another thing to reckon with (apart from room size and power/size of the sub) is the speed. having just heard two subs, and three nice systems with and without those subs (you compute the permutations, including signal path and cable worries...) I am back to my LFM2 on an outlaw amp, with two large magnepan speakers. the crucial factor is that this small sub is quick enough to supplement and enhance the sound from the two planar speakers. the other woofer (six times the price) was not able to blend in.