Also, I am of the opinion that when sound is coming from the rear and bouncing willy-nilly about the room, it may give a sense of depth to the soundstage but can’t really be good for imaging compared to a nice closed-back point or line source, or even time-aligned speaker.
@toddalin How it works is if the rear of the speaker is far enough from the wall (about 5 feet) then there is about a 10millisecond delay of the rear firing information to reach your ear. If a bit less than that, the ear will interpret it as harshness (which is the same reason side wall reflections should be avoided) but at about 10mS, the ear can interpret the information as echo location.
The result is a more palpable soundstage. IOW, it is excellent for imaging. BTW most ESLs and planar speakers like Magnaplanars are open baffle so this should come as no surprise.