This is it. As it appears in the 1997 Audi radio manual. Page 5

The noise level in the vehicle increases you drive faster. In the past, you have had to adjust the volume of the radio by hand.

Now, "GALA" automatically adjusts the volume whether you are listening to the radio, a cassette or a CD in line with the speed of the car.

"GALA" can be switched on and off with the treble control.

* Release button (3) {treble button} by pressing it briefly.
* To switch on: Turn button to the right.
* To switch off: Turn button to the left.

If you want to re-adjust the volume (e.g. due to different radio stations or cassettes), you only have to operate the volume control "GALA" continues to operate automatically.

For changing basic setting of "GALA" see page 13.

Page 13: Altering the basic volume of the speed-dependent volume control (GALA)
* Press and hold the "TP" button and switch radio on. "TA" appears in the display with a bar diagram.
* Press "TP" button briefly. "GALA" appears in the display with bar diagram.
* To increase volume press button at the top. { left of rotary Volume knob} The bar will move to the right.
* To decrease volume press button at the bottom. { left of rotary Volume knob } The bar will move to the left.

Page 14 IMPORTANT !!!!
* To store the new volume setting press button at top and bottom SIMULTANEOUSLY. {Just press both buttons to the left of the rotary volume knob at the same time}. "GALA" will disappear in the display.
* Switch radio off and on again.

MY COMMENTS,

TRY MOVING THE BAR DIAGRAM INDICATOR TO EACH END OF THE GALA DISPLAY TO SEE IF YOU HEAR A VERY SLIGHT DIFFERENCE. IT'S NOT THAT NOTICEABLE, REALLY.

That's it. Remember it is SPEED dependent. You will most likely only notice that the radio volume LOWERS when you come off a short highway ramp and quickly stop at a light.

They should have made it sensitive to cabin NOISE. That way we could leave our windows down and notice the effect.