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what test tones

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=75691
Printed Date: September 06, 2025 at 4:38 PM


Topic: what test tones

Posted By: timmyjimmy5150
Subject: what test tones
Date Posted: April 04, 2006 at 7:28 PM

I want to se the gain on my 4 channel 450/4 JL amp -----

I want to use a test tone CD ......

I have 2 sets of component speakers........ but I have no idea which test tone to use...

Any help?  I will be using a DMM

TJ




Replies:

Posted By: coppellstereo
Date Posted: April 04, 2006 at 7:54 PM
to set gain I think you just play normal music, whatever you typically listen to.

To set crossovers you can use the test tones.

but you are right, test tones will be easier to measure with the dmm

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Posted By: stevdart
Date Posted: April 04, 2006 at 9:06 PM

search for 'gain'

Use the test tones for all:  setting the head unit output level, setting the gains, and setting the crossovers.  Use a DMM as a backup but also use your ears to hear the clipping, which is quite apparent when running a pure sine wave.  And use ear plugs to block out some of the db's.

 



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Build the box so that it performs well in the worst case scenario and, in return, it will reward you at all times.




Posted By: coppellstereo
Date Posted: April 04, 2006 at 9:52 PM
you can set your gain even with the volume low, is that correct?

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Posted By: stevdart
Date Posted: April 04, 2006 at 10:02 PM

No, gain is set at just below the point of clipping.  In other words, at full blast.  Crossover settings, on the other hand, may be set at very low volume so that you can more easily distinguish the dropoff of sound at the desired frequency.

By the way, keep the sine tones in short duration so that the voice coils don't overheat.  You may need to allow some cooling time as well, so take your time doing the gain setting.  When testing voltage output using a DMM, the speakers are disconnected, so length of time to test is not important with this method.  But as I said above, you'll be better off using your hearing over the DMM / Ohm's Law method, simply for the fact that there are a few assumptions that have to be made when you measure voltage for the purpose of setting gain.  One is that the amplifier's power output is truly rated.  We know what a farce that can be nowadays.



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Build the box so that it performs well in the worst case scenario and, in return, it will reward you at all times.





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