Audio Volume on Radio increases and decreases at will how to disable

On my non-JBL system, in the "audio" screen, in the lower-right I believe is a button which, I believe says "DSP". This opens up another screen that allows you to select the level of automatic gain control, or something like that. I'll update when I get out to the car and actually walk through it.

**edit. Okay, for non-JBL (single disk CD), press "audio" button on screen bezel, then near the lower-left is the "DSP" button which gets you into the "ASL" screen. Then select "Off".