mm not convinced by all of this.
I had an Arcam AVR350 - which struggled at higher volumes driving my Tannoys all round (all fronts are 6 ohms) - at higher volumes it started to get harsher sounding, and it was rated and tested at something like 105W/channel all channels driven.
I often see posts here from people who insist the internal amps of an AVR should be rated ACD and that's the only rating that is meaningful. Well, Arcam may be closer (relative to HK) to the ACD camp.
If I were to manufacture an AVR and must choose between spending the fixed manufacturing budget on the following options, both to have the same feature set on the prepro side,
Option1, to achieve an ACD rating that is approximately the same as 1, and 2 channel driven ratings:
a) Stronger power supply for 7X110W ACD (e.g. Arcam, NAD, HK).
b) Weaker amp section (much has been spent on the power supply already) that really cannot do no much more than 110W each.
Option2, to maximimize 1 and 2 channel ratings, for better (relatively speaking) dynamics but, allow ACD rating to fall below 1, and 2 chanel driven ratings:
a) Weaker power supply for say 7X80W or even slightly lower ACD (e.g. some mid range Onkyo, Denon, Yamaha, Pioneer, Marantz or even some Sony models)
b) Stronger amp section (from money saved on the weaker power supply) so the 1, 2 channel driven ratings could be as high as 170, 150W tested and typically >200W into 4 ohms by use of higher power transistors,
I would take Option2 based on most real world applications that do not pump out high SPL from all channels are the same time but at any time there could be high peak demands on 1,2 or 3 channels simultaneously.
Besides, for real worry free power ratings, an external amplifier is a must. A unit made under Option2 above should only require a 5 channel external amp because in all likelihood, the two back surround channels can be powered by the AVR easily. Option1 would be more suited to people who enjoy mostly rock concerts and anything similar that generate steady high SPL and who don’t care as much about dynamics for most movie watching and serious two channel music listening.
It is a good thing that we have choices such as the NAD, HK on one camp and many others on the other, with a few sort of in between. So we have them all, how can anyone complain?