JL Audio XD400/4 Multi-Amplifier Systems Using the Preamp Outputs, Rear pairs of stereo outputs

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).

Multi-Amplifier SYSTEMS Using the “Preamp Outputs” of the

XD400/4, it is easy to configure many different multi-amplifier systems.

The most common type involves the addition of a subwoofer amplifier, such as the XD600/1. Common configurations of such a system are described below.

Bi-Amplified System with one XD400/4 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 XD400/4 will drive front component speakers in stereo with 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).

Here are three possible configuration options:

A)Fade Subwoofer Level vs. HF Level: Required: a source unit or processor with front

and rear pairs of stereo outputs.

Input Connections: one stereo pair of source unit outputs is connected to the “CH 1 (Left)” and “CH 2 (Right)” inputs of the XD400/4 (select “2 Ch.” on the “Input Mode” switch). The second stereo pair of source unit outputs is connected to the subwoofer amplifier inputs.

Result: 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 XD400/4’s “Input Sens.” settings and will not be user adjustable from the front of the vehicle.

B)Subwoofer Level Control Only:

Required: a source unit or processor with left, right and dedicated subwoofer outputs.

Input 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 (select “2 Ch.” on the “Input Mode” switch). The source unit’s dedicated subwoofer output is connected to the subwoofer amplifier inputs.

Result: 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.

C)Front to Rear HF Fading and Subwoofer Level Control:

Required: a source unit or processor with front and rear pairs of stereo outputs plus a dedicated subwoofer output.

Input Connections: one 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 of the XD400/4 (select

“4 Ch.” on the “Input Mode” switch). The source unit’s dedicated subwoofer output is connected to the subwoofer amplifier inputs.

ENGLISH

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