JL Audio 450/4v2 Owners Manual

OWNER’S MANUAL

four-channel system amplifier

Thank you for purchasing a JL Audio amplifier for

your automotive sound system.

Your amplifier has been designed and manufactured to exacting

standards in order to ensure years of musical enjoyment in your vehicle.

For maximum performance and extended warranty

coverage, we highly recommend that you have your new amplifier

installed by an authorized JL Audio dealer. Your authorized

dealer has the training, expertise and installation equipment to ensure

optimum performance from this product. Should you

decide to install the amplifier yourself, please take the time

to read this manual thoroughly so as to familiarize yourself

with its installation requirements and setup procedures.

If you have any questions regarding the instructions in this

manual or any aspect of your amplifier’s operation, please contact your

authorized JL Audio dealer for assistance. If you need further assistance,

please call the JL Audio Technical Support Department

at [phone] during business hours.

2 | JL Audio - 450/4v2 Owner’s Manual

3

PROTECT YOUR HEARING!

+12VDC Ground Remote CH 1 & 2 Filter SectionCH 1 & 2 Bass Control CH 3 & 4 Filter SectionCH 1 & 2 Input Section CH 3 & 4 Input Section CH 3 & 4 Sp eaker Outputs

Left Output Right Output HP Filter Freq. (Hz)

Remote

Bass Port

CH 3
(Left)

CH 4

(Right)

CH 1
(Left)

CH 2

(Right)

Freq. Range

Input Voltage Input Sens.Input Sens.

Input Mode

2ch | 4ch

Filter Type

LP | BP | HP

x1 | x10Low | High

Input Voltage

Low | High

High-Pass Filter

Off | 12dB | 24dB

Freq. Range

Filte r Mode | Slope

x1 | x10 Off | 12dB | 24dB

Infrasonic Filter

Off | 30Hz

Bass EQ

Off | On

Signal From

1 & 2 | 3 & 4 | All

50

60

7595130

200

50050

60

7595130

200

500

Filter Freq. (Hz)

450/4v2

Four-Channel System Amplifier

Pream p Output Section

1 & 2

Inputs

Only

Either

feature

sums the

CH 1&2 input

signals to

mono when

activated.

1 & 2

and

3 & 4

Bridged: 150W x 1 (3-8Ω)

Left Right

75W

(1.5-4Ω)

75W

Bridged: 300W x 1 (3-8Ω)

Left Right

150W

(1.5-4Ω)

150W

CH 1 & 2 Sp eaker Outputs

Also sets
low-pass
cutoff for
CH 1 & 2

Bandpass

Filter

(if selected)

CH 1&2

Filter Slope

Selection / Defeat

(pg. 9)

Infrasonic Filter

On/O Switch

(pg. 11)

Preamp Output

Signal Selector

(pg. 10)

Left and Right

Preamp Output Jacks

(pg. 10)

Jack for
Remote Bass
Control Knob

(pg. 11)

CH 3&4

Input Voltage

Range Selector

(pg. 7)

Selects

2ch / 4ch

Input Mode

(pg. 7)

CH 3&4

HP Filter Slope

Selection / Defeat

(pg. 9)

CH 3&4

Filter Frequenc y

Range Selector

(pg. 9)

Selects CH 3&4

High-Pass Cuto

Frequency and Low-Pass

Cuto for CH 1&2 Bandpass

Filter

(pg. 10)

CH 3&4

Input Sensitivity

Control

(pg. 8)

CH 1&2

Left and Right

Input Jacks

(pg. 7)

CH 3&4

Left and Right

Input Jacks

(pg. 7)

Bass EQ

On/O Switch

(pg. 11)

CH 1&2

Filter Frequency

Range Selector

(pg. 9)

CH 1&2

Input Voltage

Range Selector

(pg. 7)

Remote Turn-On

Connector

(pg. 7)

Chassis Ground

Connector

(pg. 6)

+12 V Power

Connector

(pg. 6)

CH 1&2

Speaker Outputs

(pg. 11)

Selects CH 1&2

HP or LP Cuto

Frequency or HP Cuto

of Bandpass Filter

(pg. 8)

CH 3&4

Speaker Outputs

(pg. 11)

CH 1&2 Input

Sensitivity Control

(pg. 8)

We value you as a long-term customer. For
that reason, we urge you to practice restraint in
the operation of this product so as not to damage
your hearing and that of others in your vehicle.
Studies have shown that continuous exposure to
high sound pressure levels can lead to permanent
(irreparable) hearing loss. This and all other
high-power amplifiers are capable of producing
such high sound pressure levels when connected
to a speaker system. Please limit your continuous
exposure to high volume levels.

While driving, operate your audio system in
a manner that still allows you to hear necessary
noises to operate your vehicle safely (horns,
sirens, etc.).

SERIAL NUMBER

In the event that your amplifier requires
service or is ever stolen, you will need to
have a record of the product’s serial number.
Please take the time to enter that number in
the space provided below. The serial number
can be found on the bottom panel of the
amplifier and on the amplifier packaging.

Serial Number:

INSTALLATION APPLICATIONS

This amplifier is designed for operation in
vehicles with 12V, negative-ground electrical
systems. Use of this product in vehicles with
positive ground and/or voltages other than 12V
may result in damage to the product and will void
th e w ar ran ty.

This product is not certified or approved for
use in aircraft.

Do not attempt to “bridge” the outputs of this

amplifier with the outputs of a second amplifier,
including an identical one.

PLANNING YOUR INSTALLATION

It is important that you take the time to read
this manual and that you plan out your
installation carefully. The following are some
considerations that you must take into account
when planning your installation.

Cooling Efficiency Considerations:

Your JL Audio amplifier employs an
advanced ty pe of heat management, called
RealSink™. This feature takes advantage of
convection and radiation effects to remove
heat from the amplifier circuitry. For optimum
cooling performance, the vertical heat sinks
located at the back of the amplifier should be
exposed to as large a volume of air as possible.
Enclosing the amplifier in a small, poorly
ventilated chamber can lead to excessive heat
build-up and degraded performance. If an
installation calls for an enclosure around the
amplifier, we recommend that this enclosure
be ventilated with the aid of a fan. In normal
applications, fan-cooling is not necessary, but
you still need to follow some basic guidelines:

• Amplifier mounted vertically with heat sink fins

pointing up: Optimum

• Amplifier mounted horizontally,

right side up: Good

• Amplifier mounted horizontally, but upside

down: Fair (not recommended if there is
less than 1 inch (2.5 cm) clearance above the
amplifier heat sinks)

• Amplifier mounted vertically with heat sink fins

pointing laterally: Fair

• Amplifier mounted vertically with heat sink fins

pointing down: Poor (not recommended)

If mounting the amplifier under a seat,
make sure there is at least 1 inch (2.5 cm) of
space above the amplifier’s outer shell to permit
proper cooling.

Safety Considerations:

Your amplifier needs to be installed in a dry,
well-ventilated environment and in a manner
which does not interfere with your vehicle’s safety
equipment (air bags, seat belt systems, ABS brake
systems, etc.). You should also take the time to
securely mount the amplifier using appropriate
hardware so that it does not come loose in the
event of a collision or a sudden jolt to the vehicle.

Stupid Mistakes to Avoid:

• Check before drilling any holes in your vehicle

to make sure that you will not be drilling
through a gas tank, brake line, wiring harness or
other vital vehicle system.

• Do not run system wiring outside or underneath

the vehicle. This is an extremely dangerous
practice which can result in severe damage to
your vehicle and person.

• Protect all system wires from sharp metal

edges and wear by carefully routing them,
tying them down and using grommets and
loom where appropriate.

• Do not mount the amplifier in the engine

compartment, under the vehicle, on the roof
or in any other area that will expose the
amplifier circuitry to the elements.

4 | JL Audio - 450/4v2 Owner’s Manual

5

PRODUCT DESCRIPTION

The JL Audio 450/4v2 is a four-channel system

amplifier utilizing patented Absolute Symmetry™

Class AB technology for all channels. All
channels benefit from JL Audio’s exclusive R.I.P.S.

power supply design which optimizes the output

of each channel pair for any impedance between

1.5 and 4 ohms per channel.
The staggered power distribution of the 1&2

and 3&4 channel pairs (150W x 2 for CH 1&2 and
75 x 2 for CH 3&4) allows for a wide variety of
application options. The 450/4v2 can be operated
in the following modes:

1) As a full-system amplifier in bi-amp mode with

CH 1&2 driving subwoofers in low-pass mode
(150W x 1 or 300W x 1) and CH 3&4 driving
main speakers in high-pass mode (75W x 2).

2) As a high power four-channel satellite

amplifier in a bi-amplified system, delivering
high-passed signals to front and rear speaker
systems. In this mode, we recommend that CH
1&2 drive the front speaker systems and CH
3&4 drive the rear speaker systems. Preamp
outputs permit connection of a separate
amplifier to drive the subwoofer system.

3) As a high power four-channel satellite

amplifier in a tri-amplified system,
delivering band-passed signals through
CH 1&2 to mid-bass speakers and high­passed signals through CH 3&4 to mid­range/ tweeter speaker systems. Preamp
outputs permit connection of a separate
amplifier to drive the subwoofer system.

4) As a high power three-channel satellite

amplifier, delivering 150W x 3 at 4Ω in high­pass mode to lef t, center and right speaker
systems. This requires bridging the outputs of
CH 3&4 to create an equal power third channel
to complement CH 1&2. Preamp outputs
permit connection of a separate amplifier to
drive the subwoofer system.

The 450/4v2’s flexible input and crossover
sections permit operation with a wide variety
of source units and system configurations. The
450/4v2 can operate with a single pair of stereo
inputs or with separate inputs for CH 1&2 and
CH 3&4, if the source unit is equipped with front
and rear outputs. The 450/4v2’s preamp output
can send pass-through signals from the CH 1&2
inputs only or the CH 3&4 inputs only or it can
sum all four input channels to feed a subwoofer
amplifier. This latter mode allows for non-fading
sub-bass with front to rear satellite fading.

As we said, it’s very flexible.

TYPICAL INSTALLATION SEQUENCE

The following represents the sequence for
a typical amplifier installation, using an
aftermarket source unit or OEM Interface
processor (like the CleanSweep® CL441dsp).
Additional steps and different procedures may
be required in some applications. If you have

any questions, please contact your authorized

JL Audio dealer for assistance.

1) Disconnect the negative battery post

connection and secure the disconnected cable
to prevent accidental re-connection during
installation. This step is not optional!

2) Run power wire (minimum 4 AWG)
from the battery location to the amplifier
mounting location, taking care to
route it in such a way that it will not be
damaged and will not interfere with
vehicle operation. Use 2 AWG or 1/0
AWG power wire if additional amplifiers
are being installed with the 450/4v2.

3) Connect power wire to the positive battery
post. Fuse the wire with an appropriate fuse
block (and connectors) within 18 inches (45
cm) wire length of the positive battery post.
This fuse is essential to protect the vehicle.

Do not install the fuse until the power wire

has been connected to the amplifier.

4) Run signal cables (RCA cables) and remote
turn-on wire from the source unit to the
amplifier mounting location.

5) Run speaker wire from the speaker systems to
the amplifier mounting location.

6) Find a good, solid metal grounding point
close to the amplif ier and connect the
negative power wire to it using appropriate
hardware. Use minimum 4 AWG power wire,
no longer than 36 inches (90 cm) from the
amplifier to the ground connection point. In
some vehicles, it may be necessary to upgrade
the battery ground wire. (See page 6 for
important notice).

7) Securely mount the amplifier using
appropriate hardware.

8) Connect the positive and negative power
wires to the amplifier. A fuse near the
amplifier is not necessary.

9) Connect the remote turn-on wire
to the amplifier.

10) Connect the RCA input cables
to the amplifier.

11) Connect the speaker wires to the amplifier.

12) Carefully review the amplifier’s control
settings to make sure that they are set
according to the needs of the system.

13) Install power wire fuse (60A for a
single 450/4v2) and reconnect the negative
battery post terminal.

14) Turn on the source unit at a low level

to double-check that the amplifier is
configured correctly. Resist the temptation
to crank it up until you have verified the
control settings.

15) Make necessary adjustments to the input

sensitivity controls to obtain the right
overall output and the desired balance
in the system. See Appendix B (page 22)
for the recommended input sensitivity
setting method.

16) Enjoy the fruits of your labor with your

favorite music.

6 | JL Audio - 450/4v2 Owner’s Manual

7

CH 3
(Left)

CH 4

(Right)

CH 1
(Left)

CH 2

(Right)

Freq. Range

Input Voltage Input Sens.Input Sens.

Input Mode

2ch | 4ch

x1 | x10 Low | High

Input Voltage

Low | High

High-Pass Filter

Off | 12dB | 24dB

50

60

7595130

200

50050

1 & 2

Inputs

Only

1 & 2

and

3 & 4

Bridged: 150W x 1 (3-8Ω)

Left Right

75W

(1.5-4Ω)

75W

Also sets
low-pass
cutoff for
CH 1 & 2
Bandpass

Filter

(if selected)

CH 3
(Left)

CH 4

(Right)

Input Voltage Input Sens.Input Sens.

|

High

Bridged: 150W x 1 (3-8Ω)

Left Right

75W

(1.5-4Ω)

75W

POWER CONNECTIONS

+12VDC Ground Remote CH 1 & 2 Filter SectionCH 1 & 2 Bass Control CH 3 & 4 Filter SectionCH 1 & 2 Input Section CH 3 & 4 Input Section CH 3 & 4 Spea ker Outputs

Left Output Right Output HP Filter Freq. (Hz)

Remote

Bass Port

CH 3
(Left)

CH 4

(Right)

CH 1
(Left)

CH 2

(Right)

Freq. Range

Input Voltage Input Sens.Input Sens.

Input Mode

2ch | 4ch

Filter Type

LP | BP | HP

x1 | x10 Low | High

Input Voltage

Low | High

High-Pass Filter

Off | 12dB | 24dB

Freq. Range

Filter Mode | Slope

x1 | x10 Off | 12dB | 24dB

Infrasonic Filter

Off | 30Hz

Bass EQ

Off | On

Signal From

1 & 2 | 3 & 4 | All

50

60

7595130

200

50050

60

7595130

200

500

Filter Freq. (Hz)

450/ 4

v2

Four-Channel System Amplifier

Preamp Ou tput Sec tion

1 & 2

Inputs

Only

Either

feature

sums the

CH 1&2 input

signals to

mono when

activated.

1 & 2

and

3 & 4

Bridged: 150W x 1 (3-8Ω)

Left Right

75W

(1.5-4Ω)

75W

Bridged: 300W x 1 (3-8Ω)

Left Right

150W

(1.5-4Ω)

150W

CH 1 & 2 Spea ker Outputs

Also sets
low-pass
cutoff for
CH 1 & 2
Bandpass

Filter

(if selected)

IMPORTANT

!

Before installing the amplifier,
disconnect the negative (ground) wire
from the vehicle’s battery. This will prevent
accidental damage to the system, the vehicle
and your body during installation.

The 450/4v2’s “+12 VD C” and “Ground”

connections are designed to accept 4 AWG power
wire. 4 AWG is the only recommended power

wire size for this amplifier.

If you are installing the 450/4v2 with other
amplifiers and wish to use a single main power
wire, use 2 AWG or 1/0 AWG main power wire
(depending on the overall current demands of
all the amplifiers in the system). This 2 AWG
or 1/0 AWG power wire should terminate into
a distribution block mounted as close to the
amplifiers as possible and should connect to the
450/4v2 with 4 AWG power wire.

Note: Smaller AWG numbers mean bigger wire
and vice-versa (1/0 AWG is the largest,
2 AWG is smaller, then 4 AWG, then
8 AWG, etc.).

To connect the power wires to the amplifier,
first back out the set screw on the top of the
amplifier, using the supplied 2.5 mm hex wrench.
Strip 1/2 inch (12 mm) of insulation from the
end of each wire and insert the bare wire into
the receptacle on the front panel of the amplifier,
seating it firmly so that no bare wire is exposed.
While holding the wire in place, tighten the set
screw firmly, taking care not to strip the head
of the screw.

The ground connection should be made using
the same gauge wire as the power connection
(4 AWG) and should be kept as short as possible,
while accessing a solid piece of sheet metal in the
vehicle. The surface of the sheet metal should
be sanded at the contact point to create a clean,
metal-to-metal connection between the chassis
and the termination of the ground wire. For
optimal grounding, we recommend the use
of a JL Audio ECS master ground lug
(XB-MGLU). Alternatively, a sheet metal
screw or bolt can be used with a star washer.

Any wires run through metal barriers (such
as firewalls), must be protected with a high
quality insulating grommet to prevent damage
to the insulation of the wire. Failure to do so
may result in a dangerous short circuit.

Many vehicles employ small (10 AWG - 6 AWG)
wire to ground the battery to the vehicle chassis
and to connect the alternator’s positive
connection to the battery. To prevent voltage
drops, these wires should be upgraded to 4
AWG when installing amplifier systems with
main fuse ratings above 60A.

Fuse Requirements

It is absolutely vital that the main power
wire(s) to the amplifier(s) in the system be
fused within 18 inches (45 cm) of the positive
battery post connection. The fuse value at each
power wire should be high enough for all of the
equipment being run from that power wire. If
only the 450/4v2 is being run from that power
wire, we recommend a 60A fuse be used. AGU
(big glass fuse) or MaxiFuse™ (big plastic-body
fuse) types are recommended.

No fuse is required or recommended directly
before the amplifier power connection. If one is
desired, we recommend the use of a 60A AGU
fuse or MaxiFuse™ type.

TURNON LEAD

The 450/4v2 uses a conventional +12V remote
turn-on lead, typically controlled by the source
unit’s remote turn-on output. The amplifier will

turn on when +12V is present at its “Remote”

input and turn off when +12V is switched off. If
a source unit does not have a dedicated remote
turn-on output, the amplifier’s turn-on lead can
be connected to +12V via a switch that derives
power from an ignition-switched circuit.

The 450/4v2’s “Remote” turn-on connector

is designed to accept 18 AWG – 8 AWG wire. 12
AWG is more than adequate for this purpose.
To connect the remote turn-on wire to the
amplifier, first back out the set screw on the top
of the amplifier, using the supplied hex wrench.
Strip 1/2 inch (12mm) of wire and insert the
bare wire into the receptacle on the front panel
of the amplifier, seating it firmly so that no bare
wire is exposed. When using smaller wire, it may
be necessary to strip 1 inch of insulation from
the wire and fold the bare wire in half prior to
insertion. While holding the wire in the terminal,
tighten the set screw firmly, taking care not to
strip the head of the screw and making sure that
the wire is firmly gripped by the set screw.

CH 1&2 / CH 3&4 INPUT SECTIONS

The 450/4v2 has two separate input sections,
one for CH 1&2 and another for CH 3&4. Each
section contains a pair of RCA-type input jacks,

an “Input Voltage” switch and an “Input Sens.”

rotary control.

The “CH 1&2 Input Section” also contains

an “Input Mode” switch to allow operation of

all four amplifier channels with one or two pairs
of input signals.

1) Input Mode Switch: If you wish to operate all
four channels of the 450/4v2 with a single pair

of stereo inputs, select the “2ch” position on
the “Input Mode” switch and connect a single

pair of input cables to the input jacks in the

“CH 1&2 Input Section”. In this mode, the

amplifier will route the signals connected to
the CH 1&2 inputs to CH 3&4 as well.

If you wish to use separate inputs for CH 1&2
and CH 3&4 (to allow front-to-rear fading, for
example) and the source unit is equipped with

front and rear outputs, select “4ch” on the “Input
Mode” switch located in the “CH 1&2 Input
Section”. In this mode, you must connect separate

pairs of input cables to each input section.

2) Input Voltage Range: A wide range of signal

input voltages can be accommodated by each
of the 450/4v2’s input sections (200mV – 8V).
This wide range is split up into two sub-ranges,
accessible via switches located in each input
section of the amplifier. Be aware that each

input section’s “Input Voltage” switch will

have to be configured, regardless of how many
input cables are actually feeding the amplifier.

T h e “ Low” position on each “Input Voltage”

switch selects an input sensitivity range

between 200mV and 2V. This means that the

“Input Sens.” rotary control will operate

within that voltage window. If you are using an

aftermarket source unit, with conventional

preamp-level outputs, this is most likely the

position that you will use. The “High” position

on each “Input Voltage” switch selects an

input sensitivity range between 800mV and 8V.

This is useful for certain high-output preamp

level signals as well as speaker-level output

from source units and small amplifiers.

To use speaker-level sources, splice the speaker

output wires of the source unit or small

amplifier onto a pair of RCA plugs for each

input pair or use the JL Audio ECS Speaker

Wire to RCA adaptor (XB-CLR AIC2-SW).

8 | JL Audio - 450/4v2 Owner’s Manual

9

CH 3
(Left)

CH 4

(Right)

Freq. Range

Input Voltage Input Sens.Input Sens.

|

4ch

x1 | x10 Low | High

High-Pass Filter

Off | 12dB | 24dB

50

60

7595130

200

50050

1 & 2
and
3 & 4

Bridged: 150W x 1 (3-8Ω)

Left Right

75W

(1.5-4Ω)

75W

Also sets
low-pass
cutoff for
CH 1 & 2

Bandpass

Filter

(if selected)

IMPORTANT

!

CH 3
(Left)

CH 4

(Right)

CH 1

(Left)

CH 2

(Right)

Freq. Range

Input Voltage Input Sens.Input Sens.

Input Mode

2ch | 4ch

Filter Type

LP | BP | HP

x1 | x10 Low | High

Input Voltage

Low | High

High-Pass Filter

Off | 12dB | 24dB

Freq. Range

Filter Mode | Slope

x1 | x10 Off | 12dB | 24dB

50

60

7595130

200

50050

60

7595130

200

500

Filter Freq. (Hz)

1 & 2

Inputs

Only

1 & 2

and

3 & 4

Bridged: 150W x 1 (3-8Ω)

Left Right

75W

(1.5-4Ω)

75W

Also sets
low-pass
cutoff for
CH 1 & 2
Bandpass

Filter

(if selected)

The output of the amplifier will decrease for
a given input voltage when the “Input
Range” switch is placed in the “High”
position. Conversely, the output will be
higher with the switch in the “Low” position.
While this may sound counter-intuitive, it is
correct as described.

3) Input Sensitivity Adjustment: Located next

to the “Input Voltage” switch in each input
section is a rotary control labeled “Input
Sens.”. Once the appropriate “Input Voltage”

range has been selected, this control can be
used to match the source unit’s output voltage
to the input stage of each pair of amplifier
channels for maximum clean output. Rotating
the control clockwise will result in higher
sensitivity (louder for a given input voltage).
Rotating the control counter-clockwise will
result in lower sensitivity (quieter for a given
input voltage). To properly set each pair
of amplifier channels for maximum clean
output, please refer to Appendix B (page 22)
in this manual. After using this procedure,
you can then adjust the relative level of each
channel pair by adjusting the input sensitivity
downward on either or both channel pairs, if
they require attenuation to achieve the desired

system balance. Do not increase the “Input
Sens.” setting for any amplifier in the system

beyond the maximum level established during
the procedure outlined in Appendix B (page

22). Doing so will result in audible distortion

and possible speaker damage. Be aware that

both “Input Sens.” adjustments will have to be

made, regardless of how many input cables are
feeding the amplifier. These controls will allow
you to set the appropriate relative levels for CH
1&2 relative to CH 3&4 and other amplifier
channels in the system.

CROSSOVER CONTROLS

Crossovers are groups of individual electronic
filters which allow only certain frequency
ranges to pass through them by attenuating
frequencies outside the selected range. These
filters allow the user to specify what frequency
range will be sent out of each channel section
of the amplifier. This, in turn, allows each
speaker system to only reproduce a range of
frequencies it is well-suited for, resulting in
reduced distortion and improved fidelity.

CH 1&2 Filter Section:

1) “ Filter Type” Control: Located in the

“CH 1&2 Filter Section”, this switch allows

you to configure the CH 1&2 filter into one
of three filter types:

“ LP” (Low-Pass): Configures the CH 1&2

filter to attenuate frequencies above

the selected filter frequency. Useful

for connection of subwoofer(s) to CH

1&2 in a bi-amplified system.

“ BP” (Bandpass): Configures the filter to

attenuate frequencies above the selected filter

frequency and below the frequency selected

in the CH 3&4 High-Pass Filter. This creates

a true bandpass filter well-suited for driving

mid-bass or mid-range speakers in a tri-

amplified system.

“ HP” (High-Pass): Configures the CH 1&2

filter to attenuate frequencies below the

selected filter frequency. Useful for connection

of component speakers to CH 1&2 in a bi-

amplified system.

CH 3&4 Filter Section:

2) “Filter Mode/Slope” Control: This switch

allows you to defeat the CH 1&2 filter or select
from two filter slopes.

“Off”: Defeats the filter for CH 1&2 completely,

allowing the full range of frequencies present
at the inputs to feed that pair of channels.

This is useful for systems utilizing outboard

crossovers or requiring full-range reproduction
from that pair of channels.

1) “ High-Pass Filter” Control: This switch allows

“ 12dB”: Configures the filter for CH 1&2

to attenuate frequencies above or below the

you to defeat the CH 3&4 filter or select from

two different filter slopes.
selected filter frequency at a rate of 12 dB per
octave (Butterworth alignment).

“ Off”: Defeats the filter for CH 3&4 completely,

allowing the full range of frequencies present

“ 24dB”: Configures the filter for CH 1&2

to attenuate frequencies above or below the
selected filter frequency at a rate of 24 dB per

octave (Linkwitz-Riley alignment).

Depending on the speaker system and

the vehicle, different filter slopes may be
required to produce a smooth transition
between the sound of different speakers in the

at the inputs to feed that pair of channels.

This is useful for systems utilizing outboard

crossovers or requiring full-range reproduction
from these channels.

“ 12dB”: Configures the high-pass filter for CH

3&4 to attenuate frequencies below the selected
filter frequency at a rate of 12 dB per octave

(Butterworth alignment).
system. Experiment to find the slope which
best matches the acoustic requirements of

the system. The sharper “24dB” setting will

do a better job of protecting small speakers
with limited power handling. The shallower

“ 24dB”: Configures the high-pass filter for CH

3&4 to attenuate frequencies below the selected

filter frequency at a rate of 24 dB per octave

(Linkwitz-Riley alignment).
“12dB” octave setting allows the rear speakers

to reproduce more low-frequency content.

3 ) “ Freq. Range” Control: When thrown to

the right, this switch multiplies the cutoff

frequency selected by the rotary “Filter Freq.
(H z)” control by a factor of 10. In the “x1”

position, the range of the rotary control is
50 - 500 Hz (as marked). In the “x10”
position, the range of the rotary control is

500 Hz - 5 kHz (5000 Hz).

4) “ Filter Freq. (Hz)” The filter frequency

markings surrounding this rotar y control
are for reference purposes and are generally
accurate to within 1/3 octave or better. If you
would like to select the filter cutoff frequency
with a higher level of precision, consult the
charts in Appendix A (page 22) of this manual.

Depending on the speaker system and the

vehicle, different filter slopes may be required to
produce a smooth transition between the speakers
in the system. Experiment to find the slope
which best matches the acoustic requirements

of your system. The sharper “24dB” setting

will do a better job of protecting small speakers
with limited power handling. The shallower

“12dB” octave setting allows the rear speakers to

reproduce more low-frequency content.

2 ) “Freq. Range” Control: When thrown to the

right, this switch multiplies the cutoff frequency

selected by the rotary “Filter Freq. (Hz)”
control by a factor of 10. In the “x1” position,
the range of the rotary control is 50 - 500 Hz (as
marked). In the “x10” position, the range of the
rotary control is 500 Hz - 5 kHz (5000 Hz).

10 | JL Audio - 450/4v2 Owner’s Manual

11

IMPORTANT

!

Remote

Bass Port

CH 3

(Left)

CH 4

(Right)

CH 1

(Left)

CH 2

(Right)

Freq. Range

Input Voltage Input Sens.Input Sens.

Input Mode

2ch | 4ch

Filter Type

LP | BP | HP

x1 | x10 Low | High

Input Voltage

Low | High

High-Pass Filter

Off | 12dB | 24dB

Freq. Range

Filter Mode | Slope

x1 | x10 Off | 12dB | 24dB

Infrasonic Filter

Off | 30Hz

Bass EQ

Off | On

50

60

7595130

200

50050

60

7595130

200

500

Filter Freq. (Hz)

1 & 2

Inputs

Only

Either

feature

sums the

CH 1&2 input

signals to

mono when

activated.

1 & 2
and
3 & 4

Bridged: 150W x 1 (3-8Ω)

Left Right

75W

(1.5-4Ω)

75W

Bridged: 300W x 1 (3-8Ω)

Left Right

150W

(1.5-4Ω)

150W

CH 1 & 2 Spea ker Outputs

Also sets
low-pass
cutoff for
CH 1 & 2
Bandpass

Filter

(if selected)

3) “ Filter Freq. (Hz)” The filter frequency

Left Output Right Output HP Filter Freq. (Hz)

Remote

Bass Port

CH 3
(Left)

CH 4

(Right)

CH 1
(Left)

CH 2

(Right)

Freq. Range

Input Voltage Input Sens.Input Sens.

Input Mode

2ch | 4ch

Filter Type

LP | BP | HP

x1 | x10 Low | High

Input Voltage

Low | High

High-Pass Filter

Off | 12dB | 24dB

Freq. Range

Filter Mode | Slope

x1 | x10 Off | 12dB | 24dB

Infrasonic Filter

Off | 30Hz

Bass EQ

Off | On

Signal From

1 & 2 | 3 & 4 | All

50

60

7595130

200

50050

60

7595130

200

500

Filter Freq. (Hz)

Preamp Ou tput Sec tion

1 & 2

Inputs

Only

Either

feature

sums the

CH 1&2 input

signals to

mono when

activated.

1 & 2

and

3 & 4

Bridged: 150W x 1 (3-8Ω)

Left Right

75W

(1.5-4Ω)

75W

Bridged: 300W x 1 (3-8Ω)

Left Right

150W

(1.5-4Ω)

150W

CH 1 & 2 Spea ker Outputs

Also sets
low-pass
cutoff for
CH 1 & 2
Bandpass

Filter

(if selected)

Remote

Bass Port

CH 3

(Left)

CH 4

(Right)

CH 1
(Left)

CH 2

(Right)

Freq. Range

Input Voltage Input Sens.Input Sens.

Input Mode

2ch | 4ch

Filter Type

LP | BP | HP

x1 | x10 Low | High

Input Voltage

Low | High

High-Pass Filter

Off | 12dB | 24dB

Freq. Range

Filter Mode | Slope

x1 | x10 Off | 12dB | 24dB

Infrasonic Filter

Off | 30Hz

Bass EQ

Off | On

50

60

7595130

200

50050

60

7595130

200

500

Filter Freq. (Hz)

1 & 2

Inputs

Only

Either

feature

sums the

CH 1&2 input

signals to

mono when

activated.

1 & 2

and

3 & 4

Bridged: 150W x 1 (3-8Ω)

Left Right

75W

(1.5-4Ω)

75W

Also sets
low-pass
cutoff for

CH 1 & 2

Bandpass

Filter

(if selected)

markings surrounding this rotar y control
are for reference purposes and are generally
accurate to within 1/3 octave or better. If you
would like to select the filter cutoff frequency
with a higher level of precision, consult the
charts in Appendix A (page 22) of this manual.

Preamp Output Section

The 450/4v2 incorporates a pass-through
preamp output section, so that additional
amplifiers can be added to the system. This pass­through pre-amp output can be configured three

different ways using the switch labeled “Signal
From” in the “Preamp Output Section”.

1) “ 1& 2”: The preamp output delivers the same

signal that is connected to the 450/4v2’s
CH 1&2 Inputs. This mode is useful for
feeding a subwoofer amplifier when the
450/4v2 is being used to drive front and rear
speaker systems. This preamp output mode
will track the signal level of CH 1&2, allowing
fading of the rear channels without affecting
the subwoofer level.

2) “ 3&4”: The preamp output delivers the same

signal that is connected to the 450/4v2’s CH
3&4 Inputs. This mode is useful for feeding a
subwoofer amplifier when the 450/4v2 is being
used to drive front and rear speaker systems.
This preamp output mode will track the signal
level of CH 3&4, allowing fading of the front
channels without affecting the subwoofer level.

3) “ ALL”: This mode delivers a sum of the signals
being fed to the “CH 1&2 Input Section” and
“CH 3&4 Input Section” of the amplifier.

The Preamp Output signal is not affected by

the “LF Boost” or “Infrasonic Filter” 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). When
the 450/4v2 is being used to drive front and
rear speaker systems, this preamp output mode
will deliver a summed front/rear signal to the
subwoofer amplifier, while permitting fading
of the front and rear speaker systems from the
source unit.

Note: The signal level of the “Preamp Output ”

is always low level regardless of the voltage
applied to this amplifier’s inputs and the
setting chosen on this amplifier’s “Input
Range” switch. A JL Audio amplifier receiving
signal from this preamp output should have
its “Input Range” switch set to “Low”.

CH 1 & 2 Bass Control

This section provides two basic bass processing

tools for CH 1&2: a 24 dB/octave infrasonic filter

at 30 Hz and a +6 dB boost circuit centered at 48
Hz. Activation of either feature automatically

sums the CH 1&2 input signals to mono. (These
features should only be used when driving
subwoofer(s) from CH 1&2).

1) “Infrasonic Filter”: The infrasonic filter is a

24 dB/octave high-pass filter, with a fixed

cutoff frequency of 30 Hz. This filter is

designed to conserve amplifier power and
protect subwoofer systems without audibly
degrading the sub-bass output. With ported
enclosures, the use of the infrasonic filter
is highly recommended to protect the
speaker(s) from excessive excursion below
box tuning. With sealed enclosures, the
use of the filter is less necessary, but can
still help protect the speaker system. The
infrasonic filter can be completely defeated

by selecting the “Off” position on the
“Infrasonic Filter” switch. This bypasses all

signal from flowing through the circuit.

2) “ Bass EQ”: This switch allows the user to

activate a 6 dB boost centered at 48 Hz.

3) “ Remote Bass Port”: Allows you to connect an

optional remote boost knob (sold separately,
JL Audio Model RBC-1) that can be mounted
in the front of the vehicle. With the RBC-1
connected, the boost is no longer limited to 0
or +6 dB, allowing a range of 0-15 dB of boost
to be selected.

The “Bass EQ” and “Infrasonic Filter” features
will only operate when the CH 1&2 filter is
activated and in low-pass mode. If you are
using an external active crossover and would
like to use the “Bass EQ” and “Infrasonic
Filter” features, set the “Filter Mode/Slope”
switch on “12dB” and rotate the frequency
selection knob fully clockwise to the “500 Hz”
position. This will activate the bass controls
without significantly affecting the crossover
point selected by the external active crossover.

SPEAKER OUTPUTS

The 450/4v2 employs JL Audio’s exclusive
Regulated, Intelligent Power Supply (R.I.P.S.)
design. The operation of the R.I.P.S. system is
independent for each pair of channels. This
sophisticated power supply allows the amplifier
to produce its optimum power (150 watts x 2 for
channels 1&2 and 75 watts x 2 for channels 3&4)
over a wide range of speaker impedances.

Unlike conventional amplifiers that require
a specific impedance to produce optimum
power, the R.I.P.S.-equipped 450/4v2 gives
you the freedom to use a variety of speaker
configurations that achieve final nominal
impedances between 1.5 – 4Ω per channel in
stereo (without sacrificing power output or
sound quality). When bridged, each channel

pair will optimize output between 3 – 8Ω.

The operation of the R.I.P.S. circuitry is
entirely automatic and adjusts itself every time
the amplifier is turned on according to the
lowest impedance present at the speaker load.
There are no user controls to configure. The
system operates through multiple stages of

impedance optimization, choosing the stage

most appropriate to the actual impedance of the
speakers you connect to it.