Keep it SIMPLE!!
Everything in the single path has to have some percent of negativity
it absolutely impossible not to. Yes a marginal grain here/there.
Myself I completely solved 98% of the room injections.
Bought a high back leather chairs (2) with upper wrapped
wings. Yes vintage. Say styles of the 60's. Look very much a like a
Nascar racing seat to keep drivers head from over rotating Left/R'.
Stops 99% of any behind you back wall reflections. Upper wings 80% of them same to the left and right of my ears.
I place calibrated mike in each chair head /ear high to confirm the chairs really work to reduce standing waives etc.etc. Before not as real that the artist is right there with my Wilsons.
Now! Almost the sense you could touch them. Well almost,