Horn speakers with Imaging?

Some do but I think most don't. I find the Edgarhorns to image quite well within a fairly narrow sweet spot. The SP Tech speakers also image well over a wider area. I'm afraid that I can hear the loudspeaker as the sound source with most other horn systems that I can think of offhand; in general the qualities that draw people to horn loudspeakers lie in other areas.

There is a horn loudspeaker in development that images quite well and does an exceptional job of disappearing as the sound source, as the designer has gone to extraordinary lengths to minimize image-degrading and coloration-generating artifacts from both the horn and cabinet. I've heard the prototypes, and intend to become a dealer for this speaker when it becomes available, hopefully within the next few months.

I'm sure my observations here are incomplete, so hopefully others will share their knowledge.

The Köchel K-300 horns offer outstanding imaging.

I have a homebuilt cabinets for JBL S8R system with potato masher horns. Awsome imaging and soundstage. I think it depends on how you set them up and how you drive them. Did you check to see if the speakers were connected in phase? That may be why you have no imaging. Check the driver hookups in addition to the amp to speaker connection..