High fidelity - Wikipedia

High fidelity (often shortened to Hi-Fi or HiFi) is the high-quality reproduction of sound. ... It is important to audiophiles and home audio enthusiasts. Ideally ... Highfidelity FromWikipedia,thefreeencyclopedia Jumptonavigation Jumptosearch High-qualityreproductionofsound Forotheruses,seeHighfidelity(disambiguation). Thisarticleneedsadditionalcitationsforverification.Pleasehelpimprovethisarticlebyaddingcitationstoreliablesources.Unsourcedmaterialmaybechallengedandremoved.Findsources: "Highfidelity" – news ·newspapers ·books ·scholar ·JSTOR(January2016)(Learnhowandwhentoremovethistemplatemessage) Hi-fispeakersareakeycomponentofqualityaudioreproduction. Highfidelity(oftenshortenedtoHi-FiorHiFi)isthehigh-qualityreproductionofsound.[1]Itisimportanttoaudiophilesandhomeaudioenthusiasts.Ideally,high-fidelityequipmenthasinaudiblenoiseanddistortion,andaflat(neutral,uncolored)frequencyresponsewithinthehumanhearingrange.[2] Highfidelitycontrastswiththelowerqualitysoundproducedbyinexpensiveaudioequipment,AMradio,ortheinferiorqualityofsoundreproductionthatcanbeheardinrecordingsmadeuntilthelate1940s.Inlo-fimusic,suchdefectsarethemselvesaspectsofthemusic. Contents 1History 2Listeningtests 3Semblanceofrealism 4Modularity 5Modernequipment 6Seealso 7References 8Furtherreading 9Externallinks History[edit] BellLaboratoriesbeganexperimentingwitharangeofrecordingtechniquesintheearly1930s.PerformancesbyLeopoldStokowskiandthePhiladelphiaOrchestrawererecordedin1931and1932usingtelephonelinesbetweentheAcademyofMusicinPhiladelphiaandtheBelllabsinNewJersey.Somemultitrackrecordingsweremadeonopticalsoundfilm,whichledtonewadvancesusedprimarilybyMGM(asearlyas1937)andTwentiethCenturyFoxFilmCorporation(asearlyas1941).RCAVictorbeganrecordingperformancesbyseveralorchestrasusingopticalsoundaround1941,resultinginhigher-fidelitymastersfor78-rpmdiscs.Duringthe1930s,AveryFisher,anamateurviolinist,beganexperimentingwithaudiodesignandacoustics.Hewantedtomakearadiothatwouldsoundlikehewaslisteningtoaliveorchestra—thatwouldachievehighfidelitytotheoriginalsound.AfterWorldWarII,HarryF.Olsonconductedanexperimentwherebytestsubjectslistenedtoaliveorchestrathroughahiddenvariableacousticfilter.Theresultsprovedthatlistenerspreferredhigh-fidelityreproduction,oncethenoiseanddistortionintroducedbyearlysoundequipmentwasremoved.[citationneeded] Beginningin1948,severalinnovationscreatedtheconditionsthatmademajorimprovementsofhome-audioqualitypossible: Reel-to-reelaudiotaperecording,basedontechnologytakenfromGermanyafterWWII,helpedmusicalartistssuchasBingCrosbymakeanddistributerecordingswithbetterfidelity. Theadventofthe33⅓rpmLongPlay(LP)microgroovevinylrecord,withlowersurfacenoiseandquantitativelyspecifiedequalizationcurvesaswellasnoise-reductionanddynamicrangesystems.Classicalmusicfans,whowereopinionleadersintheaudiomarket,quicklyadoptedLPsbecause,unlikewitholderrecords,mostclassicalworkswouldfitonasingleLP. FMradio,withwideraudiobandwidthandlesssusceptibilitytosignalinterferenceandfadingthanAMradio. Betteramplifierdesigns,withmoreattentiontofrequencyresponseandmuchhigherpoweroutputcapability,reproducingaudiowithoutperceptibledistortion.[3] Newloudspeakerdesigns,includingacousticsuspension,developedbyEdgarVillchurandHenryKlosswithimprovedbassfrequencyresponse. Inthe1950s,audiomanufacturersemployedthephrasehighfidelityasamarketingtermtodescriberecordsandequipmentintendedtoprovidefaithfulsoundreproduction.Whilesomeconsumerssimplyinterpretedhighfidelityasfancyandexpensiveequipment,manyfoundthedifferenceinqualitycomparedtothethen-standardAMradiosand78-rpmrecordsreadilyapparentandboughthigh-fidelityphonographsand33⅓LPssuchasRCA'sNewOrthophonicsandLondon'sFFRR(FullFrequencyRangeRecording,aUKDeccasystem).Audiophilespaidattentiontotechnicalcharacteristicsandboughtindividualcomponents,suchasseparateturntables,radiotuners,preamplifiers,poweramplifiersandloudspeakers.Someenthusiastsevenassembledtheirownloudspeakersystems.Inthe1950s,hi-fibecameagenerictermforhomesoundequipment,tosomeextentdisplacingphonographandrecordplayer. Inthelate1950sandearly1960s,thedevelopmentofstereophonicequipmentandrecordingsledtothenextwaveofhome-audioimprovement,andincommonparlancestereodisplacedhi-fi.Recordswerenowplayedonastereo.Intheworldoftheaudiophile,however,theconceptofhighfidelitycontinuedtorefertothegoalofhighlyaccuratesoundreproductionandtothetechnologicalresourcesavailableforapproachingthatgoal.Thisperiodisregardedasthe"GoldenAgeofHi-Fi",whenvacuumtubeequipmentmanufacturersofthetimeproducedmanymodelsconsideredendearingbymodernaudiophiles,andjustbeforesolidstate(transistorized)equipmentwasintroducedtothemarket,subsequentlyreplacingtubeequipmentasthemainstreamtechnology. Inthe1960s,theFTCwiththehelpoftheaudiomanufacturerscameupwithadefinitiontoidentifyhighfidelityequipmentsothatthemanufacturerscouldclearlystateiftheymeettherequirementsandreducemisleadingadvertisements.[4] Themetal-oxide-semiconductorfield-effecttransistor(MOSFET)wasadaptedintoapowerMOSFETforaudiobyJun-ichiNishizawaatTohokuUniversityin1974.PowerMOSFETsweresoonmanufacturedbyYamahafortheirhi-fiaudioamplifiers.JVC,PioneerCorporation,SonyandToshibaalsobeganmanufacturingamplifierswithpowerMOSFETsin1974.[5]In1977,HitachiintroducedtheLDMOS(lateraldiffusedMOS),atypeofpowerMOSFET.HitachiwastheonlyLDMOSmanufacturerbetween1977and1983,duringwhichtimeLDMOSwasusedinaudiopoweramplifiersfrommanufacturerssuchasHHElectronics(V-series)andAshlyAudio,andwereusedformusicandpublicaddresssystems.[5]Class-Damplifiersbecamesuccessfulinthemid-1980swhenlow-cost,fast-switchingMOSFETsweremadeavailable.[6]ManytransistorampsuseMOSFETdevicesintheirpowersections,becausetheirdistortioncurveismoretube-like.[7] Apopulartypeofsystemforreproducingmusicbeginninginthe1970swastheintegratedmusiccentre—whichcombinedaphonographturntable,AM-FMradiotuner,tapeplayer,preamplifier,andpoweramplifierinonepackage,oftensoldwithitsownseparate,detachableorintegratedspeakers.Thesesystemsadvertisedtheirsimplicity.Theconsumerdidnothavetoselectandassembleindividualcomponentsorbefamiliarwithimpedanceandpowerratings.Puristsgenerallyavoidreferringtothesesystemsashighfidelity,thoughsomearecapableofverygoodqualitysoundreproduction. Audiophilesinthe1970sand1980spreferredtobuyeachcomponentseparately.Thatway,theycouldchoosemodelsofeachcomponentwiththespecificationsthattheydesired.Inthe1980s,anumberofaudiophilemagazinesbecameavailable,offeringreviewsofcomponentsandarticlesonhowtochooseandtestspeakers,amplifiers,andothercomponents. Listeningtests[edit] Seealso:Codeclisteningtest Listeningtestsareusedbyhi-fimanufacturers,audiophilemagazines,andaudioengineeringresearchersandscientists.Ifalisteningtestisdoneinsuchawaythatthelistenerwhoisassessingthesoundqualityofacomponentorrecordingcanseethecomponentsthatarebeingusedforthetest(e.g.,thesamemusicalpiecelistenedtothroughatubepoweramplifierandasolid-stateamplifier),thenitispossiblethatthelistener'spre-existingbiasestowardsoragainstcertaincomponentsorbrandscouldaffecttheirjudgment.Torespondtothisissue,researchersbegantouseblindtests,inwhichlistenerscannotseethecomponentsbeingtested.AcommonlyusedvariantofthistestistheABXtest.Asubjectispresentedwithtwoknownsamples(sampleA,thereference,andsampleB,analternative),andoneunknownsampleX,forthreesamplestotal.XisrandomlyselectedfromAandB,andthesubjectidentifiesXasbeingeitherAorB.Althoughthereisnowaytoprovethatacertainmethodologyistransparent,[8]aproperlyconducteddouble-blindtestcanprovethatamethodisnottransparent. Blindtestsaresometimesusedaspartofattemptstoascertainwhethercertainaudiocomponents(suchasexpensive,exoticcables)haveanysubjectivelyperceivableeffectonsoundquality.DatagleanedfromtheseblindtestsisnotacceptedbysomeaudiophilemagazinessuchasStereophileandTheAbsoluteSoundintheirevaluationsofaudioequipment.JohnAtkinson,currenteditorofStereophile,statedthatheoncepurchasedasolid-stateamplifier,theQuad405,in1978afterseeingtheresultsfromblindtests,butcametorealizemonthslaterthat"themagicwasgone"untilhereplaceditwithatubeamp.[9]RobertHarleyofTheAbsoluteSoundwrote,in2008,that:"...blindlisteningtestsfundamentallydistortthelisteningprocessandareworthlessindeterminingtheaudibilityofacertainphenomenon."[10] DougSchneider,editoroftheonlineSoundstagenetwork,refutedthispositionwithtwoeditorialsin2009.[11][12]Hestated:"Blindtestsareatthecoreofthedecades'worthofresearchintoloudspeakerdesigndoneatCanada'sNationalResearchCouncil(NRC).TheNRCresearchersknewthatfortheirresulttobecrediblewithinthescientificcommunityandtohavethemostmeaningfulresults,theyhadtoeliminatebias,andblindtestingwastheonlywaytodoso."ManyCanadiancompaniessuchasAxiom,Energy,Mirage,Paradigm,PSB,andReveluseblindtestingextensivelyindesigningtheirloudspeakers.AudioprofessionalDr.SeanOliveofHarmanInternationalsharesthisview.[13] Semblanceofrealism[edit] Stereophonicsoundprovidedapartialsolutiontotheproblemofcreatingtheillusionofliveorchestralperformersbycreatingaphantommiddlechannelwhenthelistenersitsexactlyinthemiddleofthetwofrontloudspeakers.Whenthelistenermovestotheside,however,thisphantomchanneldisappearsorisgreatlyreduced.Anattempttoprovideforthereproductionofthereverberationwastriedinthe1970sthroughquadraphonicsound.Consumersdidnotwanttopaytheadditionalcostsandspacerequiredforthemarginalimprovementsinrealism.Withtheriseinpopularityofhometheater,however,multi-channelplaybacksystemsbecamepopular,andmanyconsumerswerewillingtotoleratethesixtoeightchannelsrequiredinahometheater. Inadditiontospatialrealism,theplaybackofmusicmustbesubjectivelyfreefromnoise,suchashissorhum,toachieverealism.Thecompactdisc(CD)providesabout90decibelsofdynamicrange,[14]whichexceedsthe80 dBdynamicrangeofmusicasnormallyperceivedinaconcerthall.[15]Audioequipmentmustbeabletoreproducefrequencieshighenoughandlowenoughtoberealistic.Thehumanhearingrange,forhealthyyoungpersons,is20 Hzto20,000 Hz.[16]Mostadultscan'thearhigherthan15,000 Hz.[14]CDsarecapableofreproducingfrequenciesaslowas0 Hzandashighas22,050 Hz,makingthemadequateforreproducingthefrequencyrangethatmosthumanscanhear.[14]Theequipmentmustalsoprovidenonoticeabledistortionofthesignaloremphasisorde-emphasisofanyfrequencyinthisfrequencyrange. Modularity[edit] ModularcomponentsmadebySamsungandHarmanKardon ASony"midi"hififromthelate1980s.Despiteitsappearancemimickingseparatecomponents,thisisanall-in-oneunitfeaturingarecordplayer,dualcassettedecks,adigitaltunerandanamplifier.OthermidisystemsintegratingaCDplayerwerealsoincreasinglycommonbythispoint. Integrated,mini,orlifestylesystems(alsoknownbytheoldertermsmusiccentreormidisystem[17][18])containoneormoresourcessuchasaCDplayer,atuner,oracassettetapedecktogetherwithapreamplifierandapoweramplifierinonebox.Althoughsomehigh-endmanufacturersdoproduceintegratedsystems,suchproductsaregenerallydisparagedbyaudiophiles,whoprefertobuildasystemfromseparates(orcomponents),oftenwitheachitemfromadifferentmanufacturerspecialisinginaparticularcomponent.Thisprovidesthemostflexibilityforpiece-by-pieceupgradesandrepairs. Forslightlylessflexibilityinupgrades,apreamplifierandapoweramplifierinoneboxiscalledanintegratedamplifier;withatuneradded,itisareceiver.Amonophonicpoweramplifieriscalledamonoblockandisoftenusedforpoweringasubwoofer.Othermodulesinthesystemmayincludecomponentslikecartridges,tonearms,hi-fiturntables,digitalmediaplayers,DVDplayersthatplayawidevarietyofdiscsincludingCDs,CDrecorders,MiniDiscrecorders,hi-fivideocassetterecorders(VCRs)andreel-to-reeltaperecorders.Signalmodificationequipmentcanincludeequalizersandnoise-reductionsystems. Thismodularityallowstheenthusiasttospendaslittleorasmuchastheywantonacomponentthatsuitstheirspecificneedsandaddcomponentsasneedarisesandfundsareavailable.Inasystembuiltfromseparates,sometimesafailureononecomponentstillallowspartialuseoftherestofthesystem.Theentiresystemisunusablewhileanintegratedsystemisbeingrepaired.Amodularsystemintroducesthecomplexityofhavingmultiplecomponentswithcablingandconnectivity,anddifferentremotecontrolsforeachunit. Modernequipment[edit] Somemodernhi-fiequipmentcanbedigitallyconnectedusingfibreopticTOSLINKcables,USBports(includingonetoplaydigitalaudiofiles),orWi-Fisupport. Anothermoderncomponentisthemusicserverconsistingofoneormorecomputerharddrivesthatholdmusicintheformofcomputerfiles.WhenthemusicisstoredinanaudiofileformatthatislosslesssuchasFLAC,Monkey'sAudioorWMALossless,thecomputerplaybackofrecordedaudiocanserveasanaudiophile-qualitysourceforahi-fisystem.Thereisnowapushfromcertainstreamingservicestoofferhi-fiservices. Streamingservicestypicallyhaveamodifieddynamicrangeandpossiblybitrateslowerthanaudiophileswouldbehappywith.Tidalhaslaunchedahi-fitierthatincludesaccesstoFLACandMasterQualityAuthenticatedstudiomastersformanytracksthroughthedesktopversionoftheplayer.Thisintegrationisalsoavailableforhigh-endaudiosystems. Seealso[edit] Audiosystemmeasurements Comparisonofanaloganddigitalrecording DIYaudio EdwinHowardArmstrong Entertainmentcenter High-endaudio Lo-fimusic Wifeacceptancefactor Wi-Fi,awirelesstermderivedfromhi-fi References[edit] ^Hartley,H.A.(1958)."Highfidelity".AudioDesignHandbook(PDF).NewYork,NewYork:GernsbackLibrary.p. 7,200.LibraryofCongressCatalogCardNo.57-9007.Archivedfromtheoriginal(PDF)on2009-01-27.Retrieved2009-08-08.Iinventedthephrase'highfidelity'in1927todenoteatypeofsoundreproductionthatmightbetakenratherseriouslybyamusiclover.Inthosedaystheaverageradioorphonographequipmentsoundedprettyhorriblebut,asIwasreallyinterestedinmusic,itoccurredtomethatsomethingmightbedoneaboutit. ^"Frequencyresponse".www.hi-fiworld.co.uk. ^DavidLander(June–July2006)."TheBuyablePast:ClassicHi-FiComponents".AmericanHeritage.Archivedfromtheoriginalon2007-02-23. ^Lachenbruch,David(1963-03-23).Billboard.NielsenBusinessMedia,Inc.p. 47.CS1maint:dateandyear(link) ^abDuncan,Ben(1996).HighPerformanceAudioPowerAmplifiers.Elsevier.pp. 177-8,406.ISBN 9780080508047. ^Duncan,Ben(1996).HighPerformanceAudioPowerAmplifiers.Newnes.pp. 147–148.ISBN 9780750626293. ^Fliegler,Ritchie;Eiche,JonF.(1993).Amps!TheOtherHalfofRock'n'Roll.HalLeonardCorporation.ISBN 9780793524112. ^Spanos,Aris(1999).ProbabilityTheoryandStatisticalInference.CambridgeUniversityPress.p. 699.ISBN 0-521-42408-9. ^JohnAtkinson(2005-07-17)."BlindTests&BusStops". ^RobertHarley(2008-05-28)."BlindListeningTestsareFlawed:AnEditorial".TheAbsoluteSound.Archivedfromtheoriginalon2011-09-30.Retrieved2011-09-29. ^DougSchneider(2009-05-01)."TheMisinformedMisleadingtheUninformed–ABitAboutBlindListeningTests".GoodSound!.Retrieved2011-09-29. ^DougSchneider(2009-06-01)."ABitMoreAboutBlindListeningTests(6/2009)".GoodSound!.Retrieved2011-09-29. ^Dr.SeanOlive(2009-04-09)."TheDishonestyofSightedListeningTests".Retrieved2011-09-29.[self-publishedsource?] ^abcFries,Bruce;MartyFries(2005).DigitalAudioEssentials.O'ReillyMedia.pp. 144–147.ISBN 0-596-00856-2.Digitalaudioat16-bitresolutionhasatheoreticaldynamicrangeof96dB,buttheactualdynamicrangeisusuallylowerbecauseofoverheadfromfiltersthatarebuiltintomostaudiosystems."..."AudioCDsachieveabouta90-dBsignal-to-noiseratio.""Mostadultscan'thearfrequencieshigherthan15 kHz,sothe44.1 kHzsamplingrateofCDaudioismorethanadequatetoreproducethehighestfrequenciesmostpeoplecanhear. ^Eargle,John(2005).HandbookofRecordingEngineering.Springer.p. 4.ISBN 0-387-28470-2. ^D'Ambrose,Chris(2003)."FrequencyRangeofHumanHearing".ThePhysicsFactbook.RetrievedOctober11,2009. ^ArgosCatalogueAutumn/Winter1986.Argos.1986.pp. 258–259.Archivedfromtheoriginalon2020-05-27."MidiSystems[..]Scheider2500RRemoteControlMidiSystem[..]AmstradMS-45MidiSystem[..]ToshibaS103KMidiSystem[etc]AltURL ^"MatsuiMIDI47".14March2010. Furtherreading[edit] PierPaoloFerrari(2016).TheHi-Fi'sGoldenAge(1st ed.).Bergamo,Italy:Sandit.ISBN 978-88-6928-171-6. JanetBorgerson;JonathanSchroeder(2017).DesignedforHi-FiLiving:TheVinylLPinMidcenturyAmerica.Cambridge,MA:MITPress.ISBN 9780262036238. PierPaoloFerrari(2017).High-Fidelity(1st ed.).Bergamo,Italy:SanditLibri.ISBN 978-88-6928-254-6. 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