reedal

No, you are right. There is certainly the possibility of a similar way to manage a form of automatic gain control, but not in the way I was thinking. I'll definitely have to do some more looking into it, just a different direction.

Look at home audio where you have no gain to mess with, i guess car audio could do the same thing, but i really don't know enough about the why to give an opinion on it.

I think when there is an audio input, like a TV output (or something that isn't controllable) to a home audio receiver, it emits a consistent level of output (say doesn't exceed a given output voltage, sort of like a maxed unclipped headunit) and the receiver volume is just your gain knob.