Well I did more work on the front wall, hung my projector screen and fit my home made bass traps in the corners last night. (these have 9 inches of safe n sound)
I did a few other things while I had the wall open.
I ran two dedicated 20 amp using 10/2 aluminum armoured power lines. I ground the armour only at the breaker box and recommend this over basic 10/2 as it reduces electromagnetic radiation by 75%.
I changed my speaker cables from basic blue jeans to audio sensibility statement's.
I changed my interconnects from audio quest red river to audio sensibility statement se's xlr's
And obviously I added the huge diffuser.
My excellent soundstage grew a tiny bit more but what changed dramatically was being able to locate instruments and voices within the stage. (if that makes sense)
Now what jumped out at me. With just my mains running (no subwoofers). The first song I listened too was Disturb (sound of silence) I turned it up until the song starts to fatigue or (annoy my ears). Well I was able to take my system to a level where his voice was impacting me considerably more than before, I still liked what I was hearing but I could tell it was louder than I should be listening too. So I turn on my db meter and was shocked it was peaking to 102db before the most I really could ever listen to was 95db peaks.
I keep my db meter close and I want to keep my hearing so I listen to music at 85 peaking to 90db ish.
This combination of change's was dramatic and I am very happy with the results so far.