8
Special Design Features
Dedicated Power TheWisdomAudioamplier/speakersystemisdesignedtotakeadvantageof
afactthathashithertobeenunderstoodonlybyarelativelysmallnumberof
audiophiles:speakerssoundbetterwhentheyaredrivendirectlybydedicated,
highqualityampliers.
Youmightthinkthatyouhavedonesointhepast.Afterall,youconnected
yourreceiveroramplierdirectlytotheloudspeakercabinet,usinghighquality
wire.Butinalmostallcases,thatconnectionledtoapassivecrossovernetwork
withinthespeakercabinet,madeupofresistors,capacitorsandcoilsofwire
calledinductors.Thepassivecrossoverhadthejobofsplittingupthesignal
tothewoofer,midrange,andtweeterinsidethecabinet.Bydesign,itcreated
acomplex,reactivecircuitbetweentheamplierandthedriversthatactually
makethemusic.
TheWisdomAudioapproachdoesnotsufferfromthiscompromise.TheSC-1is
anactive(notpassive)crossoverthatdividesthemusicsignalwhilestillatapre-
amplierlevel.Itcandosowithfargreateraccuracyandconsistencythanpas-
sivecomponentsinaspeakerbox,withtheirinevitableproductiontolerances.
Theseseparatesignalsarethenroutedtodedicatedamplierswhichneedwork
withonlyaportionoftheaudiblerange.InthecaseoftheSA-3amplierchan-
nels,theyneedhandleonlythebass;themidrangeandtrebleareroutedtoa
separateamplierofyourchoosingthatdrivestheplanarmagneticpanels.
Thisapproachiscalled“bi-amplication”sinceeachspeakerisactuallyusing
twochannelsofamplication.Itprovidesseveralimportantbenets:
• Greater excitement due to improved dynamics.Obviously,
havingtwoampliersallowsyoutousemorepoweronaper-
speakerbasis,butthisisaboutmorethansimplyplayingloudly.
Themoment-to-momentdynamiccontrastsarevastlyimproved,
thankstothefactthattheinefcientbufferthatwouldhavebeen
thepassivecrossoverismissing.Theampliersareconnected
directlytotheirrespectivedrivers,soeverynuanceinthesignalis
preserved.
• Improved detail and intelligibility thanks to lower distortion.
Onemajorsourceofloudspeakerdistortion—thepassivecross-
overitself—hassimplybeeneliminated.Plus,eachamplierhas
asimplertask,beingresponsibleforonlypartoftheaudiblespec-
trum.Thisfactreducesseveraltypesofdistortion,mostnotably
clipping(sinceallofitspowerisavailableforlesswork)andinter-
modulationdistortion(sincetheamplierseesfewerfrequencies).
• Improved clarity and control.Theamplier’s“dampingfactor”
isonewayofmeasuringitsdegreeofcontroloverthemotionof
thedrivertowhichitisconnected.Unfortunately,whenapassive
crossoverintervenes,theamplierisnolongerdirectlyconnected
tothedriveritisaskedtocontrol.Asaresult,itlosesmuchofthe
precisionitsdesignersworkedsohardtoachieve.Byavoiding
theneedforapassivecrossoverandconnectingdirectlytothe
transducer,theamplier’sabilitytocontrolthemotionofthedia-
phragmismaximized.