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

Mark Brown broonie at opensource.wolfsonmicro.com
Wed Feb 17 15:12:33 CET 2010

On Wed, Feb 17, 2010 at 01:55:08PM +0000, James Courtier-Dutton wrote:

> 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.

That's not universally true - for example, with microphones you really
do want to have substantial amplification before the ADC sees them,
otherwise you'll at best get poor resolution due to the signal being
nowhere near full scale.  Sometimes this will be done by a fixed gain
stage that isn't visible to software, but not always.  Things in the
digital domain also tend to be at least equivalent to doing the work in
the CPU.

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