I don't work much indoors during the summer half of the year. So the other half is closing in. After reading about VPR's it says one should preferably use hot rolled steel plates, and not cold rolled steel plates as they are more rigid, less flexible. Unobtanium in Norway. So ready on one of the side wall is 12,6 sqm. of Caruso Isobond WLG-035, the other side wall will have 4,5sqm and the back wall 7.5sqm. I can't do this before I have documented the steel plate and done some initial measurements. Which ever way you turn, the ass is behind you.
So for some diversion of my troubles, I bought some close distance GIK Acoustics Versifusor's to use in the ceiling, it's EPS so takes ages too rub with sandpaper to get smooth even used some plaster/putty before painting. Still don't f.... look like a piano finnish...

My son was in Edinburgh Scotland in the art school Edinburgh Academy with his strings youth orchestra, it was a medium large oval room maybe 500 sqm, high vaulted ceiling with a galleri and lots of large intrusions, chandaliers, ornamented figures in the ceiling and lots of other ornaments all around (aka diffusion) and a lifted window canopee in the center of the ceiling, not a bare room at all, but all brick. For strings it was heaven, sitting in the middle of the room was immaculate, astounding airy immersive sound.
If we do rock or blues (amplified music), we don't need that, we need short even decay across frequency, especially drums and bass, and somewhat guitars and certainly vocals, the chorus ladies and all other acoustic instruments live in a short decay world, that they can do nothing about, their remedy is to work in a space with good diffusion for the wibe.
Long and short decay is 2 different worlds that try to meet...