On 06.05.2020 14:45, S. wrote:
  Len Ovens wrote
  Use jack as the back end for pulse and unload the
alsa and udev modules
 from pulse. 
 Hmm, that's an interesting idea, I hadn't thought about Jack. (I use it Jack
 on another machine for music production, but not on my main workstation.)
 So you seem to be suggesting that Pulse is directly responsible for
 manipulating the levels? I assumed that it was Chromium and its spinoffs
 (Chrome and Electron apps), using an AGC function specifically as part of
 the WebRTC protocol: 
That is probably the source of the level change requests, but it is
PulseAudio that forwards this to the hardware (via ALSA drivers).
Without the direct hardware access PulseAudio can still fulfill the
request, but only by the digital signal manipulation which should be
less invasive.
I guess it might be possible to stop PA from using ALSA mixer controls
even without unloading ALSA support all together.
Jacek