You can still use the passive crossover that came with your speakers to biamp. You will need an extra set of interconnect cables and speaker cables to go from the amps to the crossover and from the crossover to the speakers. The speaker's owner's manual should describe this in detail. Your passive crossover "should" have a jumpered high and low output connectors similar to your speaker's jumpered high and low connectors. To biamp, turn everything off, disconnect the jumpers on the crossover and the speakers. Then connect both amp's inputs to the outputs of the pre-amp. use "Y" connectors if your pre-amp only has one set of output terminals. Then connect one amp's output to the high input of the crossover for the right and left speakers, and the other amp's output to the low input of the crossover for the right and left speakers. Then take the high outputs of the crossover and run those over to the high inputs of the right and left speaker and take the low outputs of the crossover and run those over to the low inputs of the right and left speakers. you will need one additional set of interconnect cables for the second amp and short speaker cables (four sets) from the amps to the crossovers of the speakers. Place the amps as close to the speakers as you can to minimize cable lenght. It is better to have as short speaker cables as possible (much more signal loss) than interconnect cables. you will then need four sets of speaker cables from the crossover outputs to the inputs of each speakers. Again, the crossovers should be sitting right next to or on each speaker, so the cable length should be really short. You will also find that with really short speaker cable lenghts, the type of speaker cable really will not effect the sound much. In other words, try 10 gauge Mogami before you spend a large amount on expensive speaker cables. 10 gauge Mogami is really good stuff and as I said, with really short lengths, it doesn't matter much. Use decent to very good interconnect cables.