$25K HT System - Amp question

[Nuke]

In the latest Audioholics $25K system recommendation, regarding the amp, one of the recommendations is a Denon 4306 combined with an Emotiva MPS-1 (a combo I was considering).

Then it says: "We suggest using the (MPS-1) amp to power the main five speakers in your theater and using the Denon's internal amps to power the back channels..." I'm curious as to why this set up would be the best way to go... the MPS-1 has seven channels, right? Wouldn't it be better to use all seven of those instead of just five of them?

Thanks!

Nuke

 

[Dekpm19]

I would guess the rear speakers may be closer or because at this time they are the same signal. Plus the amps in the 4306 have plenty of power for most speakers. The rears may be smaller and not need as much power to drive. But I am like you I would want all of my channels the same and spend the extra dollars for the other 2 amp channels.
Just my guess.
Allen