Eclipse CD8455 Owner's Manual page 124

How to operate the Sound Adjustment Mode
● A low-pass filter (LPF) is a filter that cuts out frequencies that are
higher than the specified frequency (treble range) and allows
lower frequencies (bass range) to pass through.
● The slope is the signal level at which frequencies that are one
octave higher or one octave lower are dampened.
The larger the slope value, the greater the slope. In addition,
when "PASS" is selected, the slope is eliminated (sound does not
pass through the filters), so that the crossover function has no
effect.
When this deck is in normal mode, it corresponds to basic speaker
systems which comprise front speakers, rear speakers, and
subwoofer. In such cases, the crossover can be used to apply the
HPF to the front and rear speakers and the LPF to the sub-woofer
so that the sound from all speakers merges properly.
In addition to the 4 speaker system, in pro mode, the adjustments
can be made to suit speaker system where the front speaker, rear
speaker and non-fader output can be switched between Hi, Mid or
Low output and the speakers can be combined according to each
range (treble range: tweeter, mid range: mid, bass range: woofer) to
provide 3-way playback. In this case, the crossover function can be
used to adjust the playback ranges so that the HPF is applied to the
treble-range speakers, the HPF and LPF is applied to the Mid-range
speakers, and the LPF is applied to the bass-range speakers so
that the sound from all speakers merges properly.
Bass range
(woofers)
20Hz
Mid range (Front and rear speakers)
fc(LPF/HPF)
63-200Hz
124
20kHz