Wayne,Did you ever sell the TAD 1602's you were parting out over the summer? If not, I'll take 'em!
I must have read 500 posts today on Hi Eff and Pi, and finally fell over your discussion of using these babies in a 4PiBR Pro 3.5 ft3 box, as well as the fact that you had a pair (at some point) to sell.
I'd put the cabs on 11" mass-loaded stands, with Bill Martinelli's horns and Eminence PS 2002's on top of them, using your 800hz (??) xover. I'd upgrade the 2002's when I recover from the shock of the initial outlay!
I would expect this combo to be quicker, lower distortion, sweeter, albeit less efficient than the Theater 4's. Does that make sense? I'm after horn speed and effortlessness used with SET's, not ultimate SPL's.
Thanks!
Keep your ears and your mind open.