4 x 8ohm svc subs for 2 ohm load?

Printed From: the12volt.com
Forum Name: General Discussion
Forum Discription: General Mobile Electronics Questions and Answers
URL: https://www.the12volt.com/installbay/forum_posts.asp?tid=1225
Printed Date: July 20, 2025 at 12:17 PM

Topic: 4 x 8ohm svc subs for 2 ohm load?

Posted By: blazer88
Subject: 4 x 8ohm svc subs for 2 ohm load?
Date Posted: June 10, 2002 at 3:37 PM

I am currently running 4 MTX Thunder 5000 15" subs in a 12cu.ft. ported enclosure as per MTX specs. I have 8 ohm subs and have a pair of MTX Thunder 2160's running at 4 ohm mono to power them. They are getting roughly 450 watts per pair. My question is can I purchase a 2ohm mono-block amp to run the 4 subs and if I can how would I wire them to run at 2 or even 1 ohm. I plan on selling the 2160's in order to purchase the mono amp. If anyone has a 1 or 2 ohm mono amp they would like to trade straight up or + cash let me know. That's if I can wire it to run all 4 subs. Thanx, blazer88@hotmail.com

Replies:

Posted By: vi-kan
Date Posted: July 01, 2002 at 12:25 PM

Theoretically, If you wire your circuit in series (amp output to speaker one pos and then from speaker one pos to speaker two pos) your resistance will increase with every connection. In retrospect, if you wire your circuit in parallel (amp to pos on speaker one and again, amp to pos on speaker two), you will be dividing your resistance.

So, if you took all four subs and wired them in parallel to the amp, your amp would "see" 1 ohm. Whereas if you wired your amp to speaker one pos, then from speaker one pos to speaker two pos and so forth, your resistance would increase, adding all impedance ratings of all four speakers. Hope this helps.

vi-kan

Posted By: vi-kan
Date Posted: July 01, 2002 at 12:48 PM

***Correction***

Theoretically, If you wire your circuit in series (amp output to speaker one pos and then from speaker one pos to speaker two neg) your resistance will increase with every connection. In retrospect, if you wire your circuit in parallel (amp to pos on speaker one and again, amp to pos on speaker two), you will be dividing your resistance.

So, if you took all four subs and wired them in parallel to the amp, your amp would "see" 1 ohm. Whereas if you wired your amp to speaker one pos, then from speaker one pos to speaker two neg and so forth, your resistance would increase, adding all impedance ratings of all four speakers.

Sorry for the confusion.

vi-kan

Posted By: GlassWolf
Date Posted: July 01, 2002 at 12:54 PM

wire each pair of 8-ohm subs in parallel. this gives you two 4-ohm loads.
then wire each pair in parallel, making a single 2-ohm connection.
now wire this to a mono (single-channel) sub-woofer amplifer.
do NOT bridge a stereo amp to run this configuration though, unless that stereo bridged amp can support a 1-ohm load, as bridging the stereo amp makes it see half of the actual load due to the internal circuitry of bridging.

-------------
-GlassWolf
Pioneer Stage-4, Orion, DynAudio, Fi