Vauxhall Astra GTC Infotainment Manual page 21

20 Introduction
Press the TONE button to open the
tone menu.
Setting bass, middle and treble
Select Bass:, Midrange: or Treble:.
Set the desired value for the selected
option.
Setting the volume distribution
between front - rear
Select Fader:.
Set the desired value.
Setting the volume distribution
between right - left
Select Balance:.
Set the desired value.
Setting an individual setting to "0"
Select the desired option and press
and hold the multifunction knob for
a few seconds.
Setting all settings to "0" or "Off"
Press and hold the TONE button for
a few seconds.