JL Audio HD900/5 Owner's Manual page 12

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 HD900/5 can be easily configured to drive
a complete bi-amplified system consisting of a
subwoofer and four main speakers or a subwoofer
and two main speakers.
bi-amplified system with one Hd900/5
driving four main speakers plus subwoofer
(5-channel mode)
In this configuration, the "Front" channels
of the HD900/5 will drive front component
speakers (stereo 100W x 2 @ 4Ω) with high-
pass filtering. The "Rear" channels will drive
rear component speakers in stereo (100W x 2
@ 4Ω) with high-pass filtering. The subwoofer
channel will drive the subwoofer system
(500W x 1 @ 1.5-4Ω) with low-pass filtering.
Once the input sections have been configured
appropriately, go to the "Front Channel
Controls" Section. Select "12dB" or "24dB" on
the "High-Pass Filter" and an appropriate "Filter
Freq." (80-90 Hz is a good starting point).
Next, turn your attention to the "Rear
Channel Controls" Section and select "12dB"
or "24dB" "High-Pass Filter" switch and an
appropriate "Filter Freq." (again, 80-90 Hz is a
good starting point).
Finally, in the "Subwoofer Channel
Controls" Section, select "12dB" or
"24dB" on the "Low-Pass Filter" Switch
and a "Filter Freq." of 80-90 Hz.
After proper adjustment of the HD900/5's
"Input Range" and "Input Sens." controls,
you can fine tune filter frequencies
and slopes and attenuate each channel
section to achieve proper balance.
12 | JL Audio - HD900/5 Owner's Manual
bi-amplified system with one Hd900/5
driving two main speakers plus subwoofer
(3-channel mode)
In this configuration, the "Front" channels
of the HD900/5 will be bridged to drive the
left front component speaker system (150W x
1 @ 4Ω) with high-pass filtering. The "Rear"
channels will be bridged to drive the right front
component speaker system (150W x 1 @ 4Ω),
also with high-pass filtering. The "Subwoofer"
channel will drive the subwoofer system
(500W x 1 @ 1.5-4Ω) with low-pass filtering.
For information on proper bridging
techniques refer to the section titled "Bridging
Considerations" in this manual (page 14).
Once the input sections have been configured
appropriately, go to the "Front Channel
Controls" Section. Select "12dB" or "24dB"
on the "High-Pass Filter" and an appropriate
"Filter Freq." (80-90 Hz is a good starting point).
Next, turn your attention to the "Rear
Channel Controls" section and set it exactly the
same as you set the "Front Channel Controls".
Finally, in the "Subwoofer Channel
Controls" section, select "12dB" or
"24dB" on the "Low-Pass Filter" switch
and a "Filter Freq." of 80-90 Hz.
After proper adjustment of the HD900/5's
"Input Range" and "Input Sens." controls,
you can fine tune filter frequencies and
slopes and attenuate each channel section to
achieve proper balance. Keep in mind that
the left and right front speakers will have
independent "Input Sens." controls in this
configuration, and these need to be carefully
matched for proper stereo performance.