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4 ohm speakers

topdownsound

topdownsound

Active Member
I'm still trying out AVRs and like the Denon 3800h. One of my criteria is to be able to connect 4 ohm speakers if I ever want to in the future. The Denon has no problem with this - the manual says just set the impedance in the AVR to 4 ohms and drive on.

I was looking at the Yamaha A4A and while the marketing claims 4 ohm speakers can be connected, if you look in the manual, it says that if you have 4 ohm speakers, you should set the AVR impedance to 6 ohms. I looked at the A6A and the A8A. Same thing. Set the impedance to 6 ohms for 4 ohm speakers.

Am I off-base or is Yamaha limiting current draw, essentially de-rating the 4 ohm speakers? It feels as if this is a marketing ploy - "Sure, our unit can handle 4 ohm speakers" but only if you call them 6 ohm and by the way, you can't have 4 ohm speakers throughout the system, only the fronts, per the manual. Just seems a bit misleading.
 
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Any one with an impedance switch for lower ohms is doing some sort of extra limiting. In theory a 6 ohm setting would have less limiting than a 4 ohm setting, and the 8 ohm setting less limiting than either 6 or 4 setting.

Typically it's not to protect the amp from damage, it's a way for manufacturer to make it easier for them to pass certain tests.

There is good information about that in a nice Audioholics article from some years ago. Their conclusion/opinion, leave the switch on 8 ohms regardless that the speakers may be 6 or 4 ohms. From my experience with a Sony receiver that had a 4/8 switch, it indeed worked better set to 8 ohms despite 4 ohm speakers and never a lick of trouble.
 
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Most of the newer AVRs, other than the lower powered low-cost ones, are 4-ohm capable without any set-up switching.
 
topdownsound said:
I'm still trying out AVRs and like the Denon 3800h. One of my criteria is to be able to connect 4 ohm speakers if I ever want to in the future.
Click to expand...

Look for an AVR with front L and R preout, hook up your choice of amplifier if you ever get more difficult to drive speakers.
 
The switch drops the rail voltage of the amplifier, keeping the output devices in their Safe Operating Area, or SOA. The lower impedance seen by the amplifier somewhat offsets the power loss from the voltage drop. What ever power lost is largely irrelevant anyway.
 
It's a longish-read, but worth it if this is a concern for any given person.

You may decide you'd rather have the full meal than 1/2 portion. ;)

www.audioholics.com

Setting the A/V Receiver Impedance Selector Switch

This article explores the purpose and function of the impedance switch found on some A/V receivers. Tradeoffs of following manufacturers recommended settings are also discussed. YouTube video inside.
www.audioholics.com www.audioholics.com
 
Yamaha makes very good products.. I haven't dealt with one yet that won't handle a 4ohm load..
But there is more to it than that..
How loud are the speakers being driven, and for how much time..?
Is the AVR well vented, they'll run warmer..
 
I'm coming from an Yamaha RX-V371. I'm not at all sure it will handle a 4 ohm set of fronts for how I listen to music. The manual mentions nothing about 4 ohm speakers, just 6 and 8, so I'm guessing it is not a good idea with that receiver.

I read the linked article. Much of the science was over my head but the takeaways, I'm doing them all with my Yamaha, so that made me feel better even with my 6 and 8 ohm present setup. I had already concluded that if I wanted to run 4 ohm speakers, I'll need an AVR with the capability to run preouts to an amp and the RX-V371 does not have any preouts other than the sub, so that's one of the reasons I'm looking at a different AVR, with the ability to run an amp as a must-have.

On the upside, I finally read enough about crossovers and subwoofers and room placement to make mine sound pretty damned good. I was shocked at how much things improved by moving the sub to a different placement and how little effect the 80/60 crossover decision made in the final outcome. Once I found the right placement, choosing 80 or 60 meant very little in terms of what difference I heard.
 
Well, thing is you're going to get some clues if it's really causing a problem like it goes into protection from getting hot. If the unit has plenty of ventilation and that happens, then, yeah, maybe want to rethink things. But, it's not like it's just going to blow up from merely the proximity of 4 ohm speakers. ;)

As the article said, setting the switch for lower impedance mainly just causes the unit to clip sooner. That's certainly not conducive to good sound if you have a propensity to turn it up some.
 
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Good point.

Maybe someone could explain this statement from the linked article:

Suffice it to say, those who favor LP's over digital media must be proud owners of high order subsonic filters as part of their electronic arsenal. The effect of even a modest amount of low frequency energy in the subsonic range can cause the loudspeaker, especially vented designs, to move wildly causing gross distortions under extremely high excursions they were never designed for.

I didn't quite get that because I don't know what a high order subsonic filter is. I think it is referring setting the crossover freq to the subwoofer and taking that load from the speakers, so they don't have to try to produce that really low bass, which makes the woofer move so much (excursion)? If so, I guess I'm already doing that by setting my AVR to cross to the sub at 80. Is this correct? I'm definitely in the LP camp.
 
What they're talking about is a very low frequency high pass filter to prevent "rumble" or other low frequency resonances from records/turntables/tone arms making the woofers move in and out at typ. subaudible frequencies.

Sometimes referred to as subsonic filter and or rumble filter.

This subsonic filter/high pass would be well below the subwoofer crossover to the main speakers. 15Hz, 20Hz, 30Hz type deal.
 
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My ART DJ Pre II preamp has an option to engage a rumble filter. I will turn it on. Thank you very much for the education!!!

Of course, the ART is known for the incredible brightness of its LEDs. Turning another one on like this kind of turns it into a passable night light. Useful at my age for the inevitable mid-night trip to the loo.

I appreciate the information on this site. Learning a lot.
 
The idea of a necessary switch tells me Yamaha is back to doing their old tricks that lets them sneak by at a lower production cost. They did such nonsense in the 20th Century and is why I would never own anything Yamaha.
 
Just purchased an Onkyo TX-RZ50 on sale from Amazon. 974.00 reg. 1500.00. Great buy and a well built unit. Comes with the best autotune Dirac live and all the new stuff plus has all the pre-outs and is 140 WPC and supports 4 ohms. Lot cheaper and just as good as Denon or Yamaha and on sale.
 
twiiii said:
The idea of a necessary switch tells me Yamaha is back to doing their old tricks that lets them sneak by at a lower production cost. They did such nonsense in the 20th Century and is why I would never own anything Yamaha.
Click to expand...

From what I've seen the majority regardless of brand have either a switch, a setting in the software, and some may even auto detect and adjust automatically.
 
TRUE!! I followed up with calls to Denon and Yamaha customer service. Both stated that if you choose 4 ohm in the impedance section, the unit engages a protection feature that will limit the current draw. So while the manuals for both state that you can use 4 ohm speakers, the switch setting is a dead giveaway that the unit handles 4 ohm speakers by limiting the current. Yamaha does this explicitly by recommending 4 ohm speakers be set to 6. Denon does it by setting the option to 4 but in the end, all you are doing is engaging a protection circuit.

Yamaha went further and stated that with 4 ohm speakers, it was fine to leave the impedance setting at 8 and as long as you don't turn the wick up to where your ears are bleeding, the unit will not be harmed. As in a previous post, heat is your guide. The AVR won't blow up if you put a 4 ohm speaker in the same room.

My question, then, is whether clipping is occurring at some point with this sort of system. If so, then the real answer is: if you have 4 ohm speakers and want to attach to an AVR, plan on using an external amp for the LCR channels.

Realistically, I don't think the people buying 4 ohm speakers are relying on their AVR to pass sound. So this is all probably a moot point.
 
For what it's worth, Number 2 post in this thread by @whoaru99 says it all. All my speakers are nominal at 6 ohm, but operate more at 4 ohm. I followed Audiohaulics advice years ago, and have never had/seen an issue. Set at 8 ohm, and don't go Animal House nuts on the volume. I have a Yamaha RX-a3070. I calibrated reference levels at -0 db and am satisfied with volumes at -16 to -10. I do use a Aircom amp cooler, and have never seen a temp above 110 f. It normally runs at around 82 to 90 f. Hope this gives you some referance's.

Garry~

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