Originally Posted by mlazoff
Hi Sivadselim. The Yamaha lets you to turn their 7.1 channel into a 5.1 with the other two channels used to bi-amp the front speakers. Is that what you mean by active bi-amp? If so, how might it not be done properly -- you remove the bridges and hook it up, no?
That would be passive
bi-amping. The only thing it does for you is get you a little more headroom (~3dB). It's basically the same as increasing (but not doubling) the power to the speakers. Even with the bridges removed, the crossover, electronically, still completes a circuit.
With a passive bi-amp, the amplifiers still have to amplify a full-range signal and the speaker's internal crossover is what sends the correct frequencies to the proper drivers. Most people frown upon passive bi-amping with a receiver's "extra" amps, because receivers usually have a single power supply which is shared by all the amps. Using 4 amps, instead of 2, which share a power supply is not the same as "doubling" the power to the speakers. If you were going to passively bi-amp, I would recommend you at least use outboard, dedicated amplifiers.Active
bi-amping means using upstream external crossovers that separate the frequencies before the amplifier stage. The amplifiers then only have to amplify certain frequencies and are used to drive the speaker's drivers that are no longer connected to the speaker's internal crossover. With an active bi-amp setup you are able to tweak the amount of power that goes to each driver much more specifically and precisely, allowing you to completely "tune" the output of the speaker. Active bi-amping is usually a pretty expensive endeavor.
Active bi-amping is much, much different from simply passively bi-amping. Most audiophiles do not consider passive bi-amping to be bi-amping at all.
I would not recommend you passively bi-amp with the "extra" 2 amps in your receiver. But in the end, it's your decision.
You can do a search on passive bi-amping, active bi-amping, passive versus active bi-amping, and read about all the caveats involved.