# 2ohm vs 4ohm? explanation please



## MPTech (May 17, 2013)

What is the difference between 2ohms & 4ohms speakers?

I had planned to buy a set of Polk DXi690, that are rated at 100 watts RMS @ 4ohms.
I already have a Kenwood KAC-8405 amplifier rated at 60 watts RMS x 4 at 4 ohms (90 watts x 4 at 2 ohms).

If I understand correctly 4ohm speakers are better than 2ohm, but I don't understand why.

I saw another set of speakers (JBL GTO938) that received a higher review rating in top 10 speakers, but they are rated: "300 Watts peak power handling; 2 ohm impedance".
then goes on to explain "_True 4-Ohm Topology 
Low-impedance speaker voice coils extract more power from your amp for more powerful performance than high-impedance coils do. JBL GTO938 speakers use a lower-impedance voice coil than a typical 4-ohm speaker to extract the most power possible from all amplifiers engineered to drive loads of 4 ohms or less. And the GTO938 is compatible with both aftermarket head units and factory-installed systems. Since many factory-installed systems incorporate 2-ohm speakers and include amplifiers designed to drive 2-ohm loads, replacing those reduced-impedance speakers with a typical 4-ohm model will reduce the power output from the amplifier. For the most powerful performance, the GTO938 makes the best use of any amplifier by providing an optimum 2-ohm load_."

so, now I'm confused again. too much marketing hype, I'm sure!

which would you buy, with my Amp?

Can someone explain this in non-audiophile terms?
(I don't need to wire anything differently, do I?)


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## gijoe (Mar 25, 2008)

2ohms vs. 4ohms is just a matter of resistance. The lower the resistance (ohms) the more power the speaker will pull from the amp. If the amp is stable at 2ohms then a 2ohm speaker will get more power than a 4ohm speaker. There is no "better" when it comes to this, it just depends on the amp that you have and what it's capable of. The more power that the amp is producing, the harder it's working, so if you can get the desired output at 4ohms then you'll be saving your amp from working harder. The speakers that you have are 4ohms, so you will need to look at the 60 watt figures.


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## sqshoestring (Jun 19, 2007)

Speakers operate kind of like light bulbs. If you want a brighter bulb let more current through it. A smaller watt bulb will have more resistance and pass less current. Speakers do the same thing with your amp, the speaker controls the power with its impedance (resistance). The speaker can let more or less power through. An amp is built to operate at recommended ohm loads, the lower the ohms the more power goes through the speaker and the amplifier outputs. It is harder on the amp but much more so if not designed for that low of a load. Impedance is the same type thing as resistance, but since a speaker is always changing resistance the dynamic measure of impedance is used. For non electronics people just consider them the same. For electricity the 'load' is always what is being run by the power be it a speaker or motor or bulb, etc. The load has resistance or it would short out the power supply.

Those speakers tend to be for if you want to run your amp at 2 ohms and only want one set of speakers, then you must run 2 ohm speakers as most coax/etc non-sub car speakers are 4 ohm. It does give a boost but not a huge amount. The sensitivity of the speakers can have that much effect in some cases.


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## MPTech (May 17, 2013)

thanks for the quick reply gijoe and sqshoestring

I don't have any speakers yet, that's what I'm trying to decide.

I was planning: Polk DXi690, that are rated at 100 watts RMS @ 4ohms.

then I saw JBL GTO938 "300 Watts peak power handling; 2 ohm impedance", but it goes on to explain they are "True 4-Ohm Topology" ........ "JBL GTO938 speakers use a lower-impedance voice coil than a typical 4-ohm speaker to extract the most power possible from all amplifiers engineered to drive loads of 4 ohms or less." (sounds like marketing BS)

which speaker would you recommend?
Polk DXi690, 4 ohms, Specs/Performance: 9.1/10, Sound Quality: 9.4/10
or
JBL GTO938, 2 ohms, Specs/Performance: 9.4, Sound Quality: 10/10


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## syc0path (Jan 23, 2013)

MPTech said:


> "_JBL GTO938 speakers use a lower-impedance voice coil than a typical 4-ohm speaker to extract the most power possible from all amplifiers engineered to drive loads of 4 ohms or less. And the GTO938 is compatible with both aftermarket head units and factory-installed systems. SFor the most powerful performance, the GTO938 makes the best use of any amplifier by providing an optimum 2-ohm load_."
> 
> so, now I'm confused again. too much marketing hype, I'm sure!
> 
> which would you buy, with my Amp?


Yeah, too much marketing. I've never seen a HU (OEM or aftermarket) that can handle a 2ohm load. So how can these speakers be 2ohm if they're compatible w/ HUs?? 

I don't trust that site that u linked to either. It looks like they rate everything very high just to get u to buy it. I would do some more research before u buy either.

In fact, u may not want to buy anything. Rear speakers have to be tuned very carefully to avoid pulling the soundstage to the rear of the car, hurting the imaging, and causing phasing issues w/ the sub. I haven't run rear speakers in years for these reasons.


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## Alrojoca (Oct 5, 2012)

Most likely those JBL' s are not 2.ohms maybe like 2.8 or 3.1 average and they call it a 2 ohm speaker just to pick a number between four and two and not picking up 3 since that is not used.


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