Chevrolet 1998 Tracker Owner's Manual page 136

Setting the Tone
BASS: Press this knob lightly so it extends. Turn me
knob to the right to increase bass and to the left to
decrease bass.
Adjusting the Speakers
BAL: Press this knob lightly so it extends. Then pull the
knob all the way out. Turn the knob to the right for the
right speakers and to the left for the left speakers. The
middle position balances the sound between the speakers.
FADE: Press this knob lightly so it extends. Then pull
the knob all the way out. Turn the knob to the right to
adjust the sound to the rear speakers and to the left for
the front speakers. The middle position balances the
sound between the speakers.
Push these knobs back into their stored positions when
you're not using them.
TREB: Press this knob lightly so it extends. Turn the
knob to the right to increase treble and to the left to
decrease treble. If a station is weak or noisy, you may
want to decrease the treble.
Push these knobs back into their stored positions when
you're not using them.
TONE: Press this button to choose preset bass and
treble equalization settings designed for ROCK, NEWS,
POP, JAZZ and CLASSIC. ROCK will appear when
you first press TONE. Each time you press it, another
setting will appear on the display. If you press it one
more time, after CLASSIC appears on the display, tone
control will be back to the BASS and TREB knobs.