I have a sound stage problem described below that I'm pretty sure is partly related to the room and treatments. I posted here instead of The Acoustics Circle because the question is specific to the diffusion panels GR just added
https://gr-research.com/product/diffusion-panels/.
In the images below I'm considering replacing front corner and sidewall traps with diffusers and adding front wall coverage. Details are below but my basic question is whether or not reworking the GIK base traps with the diffusion panels GR started carrying a few weeks ago would be as effective as free hung panels.
In the pics below you'll see GIK corner and RH sidewall first reflection traps, two free standing traps, and rear wall traps. To rework I'd replace the absorptive material in the traps with panels cut to fit in the GIK enclosures. It may seem ridiculous, which it may well be, but I'd rather look at the GIK enclosures (which the wife has already accepted) than the bare panels and I don't want the hassle of trying to sell them. A problem is the corner traps and free standing panels are only 21" wide so I'd have to cut the panels to fit.
The idea would be to rehang the reworked sidewall panels and line the front wall with the corner traps reworked flat and the free standing panels which would be hung on the wall. I'd use separate removable panels sitting in front of the TV (or maybe one of the sidewall panels) for critical listening and leave the rear wall traps as is.
System: Eversolo DMP A8 > Schiit Lyr+ > Schiit Aegir > Spatial M4 Sapphires. BJC SE interconnects, Moon Audio Black Dragon speaker cables. Stock power cables. Panamax MR4000 surge protector.
Listening space is 11' x 14' x 8' in a room that is 20' x 14'. Speakers are 3' from the front wall, 5-1/2' center to center, and the RH speaker center is 3' from the RH side wall. LP is 6-1/2 feet from the speakers and 4-1/2' from the back wall (it's actually in front of the sofa - a nice comfy folding chair).
The Lyr+, repurposed from desk top duty, would be next. What it's replaced with would depend somewhat on how effective the treatment changes are at improving the problem described below.
Problem:
I like the overall tone with acoustic stuff up to small ensemble in size but lower mids / bass gets congested when the music gets more complex.
Aside from what I'm increasingly convinced is a problem with my ears, the sound stage width and height are pretty good and has decent depth but is pretty flat. In something like Dave Brubeck Take Five from Time Out on Qobuz instruments seem well placed left and right and front to back - I'm satisfied - but in general vocals seem to be too recessed. Mids and upper mids wander occasionally and at times instrument vertical placement - guitars in particular - seems to be off / asymmetric with instruments on the left seemingly higher than the right. That may how it's supposed to be but it's weird and throws off the experience.
Comparing the FR and waterfall plots with and without treatments, the treatments aren't really doing much in my space. I do have a couple of room modes to deal with (which is part of the reason for settling on the DMP A8) but the FR is close enough to being identical and the room is borderline dead without the treatments. Should I expect diffusion to liven up the space?



