Planar close to a rear wall? Quad for example?

Owning stats for a number of years makes me wonder -HOW???

If its not common knowledge than it should be: all planar speakers need to be a minimum of 5 feet from the rear wall!

Any closer results in tonal colorations, the most pronounced being in the bass. Oddly, the only speaker I have seen that worked at all well at distances closer was indeed the '57, but invariably the owner was using a transistor amplifier, which cannot play bass on the speaker. Nevermind- the backwave reinforcement 'sort of' takes care of that. But put a good tube amp on a setup like that and the owner complains of too much one-note bass.

I used to have my Apogee Stages 18 inches from the wall
and they sounded fine--not boomy or compressed at all.
Maybe the soundstage was a somewhat flat but the tonality
and realism of the Stages was so awesome that I didn't care. I don't have them anymore because the left one's woofer broke.

I had to sell the Quad 63's I purchased from QS and D several weeks after I bought them as I couldnt pull them out more than 3.5 feet or so from the front wall.
Thought this would be enough before I bought them-- I had heard 3-6 feet was "ideal."
Once I had them in-house-- I realized it wasnt ideal whatsoever. No matter what position I tried them in or how much toe-in etc.-- couldnt get them to sound like I know I've heard them sound in a good set-up. Not even close. Dont waste your money until you've got the space.

Magnepan MC-1's are made to mount on the wall. I am running a pair on a wall that frames a picture window in front of my desk. I have the speakers about 5 feet apart and 4 feet from my listening position. Sandwiched between the speakers and the wall are acoustical panels (BAD) that are 18 inches by 48 inches high. I am supplementing the base with a quad sub. The tonal quality is very good but I struggle with imaging being so close to the speaker. Voices are good, but instruments tend to be smeared to the sides. It is not ideal but I cannot think of anything better given that I want to sit so close to the window/wall for the view while I work. I tried a pair of Gallo Due bookshelf speakers and they were waaay to "hot" sitting that close. The MC-1's are not too agressive at all, I just miss the imaging and depth.