JL Audio G4500 Car Amplifier User Manual


 
D) Front to Rear HF Fading and Subwoofer
Level Control:
R e q u i r e d : a source unit or processor with
front and rear pairs of stereo outputs plus a
dedicated subwoofer output.
Inp ut Connections: one stereo pair of source unit
outputs is connected to the CH 1 (Left) and
CH 2 (Right) inputs of the G4500.
The second stereo pair of source unit
outputs is connected to the CH 3 (Left)
and CH 4 (Right) inputs of the G4500
(select Discrete on the CH 3&4 Input
From switch). The source unit’s dedicated
subwoofer output is connected to the
subwoofer amplifier inputs.
R e s u l t : 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 subwoofer amplifier’s “Input Sens.”
with the source unit’s subwoofer level control
set at 3/4 of full output.
Crossover Setup for Bi-Amplified System with
one G4500 and a separate subwoofer amplifier:
Once the input and preamp output sections
have been configured appropriately, go to the
Channel 1 & 2 Controls and Channel 3 &
4 Controls You will set both control sections
identically to start:
Select HP (high-pass) on the Filter Mode
switch and an appropriate Filter Freq. (80 Hz is
a good starting point). Make these adjustments to
both control sections.
After proper adjustment of the G4500’s
Input Sens. controls, and the subwoofer
amplifier’s input sensitivity controls, you can fine
tune filter frequencies and attenuate either pair
of channels to achieve proper balance. For proper
adjustment of the Input Sens. controls of the
G4500 use the method shown in Appendix A
(page 14). For precise filter frequency information
for the G4500 refer to Appendix B (page 15).
Refer to the subwoofer owner’s manual for
proper adjustments.
Next, turn your attention to the Channel 1 &
2 Controls and select HP (high-pass) on the
Filter Mode switch and an appropriate Filter
Freq. (again, 80 Hz is a good starting point).
After proper adjustment of the “Input Sens.
controls for both channel pairs using the method
shown in Appendix A (page 14), you can fine
tune filter frequencies and attenuate either pair
of channels to achieve proper balance. For precise
filter frequency information refer to Appendix B
(page 15).
Bi-Amplified System with one G4500 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 amplifiers have this feature.
In this configuration, channels 1&2 of the G4500
will drive front component speakerswith high-
pass filtering. Channels 3&4 will drive
rear component speakers in stereo, also with
high-pass filtering. The separate amplifier
will drive the subwoofer system with low-pass
filtering (80 Hz is a good starting point).
Input connection options for a bi-amplified
system with one G4500 and a separate subwoofer
amplifier are as follows:
A) No User Adjustability:
R e q u i r e d : a basic source unit or processor with
one pair of stereo outputs.
Inp ut Connections: a single pair of stereo source
unit outputs is connected to the “CH 1 (Left)
and “CH 2 (Right)” inputs of the G4500 (select
1&2” on the “CH 3&4 Input From” switch).
Connect the subwoofer amplifier inputs to
the preamp outputs of the G4500 (Select
1&2” on the “Pre-Outs Input From” switch.
Alternatively, the G4500 can receive its input
from the subwoofer amplifier’s preamp output
set to “full-range” mode (if applicable).
R e s u l t : the relative level of the LF and front
and rear HF channels will be fixed by the
G4500’s “Input Sens.” settings (as well as the
subwoofer amplifier’s settings) and will not be
user adjustable from the front of the vehicle.
B) Fade Subwoofer Level vs. HF Level:
R e q u i r e d : 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 (Left)” and
CH 2 (Right)” inputs of the G4500 (select
1&2” on the “CH 3&4 Input From” switch).
The second stereo pair of source unit outputs
is connected to the subwoofer amplifier
inputs.
R e s u l t : 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 G4500’s
Input Sens.” settings and will not be user
adjustable from the front of the vehicle.
C) Subwoofer Level Control Only:
Req uired: a source unit or processor with left,
right and dedicated subwoofer outputs.
Inp ut Connections: The main stereo pair
of source unit outputs is connected to the
CH 1 (Left) and CH 2 (Right) inputs
of the G4500 (select 1&2 on the CH 3&4
Input From switch). The source unit’s
dedicated subwoofer output is connected to
the subwoofer amplifier inputs.
R e s u l t : 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 subwoofer amplifier’s “Input Sens.”
with the source unit’s subwoofer level control
set at 3/4 of full output.
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