Re: Yet another sub array question
You've touched on the fundamental choices and each has implications. I'll ask the questions first: indoors or out? SPL expectations and program material?
You can do a 3 box end-fire on each side of the stage - you get forward directivity - but it's still a dipole array so you'll have the usual power alley down the middle, flanked by a null lobe, all of which will vary depending on frequency. Likewise if you were to do 'reversed box, polarity flipped and delayed' cardioid array on each side. The benefit of either choice is that you put less LF behind the PA and somewhat less LF on the stage (frequency dependent). The old-skool "stack 'em up and let 'em rip" puts lots of LF on the stage and behind the PA with all the power alley issues.
A center cluster puts lots of LF on the deck. Lots of it. A delayed/stepped horizontal deployment tends to affect the horizontal coverage much more than it affects the front-to-back, so you still have the LF on the deck issue. One deployment I saw recently used a center clustered cardioid arrangement, 2 clusters in center and 1 more off-stage (each side) of the center cluster by about 6'. Total of 4, 3 box clusters. I wasn't on stage while it was in use so I can't comment on it was for the performers, but if you can model that it might be a possibility.
An endfire array, 2 wide/3 deep on one side of the stage might be useful.
Ultimately I think it depends on the program material and SPL expectations. You're covering 45,000 sqft. That's not a small area.
