Thanks. I'm excited na. Do you think that I need to bi-amp my 9.1? I will be using a 5.1 setup since my couch is against the wall. So I can use the surround back channels for bi-amping. Please advise.
I don't believe there's any benefit to bi-amping using the same receiver.
Why do receivers provide the option? Because the receiver company's marketing department believes it will improve sales. And they are probably right.
To get a real improvement, true bi-amping requires:
(a) Separate amps, each with its own power supply; and
(b) An electronic crossover that splits the signal before reaching the amplifier.
"Bi-amping" from the same receiver via the unused surround back channels fails on both counts because:
(a) The unused back surround channels are separate amp sections, but all 7 sections use the same power supply. Whether you divide the power into 7 amp sections or 5 amp sections, the total power from the same power supply remains the same.
(b) The receiver does not have a crossover that splits the signal into high and low frequency for the same channel. Sure, the receiver has an internal electronic crossover, but that crossover only splits the signal into main & subwoofer channels --- it does not split the signal into high & low for the same channel.
Using the same receiver, whether you bi-amp or not: (a) Your main channels receive the same total power; and (b) Your high-frequency and low-frequency speakers on the same speaker box receive the same full-frequency signal. The passive crossover filters on the speaker groups inside the speaker box will just dump the power of the unwanted frequencies into resistors which will dissipate as heat.
Therefore, bi-amping from the same receiver is useless, IMO.
Why do some users report an improvement? Because they're giving a subjective report that was not based on a double-blind ABX test.