I have a sound source connected via line-in to my computer. But when I change the master volume, only the volume of sounds being played on the computer (e.g. media, alerts, etc.) changes; the output volume of the line-in source does not change. How do I control that?
To clarify, I don't just want to control the line-in output volume, I want to control the normal "output volume" from one control only, and I want that to affect also the line in output volume. Something like a "master volume" that would affect everything that comes out of the sound card output.
The "master volume" I see when running the command "alsamixer" only affects the sound that comes from the main pc, not from the line in.