Horns: Why don't they image well?

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. 

Most people's experience with horns is limited to VOT. VOT horns were designed for movie theaters and other such large rooms - not for your average living room.  A properly designed and built horn system can and does image realistically well. My experience with horns comes primarily from my long association with Dr. Bruce Edgar (Edgarhorn) who designed and built some of the finest horn systems I've ever heard. I've "rolled" some of my own and I assure you that they sounded and imaged remarkably well, too. If you're anywhere near So Cal I urge you to get in touch with Cyrus Brenneman (I can help) who has an exceptionally well sounding horn system based on Edgarhorn. Be prepared to be amazed. 

I love my Heresy III , unfortunately they've been boxed up for 6 months...  just got them to my new place and am picking up a nice BDI rack in the morning...  can't wait to fire them back up this weekend.   They sound way better than that Altec blutooth speaker I've been using.

Anytime you use a giant waveguide to spread high frequencies you are trading off a large soundstage (flat power response) with less precise imaging (since the highs are getting stretched over a wider area).

As I mentioned earlier there is a new Klipsch La Scala.  It is the model AL5.

Partly correct, but for many years horn systems have included "phase plugs" or their equivalent to keep horns from "beaming" high frequencies. The high end horn systems I use for pro sound are designed to spread high frequencies over a large area, and they do that well, and the Klipsch Heresy IIIs I use in my home system easily have as good or better dispersion of high frequencies than the dynamic speakers I've owned over the years. 

Watch this folks....

I came to this thread really opposed to horns, and I'm not 100% on them today, but I'm not going to let the misinformation go unchallenged.

Horns don't "spread the sound". They mechanically couple a pressure impulse to the environment. Horns are MORE directional than dynamic drivers with more controlled dispersion. 

Indeed they are "MORE directional than ..," and It should make them less fuzzy about room acoustics, not to say they don't benefit from absolute care with regard to placement and even very minute changes in their positioning and toe-in, but that's true for a variety of speakers regardless of principle. Quite a few horn speakers can be placed in close proximity to the rear wall, with many of them even requiring it, and this alleviates to an extend their typical large size and intrusion in a living-/listening room milieu, without affecting "sound staging" negatively. 

Personally I fancy horn speakers often being rather wide (as opposed to the narrow baffle/deep enclosure seen with most direct radiating speakers), as it seems to subjectively highlight this big, vibrant "wall of sound"-like sonic presentation. If they're made with real-wood veneering or even hardwood they are also lovely to look at with their broad front panels and horns. I miss the sensation of speakers as wood furniture that actually looks and feels (and even smells) like real wood (instead of the lacquer-infested and glossy appearance from most modern speakers), while unapologetically taking up space as big sculptures in one's home environment, but that's just me.  

My own listening room is quite "alive" btw, an acoustic environment that's most pleasing for me to actually occupy, and with the all-horn speakers I use it's a non-issue sonically. Generally though I prefer diffusion over too much absorbing with any speakers, so not to rob the sound of what I regard as a natural life. But, I digress..

Partly correct, but for many years horn systems have included "phase plugs" or their equivalent to keep horns from "beaming" high frequencies.

This statement is problematic. Phase plugs are used to prevent cancellation at higher frequencies, thus extending the upper range of the device.