2009 Mercedes SLR McLaren Owner's Manual - Page 150

Controls in detail Audio system Balance Regardless of operating mode, press the AUD key repeatedly until you see BALANCE on the display. Returning audio functions to factory settings Audio system sound selection (EXT)* Regardless of operating mode, press the AUD key. You see the sound settings menu on the display. Press the EXT key. Regardless of operating mode, press and hold AUD key longer than 2 seconds. RESET will appear in the display. All settings for bass, treble and balance are returned to the center level and the volume is set to a predefined level. Press one of the function keys. Press L or R key to shift sound accordingly to the left or right speakers. or Press both L and R keys simultaneously to reset the Balance to its center level. 150