Don't forget, the ART Array isn't a "great" speaker; it's a speaker that's sensitive enought to use with flea power SET amps, and it sounds good considering the $275 cost of the parts. If you're building a line array from scratch using more expensive drivers than the ones used in the ART Array, it would be better to begin by selecting drivers that will work well in a line array (woofers that don't require too much enclosure volume), that work well together (sensitivity and minimum crossover point for the tweeter), and then design an enclosure and a crossover to optimize those drivers.