Bi-amp info on 5.1 and other multi-chan is mentioned. My Denon Stereo Receiver ( DRA-697CIHD), has Pre-out jacks on the rear panel. I understand this Pre-Out can feed another amp. Thinking of another 100 watt amp to use to bi-amp my Polk LSi12's. Has anyone out there tried this ? I understand that one should use an external electronic crossover for true bi-amping. Would my set-up mentioned provide a difference in sound ?