Dolby Laboratories DP570 4.7.2 Measuring the Average Loudness of Identified Clips

Using the DP570 Features Measuring and Setting the Dialogue Level

Dolby® DP570 Multichannel Audio Tool User’s Manual 31

characterswithdifferentvocalqualities.Inprogramswithoutdialogue,suchasamusic

concert,sectionsofaveragelevelneedtobeidentified.

Withrepresentativeaudioclipsidentified,youcanusetheDP570tosetthedialoguelevel

parameter.Youcanuseeitherthesoftwareinterfaceorthefront‐panelbuttons;forthis

operationwedescribeusingthesoftwareinterfacefirst.

4.7.2 Measuring the Average Loudness of Identified Clips

ThemeasurementfeaturecompliesfullywithIEC60804(2000‐10):Integrating‐Averagi ng

SoundLevelMeters(Leq(A))andincludestheadditionoftwodistinctmeasurementmodes

relatingtothemeasurementperioditself:infiniteandshort‐term.Thissectiondescribesthe

behaviorofbothmodes.

Leq(A)‐basedmeasurementsaremostaccuratewhentheycoversignalswithsimilar

spectra,suchasdialogue;themoresimilarthespectra,themoreaccuratethemeasurement.

ThisiswhywerecommendtheuseofLeq(A)measurementstoprovisionthedialoguelevel

valuewithinDolbyEandDolbyDigitalbitstreams.TheDP570measurementfeaturewill

yieldbestresultswhentheoperatormeasuresportionsoftheprogramthatcontainonly

minimalnondialoguematerial.

InfinitemeasurementmodeconformstothespecificationsofIEC60804(2000‐10).Inthis

mode,thecalculatedvalueisthelong‐termA‐weightedlevel,Leq(A),integratedoverthe

entireperiodsincethemeasurementwaslastreset.

Infinitemodeistypicallyusedtomeasuretheentireduration��oftheprogram,orseveral

longsectionsofaprogram,tofindthelong‐termA‐weightedlevel.SinceDialogue

IntelligenceisavailableonlyintheDolbyLM100BroadcastLoudnessMeter,wesuggest

usingthefollowingstepstoobtainanestimatedLeq(A)valuefortheentireprogram:

1. Reviewtheprogram,notingthelocationsofseveralrepresentativesectionswhere

dialogueispresent.

2. Cuethebeginningofthefirstselectedsegment.

3. ClickResettoclearpastmeasurements.

4. Measurethefirstsegment,thenclickPausetopausemeasurement.

5. Cuethesecondsegment.

6. ClickPauseagaintoresumemeasurement.

7. Continueinthisfashion,pausingmeasurementbetweenselectedsegmentsuntilthe

programiscompleted.

Note:Thesechangesharmonizeboththecoremeasurementalgorithmandthe

measurementmodesbetweentheDP570andtheDolbyLM100Broadcast

LoudnessMeter.DialogueIntelligence™,however,isavailableonlyintheLM100.