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More => Old Versions => JRiver Media Center 24 for Windows => Topic started by: mattkhan on January 01, 2019, 11:22:28 am

Title: Analyser shows a "Volume RMS" figure which seems wrong
Post by: mattkhan on January 01, 2019, 11:22:28 am

bug or there is an explanation for this behaviour I'm not aware of?

Steps to reproduce

- setup output format to passthrough the signal
- play a full scale sine wave down a single channel
- use internal volume at 100%
- look at the analyser

channel shows as ~ -3 dB as expected, peak level is also about 100%
NB: in my case I generated a sine wave at -3.1dB RMS to ensure there is no clipping (hence max levels just below 100%)

In the attached example, PEQ is active to mute all other channels and move a single channel of the input to the C, "Volume RMS" is reported as -12.1dB . If I turn this off and play both channels of the input sine wave then I get -3 on L and R and a Volume RMS of -9.

The meaning of this Volume RMS figure makes no sense to me in either case.

Title: Re: [BUG?] Analyser shows a "Volume RMS" figure which seems wrong
Post by: Hendrik on January 01, 2019, 05:39:24 pm

The first RMS value is a sum over all channel, if you play a mono signal on a 8 channel setup, it'll result in a lower overall volume RMS then when all channel are playing.

The -12 dB also makes sense to me. If all channel would be playing -3dB sine, then it would show a -3dB here, but since its 1/8th of that, the average RMS is reduced by 1/8th, which is 9dB.

Title: Re: Analyser shows a "Volume RMS" figure which seems wrong
Post by: mattkhan on January 01, 2019, 06:27:07 pm

Thanks, that does explain it.