It looks like they're using drivers a little over 2" at different angles. How do you thnk these angles would affect the wavefront? They claim 160 degree horizontal dispersion over a broad range of frequencies. I'm going to tackle a similar project with a bunch of 2" drivers and some 3/4" tweeters. I planned to use as many 2" drivers I could fit in a 7 1/2 foot line but instead of angling the woofers I would splay tweeters on both sides at angles due to the fact the high frequencies are more directional. The enclosure will be constructed of 4 or 6" PVC with small pieces of 2 inch PVC cut off with a 4.5" or 6.5" hole saw and glued to the large PVC upright. This would be used for small pro sound venues and would more than likely be supplemented by a small sub-woofer.
A line array would have some major advantages due to lack of vertical reflections and lack of acoustic decay compared to a conventional design.
I'm new at line arrays so any input into this design would be greatly appreciated.
Here's a picture of an array that I helped build for my church. This is probably larger than what you may need (sanctuary seats 1,000)but you could build the same thing on a smaller scale. The design is based on the CBT (constant beamwidth technology)research of DB Keele.