read the manual, it maybe the key...
http://www.pioneerelectronics.com/StaticFiles/PUSA/Files/DEHP4000UBOperationManual1019.pdf
SW SETTING 1 (subwoofer on/off setting)—
SW SETTING 2 (subwoofer setting)—
HIGH PASS FILTER (high pass filter)—
BASS BOOST (bass boost)—SRC LV ADJUST
Using subwoofer output
This unit is equipped with a subwoofer output
which can be turned on or off.
Also, phase can be selected between normal
and reverse.
1 Press SW to display the subwoofer setting
mode.
Press SW repeatedly to switch between the
subwoofer setting modes in the following
order.
SW SETTING 1 (subwoofer on/off setting) setting
mode—SW SETTING 2 (subwoofer setting)
setting mode
2 Select SW SETTING 1 setting mode.
3 Turn MULTI-CONTROL to select the desired
setting.
NORMAL (normal phase)—REV (reverse
phase)—OFF (subwoofer off)
# You can also perform the same operations by
pushing MULTI-CONTROL up or down.
Note
You can also switch to this setting mode in the
menu that appears by using MULTI-CONTROL.
Adjusting subwoofer settings
When the subwoofer output is on, you can adjust
the cut-off frequency and the output level
of the subwoofer.
! When the subwoofer output is on, you can
select SW SETTING 2.
1 Press SW to display the subwoofer setting
mode.
Press SW repeatedly to switch between the
subwoofer setting modes in the following
order.
SW SETTING 1 (subwoofer on/off setting) setting
mode—SW SETTING 2 (subwoofer setting)
setting mode
2 Select SW SETTING 2 setting mode.
3 Press MULTI-CONTROL to select the segment
you wish to set.
Press MULTI-CONTROL repeatedly to switch
the segment in the following order:
Cut off frequency—Level
Audio Adjustments
4 Turn MULTI-CONTROL to adjust the selected
segement.
Cut off frequency
50HZ—63HZ—80HZ—100HZ—125HZ
Level
+6 to –24 is displayed as the level is increased
or decreased.
# You can also perform the same operations by
pushing MULTI-CONTROL up or down.
Note
You can also switch to this setting mode in the
menu that appears by using
MULTI-CONTROL.
Using the high pass filter
When you do not want low sounds from the
subwoofer output frequency range to play
from the front or rear speakers, turn on the
HPF (high pass filter). Only frequencies higher
than those in the selected range are output
from the front or rear speakers.
1 Use MULTI-CONTROL to select
HIGH PASS FILTER.
2 Press MULTI-CONTROL to display the
setting mode.
3 Use MULTI-CONTROL to select the desired
setting.
Turn to change the setting.
OFF—50HZ—63HZ—80HZ—100HZ—125HZ
# You can also perform the same operations by
pushing MULTI-CONTROL up or down.
Boosting the bass
Bass boost function boosts the bass level of
sound.
1 Press and hold BASS to display
BASS BOOST setting mode.
2 Turn MULTI-CONTROL to adjust the
level.
0 to +6 is displayed as the level is increased or
decreased.
# You can also perform the same operations by
pushing MULTI-CONTROL up or down.
Note
You can also switch to this setting mode in the
menu that appears by using
MULTI-CONTROL.
Adjusting source levels
SLA (source level adjustment) lets you adjust
the volume level of each source to prevent radical
changes in volume when switching between
sources.
! Settings are based on the FM volume level,
which remains unchanged.
1 Compare the FM volume level with the
level of the source you wish to adjust.
2 Use MULTI-CONTROL to select
SRC LV ADJUST.
3 Press MULTI-CONTROL to display the
setting mode.
4 Turn MULTI-CONTROL to adjust the
source volume.
+4 to –4 is displayed as the source volume is
increased or decreased.
# You can also perform the same operations by
pushing MULTI-CONTROL up or down.
Notes
! The AM volume level can also be adjusted
with source level adjustments.
! The built-in CD player and the multi-CD player
are set to the same source level adjustment
volume automatically.
! External unit 1 and external unit 2 are set to
the same source level adjustment volume
automatically.
Audio Adjustments