JL Audio Slash 450/4 User Manual page 10

TRI-AMPLIFIED SYSTEMS
Tri-amplified systems are defined as systems in
which separate amplifier channels drive low-
frequency (LF), mid-frequency (MF) and high-
frequency (HF) speakers and are separately filtered
to send appropriate frequency ranges to each
speaker system.
The most common application of tri-amplification
in mobile audio is to drive a subwoofer system from
one or more amplifiers or channels (LF channels),
mid-range speakers from a separate amplifier or set
of channels (MF channels) and high-frequency
speakers from a separate amplifier or set of channels
(HF channels). One such configuration is to run
subwoofers off the LF channel(s), mid-bass speakers
off the MF channels, and a passively crossed over
mid/high frequency component speaker systems on
the HF channels. Another approach is to run
subwoofers off the LF channel(s), mid-woofers off
the MF channels and tweeters off the HF channels
(all actively crossed over).
By activating the CH 1&2 bandpass filter feature,
the 450/4 can easily be configured to drive a tri-
amplified system in conjunction with a separate
subwoofer amplifier that includes a low-pass filter.
CH 3&4 of the 450/1 will drive the HF speakers
(75W x 2), CH 1&2 will drive the MF speakers
(150W x 2) and the separate subwoofer amp(s)
will drive the LF speakers (subwoofers).
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Input connection options for the Tri-Amplified Stereo
mode are as follows:
A) No User Adjustability
Required: a basic source unit or processor with left
and right stereo outputs.
Input Connections: a single pair of stereo 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"). Subwoofer
amplifier inputs are connected to the preamp
outputs of the 450/4 (Select "1&2" on the "Signal
From" switch in the "Preamp Output Section").
Result: the relative level of all channels will be fixed
by the 450/4's "Input Sens. " settings and will not be
user adjustable from the front of the vehicle.
B) Fade Subwoofer Level vs. MF/HF Level
Required: a source unit or processor with front and
rear pairs of outputs is required.
Input Connections: one 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") and 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: the user has the ability to adjust the level of
the subwoofer channel relative to the mid and high-
frequency 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
Required: a source unit or processor with left, right
and dedicated subwoofer outputs is required.
Input Connections: one 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") and the source unit's
dedicated subwoofer output is connected to the
JL AUDIO 450/4
subwoofer amplifier inputs. In this mode, the 450/4's
preamp output is not used.
Result: the user has the ability to control the
absolute level of the subwoofer channel relative to
the MF and HF channels.
!
I M P O RTA N T
Set the subwoofer amplifier's "Input Sens. " with
the source unit's subwoofer level control set at 3/4
of full output. Refer to the subwoofer amplifier
owner's manual for proper adjustment.
Crossover setup for tri-amplified 3.1 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" of the 450/4. These settings will
determine the high-pass cutoff and slope of the
bandpass filtering applied to the MF (mid-frequency)
channels. Select "x1" on the "Freq. Range" switch,
"BP" (bandpass) 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". These settings will determine the high-pass
cutoff and slope of the high pass filtering applied to
the HF (high-frequency) channels as well as the low-
pass cutoff frequency and slope for the MF channels'
bandpass filter. Select "x1" on the "Freq. Range"
switch if your desired MF to HF crossover frequency
is below 500 Hz. Select "x10" on the "Freq. Range"
switch if your desired MF to HF crossover frequency
is above 500 Hz. Select "HP" (high-pass) on the
"Filter Type" switch and "12dB" or "24dB" on the
"Filter Mode/Slope" switch and an appropriate
"Filter Freq. "
JL AUDIO 450/4
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
the LF, MF and HF channel pair or with the
"Input Sens. " controls 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.
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