[alsa-devel] Verifying mixer dB data/Invalid dB data from USB cards, especially Aureon 5.1 MkII

Raymond Yau superquad.vortex2 at gmail.com
Fri Feb 26 10:38:02 CET 2010

2010/2/17 James Courtier-Dutton <james.dutton at gmail.com>

> This is a good aim, but I still think getting the correct 0dB points
> is more important to ensure the best audio quality.
> I personally think that PA should just set the hardware ALSA controls
> to 0dB and do all the volume control in software within PA.
> The 0dB points in hardware should result in the best sound quality.
> James
When you mix two stream of 16-bit audio and send to a 16 bit sound card ,
you have to add two 16-bit and shift right one bit ,

you have already add -3dB by software when perform soft mixing and you may
need to get +3dB gain in DAC if you want to maintain the same dB level if
one stream is actually silence

so set the hardware ALSA controls to 0dB is not that good for a sound server

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