Originally Posted by bobknavs
From the X3600H manual, regarding bi-amping: "This connection enables back EMF (power returned without being output) from the woofer to flow into the tweeter without affecting the sound quality, producing a higher sound quality."
That is the first time I have seen that claim for bi-amping. Considering that the amplifier channels are completely independent (beyond sharing a power supply), it's incomprehensible to me. It sounds like quasi-technical BS.
As there are no settings in the 3600 to set a crossover for bi-amping, I infer that both amps see the same signal. There may be a slight increase in effective power to the speakers, but I doubt that it's appreciable. (1dB, 25.9% more, would barely be appreciable.)
My preference? Forget bi-amping. Power LCR and the surrounds.
Here is some help concerning Denon's statement on bi-amping and some overall insight into bi-amping:
This is what Denon means:
The woofer distorts, especially at higher output levels. The woofer generates back EMF, a voltage, due to its voice coil passing through its magnetic field. (Maxwell's equations stuff.) Some of this voltage contains distortion from the woofer that is low enough in frequency to pass back through the woofer crossover and yet high enough in frequency to pass through the tweeter's crossover. Effectively some of the distortion from the woofer is driving the tweeter. Passive bi-amping eliminates this transfer of distortion to the tweeter.
This effect is more pronounced in loudspeakers with low-order crossovers, that is, 1st or 2nd order crossovers. Unfortunately such crossovers are common since they are inexpensive to implement.
Bi-amping is about sound quality. Many here seem to be interested in maximum output. Bi-amping won't help increase raw output significantly. It will help in reducing distortion that is caused by high current levels. There are many portions of a class AB amplifier where the level of distortion increases with increases in current output. Taken together it is very possible that the decreases in distortion with bi-amping will be noticeable.
As with anything in audio, the overall system, especially the loudspeakers, the room, the choice of listening material and the listener will make a significant difference.