Impedance setting on Denon AVRs

[-Matt-]

By chance I just came across a post by @Pareto Pragmatic which mentioned that you could change the speaker impedance setting on Denon AVRs. I had to check the manual to confirm, but it is in fact true. How did I miss that!

So does anyone know what that setting actually does inside the AVR? Would @amirm's measurement results change if different settings were used during tests?

The next question is which setting should I use? My main speakers are Kef R7s. They have a nominal 8Ohm spec but stated minimum of 3.2Ohms. I remember seeing a post a while ago that mentioned that speakers shouldn't dip below half of the nominal rating and that the nominal 8Ohm spec for the Kefs was therefore perhaps dubious. In fact the newer R7 Meta gets a 4Ohm nominal rating, still with a 3.2Ohm min.

 

[Chrispy]

All it does is limit power. Try this https://www.audioholics.com/audio-amplifier/impedance-selector-switch-1

 

[-Matt-]

All it does is limit power. Try this https://www.audioholics.com/audio-amplifier/impedance-selector-switch-1

Thanks for the link. Yes, that answers a lot. Glad that the default setting is probably the right one.

Just in case others are interested here are the impedance plots for...

R7 (8 Ohm nominal, 3.2 Ohm min)

R7 Meta (4 Ohm nominal, 3.2 Ohm min)

The main differences seem to be that the R7 Meta has a dip downward at about 700Hz and the peaks at 30Hz, 60Hz and 2.5kHz are slightly reduced.

Edit: Actually, the dip at 150Hz is filled in a bit for the Meta so that the minimum shifts from 150Hz to 700Hz.

Looks nothing at all like a 4 Ohm reduction across the board!

 

[peng]

Thanks for the link. Yes, that answers a lot. Glad that the default setting is probably the right one.

Just in case others are interested here are the impedance plots for...

R7 (8 Ohm nominal, 3.2 Ohm min)
View attachment 415226
R7 Meta (4 Ohm nominal, 3.2 Ohm min)
View attachment 415235

The main differences seem to be that the R7 Meta has a dip downward at about 700Hz and the peaks at 30Hz, 60Hz and 2.5kHz are slightly reduced.

Edit: Actually, the dip at 150Hz is filled in a bit for the Meta so that the minimum shifts from 150Hz to 700Hz.

Looks nothing at all like a 4 Ohm reduction across the board!

I would consider those speakers 4 ohms nominal, no idea why KEF specified them as 8 ohms nominal. Just about any well designed amps including AVRs can drive them regardless of the impedance setting, but they may or may not sound their best depending on one's listening habit and distance.

The R series, like the reference series, might also have phase angle characteristics to consider as it could present issues to the lesser amps in terms of heat dissipation. Some people like to use the so called EPDR (https://www.audiosciencereview.com/...ereophile-has-started-calculating-epdr.15497/) values that would inflate the current requirements in order to simulate the increased heat dissipation due to even lower impedance that the actual impedance shown in the impedance vs frequency curve.

Below is an example, based on the R3 meta and R5 Erin measured:

Impedance setting on Denon AVRs

By chance I just came across a post by @Pareto Pragmatic which mentioned that you could change the speaker impedance setting on Denon AVRs. I had to check the manual to confirm, but it is in fact true. How did I miss that! So does anyone know what that setting actually does inside the AVR...

www.audiosciencereview.com

Note: That's not to say your R7 meta would have such low "EPDR" values, but they might, as the designs across the R series could be similar.

To be on the conservative side, I would suggest truly 4 ohm rated amps for the R series unless you don't listen too loud and the distance is less than say 10 ft.

 

[EWL5]

I would consider those speakers 4 ohms nominal, no idea why KEF specified them as 8 ohms nominal. Just about any well designed amps including AVRs can drive them regardless of the impedance setting, but they may or may not sound their best depending on one's listening habit and distance.

The R series, like the reference series, might also have phase angle characteristics to consider as it could present issues to the lesser amps in terms of heat dissipation. Some people like to use the so called EPDR (https://www.audiosciencereview.com/...ereophile-has-started-calculating-epdr.15497/) values that would inflate the current requirements in order to simulate the increased heat dissipation due to even lower impedance that the actual impedance shown in the impedance vs frequency curve.

Below is an example, based on the R3 meta and R5 Erin measured:

Impedance setting on Denon AVRs

By chance I just came across a post by @Pareto Pragmatic which mentioned that you could change the speaker impedance setting on Denon AVRs. I had to check the manual to confirm, but it is in fact true. How did I miss that! So does anyone know what that setting actually does inside the AVR...

www.audiosciencereview.com

Note: That's not to say your R7 meta would have such low "EPDR" values, but they might, as the designs across the R series could be similar.

To be on the conservative side, I would suggest truly 4 ohm rated amps for the R series unless you don't listen too loud and the distance is less than say 10 ft.

View attachment 415241View attachment 415242

8 ohm speakers are an easier sale! I agree it's confusing when "8 ohm nominal" is nowhere close!

This would make most 2021 PAC AVRs a risky purchase for sure!

 

[-Matt-]

To be on the conservative side, I would suggest truly 4 ohm rated amps for the R series unless you don't listen too loud and the distance is less than say 10 ft.

So far I have been more than happy with driving them from the AVR, but I am constantly tempted by the reviews for purifi and hypex based power amps. Would you consider them to be "truly 4 ohm rated amps"?

 

[peng]

So far I have been more than happy with driving them from the AVR, but I am constantly tempted by the reviews for purifi and hypex based power amps. Would you consider them to be "truly 4 ohm rated amps"?

I am not surprised at all, that's why when people ask whether they need an ext. amp, I would suggest they figure out their need based on their listening habit and distance, as those factors could have as much or more impact than the 8 vs 4 ohms.

The Purifi and Hypex based power amps are rated for 4 ohms, but not 4 ohm rated amps are equal in terms of how warm/cool they would run, and how tolerance, as some have better heat sinks than others.

 

[pogo]

I once asked Denon about this. Here the answer from Denon:

Dear Mr. xxx,
thank you very much for contacting us.

As technical data, we recommend the connection of loudspeakers with an impedance of 6 to 16 ohms, for some models like the Avr-X4800H it is 4 to 16 ohms. Any type of loudspeaker with this nominal impedance can be operated without hesitation.

The nominal impedance is the specification of the resistance at dormant state. During operation and with increasing volume, the actual impedance can deviate greatly from the nominal impedance. In addition, the impedance is frequency dependent. The impedance can then assume values significantly below the nominal impedance to below 1 Ohm. With the variety of models offered and the most diverse properties, we can therefore not make a generally binding recommendation. Since a low impedance means an increased power output and thus a higher heating of the amplifier, a critical operating condition can be reached, which could mean a defect in the amplifier or the loudspeakers.

Therefore, make sure that the minimum impedance (in the entire frequency spectrum) should generally not fall below a value of 3.2 ohms.

With current AV receivers, you can change the impedance of the connected speakers with the help of a key combination described in the operating instructions. If you select 4 Ohm here the amplifier limits the available power to prevent overloads.

So in your case, the Nubert nuLine 34 speakers are not recommended.

With best regards
Your Product Support Team

Translated from German

 

[peng]

So far I have been more than happy with driving them from the AVR, but I am constantly tempted by the reviews for purifi and hypex based power amps. Would you consider them to be "truly 4 ohm rated amps"?

I would consider them 4 ohm capable amplifiers, but again, it is not black and while as many people thing it is. For example, you need to read the specifications in detail carefully, it may be rated 500 ohm 4 ohms but it may also say "depending on the amp's thermal design....", something like that..

On the other hand, in theory, even for amps rated 8 ohms such as AVRs, they can drive 4 ohm nominal speakers for owners who know what they are doing.

I used numerical examples many times on this forum but such questions keep coming up regardless.

One simple example/explanation is, if the amp is truly rated 100 W into 8 ohms, it could then be truly rated 50 W into 4 ohms if the manufacturer wanted to. They likely wouldn't do it that way for marketing related reasons. In reality, if you put that amp (100 W 8 ohms) on say, Amir's test bench, it will likely do better than 50 ohms. For Denon AVR, it would likely do around 120 to 140 W into 4 ohms because those power sweep tests usually wouldn't be subjected to the test load for more than some seconds, not minutes. So that's why you could be "more than happy" with your speakers that dip below 3 ohms at some points but that does not mean you shouldn't use amps rated for 4 ohms, in fact you should.

If you ask Denon, they are going to tell you not to do it, for obvious reasons including liability, warranty claim concerns, safety hazards etc. Those who answered questions on the front line may not be very technically knowledgeable, though they have training and other resources to help them answer most questions.