How to change mixing of channels by pulse audio / alsa

Question

I have a recent problem with my sound configuration. Basically, it's way too loud until I set the volume below 10%. And then it's very quickly too silent. Using the alsa mixer, I can set the headphone volume and PCM volume to about 50% and then obtain a reasonable range on the master. But any application using pulse will reset all the non-master channels to max and kill my ears instantly.

Is there a way to force pulse to NOT change the other channels? I tried to look for information, and it seems that I need to change the channels from "mixin" to "ignore" in the configuration file, but there are so many configuration files, and I haven't found which ones are actually used by my system. So in the end, I am not even sure that what I think is correct.

Can someone tell me: how to find the exact configuration files I need to change, or how to override the global configuration with some local one? and what I need to actually change?

Thanks.

Answer 1

So in the end, I figured out that my profile was called analog-output-headphones. And the relevant configuration file is there:

/usr/share/pulseaudio/alsa-mixer/paths/analog-output-headphones.conf

For some reason, the configuration of my alsa card is such that the master volume doesn't do anything and I haven't found how to change that. But I can "ignore" the master and only act on the headphones ... This is not ideal, but currently works.