Kurzweil PC3K Series - Expansion; Multiband Compression; Gates

Effects
Compressors, Expanders, and Gates
9-15
SmoothTimesmoothstheoutputoftheexpander’senvelopedetectorbyputtingalowpassfilter
inthecontrolsignalpath. SmoothingwillaffecttheAttackorReleasetimesonlywhenthis
parameterislongerthanoneoftheothertimes.Therangeis0.0to228.0ms.
SignalDly(Delay)putsa
smalldelayinthesignalrelativetothesidechainprocessing,sothat
thecompressor(orgate)“knows”whattheinputsignalisgoingtobebeforeithastoactonit.
Thismeansthecompressioncankickinbeforean attacktransientarrives.Inthe
SoftKneeCompressandHardKneeCompressalgorithms,delay
isreallyonlyusefulinfeed‐
forwardconfiguration(Fd bkComprsis“Out”).Forothercompressors,thedelaycanbeusefulin
feedbackconfiguration(FdbkComprsis“In”).Therangeis0to25ms.
Ratioistheamountofgainreductionimposedonthecompressedsignal,adjustablefrom1.0:1
(noreduction)to100:1,
andInf:1.
ThresholdisthelevelindBFS(decibelsrelativetofullscale)abovewhichthesignalbeginstobe
compressed.Adjustablefrom‐79.0to0dB.
MakeUpGainallowsadditionaloutputgaintocompensateforgainreductioninthe
compressor.ItisessentiallythesameparameterasOutGain,withwhich
itissummed.The
minimumis‐79.0,andthemaximumsummedgain(MakeUpGain+OutGain)is+24.0dB.
Expansion
AlgorithmscontainingExpandershavethesecontrols:
AtkorExpAtk(Attack),howfasttheexpanderturnsoffwhentheinputsignalrisesabovethe
thresholdlevel,adjustablefrom0.0to228.0ms.
RelorExpRel(Release),howfasttheexpanderturnsbackonafterthesignaldropsbelowthe
thresholdlevel,
adjustablefrom0to3000ms.
RatioorExpRatio,howmuchthegainisreducedbelowtheexpansionthreshold,adjustable
from1:1.0(noexpansion)to1:17(extremedownwardexpansion).
ThresholdorExpThreshold,thelevelbelowwhichthesignalisexpanded,adjustablefrom
‐79.0to0dB.
Inaddition,
thetwo‐segmentcompressorswithexpanderhaveseparateRatioandThreshold
controlsforeachofthecompressionsegments.
Multiband Compression
TheMultibandCompressionalgorithmhasAttack,Release,Smooth,SignalDelay,Ratio,
Threshold,andMakeUpGainparametersforeachofthethreebands(“Low”,“Mid”,and
“High”).Inaddition,ithas:
Crossover1andCrossover2.Thesesetthefrequencieswhichdividethethreecompression
frequencybands.Thetwoparametersare
interchangeable,soeithermaycontainthehigher
frequencyvalue.Therangeis16to25088Hz,inincrementsofasemitone.
Gates
SCInputletsyouselectwhichinputchannel(s)willcontrolthesidechain,whichisresponsible
foropeningandclosingthegate.ItcanbesettoL,R,ortheaverageofthetwochannels,
(L+R)/2.Youcanusethis,ifyouarrangethesignalpathsandpancontrolsappropriately,to
gate
onemonosignalwithadifferentmonosignal—thevenerable“Keyfex”effect.
GateTimeisthetimethatthegatewillstayopenafterthesidechainsignalreachesthe
Threshold.Itsrangeis0to3000ms.