[Geoff St. Germain]

Yeah, you could switch it to use an external amp. The drivers are wired out of phase so that the cones both move toward/away from the inside of the enclosure at the same time. I'm not sure what the impedance of the drivers themselves are, so it's hard to say if you should wire them in series or in parallel. If you have a multimeter you can get a good idea of the impedance if you can't find the specs for the drivers.