setting gains?

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=102067
Printed Date: May 16, 2024 at 8:57 AM

Topic: setting gains?

Posted By: jmalbright
Subject: setting gains?
Date Posted: February 10, 2008 at 8:21 PM

I have read this topic on setting gains and I understand it well for the most part. However, I have a couple of questions.

1) When calculating the voltage should I use the max power rating of my amp or the rms rating?

2) I have an MTX Thunder 421D amp that is rated at 300W RMS @ 12.5V and 420W @ 14.4V (these are actually the min. ratings and the amp actually produces more power than these ratings) and 1000W peak @ 2Ohms. If I use the RMS value for the calculation, which one should I use 300 or 420?

Here are my voltage calculations for each power rating. Please tell me which one is correct.
300W: 24.5V
420W: 29V
1000W: 44.7V

Replies:

Posted By: stevdart
Date Posted: February 11, 2008 at 12:08 AM

1. Never use "max".

2. Meter your voltage at the amplifier to find out if its closer to 12.5 or 14.4V. IMO, 14.4 is the best case scenario (for power ratings) and usually doesn't apply in real life. 12.5 to 13 volts is more realistic.

3. Is there going to be a test? ;) Answers for numbers 1 and 2 reveal the answer for this one.

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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: jmalbright
Date Posted: February 11, 2008 at 7:46 AM

I figured the RMS power rating was the right one to use, but wanted to make sure. Thanks for the reply.