I have a set of rti 10's with dual inputs and have pulled them out before to see how they subsequently hook into the crossover network.The bottom inputs go to the circuit board that handles the bottom end speakers and the top inputs go topside.Actually axiom mistakenly sent me a dual input manual with my m80's and reading between the lines if you pull the bridgeing bars you are effectively separating the top half of the speaker from the bottom half, that can then be powered with 2 separate power amps.Now if you have 2 amps each putting out 120 watts/ch it adds up to 240 going into the speaker in a bi or 2amp configuration.In a biamp configuration the axiom manual tells you to set the gain of each amp equal unless you want to alter the spectral balance, essentially saying the top and bottom of the speaker are now totally separated.So in a true biamp configuration you are splitting the speaker in half electronically and feeding the top and bottom half from 2 different amps. Hope this makes sense.