[pulseaudio-discuss] Alsamixertest

[David Henningsson]

Hi Colin,

for some reason your test of alsamixertest didn't reach me the normal 
path, so I'm pasting it in from the archives:

 > Cool. Packaged up for Mandriva too now.

Thanks :-)

 > What license do you use.
 > Couldn't seem to find any reference to it...

It should be GPLv3, thanks for noticing.

 > Ultimately the results seem to indicate that "Master" is OK,
 > but out by a bit,

Yeah, I have seen that on one of my test machines here as well, and I 
don't know if one should mark that as error, I probably shouldn't. I 
don't even know if that's a volume control or an ADC problem in that case.

 > but PCM is all kinds of broken.

PCM is indeed very broken. I've traced it down to alsactl as well, and 
if the decision was mine, I would remove it right away, but upstream 
wasn't convinced. :-( See the long thread starting at 
http://mailman.alsa-project.org/pipermail/alsa-devel/2010-August/031054.html

 > FWIW, the testing for -18.0, expected -21.04 measure -20.03dB is all a
 > little confusing. When testing for -18.0, why is 021.04 expected?
 > Perhaps some more explanation would be nice as to why the expected
 > values differ from the test value.

So when it did the initial testing signal, it set everything to 0 dB and 
the input signal received was -3.04 dB. So when setting Master to -18 
dB, it expects the input signal to be -18-3.04 = -21.04 dB.

-- 
David Henningsson, Canonical Ltd.
http://launchpad.net/~diwic