4 ohm vs. 2 ohm?

[ccajun4real 10+ year member]

What is the drawback of running at 2 ohms other than more current draw? I ask because I can not figure out why for example you would purchase a 75 x 4 amp and pay more when you can use a 2 channel amp at 2 ohms to supply the same power for alot less money. I am asking because I am about to change my amps out and do have a 4 channel but would rather use a two and keep my amps the same brand name. Thanks

Cajun

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[helotaxi 5,000+ posts]

Well you have to find speakers that can load the amp to 2 ohms. It's not like there's a switch that just lets you make more power by saying "the amps is now at 2 ohms."

 

[ccajun4real 10+ year member]

Well you have to find speakers that can load the amp to 2 ohms. It's not like there's a switch that just lets you make more power by saying "the amps is now at 2 ohms."

OIC, I was under the impression that if I hooked two speakers up to one set of +/- terminal it would automatically decrease the load to 2 ohms? So even though you hook up two 4 ohm speakers it will not lower the load huh? Thanks

Cajun

 

[crow 10+ year member]

OIC, I was under the impression that if I hooked two speakers up to one set of +/- terminal it would automatically decrease the load to 2 ohms? So even though you hook up two 4 ohm speakers it will not lower the load huh? Thanks
Cajun

It depends on how the speakers are wired. Wired in parallel, two 4 ohm speakers will present at 2 ohm load. Wired in Series, two 4 ohm speakers will present an 8 ohm load.

 

[PhatTonyDeMarco 5,000+ posts]

There is more current draw with a 4 ohm load, than with a 2 ohm load, if you are keeping the same output wattage. There is less resistance on the 2 ohm load, therefore the amp would have to draw less current in order to make said wattage.

 

[ccajun4real 10+ year member]

There is more current draw with a 4 ohm load, than with a 2 ohm load, if you are keeping the same output wattage. There is less resistance on the 2 ohm load, therefore the amp would have to draw less current in order to make said wattage.

So if I take two 4 ohm speakers and twist the two + together and hook up to the + on the amp, the twist the two - together and connect to the - terminal what is the ohm load? I know it is louder than if I only run one speaker from each +/- set.

Cajun

 

[crow 10+ year member]

So if I take two 4 ohm speakers and twist the two + together and hook up to the + on the amp, the twist the two - together and connect to the - terminal what is the ohm load? I know it is louder than if I only run one speaker from each +/- set.
Cajun

It would be wired in parallel and present a 2 ohm load to the amplifier.

Here's a good page on wiring speakers:

http://www.bcae1.com/spkrmlti.htm

 

[bass_lover1 10+ year member]

There is more current draw with a 4 ohm load, than with a 2 ohm load, if you are keeping the same output wattage. There is less resistance on the 2 ohm load, therefore the amp would have to draw less current in order to make said wattage.

I think you mixed up your 4s and 2s, because what you said is backwards.

Keeping output wattage the same, a decrease in resistance means a decrease in voltage, voltage and current are inversely proportional, which means as your voltage decreases your current draw increases to give you the same output power. Seeing as many amps in today's market are regulated and are high current, you see an increase in power going from 4 to 2 ohms, because the current draw has just increased.

 

[helotaxi 5,000+ posts]

OIC, I was under the impression that if I hooked two speakers up to one set of +/- terminal it would automatically decrease the load to 2 ohms? So even though you hook up two 4 ohm speakers it will not lower the load huh? Thanks

Yes it would lower the load and should increase the power, but you have to consider now where to mount the extra speakers. You also have to consider that you won't get twice the power so each driver is getting less power than if run by itself on an amp channel. You also have to address the cancellation issues that wreak havoc on your front stage sound which you have no way of dealing with when the speakers are wired on the same channel. The end result is that you may get some extra power and a bit of extra output, but it is rarely worth the problems that come with trying to get a little extra power.

 

[Gary S 10+ year member]

What speakers do you have, what ohm, single or dual voice coil? We need the facts so that we can reply with facts that are practical for your application.

 

[mike dressure 10+ year member]

his sub's are the planet audio z serie's and i have a feeling he spent a bit to much on them!