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

Raymond Yau superquad.vortex2 at gmail.com
Thu Feb 25 14:14:34 CET 2010

2010/2/19 Lennart Poettering <mznyfn at 0pointer.de>

> On Thu, 18.02.10 14:15, Raymond Yau (superquad.vortex2 at gmail.com) wrote:
> > VLC media player has a slider from 0% to 300% , so the user are easily to
> > know  100% is the point which there is no software gain and no software
> > autentation
> >
> > How did PA expose these software amplication in the UI so that ordinary
> user
> > can know that point ?
> Depends on the UI program. gnome-volume-control currently only puts a
> marker at the ALSA 0dB point, but not a second one where software amp
> starts.

For example , your program dbmeasure.c generate a full amplitude sine wave ,
the sine wave will be clipped for any software gain by pulseaudio , any
hardware att. by DAC cannot change the clipped sine wave

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