JL Audio J2320.4 User Manual
Page 5

8
JL Audio
9
“bass boost” Controls
Each channel pair of the J2-320.4 includes a
single band, boost-only bass equalizer controlled 
by a rotary knob marked “Bass Boost”. 
This control has a boost range of 0dB (full-
counterclockwise) to +12dB (full-clockwise) and 
is centered at 45 Hz. 
HP | Off | LP
Filter Mode
High-Pass
Low-Pass
Filter Frequency (Hz)
Filter Frequency (Hz)
Input Sens.
Input Sens.
CH 3&4
Input From
min max
min max
60
1.2k
High-Pass
60
1.2k
40
150
Low-Pass
40
150
Off +12dB
High-Level Inputs
High-Level Inputs
Bass Boost
HP | Off | LP
Filter Mode
1&2 | 3&4
Off +12dB
Bass Boost
Channel 3 & 4 Controls
CH 1 (Left)
CH 3 (Left)
Protect
Channel 1 & 2 Controls
Power
CH 2 (Right)
LEFT
RIGHT
CH 4 (Right)
Pre-Outs
Amplifier Inputs
Pre-outs
The J2-320.4 incorporates a pass-through
preamp output section, so that additional 
amplifiers can be easily added to the system. 
This pass-through pre-amp output delivers a 
summed stereo signal , combining the Ch 1 and 3 
signals into a Left Preamp Output Signal and the 
Ch. 2 and 4 signals into a Right Channel Preamp 
Output signal.
HP | Off | LP
Filter Mode
High-Pass
Low-Pass
Filter Frequency (Hz)
Filter Frequency (Hz)
Input Sens.
Input Sens.
CH 3&4
Input From
min max
min max
60
1.2k
High-Pass
60
1.2k
40
150
Low-Pass
40
150
Off +12dB
High-Level Inputs
High-Level Inputs
Bass Boost
HP | Off | LP
Filter Mode
1&2 | 3&4
Off +12dB
Bass Boost
Channel 3 & 4 Controls
CH 1 (Left)
CH 3 (Left)
Protect
Channel 1 & 2 Controls
Power
CH 2 (Right)
LEFT
RIGHT
CH 4 (Right)
Pre-Outs
Amplifier Inputs
The preamp output signal is not affected by the
“Bass Boost” processing selected for the amplifier 
or by any crossover filter selected (if the input 
signal is full-range, the preamp output will be 
full-range). 
Note: The signal level of the “Preamp Output” is 
always line-level (low voltage).
sPeaker outPuts
The J2-320.4’s speaker outputs are designed to
accept 16 AWG - 8 AWG wire.
Each pair of the J2-320.4’s channels are
designed to deliver power into speaker loads equal 
to or greater than 2 ohms per channel when using 
a “stereo” configuration and speaker loads equal 
to or greater than 4 ohms per bridged pair of 
channels when using a “bridged” configuration.
HP | Off | LP
Filter Mode
High-Pass
Low-Pass
Filter Frequency (Hz)
Filter Frequency (Hz)
Input Sens.
Input Sens.
CH 3&4
Input From
min max
min max
60
1.2k
High-Pass
60
1.2k
40
150
Low-Pass
40
150
Off +12dB
High-Level Inputs
High-Level Inputs
Bass Boost
HP | Off | LP
Filter Mode
1&2 | 3&4
Off +12dB
Bass Boost
Channel 3 & 4 Controls
CH 1 (Left)
CH 3 (Left)
Protect
Channel 1 & 2 Controls
Power
CH 2 (Right)
LEFT
RIGHT
CH 4 (Right)
Pre-Outs
Amplifier Inputs
Speaker loads below 2 ohms nominal per
channel are not recommended and may cause
the amplifier to initiate a protection mode.
Filter Controls
The active filter built into each channel
section of the J2-320.4 can be used to eliminate 
potentially harmful and/or undesired frequencies 
from making their way through the amplifier 
sections to the speaker(s). This serves to improve 
tonal balance and to avoid distortion and possible 
speaker failure. Correct use of these filters can 
substantially increase the longevity and fidelity 
of your audio system.
HP | Off | LP
Filter Mode
High-Pass
Low-Pass
Filter Frequency (Hz)
Filter Frequency (Hz)
Input Sens.
Input Sens.
CH 3&4
Input From
min max
min max
60
1.2k
High-Pass
60
1.2k
40
150
Low-Pass
40
150
Off +12dB
High-Level Inputs
High-Level Inputs
Bass Boost
HP | Off | LP
Filter Mode
1&2 | 3&4
Off +12dB
Bass Boost
Channel 3 & 4 Controls
CH 1 (Left)
CH 3 (Left)
Protect
Channel 1 & 2 Controls
Power
CH 2 (Right)
LEFT
RIGHT
CH 4 (Right)
Pre-Outs
Amplifier Inputs
1) “Filter Mode” Control: The J2-320.4 employs a
12dB per octave filter for each pair of channels 
(one filter for channels 1&2 and another filter 
for channels 3&4). Each of these filters can 
be configured independently into one of two 
filter types or defeated completely by way of the 
three-position “Filter Mode” switches:
“HP” (High-Pass): Configures the filter to
attenuate frequencies below the selected filter 
frequency at a rate of 12dB per octave. This is 
useful for connection of component speakers 
to one or both of the J2-320.4’s channel pairs in 
a bi-amplified system.
Off”: Defeats the filter completely, allowing
the full range of frequencies present at the 
inputs to feed the amplifier. This is useful 
for systems utilizing outboard crossovers or 
requiring full-range reproduction from one or 
both of the J2-320.4’s channel pairs. 
“LP” (Low-Pass): Configures the filter to
attenuate frequencies above the selected filter 
frequency at a rate of 12dB per octave. This is 
useful for connection of subwoofer(s) to one 
or both of the J2-320.4’s channel pairs in a 
bi-amplified system. 
2) “Filter Freq. (Hz)” The J2-320.4 has separate
Filter Frequency controls in each Channel 
Controls section for the low-pass filter and the 
high-pass filter. You will only use one of these 
in each channel section, depending on which 
“Filter Mode” you have selected (or none of 
them if you have selected the “Off” position for 
the “Filter Mode”).
The High-Pass filters in the J2-320.4 are fully 
variable between 60 Hz and 1.2 kHz (1200 Hz) via 
the control knobs labeled “High-Pass”. The “8 
o’clock” position corresponds to 80 Hz and is a 
good starting point for system tuning.
The Low-Pass filters in the J2-320.4 are fully 
variable between 40 Hz and 150 Hz via the 
control knobs labeled “High-Pass”. The “12 
o’clock” position corresponds to 80 Hz and is a 
good starting point for system tuning.
