- Dolby Multichannel Audio Tool User's Manual

Calibrating Speaker Playback Levels
Dolby
®
DP570 Multichannel Audio Tool User’s Manual 65
FigureA‐7 
Figure A-7 Digital Reference Level
A.3.2 Setting the Master Trim
SettheMasterTrimshowninFigure 4 ‐10to0.
A.3.3 Setting the Master Volume
Beforegeneratingtestnoise,makesurethatmasterVolumeissetlow:–20to–30.Usethe
slidershowninFigure 4‐11.
A.3.4 Picking a Target SPL
WhenpickingatargetSPL,itismostimportantthateachofthemainchannelsissettothe
samelevel;theabsolutelevelissecondary.Thefollowingexamplesaresuggestionsfor
selectinganabsolutelevel:
•Forfilmwork,testnoiseatreferencelevelinthemainchannels(Left,Right,Center)
shouldproduceanSPLof85dBc.Forfilmwork,surroundchannelsarecalibratedto
anSPLof82dBcwithSurround3dBAttenuationchecked.ThenetresultisanSPLof
85dBcwhennoiseisplayedthroughthesystem.
•Fortelevisionwork,testnoiseatreferencelevelis
typicallysettoproduceanSPL
rangingfrom79to82dBcforeachofthemainfivechannels.Thelowerreferencelevel
fortelevisionisduetotheloweraveragelisteninglevelsusedbytheconsumer
(typically70to75dBc).
•Formusicmixing,eachspeakerchannelshouldbeset
tothesameSPL(thesameas
televisionmixing).Thereisnostandardpracticeforreferencelevelsformusicmixing.
Someengineersprefertomixlouderthanothersdo,butifthelevelsbetweenchannels
arecorrect,theoveralllevelisnotasimportant.
Whenmixingfortelevisionormusic
insmallmixingroomssuchasremoterecording
trucks,surroundchannelsaregenerallyset2dBlowerthanthefrontchannels.Thistakes
intoaccounttheshortdistancetothesurroundspeakers. Experiencehasshownthatthis
settingmakesthesoundinthehomeenvironmentveryclosetothesoundheard
bythe
mixer.
Tip: TomakethisadjustmentyoumustclosetheSetupwindowtoactivatethemain
applicationscreen.Whensatisfied,reopentheSetupwindow.