Help in using JL Audio's Amplifier Input Sensitivity (“Gain”) Setting Guide

[I_Love_Bass2]

Hello, I have a new JL Audio JX500/1D amp and two JL Audio 4 ohm Subs connected to it. Now I am going to follow this guide taken from JL Audio's website:

*Necessary Equipment*

 

• AC Voltmeter (Digital display recommended)

 

• CD with a sine-wave test tone recorded at 0dB reference level in the frequency range to be amplified (ex. 50Hz for a subwoofer amplifier, 1 KHz for a midrange application). Do not use attenuated test tones (-10dB, -20dB, etc.).

 

The Nine-Step Procedure

1. Disconnect the speaker(s) from the amplifier.

2. Turn “Off ” all processing on the head unit and the amplifier (bass/treble, loudness, EQ, etc.).

3. Turn the input sensitivity control on the amplifier all the way down and switch “Input Voltage” to “Low”.

4. Set head unit volume to 3/4 of full volume. This will allow for reasonable gain overlap with moderate clipping at full volume.

5. Cross-reference the amplifier model used and impedance load per channel on the charts on the next page to determine the target output voltage.

Note: When bridging two channels, the impedance each channel works at will be one-half of the load impedance. Therefore, it is necessary to divide the actual load impedance in half and use this impedance in the chart when bridging two channels. Also, the voltage found in the chart should be doubled.

6. Verify that you disconnected the speakers before proceeding. Play a track with an appropriate sine wave (within the frequency range to be amplified) at 3/4 head unit volume.

7. Connect the AC voltmeter to the speaker output of the amplifier.

8. Increase the input sensitivity control until the desired voltage (determined in Step 5) is delivered. If multiple subwoofer amps are being used, set each one to the same exact voltage and you have also level matched them. If excessive voltage is read with the control at minimum (full counterclockwise), switch the “Input Voltage” to “High” and re-adjust.

9. Once you have adjusted each amp to its maximum unclipped output level, reconnect all the speakers and proceed to adjust the level balance between the subwoofer and satellite amplifiers by turning DOWN the input sensitivity controls of amplifiers that are playing too loudly. Do NOT increase the input sensitivity of any amplifier as this will defeat the purpose of this procedure by permitting excessive clipping (distortion).

The questions I have are:

Question 1: Is the 50Hz sine-wave test tone recorded at 0dB reference level ok to be used for this test even though I have my amps filter frequency set at 80Hz?

Question 2: Looking at my amps voltage chart: I take it I need to look at the 2ohm section as I have two 4ohm subs running in parallel to my amp? The voltage I need is 31.6 correct?

JX Amplifiers Voltage Chart:

 

JX500/1D

Imp. Voltage.

4Ω 36.9

 

3Ω. 35.5

 

2Ω 31.6

And my last question is about JL Audio RCB-1 remote level control level that I have connected to it. Should I have this disconnected when doing this test?

I haven't even got a clue how to operate the RCB-1, do not know if I have to set the Bass Boost dial in anyway or do I leave it at 0 for the RCB-1 to be working correctly?

Many thanks to anyone who can help.

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[FML 10+ year member]

Yeah, your filter is set to play frequencies 80hz and below, so you're fine where its set. Also, if your final impedance is 2Ω, then yes obviously you would set it to the recommended voltage for 2 ohms.

Lastly I would do one of two things with your bass remote. 1,get rid of it entirely. If you set your gain right, you shouldn't need it. Second, unplug it or turn it.off or flat.

 

[snyderd758 10+ year member]

find a -5 or -7db test tone to set your amp depending on the type of music you listen to. -3 or -5db for rap(or other bass heavy music) -7db for heavy metal or like music. if you use the 0db you will never see full power.