GMC 2007 Envoy Denali Owner's Manual page 245

The CD player can play the smaller 3 inch (8 cm)
single CDs with an adapter ring. Full-size CDs
and the smaller CDs are loaded in the same
manner.
If playing a CD-R, the sound quality may be
reduced due to CD-R quality, the method of
recording, the quality of the music that has been
recorded, and the way the CD-R has been
handled. There may be an increase in skipping,
difficulty in finding tracks, and/or difficulty in loading
and ejecting. If these problems occur, check the
bottom surface of the CD. If the surface of the CD
is damaged, such as cracked, broken, or
scratched, the CD will not play properly. If the
surface of the CD is soiled, see Care of Your CDs
and DVDs on page 299 for more information.
If there is no apparent damage, try a known
good CD.
Do not add any label to a CD, it could get caught
in the CD player. If a CD is recorded on a
personal computer and a description label is
needed, try labeling the top of the recorded CD
with a marking pen.
Notice: If you add any label to a CD, insert
more than one CD into the slot at a time, or
attempt to play scratched or damaged CDs, you
could damage the CD player. When using the
CD player, use only CDs in good condition
without any label, load one CD at a time, and
keep the CD player and the loading slot free of
foreign materials, liquids, and debris.
If an error appears on the display, see "CD
Messages" later in this section.
1 PREV (Previous): Press this pushbutton to go
to the beginning of the current track (if more
than eight seconds have played), or to the
beginning of the previous track (if less than
eight seconds have played). TRACK and the track
number displays. If this pushbutton is held or
pressed more than once, the player continues
moving backward through the CD.
2 NEXT: Press this pushbutton to go to the next
track. TRACK and the track number displays.
If this pushbutton is held or pressed more
than once, the player continues moving forward
through the CD.
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