Its possible that you have not actually built a line array using dome tweeters so you may be simply parroting Jim's best numbers. The reality is that it is impossible to do a 1/2 wavelength in dome tweeters with any known available tweeters. You can use 3/4 inch ND20A;s and cut the flanges so that the c-to-c distance is .91 or so.

PE's newer 1/2 inch domes were not available when i built the system, and they might work. However their FR and other characteristics are rather inferior to the ND20A .75 inchers, IMO.

I have done this. According to my figures, comb filter distortion doesn't begin to kick in for people in stationary listening positions until above 15Khz. While some people may experience lack of air here I don't. I used 30 ND20A's cut to my specs crossing at 2400hz in each channel(60 total).

Sound is fabulous. I discussed the design with Jim Griffin as I was building it. While I could use tone controls or the system DOD constant Q 1/2 octave equalizer to boost the high frequencies to compensate for any comb filter distortion there is no need to do so. It is important to Tri-amp the system, though, to get full value from your tweeter array.

Marlboro

• Calipso Line Array Speakers