# 4 Ohm Speakers?



## needspeed52 (Aug 2, 2008)

Hello,
I was considering purchasing 3 Behringer Truth 2031P monitors to use as side surrounds and a center in a second setup. I have an Onkyo TX-SR702 with external amp driving mains and wanted to use the 702's amps to drive the 3 Behringers, the 702's spec sheet gives a dynamic or peak power rating for 4 Ohm speakers but Onkyo support says that it will work but may cause serious damage to receiver, speakers or both. I just wanted to get you guys take on this. Thoughts appreciated. Thank you.
Jeff


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## bambino (Feb 21, 2010)

I stay away from 4ohm speakers when it comes to running them off an AVR as they demand more load on the unit, now when it comes to outboard amps that have specific ratings for driving 4ohm loads then i have no fear.:T


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## GranteedEV (Aug 8, 2010)

4 ohm nominal impedance can mean a lot of things. It could mean that the speaker is constantly in the 4 ohm range, it could mean it has 3 ohm dips, it could even mean that the speaker usually acts like a 6 ohm speaker but has some dips. Looking at the impedance graph is a good place to start, it tells us a lot more than just "4 ohm" - IE where the impedance dips come. If the impedance dips are below the crossover frequency, you'll probably be just fine, although with still lower fidelity on the sound quality, which i'll elaborate on in a bit.

The main thing is that it means it will often have double the amplifier current compared to an 8 ohm nominal speaker. The consequence of this is that the amp may generate unusual amounts of heat and distortion, and may simply shut down. If an amplifier isn't made for a nominal 4 ohm load, it's usually going to have dissapointing control over a speaker when impedance drops and won't sound very good. You'll most certainly not be able to push the receiver all that far. Less amplifier control can result in sloppy bass, recessed voices, and exaggerated highs.

With all that said however, movie surround duty is a reasonably easy load for most amps, and onkyos aren't exactly poorly built - the SR702's specs say it's 4 ohm capable so you'll probably very much get away with it for your purposes as long as you don't push them to extreme levels for extended periods in multichannel music. Get away with it isn't optimal, but if you're smart you should be fine. Keep the receiver well ventilated and use it intelligently... the amp taking the load off your mains will definitely make a difference.

Do you already have the external amplifier or are you just planning on it? Adding an Emotiva UPA-7 will shore up any potential issues and still power your mains very well. Or maybe a UPA-5 and you can keep your current amp.


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## Prof. (Oct 20, 2006)

I have the 2030p's which are 8 ohm..
Even though the bass/midrange driver is slightly smaller then the 2031p's, some reviewers have said that they preferred the 2030p for their overall cleaner sound..
I've not heard the 2031p's, so I can't comment on the actual differences..but to me the 2030p's sound very good..


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## needspeed52 (Aug 2, 2008)

GranteedEV said:


> 4 ohm nominal impedance can mean a lot of things. It could mean that the speaker is constantly in the 4 ohm range, it could mean it has 3 ohm dips, it could even mean that the speaker usually acts like a 6 ohm speaker but has some dips. Looking at the impedance graph is a good place to start, it tells us a lot more than just "4 ohm" - IE where the impedance dips come. If the impedance dips are below the crossover frequency, you'll probably be just fine, although with still lower fidelity on the sound quality, which i'll elaborate on in a bit.
> 
> The main thing is that it means it will often have double the amplifier current compared to an 8 ohm nominal speaker. The consequence of this is that the amp may generate unusual amounts of heat and distortion, and may simply shut down. If an amplifier isn't made for a nominal 4 ohm load, it's usually going to have dissapointing control over a speaker when impedance drops and won't sound very good. You'll most certainly not be able to push the receiver all that far. Less amplifier control can result in sloppy bass, recessed voices, and exaggerated highs.
> 
> ...



Thanks Grant, they would only be used in a HT setup, and yes I have a external amp, the UPA-2, which I am very happy with. I looked at the UPA-5 today and EMO has it on backorder. The UPA-7 is also an option I am considering, my main concern is using only three of the seven amps of the 702 to drive the three 2031p's, I was hoping I could get away with doing that considering the external amp is delegated to driving the mains, the receiver is in a very well ventilated location and I would use it intelligently but I would not settle for less than optimal SQ which I believe would be the case. I will rethink this situation and go from there. Thanks for your responce.
Jeff


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## needspeed52 (Aug 2, 2008)

PS..I just thought the 702 which draws 8.1 A of current could handle the 4Ohn load, I've compared the newer Onkyo 700 series receivers and none of them have near this power spec, but then again I don't know how much the 8.1A current would contribute to driving difficult loads. Thanks again


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## needspeed52 (Aug 2, 2008)

Prof. said:


> I have the 2030p's which are 8 ohm..
> Even though the bass/midrange driver is slightly smaller then the 2031p's, some reviewers have said that they preferred the 2030p for their overall cleaner sound..
> I've not heard the 2031p's, so I can't comment on the actual differences..but to me the 2030p's sound very good..



Thanks Prof, the 8.5 bass/mid driver is what attracted me to the 31's, I did not realize the 30's are 8 Ohm, I will take a look at those, I realize there are some mods for these speakers that could improve on an already decent sounding speaker. Thanks again.
Jeff


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## needspeed52 (Aug 2, 2008)

bambino said:


> I stay away from 4ohm speakers when it comes to running them off an AVR as they demand more load on the unit, now when it comes to outboard amps that have specific ratings for driving 4ohm loads then i have no fear.:T


Thanks Bam for the heads up, appreciate it.
Jeff


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## Guest (Nov 2, 2010)

Any reason you don't want to use the smaller 8ohm version? Its suppose to be flat to 75hz, so crossing over HT at 80hz should be no problem. Save a little coin, and have a safe 8ohm load.


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## callas01 (Oct 24, 2010)

I have a friend that runs his Totem Rainmakers and Rainmaker center off his HK 254, the Rainmakers are 4 ohms Nominal and he hasn't had any issues. I know he is planning a receiver upgrade soon to Arcam 500. However the several months hes used the HK its been just fine.

Also, I am picking up my Dynaudio Excite X16s, they are listed at 4 ohms, but they never dip below 4 ohms and actually have a nominal ohm rating of 5.86 ohms. I will be using my Sony for a short time until I get an Integra or Marantz AVR. HOWEVER I will say that the Dyns have an Impedance Correction so they are compatible with AVRs.


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## needspeed52 (Aug 2, 2008)

Generic said:


> Any reason you don't want to use the smaller 8ohm version? Its suppose to be flat to 75hz, so crossing over HT at 80hz should be no problem. Save a little coin, and have a safe 8ohm load.


Gen, I quess there really isn't any definitive reason, I just like the bigger driver, and I think it would make a nice center channel speaker, I'm not a fan of MTM configured centers, just my opinion.


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## Guest (Nov 2, 2010)

needspeed52 said:


> Gen, I quess there really isn't any definitive reason, I just like the bigger driver, and I think it would make a nice center channel speaker, I'm not a fan of MTM configured centers, just my opinion.


I can fully understand wanting a bigger driver. Its just that smaller ones can be better at midrange. I don't know if that is true for behringer, but it is for the dayton classic drivers. Either way, if your going to cross over at 80hz to your sub, I'm not sure you will gain anything by having a bigger woofer. The smaller one should have you covered for what you need.


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## needspeed52 (Aug 2, 2008)

Generic said:


> I can fully understand wanting a bigger driver. Its just that smaller ones can be better at midrange. I don't know if that is true for behringer, but it is for the dayton classic drivers. Either way, if your going to cross over at 80hz to your sub, I'm not sure you will gain anything by having a bigger woofer. The smaller one should have you covered for what you need.


Gen, thank you for the info.
Jeff


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