Ki
Very busy so the reply will be sketchy. I no longer have my system ... nor the room . It was a concrete room with 25 x 16 x 12 ( L x W XD). The Room treatment was an adventure in itself as I learned how the use of Tube traps and other absorptive measured can mitigate the effect of standing waves ..., measuring (yes ) with a spectrum analyzer and listening, listening some more.
Now a few tricks.
First it is very important to pull the speakers a good distance from the walls... more so than you would with a box speaker. The reason is that while you may get some increase in low bass (<50 Hz) by being close to the back wall, you may get some strong cancellation in the mid bass ( 60~200 Hz) and the general feeling will be one of light, overly thin tonal balance. So 3~4 feet from the back wall if possible is a good start.
Now with the speakers facing straight away ( no toe -in , that'll come later) have them as close as possible almost touching each other .. Play a mono recording of a voice and start moving them away from each other until the center fill disappears .. Now bring them back slowly toward each other so that the center fill remains AND the tonal balance remains satisfactory ...
Now Pay attention to the level of the mid bass .. Playt some recording with good mid vass information, a piece with cello if you are into classical music or electric bass ... ( The cello range is better) ... Move the speakers from the back wall a tad more and pay attention to the bass ( I am assuming you would be some distance from the back wall ( preferably a good distance and not seating in a null ( I have seen many audiophile move the speakers to death while seating in a null or a through of wide frequency range ...)... You will get to a point where the balance between mid and Low bass is satisfactory, I repeat that with the 20.1 you can get gut wrenching surprisingly low bass . I mean the kind of bass most audiophiles have no idea of ... I digress but this is the kind of bass these speakers are capable of .. BIG, LOW and LOUD bass .. Wall shaking kind of bass.
Supposing the bass is good but not the rest, especially imaging you then start focusing on the midrange. First of all absorption AND diffusion of the back wave are important for image specificity. To get to the point where the instruments have body and their position in space is clear a 3-D kind of effect requires very serious absorption of the back wave and diffusion of the same to repeat myself. Tube traps help but also in my experience, The RPG diffusor, I lked what the fractal did in my system. You will be surprised how solid the imaging of planar can be by proper treatment of the back wave ( which should by the way be as attenuated and diffused as possible, the fake widening of the stage one obtains with too strong a back wave is not very realistic IMO) .
Now comes the toe-in .. it should be performed as lowly as possible with respect to the seating position. I am assuming that the back wave and side reflections are taking care of. I would quickly add that tside reflections are not a big problem with planars in general, yet it is important to provide some attenuation on the sides ..
Ok!! , Toe-in now. Turn the speakers slowly toward the listener maintaining the distance previously found for the distance between speakers ... The toe-in shouldn't be dramatic, else you have speakers too far apart. The things to pay attention to are: width of stage, quality of treble , center fill and overall tonal balance ... The Treble will become cleaner and cleaner, not grittier, it must be extended with no overt peakeness in the lower treble ...
Truly there is much more to than this necessarily short survey but do know that the 20.1 are indeed capable of the kind of bass that rattles windows, house structure and internal organs ... They also can take immense power (if it is clean) and are capable of performance only speakers costing5 times and more are capable of .. a true gem if you ask me ... One of the best speakers at any price
Frantz
P.S. PM for more ...