Horns: Why don't they image well?

I was just going to provide the same link.
Can't wait to all the detractions.

Well, you can always just install an old JBL C-31 in one corner and forget imaging.  The sound will still be there in the room with you! :-)

Well, you can always just put an old JBL C-31 in one corner, and forget imaging.  The music will still be there in the room with you! :-)

 I have owned apogee divas in the past which were pretty much one of the best imaging speakers I’ve ever heard. Now I own a 604E based system with Fostex tweeters on top and DIY dual subs on the bottom. True full range. They image just as good as the divas.   In fact they almost do a dense ball of sound image in the middle even better.   And they throw sound well outside the boundaries of the speakers as well. I partially attribute that to the tweeter horns dispersion pattern which widens it out a bit more than your typical dynamic driver. 
 Also voodoo funk  in advertently brings up a great point, the room has a huge contribution to how well the speakers will image. 
 Essentially a horn or wave guide couples the driver to the air better than without. I can’t see how that would be a bad thing in anyway.