All right. The power consumption rating on the back of power amps, receivers, etc., does not have anything to do with true watts RMS output. It is only what it said it is, a maximum power consumption from your wall inlet taken by the ditto electronics.
Some type of amps (class A, B, A/B, D, G, H, etc.) have different degree of efficiency.
Some tube amps will consume (draw) a lot of power (watts or amps) from the wall outlet, and will only deliver 2 watts of true output at the most into your speakers!
And some other type of transistor amps, class D (digital or ICE amp for example), will consume (power consumption) much less than others (class A for example), and deliver huge amouts of true RMS watts in all their channels (Pioneer Elite SC-09TX is a good example).
What comes in is not necessarely what goes out, as you can see now.
The power consumption figure on the back of electronics is becoming more and more superficial as of power output is concern.
Your Pioneer Elite VSX-21TXH receiver (class A/B) with 400 watts power consumption figure, is actually delivering about 70 watts RMS into 8-ohm loads at 1khz, with about 1% THD (established clipping THD point) into all seven channels driven continuously (estimation). That is pretty good if you ask me. And there is no way that in true reality, your seven channels will be driven like that from any film soundtracks.
Now, if you like using seven-channel stereo audio mode, then yes, they will be driven at full capability, but that power is mainly on peaks, not constant in actual life.
And if your speakers are very efficient (Klipsch for example), you will need only a couple watts at most to obtain a pretty loud volume level.
* Hope this gives you more understanding.
** Different manufacturers used different values for their power consumption figures, as you probably noticed. Denon, Onkyo, Marantz,... for example used A (Amps). Pioneer, Yamaha,... used Watts. And Yamaha even adds VA. In general...
*** Last, it is the same thing with humans; some people consume a lot less energy to produce more performance. Others consume a lot, and provide almost nothing. The main difference here, is that with humans, the power consumption is not indicated in their backs. :bigsmile: The true ratings are indicated on their hearts and minds, the true measure of the power build.