Cube Audio Nenuphar Single Driver Speaker (10 inch) TQWT Enclosure

David, did I read that you toe your speakers in to cross before the mlp?

@abd1  We are out the door headed to the beach. In Florida for a short break. I'll respond once we are back inside this evening. 

Your layout pics are super helpful. Hopefully, others will offer their perspectives and advice.

FYI dimensions are approximate but pretty close. Picture also depicts two subs but I'm only using 1 right now.

abd1, I understand your frustration. This is my opinion but when I had the Acoustic Zen Crescendos that have a wide dispersion ribbon tweeter, the vocals where better focused in the the center most of the time. The Cubes speakers don’t have a ribbon tweeter but have many other significant advantages as a full range single driver loudspeaker. In my set-up I struggled with the same issue to a lesser extent. When I replaced my QNAP NAS drive with an AfterDark Roon Server, replaced my component isolation, lowered the noise floor by adding ac filtration, and added Stilpoint Apertures, the center fill improved greatly. I have my Nenuphars with 5 degrees of toe in, 11” from the front wall, 91” apart and I sit 10’ from the front baffle in a 15’ wide room open to a kitchen area. I’m going to point out the elephant in the room now. You have a difficult room to work with. The side wall(s) first reflections are asymmetrical and your room closely resembles a square. If you could position you system (speakers and electronics) in the bay window area, that would be more ideal but impractical. If you have a basement below the room, then you could locate your electronics down there while leaving your speakers in the bay window area. Before doing all of that, I would try David’s set-up and toe the speakers in so they intersect in front of your listening position.

@abd1 This won't help with bass frequencies, but if you're wondering about the impact of your cutout, one useful technique can be to carry around a bluetooth speaker (obviously the closer to full range the better) and listen to how the sound changes as you move it into that space.  That can give you a sense of what frequencies are being altered by the reflected sound from your main speakers. (Note, this is also useful for testing room treatments like absorbers and diffusers).