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 HD600/4 can be configured to drive a bi-amplified system by itself or with a separate subwoofer amplifier.
Bi-Amplified System with one HD600/4
In this configuration, the “Rear” channels of the HD600/4 will drive subwoofers (stereo 150W x 2 or bridged 300W x 1) with low-pass filtering. The “Front” channels will drive component speakers in stereo (150W x 2) with high-pass filtering.
Crossover Setup for Bi-Amplified System with one HD600/4:
Once the input sections have been configured appropriately, go to the “Rear Channel Controls” Section. Select “LP” (low-pass) on the “Filter Mode” switch and “12dB” or “24dB” on the “Filter Slope” switch and an appropriate “Filter Freq.” (80-90 Hz is a good starting point).
Next, turn your attention to the “Front Channel Controls” Section. and select “HP” (high-pass) on the “Filter Mode” switch and “12dB” or “24dB” on the “Filter Slope” switch and an appropriate “Filter Freq.” (again, 80-90 Hz is a good starting point).
After proper adjustment of the Front and Rear channel “Input Range” and “Input Sens.” controls using the method shown in Appendix C (pages 18, 19), you can fine tune filter frequencies and slopes and attenuate either pair of channels to achieve proper balance. For precise filter frequency information refer to Appendix B (page 18).
Bi-Amplified System with one HD600/4 in four-channel mode and a separate subwoofer amplifier
This configuration requires that the separate subwoofer amplifier has a built-in low-pass filter. In this configuration, the “Front” channels of the HD600/4 will drive front component speakers (stereo 150W x 2) with high-pass filtering. The “Rear” channels will drive rear component speakers in stereo (150W x 2) with high-pass filtering.
The separate subwoofer amplifier will drive the subwoofer system with low-pass filtering (select a
filter frequency of 80-90 Hz to start). The inputs
of the subwoofer amplifier can be fed from the
HD600/4’s preamp output or from a dedicated subwoofer output on the source unit.
Crossover Setup for Bi-Amplified System with one HD600/4 and a separate subwoofer amplifier:
Once the input and preamp output sections have been configured appropriately, go to the “Front Channel Controls” Section. Select “HP” (high-pass) on the “Filter Mode” switch and “12dB” or “24dB” on the “Filter Slope” switch 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 “HP” (high-pass) on the “Filter Mode” switch and “12dB” or “24dB” on the “Filter Slope” switch and an appropriate “Filter Freq.” (again, 80-90 Hz is a good starting point).
After proper adjustment of the HD600/4’s and the subwoofer amplifier’s “Input Range” and “Input Sens.”, you can fine tune filter frequencies and slopes and attenuate either pair of channels to achieve proper balance. For proper adjustment of the “Input Sens.” controls of the HD600/4 use the method shown in Appendix C (pages 18, 19). For precise filter frequency information for the HD600/4 refer to Appendix B (pages 18). Refer to the subwoofer amplifier owner’s manual for its proper adjustment levels.
Preamp Outputs
The HD600/4 incorporates a pass-through preamp output section, so that additional amplifiers can easily be connected to the same signal(s) feeding the HD600/4. These preamp output signals are accessible via a stereo pair of RCA-type jacks, labeled “Preouts”, on the Connection Panel.
L
Preouts Remot
Level
Contro
R
The term “pass-through” refers to the fact that the Preamp Output signals are not affected by any crossover filter or input sensitivity setting selected on the HD600/4 (if the input signal is full-range, the Preamp Output will be full-range). These preamp output signals are buffered to prevent noise and are always preamp level, regardless of the level of signals feeding the HD600/4’s inputs.
The pass-through Preamp Outputs can be configured two different ways using the switch labeled “Preouts From” in the “General Setup” section of the Control Panel.
1)“Front”: The preamp output delivers the same signal that is connected to the HD600/4’s
“Front Inputs”. This mode is useful for feeding a subwoofer amplifier when the
HD600/4 is being used to drive front and rear speaker systems. In this mode, the preamp output level will track with the signal level of the front input signals, allowing the user to fade the rear channels in and out, without affecting the subwoofer level.
3)“F+R” (Front + Rear): This mode delivers a sum of the signals being fed to the “Front Inputs” and the “Rear Inputs” of the amplifier. When the HD600/4 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.
REmote level control (OPTIONAL)
With the addition of the optional Remote Level Control (HD-RLC), you can control the volume of one or both channel pairs of the HD600/4 from the front of the vehicle. This is useful for subwoofer level control or even as a master volume control for the system.
The HD-RLC connects to the jack labeled “Remote Level Control” on the Connection Panel of the amplifier using a standard telephone cable (supplied with the HD-RLC).
If desired, multiple HD amplifiers can be controlled from a single HD-RLC controller using a simple phone line “splitter” and multiple phone cables.
L
Preouts Remote
Level
Control
R
When connected to the amplifier, the HD-RLC operates as follows. At full counter-clockwise rotation, the audio will mute completely. At full clockwise rotation the level will be the same as if the HD-RLC was not connected at all. In other words, it operates strictly as a level attenuator.
Depending on the application, you may want
the HD-RLC to only affect one channel pair or both channel pairs. A switch labeled “Remote Level Control” in the “General Setup” Section of the Control Panel allows you to determine whether the HD-RLC affects the level of all channels “All Ch.” or only the rear channels
“Rear Ch.”
