hyperaudio
You stated in your post that Onkyo is a member of the JEITA. what other major A/V receiver manufacturer is a member of this organization? Is Denon a member of this association?
I have used a Denon receiver before and they rate their receivers at a real world nominal rating of 8 ohms. I believe that Denon also can brandish their equipment with claims that it too can pump out considerable output with 6 ohms which you find to be a logical rating but they dont do so.
Well, err, actually, Denon does so. Publish output ratings at 6 ohms, that is.
The manual for my Denon AVR-1801 lists two different power output specs, one for 8 ohms and another for 6 ohms. The brochures I've downloaded from their site do the same.
But you're right. Denon is at least forthcoming. So as not to single out Onkyo, I've seen Yamaha AVR flyers where they conveniently publish only the dynamic (or peak) power rating and not RMS figures.
To confuse things even further, Hifi Choice notes that some published ratings are ratings at stereo settings (only two channels are active), which are higher, rather than with all channels active. This was their minor criticism with regard to the Denon AVR-3300, but which was rectified, according to them, in its replacement product, the AVR-3801.
But in their latest roundup, it seems that actual power still does fall short because of other components like inadequate power supply. As an example, here's what they had to say of the Denon AVR-1602:
It's all in the specification. Denon rates its AVR-1602 at 70+70W (front), 70W (centre) and 70+70W (surround) but this is not the same as 70W through all five channels at the same time.
The power supply simply cannot sustain the added burden, so while it delivers 2x105W, this falls to 4x52W and just 5x35W into 8ohm.
An amplifier that really offers 5x70W+ will be a lot costlier, like the HK AVR5000. Like the Denon, The Marantz SR5200 and the Onkyo DS595 dropped power considerably with all channels driven, while according to them the Harman Kardon and the NAD T761 did not deviate much from their ratings.
Cheers!
GAOL