Hi Jeffrey,LEAVE THE IMPEDANCE SETTING AT 8 OHMS :T
You can read the entire article on this subject if you like, I reco watching the 5 minute video concerning this exact subject with Gene and Hugo.............the video is on the first page of the article with the skeleton.
I hope this helps, it should answer all your questions, it did for me when I changed speakers........
Enjoy and good luck
Thanks for the information, I had actually seen the video as well a a couple of articles on the subject and that is what started me on this mission and I fully understood where they were coming from. As a retired engineer in this and similar fields, what concerned me most was the fairly significant increase in temperature when set to 8ohm even though running at moderate volume. Both the 4520 and an older Pioneer AVR both run fairly cool normally on the very same 4 ohm speakers.
I am going to dig further but what I am keen to find out is what Denon actually do in this particular model to cope with 6 and 4 ohm speakers.
I installed recently a Denon AVR 2200W for friends and that actually appears to run quite hot normally so that is another mission to measure find out what temperature it is actually functioning at