# dual 2 ohm or dual 4 ohm sub?



## teoulennon (Dec 5, 2012)

I've searched everywhere and am having trouble finding a concrete answer on this..
I've decided on a single sa-10 sub but I'm not sure whether I should get the dual 2 ohm or dual 4 ohm voice coil.
I haven't purchased the amp yet so I can pretty much choose whatever ohm I want to run the sub at - the 2 ohm vc sub @ 1 or 4 ohms OR the 4 ohm vc sub @ 2 ohms (i don't want 8)
I realize that in general I will have to pay more for the same amt of power when raising the impedance of the amp.

My question is this: is there any benefit to running the sub at a higher impedance?

Would there be more strain on my alternator, etc. if I ran the sub at 2 ohms as opposed to 4?


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## 07azhhr (Dec 28, 2011)

Since the sub you want has options for all ohm loads between 8 and 1 I would pick the amp you want and then get which ever of the 2 sub options works best for that amp. 

As for your amp questions. Yes running an amp (providing it is capable) at 2 ohms vs 4 ohms will draw more current but keep in mind that with most class ab amps the amp will not be running as efficiently as it does at full output (the 2 ohm load in this example). What this means is that lets say at 2 ohms will draw 80 amps, at 4 ohms it might still draw 65 amps. That 15 amps may or may not break you from an alternator standpoint. Class d are a bit more efficient when ran at lower output levels and the difference may be quite a bit more. The biggest advantage, imho, to running the amp at the lesser output 4 ohm load would be less heat but then you might need a larger amp to make up for the power difference and then the current draw and heat level may actually be higher then the smaller amp that is running at 2 ohms or 1 ohms.


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## Hanatsu (Nov 9, 2010)

I usually go for 4ohm DVCs if I'm running a single sub setup and a 2ohm DVC if I'm running dual subs. Most amps are fine with 2ohm loads. Not all amps are rated for 1ohm loads though.

Sent from my Samsung Galaxy 3 via Tapatalk.


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## teoulennon (Dec 5, 2012)

Thanks for the replies.
So if I'm understanding correctly, if I run it at 2 ohms it will draw more power from my alternator BUT running it at 4 ohms may require a larger amp which may draw even more power than the 2 ohm?

If I have, say, a 700w rms amp @ 2 ohms do I even need to be concerned about how much power it draws?

Besides draw on an alternator and amp heat are there any other advantages to running it at a higher impedance?

I'm leaning towards running it at 4 ohms.


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## Oliver (Jun 25, 2007)

The higher the resistance of the speaker ....

1} the less amperage the amplifier will draw, the smaller the wires (could be), they are rated for ampere draw. (i.e. might be able to connect amp with 8 awg or 10 awg versus 2 awg or 1/0 awg ).

subsequently, the fuse may be smaller that protects the wire.

I prefer an amp running easier, as opposed to running "Balls To The Wall", with my headlights morris coding the song to oncoming PO PO


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## 07azhhr (Dec 28, 2011)

Keep in mind that every thing we all have been talking about only effects mono amps. 

2 channel and 4 channel amps will run "balls to the wall" at 4ohms bridged. 

With mono amps, if they are stable to 1 ohm and you run it at 2 ohm then you are not asking it to run "balls to the wall". 

Many things to consider and 2 ohms is not always the most current hungry option. Thus why I say just choose an amp then pick your subs config.


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## teoulennon (Dec 5, 2012)

Obviously I would want to run the sub at 2 ohms because I could get a higher quality amp for a cheaper price, but I'd rather not sacrifice alternator draw or heat.

Are you saying that when considering the draw on an alternator, if an amp is stable at 1 ohm and I run it at 2 ohms it _could_ be equivalent to running a 2 ohm stable amp at 4 ohms?

I'm considering the massive audio N4 amp to run at 4 ohms (650w rms): Massive Audio N4 4000W Max Nano Monoblock Amplifier

Or some random amp to run at 2 ohms like this kicker (600w rms): Kicker CX600.1 (12cx6001) 600W RMS Class D Mono CX Car Amplifier

I think I'm just going to bite the bullet and get the N4 before I pull my hair out.


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## 07azhhr (Dec 28, 2011)

teoulennon said:


> Obviously I would want to run the sub at 2 ohms because I could get a higher quality amp for a cheaper price, but I'd rather not sacrifice alternator draw or heat.
> 
> Are you saying that when considering the draw on an alternator, if an amp is stable at 1 ohm and I run it at 2 ohms it _could_ be equivalent to running a 2 ohm stable amp at 4 ohms?
> 
> ...


Yes that is exactly what I am saying. 

If your stock electrical system is in good shape you should be good to provide under 900w without much worry of things like dimming headlights and such. 

I am running 4 amps all class ab running lower then their full tilt ohm load and only have a potential of up to 800w (setup like this) and have zero issue with draw and heat. 

I really think you will be ok with any scenario.


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## nellymerc (May 3, 2012)

As a reference to help the decision making process, I have a JBL GTO7001 running my sub at 2 Ohms. No capacitor, no upgraded alternator, or big 3 upgrade. Just a decent battery and my lights don't dim no matter how hard I push it. I haven't felt the amp to see how hot its gets but its rated for 2 Ohms so I'm not concerned. Not to mention I'm under powering the sub by a little bit but just my quick input.


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## teoulennon (Dec 5, 2012)

Well I ended up going with a kicker cx600.1 for a 2 ohm load: Kicker CX600.1 (12cx6001) 600W RMS Class D Mono CX Car Amplifier

I had a zx400.1 for almost 5 years with no problems and couldn't pass up the price of $250 w/ a free wiring kit so we'll see how it goes!
If it's not ideal I'll just replace it - live and learn right?

Thanks for all the help!


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## 07azhhr (Dec 28, 2011)

If it can make close to that 600w then I would imagine that you will be alright. So now go get that dual 4ohm sa-10.


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## teoulennon (Dec 5, 2012)

Well I wasn't so sure on the kicker amp (I can't find any info on it - it's not even on kickers website?) so I changed my order to get a massive audio N3 Massive Audio N3 Nano Monoblock 2800W Max Amplifier
It's got 700w at 2ohms and is 1 ohm stable so I feel better about it's current draw.


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## Oliver (Jun 25, 2007)

Maybe you can get some 2 awg from a local welding shop.

You can go to BCAE, basic car audio electronics, to find out how large of a fuse to use to protect your wire.


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## blazeplacid (May 19, 2008)

I'd be careful running that amp at 1 ohm. I had a nx5 and it shut off after 20 min running at 1 ohm. 
Got to hot. 
Hopefully the nx3 doesn't have the same issue 

Sent from my SAMSUNG-SGH-I747 using Tapatalk 2


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## MarkZ (Dec 5, 2005)

Oliver said:


> The higher the resistance of the speaker ....
> 
> 1} the less amperage the amplifier will draw, the smaller the wires (could be), they are rated for ampere draw. (i.e. might be able to connect amp with 8 awg or 10 awg versus 2 awg or 1/0 awg ).


...and the less output you'll have.

There's no free lunch. Less current from the alternator means less output from the sub, all else being equal.


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## 07azhhr (Dec 28, 2011)

blazeplacid said:


> I'd be careful running that amp at 1 ohm. I had a nx5 and it shut off after 20 min running at 1 ohm.
> Got to hot.
> Hopefully the nx3 doesn't have the same issue
> 
> Sent from my SAMSUNG-SGH-I747 using Tapatalk 2


He wants to run it at 2ohm for that amp.


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