Fujitsu ECLIPSE CD8443 Owner's Manual page 72

How to operate the Sound Adjustment Mode
MP3 HARMONIZER
When original sounds are converted to MP3 format, frequency
ranges that are not normally audible to the human ear are
compressed. The MP3 harmonizer can be used to play back
these compressed sounds at as close to their original form as
possible so that clear and powerful sound can be enjoyed.
NON-FADER PHASE
The sounds that are output from woofers include sounds that
are in the same frequency ranges that are output from the front
and rear speakers, and under the various conditions that can
occur inside vehicle compartments, some of these sounds may
cancel each other out. This phenomenon can be eliminated by
changing the phase of the woofer.
The phase of the woofer can be set to normal timing (in which
the output timing between the front and rear speakers and the
woofer is the same) or reverse timing (in which the output
timing between the front and rear speakers and the woofer is
different), depending on the vehicle compartment conditions.
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