[pulseaudio-discuss] Input sound random detection.

[Tanu Kaskinen]

On Mon, 2016-08-08 at 12:06 -0300, Gustavo Duarte wrote:
> Attached you can find the outputs requested.

There are changes in the "Capture" and "Internal Mic Boost" volume
levels in alsa, and in the source volume level in pulseaudio.

In the non-working case:

Capture:
Front Left: Capture 13 [42%] [3.00dB] [on]
Front Right: Capture 13 [42%] [3.00dB] [on]

Internal Mic Boost:
Front Left: 1 [33%] [12.00dB]
Front Right: 1 [33%] [12.00dB]

Source volume in pulseaudio:
Volume: 0:  14% 1:  14%
        0: -51,00 dB 1: -51,00 dB

In the working case:

Capture:
Front Left: Capture 11 [35%] [0.00dB] [on]
Front Right: Capture 11 [35%] [0.00dB] [on]

Internal Mic Boost:
Front Left: 3 [100%] [36.00dB]
Front Right: 3 [100%] [36.00dB]

Source volume in pulseaudio:
Volume: 0:  32% 1:  32%
        0: -29,80 dB 1: -29,80 dB

So in the working case the Capture volume is 3 dB lower, the Internal Mic Boost volume is 24 dB higher, and the total difference (as shown by pulseaudio) is 21.2 dB. That is quite a lot, and perhaps explains why you don't hear anything in the non-working case.

Based on this, the problem would appear to be simply too low source volume. In your original explanation, however, you said that the input volume is 100% when it's not working, and setting the volume in sound settings to 20% makes it work. It would be good to know in more detail what you mean by "sound settings" and "input volume". You could upload somewhere a screenshot of the sound settings when it's not working and input volume is 100%, and while the sound settings are open in this state, run "pactl list" again and send it to the mailing list.

-- 
Tanu