wiring three subs and amp selection

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=123163
Printed Date: May 13, 2025 at 7:02 PM

Topic: wiring three subs and amp selection

Posted By: taiwanteg
Subject: wiring three subs and amp selection
Date Posted: August 18, 2010 at 5:18 PM

I just picked up a JL stealth box that holds three 10" subwoofers

pic:
posted_image

I have two amps left over from my previous setup, and I was wondering what would be the best option to put them to use without having to buy new equipment.

Amps available:
HELIX Competition 4
Specs:
at 4 Ohms RMS/12 V: 4 x 60 W
at 4 Ohms/13,8 V: 4 x 85/150 W
at 2 Ohms/13,8 V:4 x 153/250 W
at 4 Ohms bridged: 2 x 270/450 W
at 2 Ohms bridged: 2 x 395/650 W

Alpine MRD-M605
at 4 Ohms 400 watts x 1
at 2 Ohms 600 watts x 1

Subs that I am currently looking into:
10WX
https://mobile.jlaudio.com/products_subs.php?series_id=35
Depth: 4.80 in. / 122 mm
60W min // 125W Optimum //200 void
Nominal Impedance (Znom):      4 ohm
Thermal Power Handling (Pt):      200W

10w0v2
https://mobile.jlaudio.com/products_subs.php?series_id=32
Depth: 4.90 in. / 124 mm
Nominal Impedance (Znom):      4 ohm
Thermal Power Handling (Pt):      300W
Recommend: 125-250 watts RMS

Any feedback is greatly appreciated.

Replies:

Posted By: icearrow6
Date Posted: August 18, 2010 at 6:17 PM

I can't tell by the picture, but it looks like the wiring in the box is in parallel ( all positive to positive terminal, all negatives to negative terminal).
If this is the case, with the woofers you have chosen they will yield a 1.333 ohm load on the amp. Neither of the amps you currently have can handle this load.

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Posted By: taiwanteg
Date Posted: August 18, 2010 at 6:56 PM

icearrow6 wrote:

I can't tell by the picture, but it looks like the wiring in the box is in parallel ( all positive to positive terminal, all negatives to negative terminal).
If this is the case, with the woofers you have chosen they will yield a 1.333 ohm load on the amp. Neither of the amps you currently have can handle this load.

I can re-wire the terminal posts to accommodate my Amps. Just can't figure out exactly how I can run this setup with three subs.

Posted By: taiwanteg
Date Posted: August 19, 2010 at 3:12 AM

icearrow6 wrote:

If this is the case, with the woofers you have chosen they will yield a 1.333 ohm load on the amp. Neither of the amps you currently have can handle this load.

Would 1.33 be read as 2ohms on the Amp? If so, I can probably use my Amp in 600w x 1 @ 2ohms to power the three subs?

Posted By: icearrow6
Date Posted: August 19, 2010 at 12:02 PM

no, the amp would see a number closer to 1 ohm. The amp might work, but it WILL eventually damage it.

I suppose the only real solution would be to use the HELIX amp.
One pair of the woofers, on channels 1+2 bridged.
The third woofer on the bridge of channels 3+4.

The first pair will get 395w
and the third woofer 270w

You will have to set the gains accordingly to balance all three.

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Posted By: taiwanteg
Date Posted: August 19, 2010 at 9:57 PM

icearrow6 wrote:

no, the amp would see a number closer to 1 ohm. The amp might work, but it WILL eventually damage it.

I suppose the only real solution would be to use the HELIX amp.
One pair of the woofers, on channels 1+2 bridged.
The third woofer on the bridge of channels 3+4.

The first pair will get 395w
and the third woofer 270w

You will have to set the gains accordingly to balance all three.

Humm.. that makes sense. Seems to be a possible solution. Thanks anymore tips?