Rich,
FWIW, I can't ever recall ever hearing a horn of any kind that didn't have a bit of "horn" sound to it. I can't say with absolute authority but I suspect that it has to do with the fact that there is a very narrow band of frequencies which are cou0pled more efficiently to the room due to it being a horn -- if that makes any sense. In other words, every horn has a resonant frequency, and it is always in the audible range, where as resonant frequencies of boxes can be pushed up or down to reduce their effect.
I think what it comes down to is whether you like it or not, and certainly there are horns and then there are horns. Those monster Cogent field coil horns are incredible and I culd easily live with their horn "colorations". I've never heard what one would call a completely neutral horn.
When talking with Joe Cohen last year, he speculated that the real ticket for these drivers would be a TL of some sort, but all that remains to be seen.
-- Jim