To add my 2c’s.
I have 7 Stillpoint Apertures 2’s, they claim to provide absorption, diffusion and reflection.
2 are in the front between the speakers (see my system page.)
2 each on each side wall (4 total) at first reflection point.
1 behind my listening position.
4 ASC tube traps in the corners.
And a couple of absorbent panels behind the speakers.
ozzy