>>Elden, unless you're planning to use a separate external crossover before the amplifiers(and entirely separate amplifiers)and remove or bypass the M80 crossovers, nothing significant would be accomplished.
Yep. I have never understood why manufacturers promote bi-amping without an electronic crossover. There might be some scenarios where you get a tiny improvement but it never seems worth doing.
>>On the impedance question, the separate low and high frequency sections of a speaker have the same impedance and, as Rick commented, passive biamping doesn't change this.
I'm not sure about this. My recollection is that typical crossovers have woofer/mid/tweeter wired in parallel, each with some series and parallel elements to limit the frequencies going to the driver.
If you break the connection between (woofer plus its crossover elements) and (midrange & tweeter with their crossover elements) I would expect to see different impedence curves for the two sets of terminals, if only because the impedence peaks around resonance are isolated between woof and mid/tweet.
I *think* the impedence at the woofer terminals would be very high at higher frequencies since woofers normally have a series inductor. Not sure what the mid/tweet impedence curve would look like -- the tweeter normally has a series capacitor so impedence would go very high at lower frequencies, but I don't remember what the impedence response of the bandpass RLC on the midrange looks like.
Anyways, as JohnK says this is not an avenue worth pursuing so I'm only posting for the most academic of reasons
