Big planers do a good job, but I'm not completely sold on that approach having used large dipoles AMTs. The sound is certainly spacious and less localized, but big radiating surfaces have odd artifacts and I feel that the reflected sound can lend some blurring to detail. I'm not sure their less sensitive to placement.
When I think of an excellent imaging speaker I think of exactly what I'm hearing right now with my Focals. NOTHING seems to come from the actual speakers unless the sound is very forward and in one channel. The sound stage is distinctly behind the speakers and generally extends back for yards. Objects are clearly positioned forward and back, top to bottom, and side to side beyond the boundary of the speakers. These things aren't positioned according to some hocus-pocus formula. They're within 3/4 of an inch the same distance from the front wall. I've never even measured the side walls. And I toe them by eye, kicking the right one out ever so slightly more. I don't know why, but it cures a slight wandering in the midrange. The treatment to the walls and ceiling has done a LOT more than a few inches of positioning ever has for imaging. You NEED to keep sound from rattling around the room like marbles in a can. That jazz destroys imaging. The room should be distinctly more dead to echo than other rooms in your home. Not totally dead, but clapping shouldn't yield defined slap-back.
When I think of an excellent imaging speaker I think of exactly what I'm hearing right now with my Focals. NOTHING seems to come from the actual speakers unless the sound is very forward and in one channel. The sound stage is distinctly behind the speakers and generally extends back for yards. Objects are clearly positioned forward and back, top to bottom, and side to side beyond the boundary of the speakers. These things aren't positioned according to some hocus-pocus formula. They're within 3/4 of an inch the same distance from the front wall. I've never even measured the side walls. And I toe them by eye, kicking the right one out ever so slightly more. I don't know why, but it cures a slight wandering in the midrange. The treatment to the walls and ceiling has done a LOT more than a few inches of positioning ever has for imaging. You NEED to keep sound from rattling around the room like marbles in a can. That jazz destroys imaging. The room should be distinctly more dead to echo than other rooms in your home. Not totally dead, but clapping shouldn't yield defined slap-back.