PROEL DSO480 - Page 30

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Considerthesituationofamonitorengineer listeningtoabandperform.Havingnoaccesstodynamics
processors,hehashadtoresorttomanually‘ridingthefaders’inanattempttokeepcontrolofthelevels.
Shouldthelevelofoneofthechannelsonhisdeskreachanunacceptablyhi
ghlevel,hewillturnitdown
appropriately.

Thereisahiddensidechaininoperatio neven 
inthiscase.Themainsignalpathisfed
throughthemonitordeskandthegain
controlledbyadjustingthefader.The
sidechainisformedbythefeedbackpath
betweentheengine er’searscheckingthe
levelandhisbraininstr
uctinghishandto
turnthefaderdownifthevolumegoesover 
thethresholdhehaschosen.






Inthiscase,thedelaybetweenthesignalactuallygoingoverthethreshold,theengineerre gisteringthe
situation,andthenturningthesignaldownwillbeintheorderofseveralhundredmillisecondsatbest.This
willonlybetrueifheisnotdistracted–inreality,itmaybeseveralsecondsbefo
reanygainreductionis
imposedonthesignaltobringitundercontrol.

Forananaloguedynamicsprocessor,thesituation is much
better.Controllingthegainelectronically,andnotrelyingon
ahumansidechainfeedbackmechanism,it canreactmuch
morequickly.

Theredwaveformrepresentsthei
nputtothedynamics
module,withthedottedlineshowingthethresholdforgain
controltooccur.Thereareseveralpeakstowardsthestart
ofthissignalthatareabovethethreshold,andsothe
dynamicsprocessingshouldreacttotheseasappropriate.
(Inthiscasereducethegai
n).

Thebluewaveformshowstheoutputofthedynamics
module.Thecircledpeakdemonstratesthattheprocessor
hasmissedthefirstpeakabovethethreshold(asitisvery
fastandshort),buthas‘caughtup’shortlyafterwards,
keepingallotherpeaksundercontrol.Asitisunableto
predictwh
atiscoming,thiswillalwaysbea failingwith
analoguedynamicsprocessing.