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4ohm/8ohm question

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=21002
Printed Date: May 09, 2025 at 1:13 PM


Topic: 4ohm/8ohm question

Posted By: peteacher
Subject: 4ohm/8ohm question
Date Posted: November 04, 2003 at 4:27 PM

Hello everyone...I have a typical 4 ohm amp that I have not used for ages...and I want to buy a sub that is 8ohm...

Q1. Can I use an 8ohm sub on a 4 ohm amp?
Q2. IF I bridge 2 channels on the 4ohm amp, can I use it to drive the 8ohm sub?
Q3. If I was to buy 2 of these 8ohm subs and run them in parallel, would that work?



Replies:

Posted By: superstreet786
Date Posted: November 04, 2003 at 4:31 PM
I know for sure Q3 would work but im not sure about the others

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---- 1996 Chevy S10 ----
1 Lightning Audio S2.600.2 Amp
2 Lightning Audio 12" Subs
1 Lightning Audio 1 Farad Cap




Posted By: auex
Date Posted: November 04, 2003 at 5:07 PM
1. The amp will work with many different ohm loads, just don't go below what it is stable at. 2. Yes. 3 if you wired two 8 ohm speakers parrallel it would be a 4 ohm load, so yes it would work.

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Posted By: forbidden
Date Posted: November 04, 2003 at 5:29 PM

All of your questions are answered by yes.

(1) by using a single 8 ohm sub on the amp, all it will do is knock the amps power down by 50%, not really what we want to do.

(2) Bridge the amp to 4 ohm mono, lets say that you amp produces 200w at 4 ohm mono, with 8 ohm sub hooked up, yuo now have 100w at 8 ohm mono, still not what we want.

(3) two 8 ohm subs wired in parallel equals 4 ohm mono. Exactly where your amplifier in bridged mode makes the most power. To wire in parellel, take a look at the parallel wiring chart on this site, it will show you graphically and mathematically how to hook up your speakers, need more info, there are a lot of owner / installers like myself who would be glad to help you out.



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Top Secret, I can tell you but then my wife will kill me.




Posted By: peteacher
Date Posted: November 04, 2003 at 9:01 PM
Thanks everyone...
I am wondering where I can see the wirting diagrams on this site. I have found some with relays..is that the one you are talking about "forbidden"?




Posted By: Ketel22
Date Posted: November 04, 2003 at 11:38 PM
if you click the parallel and series calc, under car audio that will be alot of help, if you need to under stand the parallel and series concepts better, i would suggest the rockford site (https://www.rockfordfosgate.com/rftech/wiringwizard/), which will show you the options with the subs that you have.

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