See also:

Lumbar support
The curvature of the seat backrest can be adjusted in such a way that it supports the lumbar region of the spine. The lower back and the spine are supported for upright posture. ▷ Press ...

Activating HDC
Press the button; the LED above the button lights up. ...

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