[pulseaudio-discuss] Config option to disable auto microphone boost?

[Laszlo KERTESZ]

Hi,
Thanks for the answer. I will test this aec_args option. It seems to do
what it says on the tin. Manually upping the gain from alsamixer to 22
seems to work fine on local tests if done beforehand (will have to do some
actual voice calls to see it in a real world scenario). Level 53 is too
much for the noise canceller as sometimes there is a periodical background
buzz.

Some additional data about the original issue:
In fact the auto mic adjustments are fine IF they dont SUDDENLY lift the
"Current" Mic Boost to 22 or, worse, 53 (never saw 100% but that would be
really really unpleasant for remote listeners, even 53 is).
Because this happens when the overall sound input level drops and PA
detects (or thinks) background noises (sometimes actual far-away voices)
and wants to compensate for it by raising the microphone gain. But the
canceller is not ready for this and there is suddenly a "boom" or very loud
"hiss" which fades in a few seconds as the noise cancellation manages to
clear it (in case of level 53 it cannot compensate fully, at least with my
analog microphone).

Also this does not seem to be an issue at all on devices that dont have
scalable mic boost (some USB headsets for example).

PS: Is there a documentation somewhere with a list of all aec_args?


Thank you.

On Sat, Apr 23, 2016 at 1:33 PM, Tanu Kaskinen <tanuk at iki.fi> wrote:

> On Thu, 2016-04-21 at 08:26 +0300, Laszlo KERTESZ wrote:
> > Hello,
> > Is there a config option to disable the automatic microphone gain
> > adjustments? I am referring to the case where the recording section in
> > alsamixer has a microphone boost option that can be adjusted.
> > When voip applications are used, particularly with echo-cancel, this
> slider
> > is automatically adjusted, sometimes causing very loud background noise.
> > This can be disabled manually if i edit the corresponding conf files in
> > /usr/share/pulse/alsa-mixer/paths/ (Debian) and i set the volume option
> > from merge to zero for the boost control then restart pulseaudio. But
> these
> > changes are overwritten on every update.
> >
> > Is there a method of achieving this without editing those files,
> preferably
> > an option in the pulseaudio's own configuration?
>
> Disabling the boost mixer element can't be done in a nice way. If echo-
> cancelling is where this causes the most problems, though, maybe
> disabling the automatic gain control of module-echo-cancel can help.
> There was a recent thread about how to do that:
> http://thread.gmane.org/gmane.comp.audio.pulseaudio.general/25742
>
> --
> Tanu
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>
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