Thanks. I'm hoping to use it with a 7pi cornerhorn and so far its looking a bit more compact than the standard Pi midhorn, which was a large part of the goal. If it works out well, you could consider it as an option on the regular 7pi, since its width matches up nicely at 18" with the side transitions or 16" without.

Here is the same 20 degrees up measurement with more gradual transitions on the top and bottom(1" of 45 degrees, then 1" of 60 degrees). I think the dip at 450hz is floor bounce I wasn't able to window out nicely.

My main concern now is that I'm losing about 3db above 900hz off-axis, both in the horizontal and vertical directions, relative to the 300-850 range. Is it worth trying a smaller dia(ie: 4.5") or 4.5" square throat from the Pi horns?