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2 ohm or 4 ohm

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=13465
Printed Date: August 21, 2025 at 3:54 PM


Topic: 2 ohm or 4 ohm

Posted By: 2001rolla
Subject: 2 ohm or 4 ohm
Date Posted: May 13, 2003 at 12:18 AM

I'm running an Alpine CDA-7893 through an Alpine MRV-F450 running a set of SPR-136A's in the front and SPR-176A's in the rear.

I want to add a sub tot he fifth channel on the amp. I've decided on the Alpine 10" Type R sub but need some advice. The sub has DVC's so I'll be wiring it in series but I need to know waht ohm rating I need... The 10" Type R sub comes in 2 ohm and 4 ohm models. What ohm sub do I need for this setup?

Thanks

-Jeff




Replies:

Posted By: wvsquirrel
Date Posted: May 13, 2003 at 1:03 AM
I haven't seen the CDA-7893 headunit, did you mean the CDA-7892? Doesn't play a role, just curious though...

As long as you're only planning on using 1 sub, then go with the SWR-1041D (4ohm DVC) and wire it in parallel. By wiring it in parallel you will get a 2ohm load and will get the most out of your amp (apx. 150watts).

BTY, just because it's a DVC doesn't mean that you have to wire in series! As long as your amp can handle the total ohm load, parallel wiring will give you more output due to a lower total ohm load (less ohms = less resistance = more power), and there's also the parallel/series configurations for multiple DVC subs as well. In this case, a single 4ohm DVC can be wired into a 2 or 8 ohm configuration. A single 2ohm DVC can be wired into a 1 or 4 ohm configuration.

According to the specs from Apline, the 12volt RMS continuous power rating of channel-5 is 150watts (regardless of 2ohm or 4ohm). So wiring-wise you can get the same wattage using a single 2ohm DVC wired in series for a 4ohm total load as you would a single 4ohm DVC wired in parallel for a 2ohm load. However, I would still go with the single 4ohm DVC wired in parallel for 2ohms because the amp will operate more efficiently at 2ohms then at 4ohms.

Also, the sub you are looking at has a 300RMS 1000Peak rating. You'll only be throwing half the RMS amount to it by using your current amp, so be prepared for it to be underpowered.

-------------
Squirrel
"No more Cpt. Kirk chit chat"
If its too loud, then you're too old
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Posted By: 2001rolla
Date Posted: May 15, 2003 at 12:15 PM

Cool! Thanks for the info.

I meant 7893... The 7893 is very similar to the 7892 but is silver and not black.

Wouldn't it be better to match the ohm load the amp is rated for? I'm not totaly up on all this ohm load stuff but yeah, I can see how running a 2 ohm load would be more efficiant.

I know I'm underpowering the sub running it from this amp but I'm not looking for earth shattering bass by any means. I really don't need the sub for my music listening habits, I just want to add a little more bottom end to some of the music where I notice it missing a bit (Mainly Pink Floyd Songs). I love the amp I have and the speakers are absolutely awesome and give out good low end as it is. I only need that little bit extra something something to bring the music up a notch...

I decided to go with the 2 ohm sub and wire it for a 4 ohm load to match the amp. I am gonna mount it up in a 1cubic foot sealed enclosure making it somewhere around .8 cubid ft. after the sub is installed. According to alpine, this should be the ideal box volume for this sub.

I'm getting the sub this Saturday and will let you know how it sounds.

-Jeff






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