Nice posts you guys! Here's my 2 cents. While most amps can play loudly very few can obtain a high SPL without distortion. Low impedance speaker design characteristics further tax amplification demands and as gain increases so does distortion. As I understand it, bi-amping should provide relief for the amps by dividing the driver load demand. Generally speaking, this should enable the amp to produce a higher SPL without as much distortion, resulting in cleaner and more focused sound. I think most people would be surprised at how much power is actually required for an amp to exhibit low distortion control over a box speaker loaded with many different dynamic drivers. Roger Sanders at Innersound.net has just released a new mono amplifier designed specifically for dynamic driver loaded box speakers rated at 1,100 watts into 8 ohms. Interesting reading.
Active VS. Passive: A passive cross-over contributes to the load on the amplifier and adds it's own sonic signature on the speaker. Like everything else in audio, it's only as good as the quality of the components implemented in the design. The amplifier exhibits control over the dynamic drivers through this passive cross-over. The way I see it, the biggest gain in using an active cross-over is by removing the passive cross-over from the circuit. This allows the amplifier direct control over the dynamic driver and in theory, should yield far better control and less distortion. Of course, your speakers should probably be designed for use with an active cross-over to achieve the full sonic benefits of this set-up. It's interesting that Joel found that the addition of an active cross-over prior to the passive cross-over produced a more satisfying musical presentation. My guess would be that the sonic signature of his active cross-over is yielding the sonic benefit, but I would think that the distortion yield on the amplification of the circuit remains unchanged from the original bi-amping he did.
Craig: For your application, I think Sean's comment is really worth investigating. I would call the people who are upgrading your amp right away and see what input they have about making these amps mono's. If they can be upgraded to mono's and retain their sonic signature that you love my advise would be to jump all over it! Good luck and if you have it done let us know how it turned out. Regards to all. -Jerie
Active VS. Passive: A passive cross-over contributes to the load on the amplifier and adds it's own sonic signature on the speaker. Like everything else in audio, it's only as good as the quality of the components implemented in the design. The amplifier exhibits control over the dynamic drivers through this passive cross-over. The way I see it, the biggest gain in using an active cross-over is by removing the passive cross-over from the circuit. This allows the amplifier direct control over the dynamic driver and in theory, should yield far better control and less distortion. Of course, your speakers should probably be designed for use with an active cross-over to achieve the full sonic benefits of this set-up. It's interesting that Joel found that the addition of an active cross-over prior to the passive cross-over produced a more satisfying musical presentation. My guess would be that the sonic signature of his active cross-over is yielding the sonic benefit, but I would think that the distortion yield on the amplification of the circuit remains unchanged from the original bi-amping he did.
Craig: For your application, I think Sean's comment is really worth investigating. I would call the people who are upgrading your amp right away and see what input they have about making these amps mono's. If they can be upgraded to mono's and retain their sonic signature that you love my advise would be to jump all over it! Good luck and if you have it done let us know how it turned out. Regards to all. -Jerie