I've tried several different crossovers - some active and some passive. the best sounding, and most flexible, i've found is the XTA DP-224. one feature in particular that i found has made a significant difference is the ability to time delay the mains. once the crossover and delays are dialed in, the integration between the sub and mains is absolutely seamless - better even than the vandersteen system, in which the HP filter and the sub amps are purpose built to provide a seamless interaction.
