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Old 02-28-2012, 07:03 AM
D'Animation D'Animation is offline
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Default Sample rate conversion & consolidate increases volume??

Hi,

I've been doing lots of stem assemblies at 24fps, consolidating to one file and then converting to 23.98fps via sample rate conversion in the import session window. I've noticed that my peaks are ~1-1 1/2 db higher using the "find level" function on the Gain audiosuite plugin. Measuring the true peak via the Nugen VisLM plug, there's usually a .5 - 1db difference. Anyone come across this phenomena? Is a bug or does the sample rate conversion change how peaks are read?
Pt8 HD 8.05, Mac OS 10.5.8
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Old 02-28-2012, 08:39 AM
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nucelar nucelar is offline
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Default Re: Sample rate conversion & consolidate increases volume??

Yes, SRC can alter the amplitude of peaks, although it is weird that VisLM true peak meter shows this too.

the first step in SRC is oversampling, where a lot of samples are interpolated between each source sample, with high order filters. In those new samples, there will be peaks higher than the source. Secondly, this upsampled wave is read at the destination sample rate, and a new sample value may well happen at the newfound peaks.

The fact that VisLM still reports higher peaks may be because it upsamples 4 times AFAIK, while the SRC probably upsamples a lot more.
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