The conical horn is actually the only shape that provides constant directivity. It starts to lose pattern control at some low frequency point based on its size but above that point, it has constant directivity through its passband.

If a horn is short, it will not load down to as low a frequency as a longer horn of the same shape. If its mouth area is small, then it won't have as good pattern control as a larger horn.

Beaming is another name for collapsing directivity and it occurs when a direct radiator becomes directional because of path length differences between points along its cross-section and listening points out in the environment. It occurs in a curved wall horn because wall angle gets narrower further down the throat.

I might suggest for you to study horn theory and learn how things work. The concepts are pretty simple so you can pick it up pretty quickly.

Does the throat area have anything to do with where the horn begins to beam? I've seen a few designs --mostly for 10" cones-- where the throat looked like the CD slot one would find in a 2" horn. Is this a similar diffraction technique?

Oops! SG1 200th episode begins, gotta go! Later!