GMC 2006 Sierra - Manual (Page 256)

Setting the Tone (Bass/Treble)
AUDIO: Push and release the AUDIO knob until BASS
or TREB appears on the display. Turn the knob to
increase or to decrease. The display will show the bass
or treble level. If a station is weak or noisy, decrease
the treble.
To adjust the bass or treble to the middle position, while it
is displayed, push and hold the AUDIO knob. The radio
will produce one beep and adjust the display level to the
middle position.
To adjust all tone and speaker controls to the middle
position, push and hold the AUDIO knob when no tone or
speaker control is displayed. ALL CENTERED will appear
on the display, you will hear a beep, and the display level
will be adjusted to the middle position.
AUTO EQ (Automatic Equalization): Press this button
to select customized equalization settings designed
for country/western, jazz, talk, pop, rock, and classical.
Selecting CUSTOM or changing bass or treble,
returns the EQ to the manual bass and treble settings.
The radio will save separate AUTO EQ settings for
each preset and source.
If the radio is equipped with the Bose ® audio system,
the equalization settings are either CUSTOM or TALK.
Adjusting the Speakers (Balance/Fade)
AUDIO: To adjust the balance between the right
and the left speakers, push and release the AUDIO
knob until BAL appears on the display. Turn the knob to
move the sound toward the right or the left speakers.
To adjust the fade between the front and the rear
speakers, push and release the AUDIO knob until FADE
appears on the display. Turn the knob to move the sound
toward the front or the rear speakers.
To adjust the balance or fade to the middle position,
while it is displayed, push the AUDIO knob, then push it
again and hold it until the radio produces one beep. The
balance or fade will be adjusted to the middle position
and the display will show the speaker balance.
To adjust all tone and speaker controls to the middle
position, push and hold the AUDIO knob when no tone or
speaker control is displayed. ALL CENTERED will appear
on the display, you will hear a beep, and the display level
will be adjusted to the middle position.
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