Mike, I didn't really follow the "negating" supposition, but an external crossover(usually electronic)has to be placed prior to the amplifiers so that each amplifier only gets an input of the desired frequency range. Once that is done and the crossover is taken care of, the internal crossover in the speaker has to be removed or at least bypassed by rewiring so that the signals from each set of speaker terminals go straight through to the appropriate driver. Very few home users actually have gone to the trouble of bi-amping, which as Alan has pointed out is of more significant benefit in professional applications involving mega-wattage.
I still find it odd that this technology has been around at affordable prices for a long time in the mobile audio side, but remains rather esoteric in the home environment. My Alpine head unit in my SUV has active 3-way parametric crossovers in the digital domain. It is great to be able to change the crossover point from 80 at -12db to 63 at -18 if that works better in your setup, or as you replace speakers. I confess, i leave the passive crossover network in place on my expensive separates just make sure i don't screw it up by accident.
Surprised this simple bit of code/chipset has not been dropped into a decent Denon AVR for real use of the 19 amps they are dropping into their AVRs these days.
And the speaker companies would love it - just think how many DIY'ers would blow the tweeter across the room seeing if it could handle a 1000 hz signal! It would open a whole new market for replacement parts.
