[The Wrench]

Ah-Ha. So it doesn't really do anything for volume, just tweaks the treble and bass equalizer a hair at lo volume settings. I have the non-nav system, and it is accessed via the right-hand button; then you get 3 settings for audio volume compensation. But none of them work like my Vette or Benz, where you can actually hear the volume increase as the speed increases (and the road noise goes up). The old Benz actually steps up at 20, 40, 60 MPH. But it's 20 years old, and that tactic works fine.
So, I guess my SRX is working as "intended" and I'll just continue to hit the wheel button as speed changes (poor engineering I think).

DG