Those are good questions , maybe Andrew will stop by and educate us. This is a copy/paste from the amp page.

Understanding the Equation

Although output with eight-channels driven looks small, the fact of the matter is that the power demands from surround channels in a home theater system are much smaller than the power demands of the front left, right and center speakers. As a result, the real-world experience with these amps is lots of power available for the power-hungry front section. a seven-channel amplifier used in a home theater system acts more like a five-channel amp for power-per-channel, as shown in the chart above.



I take this to mean that since the surround channels don't contain a lot of information their power demands are low . This would leave the amp capable of supplying the front 3 channels with the 500 watts specified. No sure why anyone would need that much power anyway ,especially with how efficient the Axiom speakers are. Typical listening requires often less than 1 watt/ch. The Emo amp is definitely a beast and the specs are impressive though I cant seem to find any 3rd party tests to verify its output. I love the internet, shopping from my chair smile

The XPR 5 needs a 20A dedicated circuit, class AB is not as efficient.

I am rereading the whole thread, maybe This will help, scroll about half way down.

Richard


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