JL Audio XD400/4 Benutzerhandbuch

Seite 12

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12 | JL Audio - XD400/4 Owner’s Manual

sYstem conFigurations

The XD400/4 is a flexible amplifier, well-

suited for a multitude of system configurations.
In this section, the most likely configurations for
a system with a single XD400/4 are explained in
detail.

Once you have selected your desired

configuration, you can use the amplifier panel
drawing on pages 18 & 19 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 XD400/4 can be configured to drive a

bi-amplified system by itself or with a separate
subwoofer amplifier.

bi-amplified system with one Xd400/4

In this configuration, channels 3&4 of the

XD400/4 will drive subwoofers (stereo or bridged)
with low-pass filtering. Channels 1&2 will
drive component speakers in stereo with
high-pass filtering.

Input connection options for a bi-amplified system
with one XD400/4 are as follows:

A) No User Adjustability:

Req uired: a basic source unit or processor

with one pair of stereo outputs.

Inp ut Connections: a single pair of stereo source

unit outputs connected to the “CH 1 (Left)
and“CH 2 (Right)” inputs of the XD400/4
(select “2 Ch. on the “Input Mode switch).

Res ult: the relative level of the LF and HF

channels will be determined by the XD400/4’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 two

pairs of stereo outputs.

Inp ut Connections: the first stereo pair of source

unit outputs is connected to the “CH 1 (Left)
and “CH 2 (Right)” inputs of the XD400/4.
The second stereo pair of source unit outputs
is connected to the “CH 3 (Left)” and “CH 4

(Right)” inputs (select “4 Ch.” on the Input

Mode” switch).

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

one pair of stereo outputs 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 XD400/4. The source unit’s dedicated
subwoofer output is connected to the “CH

3 (Left)” and “CH 4 (Right) inputs (select
4 Ch.” on the “Input Mode” switch).

Res ult: in this mode, the user has the ability to

control the absolute level of the LF channels
relative to the HF channels.

Set the “Input Sens.” in the “Channel 3 & 4

Controls” section with the source unit’s

subwoofer level control set at 3/4 of full output.

See Appendix A (page 14) for details.

Crossover Setup for Bi-Amplified System

with one XD400/4:

Once the input sections have been configured

appropriately, go to the “Channel 3 & 4

Controls”. Select “LP” (low-pass) on the “Filter

Mode” switch and an appropriate “Filter Freq.
(80 Hz is a good starting point).

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

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