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Discussion Starter #1 (Edited)
All,

Back in the '90s, I used to set amp gains by turning the level pot all the way up and then backing it down a little bit. REAL technical, I know.

In this install, I wanted to use my multi-meter to set the input sensitivity by following the instructions in the manual for my JL HD 600/4 that I use for my tweeters & mid-ranges.

I have a cheap multi-meter I bought from Parts Express years back, but figured it'd work for this job, it all seemed so simple.

However, since the amp location is in a tight space, I elongated each multi-meter lead using speaker wire, and then attached the opposite speaker wire ends to the =/- speaker wire input plug for the amp.

I then got the correct test tone from the JL website, put it on my iPhone, set it on loop, made sure the amp input was all the way down, made sure that the HU volume was 3/4 full (no EQ, etc on HU), turned on the car, and got the test tone loop going.

However, the multi-meter didn't read what I was expecting. In fact, it only registered 12.7v when I had the gain turned all the way up for the mid-range channel.

Any ideas what's going on? The amps work, the tweeters & mid-ranges work, I can play music through the system, etc.

Is it my cheap multi-meter?

The fact that I elongated the leads using speaker wire?

Because the car engine was on?

Wondering if I should just go back to my '90's method...

Thanks for any input!
 

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Discussion Starter #3
Sorry, Ray, forgot to add the HU make: Pioneer P99Rs (JDM version).

Amps are:
JL HD 600/4 for tweeters, 3" midranges
HD 600/4 for 8" midbasses (bridged)
HD 700/1 for subs (subs not installed yet)
 

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Hmmm, that deck is clean up to max volume from what I’ve read. Are your levels, xovers, eq, etc. all flat on the head unit? If your dmm shows varying voltages when you turn the gain, I doubt it’s the dmm being the issue. Double check all amp and deck settings. Do you have a link for the tone you are using?
 

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What setting do you have the meter on ?
Test it on your car battery and then start the engine and test the battery again. With motor running you should have over 13.5 volts.


Sent from my iPhone using Tapatalk
 

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Discussion Starter #7 (Edited)
Hey, I got the audio files from, here, towards the bottom of the page:
https://jlaudio.zendesk.com/hc/en-us/articles/204374120-Amplifier-Level-Setting-Guide

All of the inputs on the amps are set following the "Nine Step Procedure" in the 600/4 manual: aside from the steps I mentioned in my OP, the input voltage switch is set to "Low", & the input sensitivity pot is fully counter clockwise.

As for the HU, it's possible that there might be a setting I missed, since the display is mostly in Japanese. The obvious settings, like balance, bass, treble, loudness, fader, etc. are flat... I'll give the HU another look, and use Google translate to make out what the Japanese text says, lol.

I have the multi-meter set to AC ("V" with the sine wave over it on mine), "200" setting.

EDIT: Checked the battery, 12.2v when off, 14.3v when the car is on.
I also reset the HU, so that should mean everything is flat.

Thanks for the help!
 
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