See also:

Deactivating HDC
Press the button again and the LED goes out. HDC is automatically deactivated above approx. 37 mph/60 km/h. ...

Deleting the button assignments
1. Press buttons 1 and 8 simultaneously for approx. five seconds. 2. "OK" ...

Treble, bass, balance, and fader
▷ "Treble": treble adjustment. ▷ "Bass": depth adjustment. ▷ "Balance": left/right volume distribution. ▷ "Fader": front/rear volume ...