I like the idea of putting a SW behind each main speaker. I think this provides the best "seamless" integration. In particular I have my Maggies set up this way with dual driver subwoofer systems installed in the wall behind each of three Maggies. The idea is that they "play through" the screens, and it seems to work. The thought has occured to me that the function of the SW may be as much to absorb the out-of-phase backwave of the planar speakers, as to directly generate LF sound.
When auditioning a SW, remember that most LF sound sources are not exactly crisp, and a somewhat lumbering (not "tight")sound may be correct. It takes a while for a 30 foot organ pipe to get itself going, and the same for other LF instruments. Compare a tuba with a picalo. Percussive bass, like a drum is the only exception I can think of.
I think the Velodyne is good, but the cost of three could not be justified.
When auditioning a SW, remember that most LF sound sources are not exactly crisp, and a somewhat lumbering (not "tight")sound may be correct. It takes a while for a 30 foot organ pipe to get itself going, and the same for other LF instruments. Compare a tuba with a picalo. Percussive bass, like a drum is the only exception I can think of.
I think the Velodyne is good, but the cost of three could not be justified.