Download Roksan Glossary of Terms.xlsx

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.