Crossover Setup for Bi-Amplified System with one
450/4 and a separate subwoofer amplifier:
Once the input and preamp output sections have
been configured appropriately, go to the
“CH 1&2
Filter Section”.
Select
“x1”
on the
“Freq. Range”
switch,
“HP”
(high-pass) on the
“Filter Type”
switch
and
“12dB”
or
“24dB”
on the
“Filter Mode/Slope”
switch and an appropriate
“Filter Freq.”
(80-90 Hz
is a good starting point). The
“Infrasonic Filter”
and
“Bass EQ”
features cannot be used in this mode.
Next, turn your attention to the
“CH 3&4 Input
Section”
and select
“x1”
on the
“Freq. Range”
switch,
“HP”
(high-pass) on the
“Filter Type”
switch
and
“12dB”
or
“24dB”
on the
“Filter Mode/Slope”
switch and an appropriate
“Filter Freq.”
(again, 80-
90 Hz is a good starting point).
After proper adjustment of the 450/4’s CH
1&2 and CH 3&4, and the subwoofer amplifier’s
“Input Range”
and
“Input Sens.”
, you can fine
tune filter frequencies and slopes and attenuate
either pair of channels to achieve proper balance.
For proper adjustment of the
“Input Sens.”
controls of the 450/4 use the method shown in
Appendix B (page 20). For precise filter frequency
information for the 450/4 refer to Appendix A
(page 20). Refer to the subwoofer amplifier
owner’s manual for proper adjustments.
BI-AMPLIFIED 3.1 SYSTEM WITH ONE 450/4 IN
THREE-CHANNEL MODE AND A SEPARATE
SUBWOOFER AMPLIFIER
This configuration requires a separate subwoofer
amplifier with a built-in low-pass filter. All JL Audio
subwoofer amplifiers have this feature.
The separate amplifier will drive the subwoofer
system with low-pass filtering (select a filter
frequency of 80-90 Hz to start).The inputs of the
subwoofer amplifier will be connected to the
preamp outputs of the 450/4 or to the source unit
or multi-channel processor directly.
In this configuration, CH 1&2 of the 450/4 will
drive front-left and front-right component speakers
(stereo 150W x 2) with high-pass filtering. CH 3&4
will be bridged mono to drive a center-front
component speaker system (150W x 1) with
high-pass filtering. All three channels will have
equal power at 3 – 4
Ω
.
Input connection options for bi-amplified 3.1 system
with one 450/4 and a separate subwoofer amplifier:
A) Real Left-Center-Right Channels and
Subwoofer with Multi-Channel Source
Required:
a multi-channel processor or source unit
(Dolby Digital
®
, Dolby ProLogic II
®
, dts
®
, etc.) with
center channel output.
Input Connections:
the left-front and right-front
source unit outputs are connected to the CH 1&2
inputs of the 450/4 and the front-center channel
output of the source unit or processor is connected
to the CH 3&4 inputs of the 450/4 (select
“4ch”
on
the
“Input Mode”
switch in the
“CH 1&2 Input
Section”
). Use a “Y-adaptor” to feed both RCA jacks
on the amplifier from the single signal cable. Most
multi-channel processors and source units are also
equipped with a dedicated subwoofer output and
subwoofer level control. Connect this subwoofer
output directly to the subwoofer amplifier’s inputs.
The 450/4’s preamp outputs are not used.
JL AUDIO
450/4
15
outputs is connected to the CH 1&2 inputs of the
450/4 (select
“2ch”
on the
“Input Mode”
switch in
the
“CH 1&2 Input Section”
).The second stereo
pair of source unit outputs is connected to the
subwoofer amplifier inputs. In this mode, the 450/4’s
preamp output is not used.
Result:
with this option, the user has the ability to
fade the level of the subwoofer amplifier’s input
relative to the HF channels, but cannot control
front-to-rear fading of the HF channels.The relative
level of the front and rear HF channels will be fixed
by the 450/4’s
“Input Sens.”
settings and will not be
user adjustable from the front of the vehicle.
C) Fade HF Front to Rear with Non-Fading
Subwoofer Level
Required:
a source unit or processor with front and
rear pairs of stereo outputs.
Input Connections:
one stereo pair of source unit
outputs is connected to the CH 1&2 inputs of the
450/4 (select
“4ch”
on the
“Input Mode”
switch in
the
“CH 1&2 Input Section”
).The second stereo
pair of source unit outputs is connected to the CH
3&4 inputs of the 450/4. Connect the subwoofer
amplifier inputs to the preamp outputs of the 450/4
(Select
“ALL”
on the
“Signal From”
switch in the
“Preamp Output Section”
).
Result:
with this option, the user has the ability to
fade the HF signals from front-to-rear without
fading the signal to the subwoofer amplifier.
D) Subwoofer Level Control Only
Required:
a source unit or processor with left, right
and dedicated subwoofer outputs.
Input Connections:
The main stereo pair of source
unit outputs is connected to the CH 1&2 inputs of
the 450/4 (select
“2ch”
on the
“Input Mode”
switch in the
“CH 1&2 Input Section”
).The source
unit’s dedicated subwoofer output is connected to
the subwoofer amplifier inputs. In this mode, the
450/4’s preamp output is not used.
14
JL AUDIO
450/4
Result:
with this option, the user has the ability to
control the absolute level of the subwoofer channel
relative to the HF channels, but cannot fade the
front and rear HF channels relative to each other.
Set the CH 1&2
“Input Sens.”
with the source
unit’s subwoofer level control set at 3/4 of full
output. See Appendix B (page 20) for details.
E) Front to Rear HF Fading and
Subwoofer Level Control
Required:
a source unit or processor with front and
rear pairs of stereo outputs plus a dedicated
subwoofer output.
Input Connections:
one stereo pair (front, typically)
of source unit outputs is connected to the CH 1&2
inputs of the 450/4. The second stereo pair of
source unit outputs (rear, typically) is connected to
the CH 3&4 inputs of the 450/4 (select
“4ch”
on
the
“Input Mode”
switch in the
“CH 1&2 Input
Section”
).The source unit’s dedicated subwoofer
output is connected to the subwoofer amplifier
inputs. In this mode, the 450/4’s preamp output is
not used.
Result:
with this option, the user has the ability to
fade the front and rear HF channels relative to each
other and also has the ability to control the
absolute level of the subwoofer channel relative to
the HF channels.
Set the CH 1&2
“Input Sens.”
with the source
unit’s subwoofer level control set at 3/4 of full
output. See Appendix B (page 20) for details.
I M P O RTA N T
!
I M P O RTA N T
!
