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 |  JL Audio - MHD600/4-24V Owner’s Manual  

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 MHD600/4-24V can be configured to 

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

 

bi-amplified system with one mHd600/4-24V

In this configuration, the “Rear” channels 

of the MHD600/4-24V 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 MHD600/4-24V:

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 
mHd600/4-24V 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 MHD600/4-24V 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 MHD600/4-24V’s preamp output or from a 
dedicated subwoofer output on the source unit. 

Crossover Setup for Bi-Amplified System with 
one MHD600/4-24V 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 MHD600/4-

24V’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 MHD600/4-24V use the method shown 
in Appendix C (pages 18, 19). For precise filter 
frequency information for the MHD600/4-24V 
refer to Appendix B (pages 18). Refer to the 
subwoofer amplifier owner’s manual for its proper 
adjustment levels.

Summary of Contents for MHD600/4-24V

Page 1: ...s 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 thoroug...

Page 2: ...fier is designed for operation in vessels with 24 volt negative ground electrical systems Use of this product in vessels with positive ground and or voltages other than 24V may result in damage to the...

Page 3: ...jolt or as a result of the repeated vibrations the vessel is prone to during normal operation Stupid Mistakes to Avoid Check before drilling any holes in your vessel to make sure that you will not be...

Page 4: ...stem delivering high passed signals to front and rear speaker systems Preamp outputs permit connection of a separate amplifier to drive the subwoofer system 3 As a 600W full system amplifier in bi amp...

Page 5: ...ttery post Use the same size power wire as the wire connected to the 24V connection minimum 8 AWG 5 Run signal cables RCA cables and remote turn on wire from the source unit or interface processor to...

Page 6: ...tc We do not recommend the use of copper clad aluminum wire or CCA wire because this wire is significantly less conductive than pure copper wire Only use pure copper power wire such as JL Audio Premiu...

Page 7: ...ire and insert the bare wire into the receptacle 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...

Page 8: ...ling any holes in your vessel to make sure that you will not be drilling through a gas tank brake line wiring harness or other vital vessel system ConTROL PAnel SECURITY CoVER The MHD600 4 24V feature...

Page 9: ...n on the Input Mode switch and connect a single pair of input cables to the Front input jacks only In this mode the amplifier will route the signals connected to the Front inputs to the Front and Rear...

Page 10: ...en the Input Range switch is placed in the High position The output increases with the switch in the Low position While this may sound counter intuitive it is correct as described Input Sens Control L...

Page 11: ...h allows you to select from two filter slopes 12dB Configures the filter to attenuate frequencies above or below the selected filter frequency at a rate of 12 dB per octave Butterworth alignment 24dB...

Page 12: ...ecise filter frequency information refer to Appendix B page 18 Bi Amplified System with one MHD600 4 24V in four channel mode and a separate subwoofer amplifier This configuration requires that the se...

Page 13: ...HD600 4 24V 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 ch...

Page 14: ...r Speaker OUTPUTS The MHD600 4 24V 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 soph...

Page 15: ...el pair This requires an RCA Y Adaptor sold separately because a bridged pair of channels requires that both amplifier channels of the bridged pair receive input Connection of only one RCA input will...

Page 16: ...he amber LED will light when you connect the section that is experiencing the problem and turn the volume up 4 Alternating Red and Green lights to indicate that the amplifier is experiencing a fault t...

Page 17: ...g power supply Recommended Fuse Value Type 25A AFS AGU or MaxiFuse Rated Power Stereo 150W RMS x 4 1 5 4 22V 29V Rated Power Bridged 300W RMS x 2 3 8 22V 29V THD at Rated Power 0 03 4 per channel Aver...

Page 18: ...ipped output is very predictable This makes setting the gain structure via the input sensitivity controls very simple Following the directions below will allow the user to adjust the input sensitivity...

Page 19: ...ceeding Play a track with an appropriate sine wave within the frequency range to be amplified by each set of channels at 3 4 source unit volume 7 Connect the AC voltmeter to the Front Speaker Outputs...

Page 20: ...the speaker wires for a possible short either between the positive and negative leads or between either speaker lead and the vessel s chassis ground If a short is present you will experience distorte...

Page 21: ...ate test tone is played through the source unit disconnect the input cables from the amplifier prior to this test The frequency used should be in the range that is to be amplified by the amplifier exa...

Page 22: ...22 JL Audio MHD600 4 24V Owner s Manual INSTALLATION NOTES Use this diagram to document your amplifier s switch and control positions...

Page 23: ...23...

Page 24: ...d warranties therefore these exclusions may not apply to you This warranty gives you specific legal rights and you may also have other rights which vary from state to state If you need service on your...

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