gain setting

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=106235
Printed Date: July 03, 2025 at 11:26 AM

Topic: gain setting

Posted By: hideandseek
Subject: gain setting
Date Posted: July 19, 2008 at 3:18 PM

I've read and reread the "How to set your Gain" thread, but my situation is a little different. My amp is a Hifonics Brutus BXi1208D which is a D-class mono block and it is currently powering one(should be and soon to be 2 because one was damaged when I got it) Volfenhag ZX4712 subwoofers. The subwoofers are 500 watts rms each, but my amp will put out 600 watts to each subwoofer if it is set to the maximum performance as indicated by the other thread.(600 at 2 ohms for one subwoofer and 1200 at 1 ohm for two subwoofers)

Now since I absolutely do not want to blow my subs (call me crazy) how should I set my gains and bass boost so I will be safe. I don't have to have the maximum, just a safe level that still sounds good.

Replies:

Posted By: DYohn
Date Posted: July 19, 2008 at 3:33 PM

Well, blowing a Volfenhag speaker could only improve it posted_image

but use Ohm's law. 500 watts into 2-ohms corresponds to 31.6 volts output from the amplifier. Set the max amplifier output using the voltage measurement method.

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Posted By: hideandseek
Date Posted: July 19, 2008 at 3:46 PM

So would I use a voltmeter to measure it at the output as I'm changing the gain?

Posted By: DYohn
Date Posted: July 19, 2008 at 5:05 PM

Yes. Turn off the system, disconnect the speaker, turn it back on and play a test tone at say 60Hz, turn your HU volume up as far as you'll ever turn it, connect an AC volt meter to the amplifier speaker output, slowly turn up the gain (starting all the way down) until you read approximately 31.6 volts AC. Disconnect the meter, turn down the HU, turn off the system and reconnect the subwoofer. Should be good to go.

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Posted By: hideandseek
Date Posted: July 20, 2008 at 8:22 AM

Ok, thanks

Is there a retail store that sells test tone CD's or will I have to order one online?

Posted By: DYohn
Date Posted: July 20, 2008 at 10:58 AM

HERE's a good one you can download and burn your own CD.

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Posted By: dragon51
Date Posted: July 21, 2008 at 7:16 PM

DYohn

Is that a better way then this method that is pinned. This is the way I have always set the gains.

1. Play a typically loud music CD in your headunit. Set volume to 75%. Wear ear protection.
2. Starting with the amp gains at their lowest setting, slowly raise one gain at a time until you hear clipping from the corresponding speaker. This will sound like audible distortion.
3. Once you've found the clipping point, back the gain down until you no longer hear the distortion.