How do I find the proper sized amp?

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=51987
Printed Date: May 15, 2025 at 9:28 PM

Topic: How do I find the proper sized amp?

Posted By: mben
Subject: How do I find the proper sized amp?
Date Posted: March 16, 2005 at 7:58 AM

I need to figure out how large of an amp I need. I have a component system with 6-1/2" mid/woofers with tweeters run off crossovers. The owners manual lists the peak power at 300w and the continuous power at 100w with a nominal impedance of 4 ohms for the system. I am also installing a 6.5" Bazooka tube with a maximum 300w and continuous 150w. I am also trying to figure out if I can oversize the amp in case I go with a larger subwoofer with a maximum 500w in the future. I would appreciate any input.

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Mben

Replies:

Posted By: chucksnee
Date Posted: March 16, 2005 at 10:19 AM

You can always go with a bigger amp, but you MUST WATCH YOUR GAINS in that situation.

as for amp size with those speakers i would try and stay around the RMS or maybe split it, if you can find an amp that has 125 watts RMS that is what i would go with.

Posted By: kfr01
Date Posted: March 16, 2005 at 10:42 AM

mben: so you're looking for a 4-channel amplifier?

1st: stop even looking at the peak power - it means nothing.

2nd: a doubling of power only gains a max 3db increase in SPL. 3db is small. So, you'll barely hear any difference between a 50x4 amplifier and a 75x4 amplifier.

3rd: as long as you aren't an idiot with the volume control you can get an enormous amplifier.

4th: do take care to set the gains correctly along with not being an idiot. If you run your amplifier into severe clipping and are running a large amplifier for your speakers, there will be problems.

I'd be looking the highest quality 50x4 amplifier you can afford. 50w is more than enough for components and the probably 200w bridged is fine for your bazooka. Then, if you need a larger subwoofer in the future, go with a separate class D amplifier. OR run it off the 200w bridged - you'll probably be happy with it. Again, the actual audible difference between 200w and 500w isn't large.

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New Project: 2003 Pathfinder