Bevis, welcome. As Chris points out, you'd have to supply more information to indicate that what you propose is feasible. You say that you "can" drive the rear woofers with an amp separate from the one powering the front drivers, but the literature available to me at this time doesn't indicate this. In the excellent tests and review given the AX-5 in the August, 1988 Stereo Review it's indicated that there's only a single pair of spring clip connectors on the back. Unless the one you have is configured differently, connecting two separate amplifiers couldn't be done without performing major surgery on the connections. Further, there wouldn't appear to be any benefit in doing this, and it wouldn't result in true bi-amping unless the internal crossover was bypassed and an external crossover preceding the amplifiers was employed.
