How does the stage present itself being cubed in? I guess for HT its ok but 2 channel seems a bit cramped ! Albeit a well designed set up and pleasing top the eyes !
The stage is fine as long as I keep it as far as possible from the back wall. It is the Ethos that are the most problematic with this room layout. The panels had to be at least three feet from the back wall before they sounded right, which is why you see them sticking out so far in the room.
I originally started with a Motif-X center, but I did not like it. The Motif-X has is own built in acoustic absorption behind the panel. To me it sounded like it was inside a box. After about two weeks with it I switched to the Stage-X and what a difference! So open. Sounds just like the Ethos. The Motif-X did not blend with my Ethos in my room. The Stage-X blends perfectly, and it does not need to be as far from the walls as the Ethos to sound right either. Maybe because the panel is smaller in area than the Ethos panels...not sure, but I am completely happy with the Stage-X.
Obviously, the Stage-X is not used with 2-channel music, but certainly with 5.1 music and movies. The side walls of this opening are not having much affect on my Ethos or the Stage-X, but the back wall certainly does affect the Ethos. Maybe because the Ethos panels are out more than a foot from where the tv open side walls end, the side walls are less of an issue. But that backwall is a problem. The Ethos had to be at least three feet or the back wave makes it muddy, and the bass gets exaggerated with peaks and dips. Where they are now is fine though and I am happy. I suppose if I could bring them another 2 feet out in to the room they might be even better, but this is my living room and it is only so large and it still has to look like a living room. The back of the living room which you cannot see in this picture completely open to other rooms in the house and there are two more Ethos for Left Surround and Right Surround. They are probably 30 feet from the nearest back wall and both at least 15 feet from side walls. But right now, if I stand in the center of the four Ethos and turn 360 degrees, I do not hear the rear Ethos sounding any more open than the front Ethos, so I am happy for now. Believe me though, if I move those front Ethos even a couple inches closer to the back wall, it is very noticeable and sound just not as open and pleasing.
The opening for the TV was build many years ago when we had large rear projection TVs and of course I did not have dipole speakers back then so it was not such an issue. Now though it is really not ideal for the Martin Logans, but I have them out far enough to mitigate most of the issues. I probably will change it in the future so that I can have more open area behind the speakers.
By the way, I have all four Ethos crossed to the sub at 40hz and the Stage-X crossed at 60hz. The Velodyne DD+ software really flattens the peaks and dips in bass response in my room very well. (At least in the main seating position.) Maybe I should have bought the new models that can use Anthem Room Correction and fix any peaks and dips above 40hz.
Update: 01/02/2018
After 1 year with these speakers and various placement and crossover setting, I have finally settled on crossover at 50hz for all four Ethos, and 60hz for the Stage-X. I have the bass knob set at -1db on all four speakers. Previous attempts with crossover at 80hz with all below going to my Velodyne DD18+ gave very strong bass for movies but music sounds more natural to me with Ethos going down to 50hz. Taking Ethos below 50hz sounds a little box like to me in my room.