3 subs 2 amps ohm loads

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=104428
Printed Date: April 24, 2024 at 7:31 AM

Topic: 3 subs 2 amps ohm loads

Posted By: rajuncajun
Subject: 3 subs 2 amps ohm loads
Date Posted: May 02, 2008 at 11:15 AM

I have 3 JL 12w1s 2 are 8ohm and the other can be any ohm. I currenly have a box that is 3 chambers so each is in its on box. I have an Alpine MRV-F450 5 channel. From what I read that amps 5th channel is not stable at 2ohms so running 3 8ohm subs will give 2.67ohms. Also, I have an Alpine MRV-F540 4 channel.

Can I run 2 8ohm subs on the F450 to give 4 ohms and bridge one channel on the F540 to the 4 ohm sub? The F450 is 200watts at 4 ohms and the F540 is 200 watts bridge. Will this work or will it cause some type of noise or cancelation of sound problems. Thanks!

Replies:

Posted By: Alpine Guy
Date Posted: May 02, 2008 at 11:22 AM

No, wont work, the one sub will always be playing louder or quieter than the other two, it will sound horrible. Just use the two 8 ohm woofers in parallel.

-------------
2003 Chevy Avalanche,Eclipse CD7000,Morel Elate 5,Adire Extremis,Alpine PDX-4.150, 15" TC-3000, 2 Alpine PDX-1.1000, 470Amp HO Alt.

Posted By: rajuncajun
Date Posted: May 02, 2008 at 11:41 PM

Maybe I'll get a bite on this one. Can I run 2 8 ohm subs on the F450 200 watts at 4 ohms ( 100/sub) and 1 4 ohm on a bridge channel of the F450 at 100 watts?

Posted By: teenkertoy
Date Posted: May 03, 2008 at 5:31 AM

Your first method had the pair of woofers on the F450 getting 100w each while the single woofer on the F540 was getting 200w. You would have had to set the F540's gain at half of the F450 to match power output. Difficult, but possible to some degree.

Now your second idea fixes that problem, but you still have to be careful. You're using two different channels with two different gain adjustments, and one channel is the result of bridging two more channels! It's sketchy at best, but possible I guess. You'll have to be careful to match the gain of both the mono channel and the bridged channel to each other, and it may not sound great, but it can work.

Now I have to wonder ... why are you putting three of JL's low-end woofers in a big box instead of one of JL's mid-range woofers in a smaller box? Why not sell everything but the 5ch amp, and buy a 12w3 woofer? It can be powered from the 200w channel just fine.

-Justin

-------------
Malcom: "This is the captain. We have a...little problem with our engine sequence, so we may experience some slight turbulence and then...explode."
Jayne: "We're gonna explode? I don't wanna explode.