See also:

Sound output
Switching on/off When the ignition is switched off: press ON/OFF button on the radio. Muting When the ignition is switched on or the engine is running: press the ON/OFF button on the radio. ...

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

2010 BMW X5 M Review
On paper, the BMW X5 M seems about as incongruous as a car can be. It's a five-seat midsize crossover powered by a 555-horsepower, twin-turbocharged V-8 engine that can accelerate from zero to 60 ...