Volvo 2005 V70 - Manual (Page 120)

Volume control - Subwoofer
Turn the knob clockwise to increase volume.
Turn the knob counterclockwise to lower volume or switch off the subwoofer.
When the knob is in the middle, bass effect is "equalized".
pg. 174 Radio functions HU-650/HU-850
Sound settings
Bass
Adjust the bass by pressing the button to extend the control and turning it to the left (less bass) or to the right (more
bass). A "detent" indicates "equalized" bass. Press the button back in when you have made the adjustment.
Treble
Adjust the treble by pressing the button to extend the control and turning it to the left (less treble), or to the right (more
treble). A "detent" indicates "equalized" treble. Press the button back in when you have made the adjustment.
Fader - Balance front/rear
Adjust front/rear speaker balance by pressing the button to extend the control and turning it to the left (more sound
from the rear speakers) or to the right (more sound from the front speakers). A "detent" indicates "equalized" balance.
Press the button back in when you have made the adjustment.
Balance right/left
Adjust left/right speaker balance by pressing the button to extend the control, and turning it to the left (more sound
from the left speakers) or to the right (more sound from the right speakers). A "detent" indicates "equalized" balance.
Press the button back in when you have made the adjustment.
MID EQ level