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sYstem ConFigurations
The 450/4v2 is a very flexible amplifier, well-
suited for a multitude of system configurations.
In this section, the most likely configurations are
explained in detail.
Once you have selected your desired
configuration, you can use the amplifier panel
drawings on the bottom of the following
pages to mark the required switch positions for
easy reference.
bi-amPliFied sYstems
Bi-amplified systems are defined as systems
in which separate amplifier channels drive low-
frequency (LF) and high-frequency (HF) speakers
and are separately filtered to send appropriate
frequency ranges to each speaker system.
The most common application of bi-
amplification in mobile audio is to drive a
subwoofer system from one or more amplifiers or
channels and component speakers from separate
amplifiers or channels.
The 450/4v2 can be configured to drive a
bi-amplified system by itself or with a separate
subwoofer amplifier.
bi-amplified system with one 450/4v2
In this configuration, CH 1&2 of the 450/4v2
will drive subwoofers (stereo 150W x 2 or bridged
300W x 1) with low-pass filtering. CH 3&4 will
drive component speakers in stereo (75W x 2)
with high-pass filtering.
Input connection options for a bi-amplified system
with one 450/4v2 are as follows:
A) No User Adjustability
Req uired: a basic source unit or processor with
left and right stereo outputs.
Inp ut Connections: a single pair of stereo source
unit outputs connected to the CH 1&2 inputs of
the 450/4v2 (select "2ch" on the "Input Mode"
switch in the "CH 1&2 Input Section").
Res ult: the relative level of the LF and HF
channels will be fixed by the 450/4v2's "Input
Sens." settings and will not be user adjustable
from the front of the vehicle.
14 | JL Audio - 450/4
Owner's Manual
v2
B) Fade Subwoofer Level vs. HF Level
Req uired: a source unit or processor with front
and rear pairs of outputs.
Inp ut Connections: the first stereo pair of source
unit outputs is connected to the CH 1&2
inputs of the 450/4v2. The second stereo pair
of source unit outputs is connected to the CH
3&4 inputs (select "4ch" on the "Input Mode"
switch in the "CH 1&2 Input Section").
Res ult: in this mode, the user has the ability to
fade or control the level of the LF channels
relative to the HF channels via the source
unit's fader control without exceeding the
maximum clean output level set by each
amplifier section's "Input Sens." controls.
C) Subwoofer Level Control Only
Req uired: a source unit or processor with left,
right and subwoofer outputs.
Inp ut Connections: the main stereo pair of source
unit outputs is connected to the CH 3&4 inputs
of the 450/4v2. The source unit's dedicated
subwoofer output is connected to the CH
1&2 inputs (select "4ch" on the "Input Mode"
switch in the "CH 1&2 Input Section").
Res ult: in this mode, the user has the ability to
control the absolute level of the LF channels
relative to the HF channels.
!
IMPORTANT
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 22) for details.
Crossover Setup for Bi-Amplified System
with one 450/4v2:
Once the input sections have been
configured appropriately, go to the "CH 1&2
Filter Section". Select "x1" on the "Freq.
Range" switch, "LP" (low-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). You may also choose to activate the
"Infrasonic Filter" and/or "Bass EQ" features
in the "CH 1&2 Bass Control" section. Please
keep in mind that activation of the "Bass EQ"
may require lowering the CH 1&2 "Input
Sens." to maintain clean maximum output.
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 CH
1&2 and CH 3&4 "Input Range" and
"Input Sens." controls using the method
shown in Appendix B (page 22), you can
fine tune filter frequencies and slopes and
attenuate either pair of channels to achieve
proper balance. For precise filter frequency
information refer to Appendix A (page 22).
bi-amplified system with one
450/4v2 in four-channel mode and
a separate subwoofer amplifier
This configuration requires that
the separate subwoofer amplifier has
a built-in low-pass filter. All JL Audio
subwoofer amplifiers have this feature.
In this configuration, CH 1&2 of the 450/4v2
will drive front component speakers (stereo 150W
x 2) with high-pass filtering. CH 3&4 will drive
rear component speakers in stereo (75W x 2) with
high-pass filtering.
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 may or may not be connected
to the preamp outputs of the 450/4v2, depending
on which connection option you choose.
Input connection options for a bi-amplifier
system with one 450/4v2 and a separate subwoofer
amplifier are as follows:
A) No User Adjustability
Req uired: a basic source unit or processor with
left and right stereo outputs.
Inp ut Connections: a single pair of stereo source
unit outputs is connected to the CH 1&2
inputs of the 450/4v2 (select "2ch" on the
"Input Mode" switch in the "CH 1&2 Input
Section"). Connect the subwoofer amplifier
inputs to the preamp outputs of the 450/4v2
(Select "1&2" on the "Signal From" switch in
the "Preamp Output Section").
Res ult: the relative level of the LF and front and
rear HF channels will be fixed by the 450/4v2's
"Input Sens." settings and will not be user
adjustable from the front of the vehicle.
B) Fade Subwoofer Level vs. HF Level
Req uired: a source unit or processor with front
and rear pairs of stereo outputs.
Inp ut Connections: one stereo pair of source
unit outputs is connected to the CH 1&2
inputs of the 450/4v2 (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 450/4v2's
preamp output is not used.
Res ult: 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 450/4v2's
"Input Sens." settings and will not be user
adjustable from the front of the vehicle.
15
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