforconvertingdigitalcontent(audioandvideofiles)tosmallerfilesizes. SomeaudioencodingformatsincludeMP3,WMA,andAAC.Somevideoencodingformats includeWMVandMPEG. Aloudspeakerenclosureorloudspeakercabinetisanenclosureinwhichspeakerdriversand associatedelectronichardware,suchascrossovercircuitsand,insomecases,amplifiers,are mounted. Shortforequalization. Agraphoftheresponseofanequalizer,withfrequencyonthex(horizontal)axisand amplitude(level)onthey(vertical)axis.Equalizertypesandeffectsareoftennamedafterthe shapeofthegraphedresponsecurve,suchaspeak,dip,bell,shelf,ornotch. Equalization(EQ)referstopurposefullychangingthefrequencyresponseofacircuit, sometimestocorrectforpreviousunequalresponse(hencetheterm,equalization),andmore oftentoboostorcutthelevelatcertainfrequenciesforsoundenhancement,toremove extraneoussounds,ortocreatecompletelynewanddifferentsounds.Bassandtreblecontrols onyourstereoareEQ;soaretheunitscalledparametricsandgraphicsandnotchfilters.Alot ofhowwerefertoequalizationhastodowithwhatagraphofthefrequencyresponselooks like.Aflatresponse(noEQ)isastraightline;apeaklookslikeahill,adipisavalley,anotchisa reallyskinnyvalley,andashelflookslikeaplateau(orashelf).Theslopeisthegradeofthehill onthegraph. Anothernameforanaudiolevelcontrol.Today,thetermreferstoastraight-lineslidecontrol ratherthanarotarycontrol. AcompositegraphshowingononechartseveralexamplesofpossibleEQcurvesforagiven equalizerorequalizersection. FederalCommunicationsCommission.Thecontrollingregulatoryauthorityforbroadcasters, cablecompanies,andtelephonecompaniesintheUnitedStates. Asimpleequalizerdesignedtoremovecertainrangesoffrequencies.Alow-cutfilter(also calledahigh-passfilter)attenuatesfrequenciesbelowitscutofffrequency.Therearealso highcut(low-pass)filters,bandpassfilters,whichcutbothhighandlowfrequenciesbutleavea bandoffrequenciesinthemiddleuntouched,andnotchfilters,whichremoveanarrowband butleavethehighandlowfrequenciesalone. Adigitalvideoconnectionusedforsomedevicesinahometheater(originatingfromthe computerindustry).Nowbecomingmorecommonforaudiohometheaterconnections. Atermforaneffectsimilarinsoundtophasing.Beforewehadelectronicdelayunits,flanging wasaccomplishedbyplayingtwotapemachinesinsynchronization,thendelayingoneslightly byrubbingafingeronthereelflange.Getit? Theboxofaloudspeaker.Inanyhalfdecentspeaker,thisisnotmerelyadevicetokeepthe driversoffthefloor,butanintegralpartofthedesignofthewholeloudspeaker,contributing greatlyto--or,ifdonebadly,detractingfrom--itsperformance.Themostcommonenclosure designsarebassreflexandacousticsuspension.Goodqualityenclosuresincludestrongbracing toresistsympatheticvibrationsintheirpanels,whichcanleadtosoundcolouration. FM,orFrequencyModulationisthecarryingofinformationoverawavelengthvia electromagnetism.MostusedinFMradiobroadcastingforhighqualitystereosoundquality. AnacronymforFrontOfHouse.Seehouseandmainhousespeakers.Nobodyinvolvedwith audioevergoestotheBackofHousebecausetheyneverhavetimetodrinkenoughbeer. Freesat Freeview Frequency Frequencyrange Frequency Response FrontRow FrontSpeaker Front-projection system Gain Gainstage Gate Gauge GraphicEQ Freesatisafreetoair(nosubscription)satellitebroadcastventurebetweentheBBCandITVin theUK.ItallowsHighDefinitionbroadcaststobeviewed. Freeviewisanotherfreetoviewtelevisionservicebutisdigitalterrestrialasopposedto satellite.VersionsalsoexistinNewZealandandAustralia.Presumablythesebroadcastsare upsidedown! Thenumberoftimesaneventrepeatsitselfinagivenperiodoftime.Generallythetimeperiod foraudiofrequenciesisonesecond,andfrequencyismeasuredincyclespersecond, abbreviatedHz,honoringthephysicistDr.HeinrichHertz(whodidnotinventtherentalcar). OneHzisonecyclepersecond.OnekHz(kilo-hertz)is1000cyclespersecond.Theaudio frequencyrangeisgenerallyconsideredtobe20Hzto20,000Hz.Thiscoversthefundamental pitchandmostovertonesofmusicalinstruments. AspecificationforareceiverthatismeasuredinHertz(Hz).Thelowerfrequencyranges(for basssounds)requiremoreamplifierpowerthanthehigherfrequencyranges. Ameasureofhowaccuratelyasystemreproducesdifferentfrequencies.Inthecaseofaudioin ahometheatresystem,itisdesirableforthefrequencyresponseofawholesystem,including speakersandsubwoofer,tobefrom10hertzto20,000hertz±3dB.Thisperformancerequires averyexpensivesystemindeedand,inpractice,veryfewsystemswillproducebassdownto anythinglikethatbottomlimit.Manufacturerswhoclaimafrequencyresponseforspeakersof, say,20to20,000hertzwithoutspecifyingdecibelboundariesaretellingyounothing.Atinny twoinchtransistorradiospeakercanreproducethatrange,althoughyouwon'tactuallyhearit ateitherextremebecauseitsoutputwillbesolow.Evensubtlevariationsoflessthanhalfa decibelacrosstheaudiobandcanbequiteaudible,especiallyifthey'respreadoverafairly widebandoffrequencies,andcanthuschangethecharacterofthesound.Indeed,with speakersthesinglemeasuremostcloselyrelatedtotheirsoundisthefrequencyresponse. AmediacenterapplicationdevelopedbyApple,fortheMacintosh.IncludestheFrontRow software(builtintotheoperatingsystem)andaremotecontrol.Thisapplicationenablesyouto useaMacwithyourhometheater. ThemainpairofstereospeakersinaAVmulti-speakersystemthatarealwaysforwardfacing. Atypeofprojectionsysteminahometheaterthatincludestwoparts:afrontprojectorunit andaseparatescreen.Thelightisprojectedfromtheprojectorunitontothescreen. Themeasureofhowmuchacircuitamplifiesasignal.Gainmaybestatedasaratioofinputto outputvoltage,currentorpower,suchasavoltagegainof4,orapowergainof1.5,oritcan beexpressedindecibels,suchasalineamplifierwithagainof10dB. Anamplificationpointinasignalpath,eitherwithinasystemorasingledevice.Overallsystem gainisdistributedbetweenthevariousgainstages. Adynamicsprocessorthatautomaticallyturnsoffaninputsignalwhenitdropsbelowacertain level.Thiscanreducetheoverallnoiselevelofyourmixbyturningoffinputswhentheyarenot inuse.Threshold,attacktime,hold,andreleasetimearesomeoftheadjustablegate parameters. Thethicknessofspeakercables,suchas16-gaugeor14-gauge(thelowerthegauge,thethicker theconductorsinsidethecable). Agraphicequalizerusesslidepotsforitsboost/cutcontrols,withitsoperatingfrequencies evenlyspacedthroughtheaudiospectrum.Inaperfectworld,alinedrawnthroughthecenters ofthecontrolshaftswouldformagraphofthefrequencyresponsecurve.Or,thepositionsof theslidepotsgiveagraphicrepresentationofboostorcutlevelsacrossthefrequency spectrum.Getit? Ground Groundloop Haasprecedence effect Harmonic HDRadio HDCP HDMI HDMIin HDMIout HDTV Headroom Hertz Alsocalledearth.Groundisdefinedasthepointofzerovoltageinacircuitorsystem,the referencepointfromwhichallothervoltagesaremeasured.Inelectricalpowersystems, groundconnectionsareusedforsafetypurposes,tokeepequipmentchassisandcontrolsat zerovoltageandtoprovideasafepathforerrantcurrents.Thisiscalledasafetyground. Maintainingagoodsafetygroundisessentialtopreventelectricalshock.Follow manufacturer’ssuggestionsandgoodelectricalpracticestoensureasafelygroundedsystem. Neverremoveordisablethegroundingpinonthepowercord.Insensitiveelectronic equipment,tinycurrentsandvoltagesridingontheground(soit’snottrulyzerovolts)can causenoiseinthecircuitsandhamperoperation.Oftenagroundseparatefromthepower groundisusedasthereferencepointfortheelectronics,isolatingthesensitiveelectronics fromthedirtypowerground.Thisiscalledatechnicalground.Qualityaudioequipmentis designedtomaintainagoodtechnicalgroundandalsooperatesafelywithagoodsafety ground. Agroundloopoccurswhenthetechnicalgroundwithinanaudiosystemisconnectedtothe safetygroundatmorethanoneplace.Thisformsalooparoundwhichunwantedcurrentcan, anddoesflow,causingnoiseintheaudiosystem.Neverdisablethesafetygroundinan attempttosolvehumproblems. Apsychoacousticeffectinwhichthetimeofarrivalofasoundtotheleftandrightearsaffects ourperceptionofdirection.Ifasignalispresentedtobothearsatthesametimeandatthe samevolume,itappearstobedirectlyinfrontofus.Butifthesignaltooneear,stillatthe samevolume,isdelayedslightly,thesoundappearstobecomingfromtheearlier(non- delayed)side. Theboxofaloudspeaker.Inanyhalfdecentspeaker,thisisnotmerelyadevicetokeepthe driversoffthefloor,butanintegralpartofthedesignofthewholeloudspeaker,contributing greatlyto--or,ifdonebadly,detractingfrom--itsperformance.Themostcommonenclosure designsarebassreflexandacousticsuspension.Goodqualityenclosuresincludestrongbracing toresistsympatheticvibrationsintheirpanels,whichcanleadtosoundcolouration. Adigitalradiobroadcastthatcanbeincorporatedintoahometheaterwithoutpayinga monthlyfee.NotallreceiversarecapableofreceivingHDRadio. AnacronymforHigh-bandwidthDigitalContentProtection.HDCPisastrongcopyprotection systemusedwithDVI.Itcanlimityourabilitytomakeadigitalcopyofwhatyou'rewatching. AnacronymforHigh-DefinitionMultimediaInterface.HDMIisashort-runanalogvideo interconnectthatisusedtoconnecthometheatercomponentstohigh-definitionTVs.The HDMIinterfacecarriesbothaudioandvideosignalsoverthesamecable,andisquickly becomingtheconnectionofchoiceforhigh-definitionsystems. HDMIinputthatreceivesdata..HighDefinitionMultimediaInterfaceisacablethattransfers uncompressedvideoanddigitaldata.UsedtoconnectdigiboxesordevicessuchasDVD/Blurayplayers. HDMIouputthatsendsdata.HighDefinitionMultimediaInterfaceisacablethattransfers uncompressedvideoanddigitaldata.UsedtoconnectdigiboxesordevicessuchasDVD/Blurayplayers. High-definitionTV.AsubsetofATSCtechnology.TheHDTVoffersspectacularhigh-definition picturequalityinawidescreenformatandisnowconsideredamustforhometheatersystems. HDTVcontentisavailableintheformofbroadcastprogrammingandBlu-raydiscs. Thedifferencebetweennominaloperatinglevelandpeakclippinginanaudiosystem. Theunitoffrequency,equalto1cyclepersecond.AbbreviatedHz.kHz1000Hz,andisusually pronounced“kay”(with“Hertz”implied)bysoundprofessionswhoaskfor“alittlemoretwo andahalfK”whentheywantyoutoboost2.5kHz. Hi-Fi'isfrequentlyusedagenericnounforanystereosoundsystem.Butitshouldmore properlyberegardedasanadjective,takingduenoteoftheLatinrootsofthewordfidelity, whichmeans'truth'.Originallyhighfidelitydescribedasoundreproductionsystemthatgavea moreaccuraterenditionoftherecordingthanwascommonlyavailable.Thegreaterthe Hi-Fi accuracy,thehigherthefidelity.Inabsoluteterms,thetermchangesovertime-asaudio systemsimprove,sodothoseproperlydescribedas'highfidelity'.Averyfinehighfidelity systemfrom1970wouldnotqualifyforthetermtoday. Apersonalcomputer(thatcanbeconsideredahigh-qualitysourcedevice)thatyouattachto HomeTheaterPC; theA/Vsystemofyourhometheater.AnHTPCcanfeedaudioandvideocontentinto(and HTPC receivecontentfrom)yourhometheatersystem.YoucancreateahometheaterPCoutofan existingPC,purchaseanewhometheaterPC,orevenbuildyourown. Home-theater-in-a- Anintegratedhometheatersystemthatbundlestogetherareceiver,DVD(orBlu-ray)player, surround-soundspeakers,andcables.Otherconfigurationsarealsoavailable. box;HTIB Aloudspeakerdriverinwhichahornisplacedoverthefrontofthedriver.Theprimary advantageofthisistoincreasetheefficiencyofthetransferofmechanicalenergyfromthe drivertotheair.Howeveritusuallyresultsinreduceddispersionofsound,particularlyfor higherfrequencieswhichtendtobe'beamed'fromthehorn,andcancolourthesound. Nevertheless,somespeakermakershavespecialisedinusinghorns,especiallyKlipsch,andthey Hornloadeddriver arefrequentlyusedinprofessionalsound-reinforcementinstallations.Theincreaseinefficiency canbequitemarked.Klipschloudspeakerstendtoofferaroundninedecibelshigheroutput thanequivalentnon-hornloadedloudspeakers,whichmeanstheycanproducethesame outputfromjustoneeighthofthepowerrequiredforconventionalspeakers.Thiscan,inturn, meanlowerharmonicdistortionbecausedriverexcursionissignificantlyreduced. Acharacteristicofthescreeninafront-projectionsysteminwhichonepartofthescreenis Hotspotting brighterthantheotherparts.Choosealow-gain(less-reflective)screentoavoidthisproblem. Thecentralizedconnectionpointfortheaudioandvideoequipmentinahometheater,which Hub istypicallytheA/Vreceiver. ShortforHertz. Hz Anadvancedvideoprocessor(aninternaldevice)thatcanconvertavideosignaltoacustom Imagescaler resolutionthatismostsuitableforaspecificprojectororothertypeofdisplay. Thesensationproducedinastereoorsurroundsystemofsoundscomingfrombetween, behindand/orinfrontoftheloudspeakers.Theimagingisdescribedinvarioussubjectiveways Imaging relatingtohowtightlyfocusedthosesoundsappear,whethertheyseemtoofferafore-aft depth,whethertheygiveanimpressionofheightaswellaswidthanddepth. Impedance Infinitebaffle Inputmodule Aspecificationforanamplifierthatmeasureselectricalresistance.Mostamplifiersareratedat 8ohmsimpedance.TheA.C.resistance,capacitance,andinductanceinanelectricalcircuit, measuredinohms.Inaudiocircuits(andotheraccircuits)theimpedanceinohmscanoftenbe muchdifferentfromthecircuitresistanceasmeasuredbyadcohmmeter.Maintainingproper circuitimpedancerelationshipsisimportanttoavoiddistortionandminimizeaddednoise. Anothertermforacousticsuspension.Thetermisdescriptive,inthatifthebaffleofa loudspeakerweretobeinfinitelyextendedinalldirections,therecouldbenomovementofair betweenthefrontandbackofthedriver.Ofcourse,witharealinfinitebafflespeakerthe baffleiswrappedaroundintoaconvenientpackage. Aholdoverfromthedayswhentheonlywaythatrealconsoleswerebuiltwasinmodular fashion,onechannelpermodule.Seechannelstrip. InputSensitivity Insert Integrated Amplifier Interconnects Interlacedscan IPTV;Internet ProtocolTV IR Isolation Jitter Knee LAN LCD LCoS Letterboxing Ameasureoftheefficiencywithwhichloudspeakersturntheelectricalenergyprovidedbya poweramplifierintoacousticenergy.Themoresensitive,thegreaterthevolumeforagiven amountofpower.Thisisnormallymeasuredasthesoundpressurelevelindecibels(dBSPL) achievedbytheloudspeakerinananechoicchamberatadistanceofonemetrewitha2.83 volt1kHzsignalapplied(2.83voltsisthevoltagerequiredtodeliveronewatttoaneightohm load.)Sensitivitiesgenerallyrangefromnotmuchmorethan80dBupto100dB.Each3dB increaseinsensitivityisequivalenttodoublingtheamountofpower,soforaloudsystemitis farbettertochoosesensitiveloudspeakersratherthanpayforahigher-poweredamplifier. Noun–aplacewhereasignalpathcanbebrokenandaprocessingdeviceplacedinlinewith thesignal.It’susuallyaTRSjackwithoneconductorbeinganoutput(send)andtheotherbeing aninput(return).Thejackiswiredwithanormalconnectionsothatwithnothingpluggedin, thesendandreturnareconnectedtogether,asifitwasn’teventhere. Anamplifierconsistingofbothapreamplifierandapoweramplifier.Ifproperlydesigned,an integratedamplifiershouldofferbettersoundqualities,duetolessconnectorsandcables betweencomponents.Itisstillthecasehowever,thatmostofthehighendamplifiersare offeredastwoboxes,generallybecausetheamountofelectronicsineachmakeitdifficultto buildasensibleoneboxsolution. Short-runcablesthatyouusetoconnecthometheatercomponentsthatarelocatedwithina fewfeetofeachother(orinthesameroom). OneofthetwoscanningmethodsthatdrawsthepictureontheTVscreen.TraditionalTV systemsuseaninterlacedscan,wherehalfofthepictureappearsonthescreenatatime(the otherhalffollows1/60thofasecondlater). Atypeoftelevisionserviceprovidedbyaphonecompany.UsesthesameInternetsystems usedforcarryingWebpages,e-mail,andWebvideotoyourTV,viaabroadbandInternet connection. Infrared. Top-endHi-FiequipmentsuchasCDplayers,amplifiersandloudspeakermountings/feet requirecompleteIsolationtoperformatthehighestlevel Thephenomenonofadriftinthedigitalaudiodatadeliveredsothatitdoesnotprecisely matchthesamplingfrequency,causingconfusioninthereceivingequipmentastothe appropriatevalueofthesample.AhostofaudibleproblemswithCDsandotherdigitalformats havebeenlaidatthefeetofjitter.Thereisnodoubtthatveryprecisemasterandupsampling clockscanhelptomakeCDplayerssoundbetter. Akneeisasharpbendinacurve(anEQfrequencyresponseorcompressorgaincurve)not unlikethesharpbendinyourleg. Localareanetwork.Acomputernetworkthatlinkstwoormorecomputerstogetherwithina limitedrange.YoucanaddacomputerLANtoyourhometheaterinfrastructure,resultingina whole-homecomputingsystemthatcanmakeuseofyourhometheater. 1.(noun)Anacronymforliquidcrystaldisplay.AnLCDisaflat-panelTVdisplaywithpixels consistingofliquidcrystalmoleculesheldbetweentwosetsoftransparentelectrodes.2. (noun)ThetechnologyusedinLCDpanels,computermonitors,LCDprojectorsinafrontprojectionsystem,andmanyotherdevices. AnacronymforLiquidCrystalonSilicon.LCoSisanewertypeofprojectionsystemthatreflects lightoffoftheliquidcrystals.ThisresultsinasignificantlybrighterimagethananLCD projectionsystem. Anapproachusedtodisplaywidescreen(16:9)content(suchasmovies)onastandard(4:3) television.Letterboxingmaintainstheoriginalaspectratiobydisplayinghorizontalblackbarsat thetopandbottomofthescreen. Level Linelevel LNB Longruns Lossless Lossy LowFrequency Effectchannel LP Luminance Macros Main(house) speakers Mains MCphono MediaCenter extender Micamp Miclevel Micpre MIDI Midrangedriver Anotherwordforsignalvoltage,power,strengthorvolume.Audiosignalsaresometimes classifiedaccordingtotheirlevel.Commonlyusedlevelsare:microphonelevel(-40dBuor lower),instrumentlevel(-20to-10dBu),andlinelevel(-10to+30dBu). Asignalwhoselevelfallsbetween-10dBuand+30dBu. AnacronymforLowNoiseBlocker.TheLNBisahorn-shapeddeviceconnectedtothefrontof theparabolaofasatellitedish,usedtoblockextraneoussignals. Atypeofcablethatmakesuptheinfrastructureofawhole-homeaudioandvideonetwork. Long-runcableisdesignedtominimizesignallossduetointerference.Thelongerthesignalhas totravelovercable,themorelikelythatsignalwillbeaudiblydegraded. Acategoryofcodecsinwhichallthemusicinformationintheaudiofileispreservedwhenthe fileiscompressedandstoredonacomputer,withnolossandverylargefilesizes.Some losslesscodecsincludeWindowsMediaLossless,AppleLossless,PCM,andFreeLosslessAudio Codec(FLAC). Acategoryofcodecsinwhichpartofthemusicinformationintheaudiofileisdiscardedwhen thefileiscompressed,resultinginsmallerfilesizes.Inmanycases,thelossofthesebitsof audioisn'tnoticeable.SomelossycodecsincludeMP3,WMA,andAAC. Anaudiochannelencodedinthesoundtrackofamovieorothersurround-soundsourcethat providesthelow-frequencybasssoundsthatyouhearfromthesubwoofer.TheLFEchannelis the".1"in5.1andothersurround-soundformats. Longplaying.Aphonographrecord,oftenreferredtoasvinyl,thatplaysat33-1/3revolutions perminute. Thebrightnessportionofthetwo-componentvideosignalthatrunsthroughavideocable(the othercomponentischrominance). Sequentialcodecombinationsinaremotecontrolthatcanperformmultipletaskswiththe pushofabutton.Forexample,youcanprogramamacrothatturnsonyourTV,receiver,and DVDplayer;setsthereceivertotheappropriatesourceandoutputmodes;andstartstheDVD thatisinthetray. Themainloudspeakersforasoundreinforcementsystem.Theseareusuallythelargestand loudestloudspeakers,andareusuallypositionedsothattheirsoundseemstocomefromthe areaofthemainstage. Shortformainorhousespeakersinasoundreinforcementsystem. AnMCphonoisaphonostageamplificationboostneededtoconnectaMovingCoilcartridge usedwithavinylrecordreplaysystem.MovingCoildesignsarelowerinoutputthanaMMor MovingMagnetbutsoundmoredetailed. AspecializedtypeofmediaadapterthatenablesyoutoviewWindowsMediaCenteronyour TVwithoutrequiringthePCtobelocallyconnectedtoyourhometheater.Youcaneither purchaseastandaloneMediaCenterextenderorgetanXbox360,whichhastheMediaCenter extenderfunctionalitybuiltin. Seemicpreamp. Thetypicallevelofasignalfromamicrophone.Amiclevelsignal(usuallybutnotalways comingfromamicrophone)isgenerallylowerthan-30dBu.Withaveryquietsource(apin dropping?)thesignalcanbe-70dBuorlower. Somemicrophones,notablyvintageorvintage-stylecondensermics,deliverahighersignal levelthanthisforthesamesoundpressurelevel.A“hot”micoutputlevelisn’tnecessarilya measureofthemicrophone’squality,it’sjustanoptionthatthedesignerchose. Shortformicpreamp. AcronymforMusicalInstrumentDigitalInter-face.MIDIisthemusicindustry’sstandardserial communicationprotocolfortheinterfaceandcontrolofmusicalinstruments. Atypeofspeakerdriverthathandlesmidrangefrequencies(200Hzto2000Hz). Mixer MMphono Monaural Monitor Mono Monopole MovingCoil MovingMagnet MP3 MPEG Mult Multizonesystem MW Anelectronicdeviceusedtocombinevariousaudiosignalsintoacommonoutput.Different fromablender,whichcombinesvariousfruitsintoacommonlibation. AnMMphonoisaphonostageamplificationboostneededtoconnectaMovingMagnet cartridgeusedwithavinylrecordreplaysystem.MovingMagnetdesignsarehigherinoutput butlowerinpricethanaMCorMovingCoilbutoftensoundalittlelessdetailed. Longformono.Literally,pertainingtoorhavingtheuseofonlyoneear.Intheaudiofield, monauraldescribesasignalorsystemwhichcarriesaudioinformationonasinglechannelwith theintentofreproducingitfromasinglesource.Onemicrophoneisamonosource;many microphonesmixedtoonechannelisamonomix;astereo(or,tobepicky,atwo-channel)mix ofmanymicrophonespannedleftandrightisastereomixofmonosources.Monaural listening,andthereforemonocompatibilityofastereomix,ismoreimportantthanyoumay realize.Mostpeopleheartelevisionaudioinmono.Mostclockradiosaremono. Insoundreinforcement,monitorspeakers(ormonitorheadphonesorin-the-earmonitors)are thosespeakersusedbytheperformerstohearthemselves.Inthevideoandbroadcastworld, monitorspeakersareoftencalledfoldbackspeakers.Inrecording,themonitorspeakersare thoseusedbytheengineerandproductionstafftolistentotherecordingasitprogresses.In zoology,themonitorlizardisthelizardthatobservestheproductionstaffastherecording progresses. Shortformonaural. Apolepositionofspeakersinwhichallthedriversareononefaceoftheenclosure.Monopole speakersarealsoknownasdirectradiatingspeakersandcanbeusedanywhereinahome theatersystem. Amagneticcartridgeinwhichthestylusmovesacoilviathecantilever,whilethemagnetis fixedinposition.Movingcoilcartridgestendtohavelowermovingmassthanmovingmagnet cartridges,butalsotendtobelowerinoutputbyanorderofmagnitude.Thereare,however, highoutputMCcartridgesavailablethatproducecomparablelevelstoMMcartridges.Because thecoilmustbewiredtotheoutputs,theyalsotendtobesomewhatlowerincompliancethan MMcartridges,soarenotnormallyamenabletoverylowtrackingweights(theytypically operatebestataroundtwograms).Thesoundqualitiesaregenerallythoughttobebetterthan anyothercartridgetype. Amagneticcartridgeinwhichthestylusmovesamagnetviathecantilever,whilethecoilis fixedinposition.Movingmagnetcartridgestendtohaveahigheroutputthanmovingcoil cartridges,butalsotendtohaveahighermovingmass(possiblyreducingtheirabilitytodeliver finedetailfromrecord).Becausethemagnetisabletofreelymove,MMcartridgesgenerally offerahighercompliancethanMCcartridges,sothecartridgeswiththeverylowesttracking weights(0.75to1gram)comefromtheMMcamp. AshortenedformofMPEG-1AudioLayer3.MP3isacommonaudiofileformatfordigitally storingmusicandotheraudiofilesonacomputerorotherdevice.Usesaformoflossydata compression. AnacronymforMotionPictureExpertsGroup.MPEGisagroupthatmeetsregularlytodevelop standardsforcompressedaudioandvideoformats,suchasMPEG-2,whichiscurrentlythe mostcommonstandardusedinthevideoworld. Shortformultiple.Inaudiowork,amultisaparallelconnection(inapatchbayorwithspecially builtcablesorwiring)usedtofeedanoutputtomorethanoneinput.A“Y”cableisatypeof multconnection.Alsousedaverb,asin"Whydidyoumulttheflangerintoeveryinputinthe board?" Ahometheatersystemthatextendsbeyondasingleroom,allowingsimultaneousaccessto differentaudiosourcesofthehometheaterinmultiplerooms. MWistheacronymformilliwatt,orthemeasureofonethousandthofawatt. NetworkedPVR Networking Noise Noisefloor Normal Notchfilter NTSC Nyquistsampling theorem Octave Ohm Omnipole Opticaldigital Opticalin Opticalout OutputPower Overhang PA PanandScan Acrossbetweenapersonalvideorecorder(PVR)andvideo-on-demand(VoD),offeredbya serviceprovidersuchasacablecompany.Theharddrivethatrecordsandstoresthevideo contentyouwanttowatchislocatedintheserviceprovider'soffice. Networkingistheabilitytosendandreceivedatathroughoutanenvironment,eitherworkor domestic,usingeitherwiredorwirelessmedia. Whateveryoudon’twanttohear.Couldbehum,buzzorhiss;couldbecrosstalkordigitalhash oryourneighbor’sstereo;couldbewhitenoiseorpinknoiseorbrownnoise;oritcouldbe yourmother-in-lawrelivingthedayshehadhergallstoneremoved. Theresiduallevelofnoiseinanysystem.Thelowerthenoisefloorandthehigherthe headroom,themoreusabledynamicrangeasystemhas. Awiringmethodwhichelectricallytiestogethertwojacksortwopolesofonejacksothatin normaloperation,thereissignalflowbetweenthem.Insertingaplugbreaksthisconnection, allowingthesignalpathtobemodified.Normalwiringiscommoninpatchbaysandinsertjacks. Separatesthecolorandbrightnesspartsofavideosignalintotheircomponentpartsandsends themtotheappropriateinternalcircuitry.Notaseffectiveasacombfilter. AtechnicalstandarddevelopedbytheNationalTelevisionStandardsCommitteethatis synonymouswithanalogTV—regular(non-HD)televisionprogramming. Thistheoremstatesthat,whenananalogsignalisconvertedtoadigitalsignal,itmustbe sampledatafrequencythatisatleasttwicethehighestaudiofrequencypresentintheanalog signal.Iftheaudiofrequencyshouldexceedone-halfthesamplingfrequency,aliasingcan result.Thus,ifananalog-to-digitalconverterissamplingat44.1kHz,theaudiosignalshould notexceed22.05kHz. Arangeoffrequenciesofsomeformofrepetitivewave,wherethehighestfrequencyis preciselytwicethelowestfrequency.Inmusic,forexample,thefundamentalfrequencyofA belowMiddleCis220hertz.TheAaboveMiddleCis440hertz. Aunitofelectricalresistanceorimpedance.InaDCcircuit,thenumberofohmsofresistance offeredbyacomponentcanbecalculatedbydividingthevoltageacrossthecomponentbythe current(inamps)flowingthroughit. Apolepositionofspeakersinwhichthedriversradiatesoundinalldirections.Omnipole speakersarepopularforoutdoorapplications Amethodofcommunicatingdigitalaudiobetweencomponentsusinglightcarriedonoptical fibre.SeeTOSLink.ThedataformataccordswiththeS/PDIFspecification. TheinputsocketforanopticalorTOSlinkcable,whichtransfersdigitalaudioandvideo information. TheoutputsocketforanopticalorTOSlinkcable,whichtransfersdigitalaudioandvideo information. Theaudiosignalexitingacomponent. Asthestylustracksacrosstherecord,itisimportantthatthestylusremaintangenttothe groove.Settingoverhangwearealigningthecartridgetofollowthatidealarcacrossthe record.Inaradialtrackingtonearm,thereareonlyacoupleofpointswhenitactuallyis AcronymforPublicAddress.Today,peoplewhoworkwithPAsystemsliketosaythey’re workingin“soundreinforcement”.SeeSR. Anapproachusedtodisplaywidescreen(16:9)content(suchasmovies)onastandard(4:3) television.WithPanandScan,adecisionismadeastowhatconstitutestheactionareaineach frameofthemovie.Thatpartofthefilmframeisretained,whiletherestoftheframeislost. Shortforpanoramicpotentiometer.Apanpotisusedtoposition(orevendynamicallymove)a monauralsoundsourceinastereomixingfieldbyadjustingthesource’svolumebetweenthe Pan,panpot leftandrightchannels.Ourbrainssensestereopositionbyhearingthisdifferenceinloudness whenthesoundstrikeseachear,takingintoaccounttimedelay,spectrum,ambient reverberationandothercues. Amodeofoperationforastereoamplifierthatroutesasingleinputtobothchannels,but Parallelmono combinestheoutputsofbothchannelsintoasingleoutputbystrappingthepositivieoutput terminalstogether,therebyprovidingtwicethecurrentofanindividualoutput. A“fully”parametricEQisanextremelypowerfulequalizerthatallowssmooth,continuous,and independentcontrolofeachofthethreeprimaryEQparameters:frequency,gain,and ParametricEQ bandwidth.“Semi”parametricEQsallowcontroloffewerparameters,usuallyfrequencyand gain(i.e.,theyhaveafixedbandwidth,butvariablecenterfrequencyandgain). Passive3Drefersto3Dtelevisionswhereapairofnon-active3Dglassesarerequiredtowatch. Passive3D Theseworkcontunuouslyanddonotneedtobepoweredot=rswitchedonlikeActive3D glasses Aloudspeakerwithoutbuilt-inamplificationforallthedrivers.MostdomesticHi-Fi Passiveloudspeaker loudspeakersarepassive,notactive. Acollectionofusuallyalargenumberofjacksallowingconvenientaccesstovariouspointsina Patchbay system’sinterconnectwiring.Apatchbaycanmakereroutingsignalsveryconvenientwithout havingtofisharoundwithcablesinthebackofracksorconsoles.Seespaghetti. PulseCodeModulation.Anoldersystemforencodinganalogmusicintoalosslessdigital PCM format.MusicCDsandmanycomputer-basedsoundfiles(suchas.wavfiles)arebasedon PCM. Theoppositeofdipping,ofcourse.ApeakisanEQcurvethatlookslikeahill,orapeak. Peaking Peakingwithanequalizeramplifiesabandoffrequencies. Atypeofnetworkthatallowsmultipleuserstodownloadandsharefilessimultaneously,using Peer-to-peer;P2P adirectconnectionbetweencomputers(withouttheneedforafileserver). AnacronymforPreFadeListen.Broadcasterswouldcallitcueing.Soundfolkscallitbeingable PFL tosoloachannelwiththefaderdown. Asystemofprovidingelectricalpowerforcondensermicrophones(andsomeelectronicpickup devices)fromthemicrophoneinputjack.Thesystemiscalledphantombecausethepoweris carriedonstandardmicrophoneaudiowiringinawaythatis“invisible”toordinarydynamic microphones.Mostqualitycondensermicrophonesaredesignedtouse+48VDCphantom power.Checkthemanufacturer’srecommendations.Generally,phantompowerissafetouse Phantompower withnon-condensermicrophonesaswell,especiallydynamicmicrophones.However, unbalancedmicrophones,someelectronicequipment(suchassomewirelessmicrophone receivers)andsomeribbonmicrophonescanshortoutthephantompowerandbeseverely damaged.Checkthemanufacturer’srecommendationsandbecareful! Adynamiceffectinwhichthephaserelationshipbetweenthefundamentalandovertone componentsofasoundiscontinuallychanging.Thisisdonebypassingthesignalthroughan automaticallysweepingfilter.Theeffectisoftensimulatedbymixingoriginalsignalwitha Phasing delayed(1to10ms)versionofitself.Thetimeofthedelayisslowlyvaried,andthe combinationofthetwosignalsresultsinadramaticmovingcombfiltereffect.Acombfiltercan befoundinyourbackpocket. Everseethoseoldtelephoneswitchboardswithhundredsofjacksandpatchcordsandplugs? Ortheplugontheendofaheadphonecable?Thosearephonejacksandplugs,nowused Phonejack widelywithmusicalinstrumentsandaudioequipment.Aphonejackisthefemaleconnector, andweusethemin1/4”two-conductor(TS)andthree-conductor(TRS)versions. Themalecounterparttothephonejack. Phoneplug ShortforRCAphonojack. ShortforRCAphonoplug. TheaimoftheRPPwastofurtherdevelopthesonicachievementsoftherenownedprevious RoksanReferencePhonoStage.Thehighestpossiblequalitycomponentsareusedthroughout thecircuittoensurethebestpossiblesoundquality.Theresultisahighlydetailedand PhonoStage(RPP) insightfulperformance,whichpossessesbassweightandinvolvingrhythmicspeedalongwith upperfrequencysweetnessandawide,deepsoundstage.Designedtomatchthecurrent CaspianMseries,ittsbothperfectly,bothsonicallyandaesthetically,intoanycurrentRoksan high-endsystem. Theindividualpoints(orpictureelements)thatcombined,formanimageonadisplay. Pixels 1.(noun)SometimescalledaPDP(plasmadisplaypanel).Atypeofflat-paneldisplaythat containsmillionsofgas-filledcells(pixels)wedgedbetweentwopiecesofglass.Themost Plasma commonsizesofplasmadisplaysare42-,50-,56-,and65-inchsizes.2.(noun)Theionizedgas insideaplasmadisplay. DigitalaudioorvideofilesthatareavailablefordownloadingfromaWebsite.Usuallyavailable Podcasts inaseriesthatareoftenpackagedlikedailynewscastsorcommentary. Atermusedtodescribeanauxsend(orotheroutput)thatisconnectedsothatitisaffectedby Post-fader thesettingoftheassociatedchannelfader.Sendsconnectedthiswayaretypically(butnot always)usedforeffects. Inelectronics,avariableresistorthatvariesthepotential,orvoltage.Inaudio,anyrotaryor Pot,potentiometer slidecontrol. Theamountofenergyexpendedperunittime.Thecommonunitisthewatt.Power(inwatts) PowerHandling inaDCcircuitequalsvoltagetimescurrent(inamps).Thingsareabitmorecomplicatedwith AC. Preampoutisthestereo(leftandrightRCA)outoutfromapreamporintegratedampto Preampout connectapoweramplifer. Atermusedtodescribeanauxsend(orotheroutput)thatisconnectedsothatitisnot Pre-fader affectedbythesettingoftheassociatedchannelfader.Sendsconnectedthiswayaretypically (butnotalways)usedformonitors(foldback).Seepost-fader. Thepropertyofmanydirectionalmicrophonestoaccentuatetheirbassresponsewhenthe Proximityeffect source-to-micdistanceissmall,typicallythreeinchesorless.Singersgenerallylikethiseffect evenmorethansingingintheshower. Thepartofthemotoronaturntablethatthedrivebeltisdrivenby Pulley Personalvideorecorder.Ahometheaterdevicethatrecordsvideoontoastandardcomputer PVR harddrive.PVRs(alsocalledDVRs)connecttoaprogramservice,usuallyviaatelephoneline. TiVoisamajormanufacturerofDVRs. Awayofstatingthebandwidthofafilterorequalizersection.AnEQwithaQof.75isbroad andsmooth,whileaQof10givesanarrow,pointedresponsecurve.Tocalculatethevalueof Q,youmustknowthecenterfrequencyoftheEQsectionandthefrequenciesatwhichthe upperandlowerskirtsfall3dBbelowthelevelofthecenterfrequency.Qequalsthecenter Q frequencydividedbythedifferencebetweentheupperandlower3dB-downfrequencies.A peakingEQcenteredat10kHzwhose-3dBpointsare7.5kHzand12.5 kHzhasaQof2. Thedigitalrepresentationofananalogsignalinvolvessamplingtheamplitudeofthesignalata fastrate.Quantizationisthemeasurementoftheamplitudeatthetimeofeachsample, Quantization expressedisadigitalword.Whereananalogsignalwillbecontinuousasifitweregoingupa smoothpath,quantizationwillhavediscretesteps(similartostairsteps). RandomAccessMemoryisatypeofcomputermemorythatcanbereadfromandwrittento. RAM Phonojack Phonoplug RCAoutisanoutputfromonedevicetoanotherforaudioorvideodatausingcablewithRCA connectors LongforRCAjackorphonojack.AnRCAphonojackisaninexpensiveconnector(female) introducedbyRCAandoriginallyusedtoconnectphonographstoradioreceivers.Thephono jackwas(andstillis)widelyusedonconsumerstereoequipmentandvideoequipmentbutwas RCAphonojack quietlyfadingintoobscurityintheprofessionalandsemi-professionalsoundworld.Then phonojacksbegancroppingupinearlyproject-studiomultitrackrecorders,which (unfortunately)gavethemanewleaseonlife. ThemalecounterparttoanRCAphonojack. RCAphonoplug Rearspeakersarethespeakersmainlyusedforeffectsandambienceinamultichannelaudio RearSpeaker orvideosetup. RPTV.Atypeofprojectionsysteminahometheaterinwhichbothpartsofthefrontprojector Rear-projectionTV (theprojectorandthescreen)arehousedinasinglebox.Theprojectorilluminatesthebackof thescreeninsteadofthefront. A/Vreceiver.Adevicethatcontrolsyourhometheaterbyselectingaudio/videosources, Receiver decodingsurround-soundformats,amplifyingsound,andtuninginradioprogramming. Ameasureoftheprecisionandsharpnessofavideodisplay'spicture,basedonthepixelsor Resolution linesofresolutionavailableonthescreen.ForHDTVs,displayvendorstypicallyfocusonthe verticallinesofresolution,usually720or1080. RadioFrequencyInterference.Highfrequencyradiationthatoftenresultsfromsparking RFI circuits.Thiscanbemanifestedinanumberofwaysinaudiosystems,butisusuallyevidentas ahigh-frequencybuzzorhashsound. Atypeofcoaxiallong-runcablethatyoucanusetoconnectyourhometheatertotherestof RG6 yourhouse. Anacronymforrootmeansquare,aconventionalwaytomeasuretheeffectiveaveragevalue RMS ofanaudiosignalorotherACvoltage.MostACvoltmetersarecalibratedtoreadRMSvolts, thoughonmanymetersthatcalibrationisaccurateonlyifthewaveformissinusoidal. Readonlymemoryisatypeofcomputermemorythatcannotbewrittento,butonlyread ROM from. Rear-projectionTV. RPTV ShortforRecommendedStandard232.RS-232ismorecommonlyknownasaserial RS-232 connection.YoumightusethistypeofconnectionbetweenamodemandanolderPC.USBhas replacedmostRS-232connections. Lowfrequencynoise,usuallyfromaturntable.GiventhatRIAAequalizationbooststhebass Rumble signalfromacartridgebyanenormousamount(17dBat50hertz),thehighestqualitybearings andexcellentisolationfromtheturntable'smotorarerequiredtocontrolrumble. AnoftenrecommendedprocessfortheinstallationofnewHi-Fiequipment.Essentially, runninginisoperatingthenewequipmentforsomehours,ortens,orhundredsofhours,to bringituptopeakperformance.Loudspeakersarephysicalsystemswithsuspensionsand surroundsthatdodefinitelybenefitfrombeingrunin.Runningincablesdoesseemtoimprove Runningin theirperformance,anditiscertainlytruethatcapacitorsandsomeothercomponentsin electricalcircuitssound‘better’whenruninforsometime.Noneofthisismeasurableand therearescepticswhosaythisisallbaloney.Useyourownearstodecide! Sony/PhilipsDigitalInterfaceFormat.Awidelyuseddigitalaudioprotocol.Itisusedasthe protocolforallconsumerhomeentertainmentequipment.Itisdistinguishedfromthe professionalAES/EBUprotocolbyincorporatingtheclocktiminginformationinthemainsignal. S/PDIF Originallydesignedfor44.1and48kHzand16bits,itnowcarriesupto96kHzand24bits,plus thebitstreamsforthevariouscompresseddigitalaudiostandards.Theconnectionsusedare generallycoaxialoroptical. RCAout Ameasureoftherelativelivenessofaroom.AlowSameansaveryliveroom,andahighSa Savalue meansadeadroom.S=thetotalsurfaceareaoftheroom,anda=theaverageabsorption coefficientofallthesurfaces AnacronymforSuperAudioCompactDisc.SACDisanewerdigitalaudioformatthatoffers SACD higher-qualitysoundandgreatercapacitythanaCD. Thisistherateatwhichananalogsignalissampledduringtheanalog-to-digitalconversion process.Thesamplingrateusedforcompactdiscsis44.1kHz,butprofessionalrecordingsare Samplingfrequency oftensampledathighersamplerates,suchas96kHzoreven192kHz(that’s192,000samples persecond!). Aservicethatoffersdigitalradioprogrammingbroadcastbysatellitetoyourhometheateror Satelliteradio car.SatelliteradioservicessuchasXMRadioandSiriusoffermorethan100radiostationsand chargemonthlyaccessfees. Ameasureoftheefficiencywithwhichloudspeakersturntheelectricalenergyprovidedbya poweramplifierintoacousticenergy.Themoresensitive,thegreaterthevolumeforagiven amountofpower.Thisisnormallymeasuredasthesoundpressurelevelindecibels(dBSPL) achievedbytheloudspeakerinananechoicchamberatadistanceofonemetrewitha2.83 volt1kHzsignalapplied(2.83voltsisthevoltagerequiredtodeliveronewatttoaneightohm Sensitivity load. Sensitivitiesgenerallyrangefromnotmuchmorethan80dBupto100dB.Each3dBincreasein sensitivityisequivalenttodoublingtheamountofpower,soforaloudsystemitisfarbetterto choosesensitiveloudspeakersratherthanpayforahigher-poweredamplifier. Ameasureofthedegreetowhichleakagefromonechannelofsoundtoanotherchannel (crosstalk)islimited.Thisistypicallymeasuredindecibels(e.g.-90dBat1kHz).Whilegreat emphasisisplacedonthisfigure,therealityisthatverymodestfigureslike-20or-30dB (typicalofLPrecords)provideexcellentstereoseparationandimaging.Moreimportantisthat Separation theseparationshouldnotvarywidelybetweendifferentfrequencies,sincethiscouldleadtoa positioningmismatchbetweenthefundamentalandharmonicfrequenciesforparticular instruments. Ameasureofthedegreetowhichleakagefromonechannelofsoundtoanotherchannel (crosstalk)islimited.Thisistypicallymeasuredindecibels(e.g.-90dBat1kHz).Whilegreat emphasisisplacedonthisfigure,therealityisthatverymodestfigureslike-20or-30dB (typicalofLPrecords)provideexcellentstereoseparationandimaging.Moreimportantisthat Separation theseparationshouldnotvarywidelybetweendifferentfrequencies,sincethiscouldleadtoa positioningmismatchbetweenthefundamentalandharmonicfrequenciesforparticular instruments. Thefinedetailsinthepictureofavideodisplay.Mostdisplaysenableyoutoadjustthe Sharpness sharpnesssetting. Atermusedtodescribetheshapeofanequalizer’sfrequencyresponse.Ashelvingequalizer’s responsebeginstorise(orfall)atsomefrequencyandcontinuestorise(orfall)untilitreaches Shelving theshelffrequency,atwhichpointtheresponsecurveflattensoutandremainsflattothe limitsofaudibility.Ifyouweretographtheresponse,itwouldlooklikeashelf.Ormorelikea shelfthanahikingboot.Seealsopeakinganddipping. Connectionsbetweenhometheatercomponentsthataresittingjustafewfeetfromeach Shortruns otheroratleastinthesameroom. Aspecificationforthelevelofnoiseproducedbyasystem.Thisisnormallyexpressedinthe Signaltonoiseratio decibeldifferencebetweenthemeasurednoiseandsomereferencesignal. Signal-to-noiseratio Thisisaspecificationthatdescribeshowmuchnoiseanaudiocomponenthascomparedtothe signal.ItisusuallyexpressedindBbelowagivenoutputlevel. (S/N) ADVDorBlu-raydiscinwhichyoucanstoremediaononlyonesideofthedisc. Single-layerdisc Slap,slapback Sound reinforcement SoundStage Sources Spadelugs Spaghetti Speakers Speedcontrol (RPM) Speedof propagation SR Steradians Stereo Asingle-delayechowithoutanyrepeats.Alsoseeecho. Asystemofamplifyingacousticandelectronicsoundsfromaperformanceorspeechsothata largeaudiencecanhearclearly.Or,inpopularmusic,sothatalargeaudiencecanbeexcited, stunned,orevenpartiallydeafenedbythetremendousamplification.Meansessentiallythe samethingasPA(PublicAddress). Amoviesetwhereaudioisrecordedalongwithvideo.Butinthehomeentertainment(audio) context,thesoundstageisareabetweenapairofstereospeakersfromwhichtheyappearto makethevarioussoundsappear.Highqualityaudiosystemswillmakethesoundstageactually widerthanthisspace,andprovidesensationsofbothverticalsoundplacementanddepthin thestage,offeringa‘holographic’ormulti-dimensionalaudioeffect. Hometheatercomponents(devices)thatprovidethecontentthatyouwatchorlistento,such asDVDorBlu-raydiscplayers,DVRs,gamingconsoles,CDplayers,AM/FMtuners,turntables, orhometheaterPCs. U-shapedspeakercableconnectorsthatfitbehindascrewonafive-waybindingpost.Spade lugsprovideoneofthemostsecurecableconnections. Thatmessofwiresandcablesinthebackofyourrackand/orconsole.Youreallycantamethis. Devicesinahometheatersystemthatsupplythesoundthatyoulistento.Mosthometheaters includeasurround-soundspeakersystemwithtwofrontspeakers,onefrontcenterspeaker, twosidespeakers,twoorfourrearspeakers,andasubwoofer. TheRPMisthenewhigh-specification,ultra-accuratestatementspeedcontrolforusewiththe Xerxes20+.ConsistingofanentirelynewandhighlyadvanceddigitalspeedcontrolPCBand audiophile-gradecomponents,TheRPMrepresentsasignicantupgradefromthepreviousand long-establishedreferencespeedcontrolasfeaturedinthediscontinuedDX2.Featuringavery highqualitycrystalspeedcontrolsystem,itmaintainspitchperfectspeedstabilityforboth 33/45rpm.OnenewfeatureoftheRPMisitsability–thankstothenewadvanceddigitalspeed controlPCB–toeitherincreaseordecreasethespeed(upto6.25%eitherway).Thisisavery usefuladditionforcustomersinareasorcountriesforunstableorpoorcurrencyvoltageto attaintheexact,correctspeed. Physicalwaves,whethersoundorelectromagnetic,haveatypicalspeedofpropagation throughvariousmedia.Thisvariesdependingonthemedium.Lighttravelsthroughavacuum at3x108metrespersecond.Soundtravelsthroughroom-temperatureair(20C)at343.5 metrespersecond.Thespeedvariesslightlyaccordingtotemperature,increasingto349.3m/s at30C,fallingto337.6m/sat10C. AnacronymforSoundReinforcement,whichreferstotheprocess(orasystemfor)amplifying acousticandelectronicsoundsfromaperformanceorspeechsothatalargeaudiencecanhear clearly.Or,inpopularmusic,sothatalargeaudiencecanbeexcited,stunnedorevenpartially deafenedbythetremendousamplification.Theterm“SR”isto“PA”(PublicAddress)asthe term“environmentalcleanuptechnologist”isto“garbagecollector”. Justasaradianisanangularunitofmeasurein2-dimensionalspace,soasteradianisan angularunitofmeasurein3-dimensionalspace(solidangle). orStereophonic.Inthehome,anaudiosystemwhichdeliverstwochannelsofmusic,leftand right,tocreatetheillusionofaplaneofsoundfacingthelistener.Highqualityaudiosystems willmakethesoundstageactuallywiderthanthisspace,andprovidesensationsofboth verticalsoundplacementanddepthinthestage,offeringa‘holographic’ormulti-dimensional audioeffect. Believeitornot,stereocomesfromaGreekwordthatmeanssolid.Weusestereoor stereophonytodescribetheillusionofacontinuous,spacioussoundfieldthatisseemingly Stereo spreadaroundthelistenerbytwoormorerelatedaudiosignals.Inpractice,stereooftenis takentosimplymeantwochannels. Theamountofattenuationgiventounwantedsignalsoccuringoutsideotthetestpassbamd StopBandRejection region Amethodofsendingaudioorvideocontentinwhichthecontentplayswhileitisdelivered Streaming overyourhomenetwork,theInternet,orboth. Stylus Subwoofer Surroundsound S-video SweepEQ THD Three-way loudspeakers Timealignment Tinnitus TiVo Asmalldiamondontheendofacartridge'scantilever.ThissitswithinthegrooveofanLPand picksupthevibrationsrecordedtherein.Thestylusisgenerallysphericalorellipticalinshape, althoughothervariationshavebeendeveloped,allwithaviewtomoreaccuratelytrackingthe groovewhilereducingdamagetoit.Ellipticalstyliareonlysuitablefortrackingweightsofless thanaroundtwogramsbecausetheirlowcontactareawiththegroovecancausedamage. Aspeakerinahometheatersurroundsoundsystemthatisdesignedtoplaylow-frequency (bass)sounds.Typicallyplacedalongthefrontwalloftheroom. Afeatureinahometheatersystemthatenablesyoutotakefulladvantageofalltheaudio signalsinyoursourcecontent(suchastelevisionprogramsandDVDorBlu-raymovies). Atypeofshort-runanalogvideoconnectioninwhichcolorandbrightnessareseparatedonto twoseparatesignalpaths,sothesignalcanbypassthedisplay'scombfilter.Typicallyresultsin aclearerpicturethancompositevideo(butnotcomponentvideo). Anequalizerthatallowsyouto“sweep”orcontinuouslyvarythefrequencyofoneormore sections. Alltheharmonicdistortioncomponentsaddedtogethertogiveasummarymeasure,though oftenmisleading.Theimperfectionresidesinthefactthat,audibly,someoftheharmonic componentsareworsethanothers.Inparticular,odd-orderedharmonicsfromthefifthandup areparticularlyaudibleinaudiosystems,whilstevenharmonics(producedbyvalves)are practicallyinaudible.SolidstateamplifierstypicallyofferTHDratingsoflessthan0.1%atrated poweroutputbutcanstillhaveaudibleharmonicdistortioncharacteristics(oftenheardasa sheenor‘metallic’overlaytothesound.Valveamplifiersmightoffera2%THDbutsound extraordinarilycleanandmusical. Aloudspeakerwhichdividestheincomingsignalintothreedifferentfrequencybandsfor distributiontodrivers.Itsendshighfrequenciestothetweeter,themiddlefrequenciestothe midrangedriver,andthelowfrequenciestooneormorewoofers. Systemsforensuringthataudiosignalsfromvariousloudspeakersordriversarriveatthe listeneratthecorrecttime.Forexample,highendloudspeakermakerswillrecessthetweeter furtherintotheenclosuretoensurethatthehighfrequenciesarriveatthelisteneratthesame timeaslowerfrequencies,withaviewtodeliveringamorecoherentsound.Withsurround sounditisimportantthatthesoundfromthesurroundspeakersdoesnotarriveearly,even thoughthesespeakersareoftensituatedclosertothelistenerthanthemainspeakers;so hometheatrereceiversincorporateasystemtoallowthesoundtothesespeakerstobe (adjustably)delayedbysomemilliseconds. Theringingintheearsthatoftenresultsfromprolongedexposuretoveryloudsoundlevels.A soundintheears,suchasbuzzing,ringing,orwhistling,causedbyvolumeknobabuse! ThemajormanufacturerofDVRs.WithTiVo,youcanrecordvideocontentontoaharddriveof astandalonedevice.Twomodelsareavailable:astandarddefinitionmodeloranHDDVR, whichrecordshigh-definitioncontent.Bothrequireamonthlyserviceplan. Tonecontrols Tonearm Toslink TrackingWeight Transformer Treble TRS TS Turntable Tweak Labelled'bass'and'treble',fittedtoapreamplifiertheseprovidedameansofboostingor cuttingthebassortrebleofthesignal.Theytypicallyprovideuptotendecibelsofboostorcut at50hertzforbassand10,000hertzfortreble.Bestavoidedforhighfidelity. PositiontheattachedcartridgeinthecorrectalignmenttoplayanLPrecord.Isnormally pivotedatthebackandprovidesforanadjustabletrackingweightbytheuseofaspring-loaded orweight-loadedmechanism;andusuallyhaveadampedcueinglevertoallowthestylustobe gentlyloweredtothesurfaceoftherecord.Overtheyearssomemakershaveprovidedparallel movementtonearmswhichdonotuseapivot.IntheorytheseshouldtracktheLPbetter,but aredifficulttodesigntoworkwell. AnopticalaudiointerconnectcableusedinhometheaterstoconnectDVDplayers,HDTV tuners,videogameconsoles,andmoretotheA/Vreceiverorcontroller.Toslinkcablesuse fiberopticsthatcarrythedigitalsignalaspulsesoflight. Thecorrectdownforceandanti-skatesettingtoacartridge,soitreadsthemostinformation possiblefromtherecordwallwithoutcausingdamagetothecartridgeortherecord. AdeviceusedtoalterthevoltageofACelectricity.Thistypicallyconsistsofanironringofsome kindwithtwocoilsofwirewoundaroundit.Theinputcurrentisfedtooneofthecoils,which generatesamagneticfieldintheironringandwhich,inturn,generatesavoltageintheother coil.Theproportionofinputvoltagetooutputvoltageisthesameastheproportionofthe numberofcoilwindingsontheinput(calledthe'primary')andoutput('secondary').Most transformersuseeitherasquare-shapedringwiththeprimaryandsecondarywindingson opposingsides,oraretoroidal,whichmeansthattheringisshapedlikeadonutandthe primaryandsecondarywindingscovertheentiresurface,overlappingeachother. TransformersdonotworkwithDCelectricitybecausewhileDCcangeneratemagnetisminthe ironcore,amagneticfieldcannotinturninduceelectricityinawireunlessitischanging(orthe wireismovingwithrespecttoit). Theaudiblefrequenciestypicallyconstitutedbyfrequenciesaboveabout5,000hertz,although thedividinglinebetweenmidrangeandtrebleisoneofopinion.Thehumanearislesssensitive totreblethantomidrangefrequencies. AcronymforTip-Ring-Sleeve,thethreepartsofatwo-conductor(plusshield)phoneplug.Since theplugorjackcancarrytwosignalsandacommonground,TRSconnectorsareoftenreferred toasstereoorbalancedplugsorjacks.AnothercommonTRSapplicationisforinsertjacks, usedforinsertinganexternalprocessorintothesignalpath. AcronymforTip-Sleeve,thetwopartsofasingleconductor(plusshield)phoneplug.TS connectorsaresometimescalledmonoorunbalancedplugsorjacks.A1/4”TSphoneplugor jackisalsocalledastandardphoneplugorjack. AdevicetorotateatthecorrectspeedavinylLPrecording.Moregenerally,thewordcanrefer totheturntableitselfalongwithaninstalledtonearmandcartridge.Theplatteronthe turntable(therotatingpart)ispoweredbyasmallelectricmotor.Differenttypesofturntables aredefinedbythedrivemechanismusedtoconnectmotortoplatter.Thethreemostcommon typesareidler-wheel,beltdriveanddirectdrive.Beltdriveturntablesusearubber-likebeltor bandrunningaroundapulleyonthemotorshaftandarimontheundersideoftheplatter. Theseappearinawiderangeofturntables,frominexpensiveonesthroughtosomeofthe mostprestigiousmodelsavailable.Indirectdriveturntablesthemotorrunsslowlyandthe spindleatthecentreoftheplatterisconnectedtotheshaft.Theseappearinsomeveryhigh qualityturntablesandofferparticularadvantagesofhighaccelerationtospeed,pluselectronic speedcontrolandstability. AsubtlechangetohomeaudioorA/Vintendedtoimprovethesound.Thiscouldrangefrom merelyadjustingthesystem'scontrols,throughreplacingcablesandexperimentingwith speakerpositions,toallkindsofdampingandisolatingprocedures. Tweeterdriver Two-way loudspeakers Unbalanced Universalremote controls Upconversion USB Videosources VoD Volume VRMS VTA Wet WiFi WindowsMedia Center Wireless Wirelessaccess point WMA Wooferdriver WowandFlutter Atypeofspeakerdriverthathandlesthehigh-frequencytreblerange(above2000Hz). Aloudspeakerwhichdividestheincomingsignalintotwodifferentfrequencybandsfor distributiontodrivers.Itsendshighfrequenciestothetweeterandlowfrequenciestooneor morewoofers. Anelectricalcircuitinwhichthetwolegsofthecircuitdonothavetheidenticalimpedanceto ground.Oftenonelegisalsoatgroundpotential.Unbalancedcircuitconnectionsrequireonly twoconductors(signal“hot”andground).Unbalancedaudiocircuitryislessexpensivetobuild, butundercertaincircumstancesismoresusceptibletonoisepickup. Remotecontroldevicesusedinahometheaterthataresupposedtoworkwithanyelectronics deviceviaonboardcodedatabases.Someprogrammableremotesallowyoutocreatemacros thatperformmultipletasksatonetime. Ascalingoftheresolutionofavideosignaltoahigherresolution.Thisprocesscanoccurinside aDVDorBlu-raydiscplayer,anA/Vreceiver,oranHDTV.Forexample,anA/Vreceiverwith upconversiontakeslower-resolutionvideoinput(suchascompositeorS-video)andconvertsit toahigher-resolutionformat(suchascomponentvideoorHDMI). AnacronymforUniversalSerialBus.USBisaserialbusstandardthatallowsyoutoconnect peripheraldevicestoacomputer. Devicesinahometheatersystemthatprovidevideocontent(TVormovies),suchasDVD players,Blu-raydiscplayers,VCRs,satelliteTVreceivers,anddigitalvideorecorders. Video-on-demand.Aservicethatprovidesmovierentalsonline,similartopay-per-view(but thecontentisavailableatanytime,ratherthanatsettimes).Manycablecompaniesnowoffer VoDaspartoftheirdigitalcableservices Thesoundlevelinanaudiosystem.Perhapstheonlythingthatsomebandshavetoomuchof. AcronymforVoltsRootMeanSquare.SeeRMS. Whenanoriginalrecordmasteriscut,thecuttersitsataslightangletotherecordsurface becausethecutterheadneedstobeliftedslightlyabovetherecordsurface.Thisangleiscalled theVerticalTrackingAngle(VTA)andcanvaryfromrecordtorecord.Inthe1960smostrecords werecutwithaVTAof15degrees,butbythe1980sthestandardbecame20degrees.Yeteven thoughwehavethese‘standards’,manysuccessfulcuttingengineersstillmaketheirown choiceofVTAinordertogivethesoundaparticularcharacter,whichistheirtrademark. Asignalwithaddedreverberationorothereffectlikeecho,delayorchorusing. Atrademarkforproductsthatarebasedon802.11wirelesscomputerLANstandards. MediasoftwareincludedincertainversionsoftheMicrosoftWindowsVistaoperatingsystem (WindowVistaHomePremiumandWindowsVistaUltimate).UsingaPCwithWindowsMedia Centerisoneoftheeasiestwaystoincorporateacomputerintoyourhometheatersystem. Wirelessistheconnectivityofonedevicetoaotherthatrequiresnophysicalcabling AdevicethatactsasabasestationofawirelessLAN,connectingoneormorewirelessdevices toawiredLAN AnacronymforWindowsMediaAudio.WMAisthestandardaudioformatusedbyWindows MediaPlayer.MostWMAfilesusealossydatacompressionsystem. Atypeofspeakerdriverthathandlesthelow-frequencybassrange(below200Hz). Adefectaffectinganalogueaudiosignalsourcesthatrelyonrotatingthemedium,particularly LPsandcompactcassettes.Wowisaslow,repetitivespeedvariation,typicallyrepeatingatless thanoncepersecond.IfanLPoraudiocassetteundergoesthis,itproducesslowvariationsin theplaybackfrequency.Wowisspecifiedinpercentandspecificationsofmorethanaround 0.1%are XLR XLRIn/out XLRout Y-Cable AnXLRconnectorisatypeofelectricalconnectorusedmostlyinprofessionalaudioandvideo electronicscablingapplicationssuchasforstagemicrophonesandotheranalogsound equipment,asopposedtohomeaudio/videoequipmentusingRCAconnectors.Itis characterizedbyalargecylindricalconnectorbody,commonlywiththreeprongsorpins,but othervariantshaveanywherefromtwotosixpins. TheXLRconnectorwasanincrementalvariantthatstartedfromtheTypeOconnectormadeby Cannon(ITTCannon),whichfeaturedanoval-shapedbodyandreceptaclewiththreeprongs andalatchlockingmechanism.ItsactualpredecessorwastheXserieswithoutalocking mechanism,andby1950onewasaddedanditbecametheXLseries.By1955,thefemale connectorwasmodifiedtohavesyntheticrubberinsulationsurroundingthefemalecontacts andthiswasnowtheXLRconnector.Aswithalltypesofconnectors,thereareamaleanda femaleversion.Thelatterisdesignedtohavethegroundpin(orpin1)makecontactfirst duringinsertionandlastduringremoval.Thisensuresthatonlyminimalnoiseispickedup duringmatingoftheconnectors,allowingforlivehotpluggingorswappingwithoutanymajor noisegoingtothespeakerssuchasthecasewithRCAconnectors. XLRoutisthesocketoutstageforanXLRbalancedconnection Acablewithoneinputandtwooutputs,usedtomultasourcetotwoinputs.