I didn't care for the comb filtering issues from too many HF drivers.
I used 290's - 16 of them. They are actually slightly more efficient, handle more power, and don't forget reliable. Dual 290's on 1003's make one heckuva racket. And stacked 3-4 high certainly project. OTOH the large clusters of piezos certainly had comb filtering issues. But seems less noticeable at high freqs as the wavelength is shorter.
Since 290's only go up to 8000hz, what did you use to get the upper frequency's?
