Want To Set Gains With DMM

Printed From: the12volt.com
Forum Name: Car Audio
Forum Discription: Car Stereos, Amplifiers, Crossovers, Processors, Speakers, Subwoofers, etc.
URL: https://www.the12volt.com/installbay/forum_posts.asp?tid=116062
Printed Date: May 13, 2025 at 10:19 PM

Topic: Want To Set Gains With DMM

Posted By: jdubicki
Subject: Want To Set Gains With DMM
Date Posted: September 02, 2009 at 4:23 PM

Hopefully you guys can help. This is what I have:

HU - Pioneer DEH-P2900MP

Amp- Alpine MRP-M500 500 Watts @ 2 ohms

Subs - MTX Thunder 4000 200RMS/400Max

DMM - Ideal 61-310 Looks like this:

posted_image

Did the formula 400 x 2 = 800, sq root = 28.29

Using 50 Hz test tone and looking to get 30 volts on meter. I can barly get 2. I have tried the different settings on the DMM, but really not sure which one to use. Pretty sure test tone is at 0 db. Please help.

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2005 Honda Accord DX

Replies:

Posted By: DYohn
Date Posted: September 02, 2009 at 4:34 PM

AC volts, 200-volt scale, meter leads connected to the COM and Temp-V-Ohms terminals, measurement taken on amplifier speaker output with the speaker disconnected.

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Posted By: jdubicki
Date Posted: September 02, 2009 at 6:56 PM

The speaker has to be completely disconnected?? I have read that you need a load. Some say one terminal connected, others say both. I have done it with pos disconnected and cannot get a reading.

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2005 Honda Accord DX

Posted By: DYohn
Date Posted: September 02, 2009 at 7:22 PM

jdubicki wrote:

The speaker has to be completely disconnected?? I have read that you need a load. Some say one terminal connected, others say both. I have done it with pos disconnected and cannot get a reading.

The speaker should be disconnected. If you cannot get a reading first make sure your meter works. Test it at a household outlet that you know works. Also, you are trying to set a level with a 50Hz tone? Are you sure the crossover or the Xover in the amp is set to LP and at about 80-100Hz?

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Posted By: i am an idiot
Date Posted: September 02, 2009 at 7:44 PM

You must connect both meter leads to get a reading. Red lead on positive speaker terminal. Black lead on the negative speaker terminal.

Posted By: DYohn
Date Posted: September 02, 2009 at 7:46 PM

i am an idiot wrote:

You must connect both meter leads to get a reading. Red lead on positive speaker terminal. Black lead on the negative speaker terminal.

Ah yes, I often forget to mention the most basic part of the instructions. I guess I assume too much sometimes ... thanks!

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