I also found that a horizontal placement of woofer and tweeter may not be a bad as I originally thought. I was surprised to see in Loudspeaker Cookbook that a W/T placement performs better horizontally off axis than a W-T-W placement. It seems that the extra woofer in the W-T-W creates even deeper nulls at the crossover region off axis than a simple W-T.

My new question is, what's the difference between Eminence H295 and the SST1. According to spec, they both have the same cutoff and dispersion pattern. Yet, they're different in shape. I used the H295 in my Theatre-3's and would like to keep a CD horn for centre channel. The SST1 is several inches more narrow than the H295 and would allow to to place the two drivers closer.

thanks,
Gar.