GMC 2007 Savana Van Owner's Manual page 194

Setting the Tone (Bass/Treble)
AUDIO: To adjust the bass or the treble, press
and release the AUDIO button until BAS (bass) or
TRE (treble) appears on the display. Then
press and hold the up or the down arrow to
increase or to decrease. If a station is weak or
has static, decrease the treble.
To adjust bass or treble to the middle position,
select BAS or TRE. Then press and hold the
AUDIO button for more than two seconds until you
hear a beep. B and a zero or T and a zero
appears on the display.
To adjust both tone controls and both speaker
controls to the middle position, first end out
of audio mode by pressing another button, causing
the radio to perform that function, or by waiting
five seconds for the display to return to the time of
day. Then press and hold the AUDIO button for
more than two seconds until you hear a beep.
CEN (center) appears on the display.
194
Adjusting the Speakers (Balance/Fade)
AUDIO: To adjust the balance between the right
and the left speakers, press and release the AUDIO
button until BAL (balance) appears on the display.
Then press and hold the up or the down arrow to
move the sound toward the right or the left
speakers.
To adjust the fade between the front and the rear
speakers, press and release the AUDIO button until
FAD (fade) appears on the display. Then press and
hold the up or the down arrow to move the sound
toward the front or the rear speakers.
The fade feature may not be available on all radio
systems.
To adjust balance or fade to the middle position,
select BAL or FAD. Then press and hold AUDIO for
more than two seconds until you hear a beep. B and
a zero or F and a zero appears on the display.
To adjust both tone controls and both speaker
controls to the middle position, first end out of audio
mode by pressing another button, causing the radio
to perform that function, or by waiting five seconds
for the display to return to the time of day. Then
press and hold the AUDIO button for more than
two seconds until you hear a beep. CEN appears on
the display.