To Whom, I just picked up the Denon AVR-2807. I am looking to purchase speakers for this AVR and have stumbled across (read reviews) of the 633-T Towers. I have thoughts of buying a separate amp for the 633-T towers. I was also thinking about using the additional 2 channels for bi-amping the 633-T Towers. My question is do the 633-T have dual ...