I know that 7.1 receivers like teh onkyo and the denon plus others supply equal power, but in some 6.1 receivers Pioneer VSX-811s and Denon 1803? they give the option of hooking up two speakers, or one with the power of the sixth channel powering both speakers. I think thats how it works at least thats what I've read in the descriptions of recievers at Crutchfield among other places.