Combining 8 ohm & 4 ohm speakers on my Yamaha RX-V2600; good-bad?

[Ponzio]

I’m currently running all 8 ohm speakers (Polk mains & center and an Athena Technologies sub) on my Yamaha AVR with no issues. I have a chance to purchase a nice pair of 4 ohm Krell’s to replace my 8 ohm Polk’s mains. Am I asking for trouble (blown avr/speakers) or does changing the Yamaha setting from the current 8 ohm to 6 ohm (recommended setting for 4 ohm speakers) resolve this issue? I’ve read where it’s ok to do this but not at high volume levels. My fear is not the high volume level but I tend to run my amp continuously from 8 to 10 hours a day and the amp does get hot as it is with the 8 ohm loads. The amp is well ventilated and (knock on wood) to date it has never clipped/shut off but I don’t want to tempt fate. Anyone out there have any experience combining both 4 & 8 ohm speakers and your thoughts?

<O</OThanks

 

[fmw]

The calibration program should take care of any volume differences. As you know, lower impedance speakers draw more current. How much current draw your amplfiers can handle depends on how they are designed and how loud you play the system. In most situations the AV receivers can deal with a 4 ohm nominal impedance because in most situations we only use a fraction of the amplifiers' output capacity for any meaningful length of time. The manufacturer's impedance rating is based on full rated output. In general, I would say that, if you use a powered sub and program your speakers as "small", it shouldn't be an issue at all. If you don't, then it should only be an issue if you run things at high volume. Just check the output transistor heat sinks. As long as they are warm to the touch and not uncomfortably hot, I wouldn't worry about it. If you have to pull your hand away because of discomfort, you are probably shortening the life the component.

 

[Grador]

I agree with everything fmw said on the receiver front. On the other hand that polk center is most likely not going to mate well with the krell mains. If your primary purpose is music, and/or you're willing to drop down to a 2.1 setup then give it a try. If you insist upon a 3.1 and are doing primarily multichannel then by all means try, but be prepared for possible poor results.

 

[avengineer]

Specifically which speakers are you talking about, both Krell and Polk? Sometimes if you post the models we might find more information. As much as we would love to talk about impedance like it's a single number, it changes with frequency. I quickly found a review of the Krell LAT-1000 speaker that mentions the fact that even though the spec is 4 ohms, there is an impedance dip at 1KHz to 2 ohms.

Agreed with Grador about the mismatch between your C and L/R, though. For movies, the ideal is identical LCR speakers that can work together to create a homogenous front soundfield. Having different C speakers significantly hampers that.

You also might consider keeping the Polk setup for movies, and switch to the Krells for two-channel music. Another option, if your AVR has preamp outputs, is an external power amp for the Krells. The Emotiva stuff is about the best deal in history...

 

[Pyrrho]

I’m currently running all 8 ohm speakers (Polk mains & center and an Athena Technologies sub) on my Yamaha AVR with no issues. I have a chance to purchase a nice pair of 4 ohm Krell’s to replace my 8 ohm Polk’s mains. Am I asking for trouble (blown avr/speakers) or does changing the Yamaha setting from the current 8 ohm to 6 ohm (recommended setting for 4 ohm speakers) resolve this issue? I’ve read where it’s ok to do this but not at high volume levels. My fear is not the high volume level but I tend to run my amp continuously from 8 to 10 hours a day and the amp does get hot as it is with the 8 ohm loads. The amp is well ventilated and (knock on wood) to date it has never clipped/shut off but I don’t want to tempt fate. Anyone out there have any experience combining both 4 & 8 ohm speakers and your thoughts?

<o</oThanks

The combination of different impedances isn't a problem (in fact, having some of the speakers 8 ohms and some 4 ohms is better for your receiver than having all 4 ohm speakers), but depending on the efficiency of the speakers, the exact impedance curve, and exactly how loud you want to play it, it could be a problem for your receiver. However, there is a simple way to deal with this issue, and that is to add a separate power ąmp to deal with the 4 ohm speakers. Your RX-V2600 has preamp outputs so it would be very easy to do this, though it would cost more money.

And, as others have noted, you will likely have poor voice matching between the center speaker and the speakers you are thinking of buying. However, you would have to try it to see if you would find it objectionable or not.

 

[Ponzio]

Sorry about the late reply; 90% music in 2 channel, so that’s not an issue. There’s a LCD TV/DVD but I rarely watch DVD’s in there but I do occasionally stream Netflix. My ears are gonna drive me broke.
</O
Krell Res 3’s will be the new mains (hopefully) with an Athena Technologies sub; I’d like to get a pair of Paradigm Reference Studio 20 v.5’s but that ain’t gonna happen on my budget currently. The RX-V2600 is in a 14’x14’ room. The volume rarely goes above -10.0dB so I think I’m going to be ok, seems to be the consensus. The current mains are Polk Monitor 50’s on 12” stands at ear level (slight towing due to furniture placement). While I have been complimented on how the system sounds, at its price point, I’m trying to match the sound I’m getting in the AV room. The Polk CS2 center is ok, no great shakes, but surprisingly much better than I thought. In fact I was thinking about buying another one and use them as the mains, but I digress. I would love to get an Emo amp(s) but I must be patient.
<O</O
Most of the time I’m listening to my MP3/FLAC files networked(good)/CD-R (WOW!!!) thru my Oppo BDP-105 (that Sabre 32 DAC chip in the Oppo is nothing short of miraculous) to the Focal 1027Be’s with a Yamaha RX-V4600 in a 20’x20 AV room; I’m a happy camper.

Thank you everyone, it’s always a pleasure listening to serious hobbyists.

 

[avengineer]

Found this:Krell Resolution 2 Speaker System HT Labs Measures | Home Theater

Looks like the Res 3 impedance dips to 3.35 ohms at 8.5KHz. Shouldn't be a problem. Response looks mid-heavy. But it won't match the Polk well, though finding test data on the CS2 is hard to do, it's only a $100 center.

 

[Ponzio]

Well the Polk's (LR & C) are going to the "winter quarters" (16'x16' AV room; sons old bedroom) and I'm going to bring down the Klipsch center (much better than the CS2; can't think of the model number) but I know it still wont give me that unifying sound I'm looking for. But that's the joy of the hobby, right? Patience grasshopper, patience.

I almost jumped on a Krell center 4 months ago ($1200) on Audiogon but suddenly a matching Focal Electra CC1000Be, to go with the 1027Be's, came up for $1500 on eBay and I scarfed it up. Sometimes God smiles.