Thanks. Given the long gating(much longer than the first bounce) I'm using for this measurement, its quite flat. Should be indicative of a good in-room response.
I've noticed that floor bounce can still be visible in the measurements, but it doesn't show up as a large coherent spike with the midhorn, which is an indication of its good directivity control.
This measurement was with an even shorter horn(9" average length) and a 10"x16" mouth. It also has a slightly larger(5.5" dia) throat. I made some measurements with the 5" dia throat as well, but overall the larger throat measurements looked a bit better.
My main concern now is with off-axis(ie: +/- 20 deg) response. Its not nearly as flat as on-axis. Its possible that will just smooth out once these are in a corner, however. Have you(or anyone else) ever experimented with transitions between the conical angle and the flat front?