Hi Ledhed,
Sorry this reply is so late - I just now checked this thread again.
The single-driver speaker with great imaging was the Supravox 215-2000 EXC, and 8" field-coil-magnet driver from France. Unlike most fullrange drivers, it has no wizzer cone - which I think helps. The directional characteristics (minimial sidewall interaction from the lower treble on up) are also conducive to good imaging. Just put it in a good box with well rounded edges on the front baffle and you've got truly world-class imaging for one. Nope, I don't sell 'em.
I haven't heard any of the current generation Ohm speakers, sorry - but I think they would image well and give a much wider than normal sweet spot.
If your top priority is excellent imaging for one, the Supravox is the best I've heard so far. If you want good soundstaging for listeners over a wide area, there are better choices out there.
When judging a speaker's off-center soundstaging capabilities, keep this in mind: The ear localizes sound by two mechanisms, arrival time and intensity. For the off-center listener the nearer speaker obviously wins arrival time. In my opinion what you want is a speaker with radiation characteristics such that ideally the farther speaker wins intensity, or at least the near speaker doesn't totally dominate intensity (which unfortunately is the case with most speakers set up "normally"). The Ohms have a uniform enough pattern over a wide area that the nearer speaker only wins intensity by a little bit.
Duke
dealer/manufacturer