For a room with all wall, floor and ceiling surfaces of 8"-20" of concrete, how does 2" front insulation (AT screen), 4" ceiling, 6" rear, 2" sides up to 48" and two 24"x24"x34" super chunks in the front corners sound? The local supplier has Rockwool RHT 40:
RHT 40 2" (51mm) 3.5 pcf (56 kg/m3) 0.26 0.68 1.14 1.13 1.06 1.07 1.00
RHT 40 4" (100mm) 3.5 pcf (56 kg/m3) 1.07 1.01 1.07 1.06 1.07 1.16 1.05
To get 4" and 6" I'll be layering 2" 4'x8' sheets.
The walls have eight 20" wide columns made of 1" MDF (about 20%-30% of the side and back wall surface area is MDF with no treatment) and 1' wide soffit around the room's ceiling, made of MDF with 7" of crown made of the ultralight decorative molding (so really only 5" of flat face on the soffit is exposed). Between the columns will be thin fabric (to be picked) to let most sound through to get some reflections above ear level.
Because of water problems, all insulation and columns are held 1" off the wall to allow water to flow behind it to drains and there is no framing or drywall except near the entry into the room. Carpet is outdoor carpet/commercial like that can get wet and not very thick.
I've bought a feedback pro, test microphone, mixer, and all the other equipment to do testing but before I buy all this insulation I wanted to make sure I was fairly close on my choices.
I will be getting some paper to adhere to possibly the back wall or ceiling insulation to reflect highs. The main reason for all the insulation is try to kill the massive amounts of bass that the cement walls will reflect. That's why I'm looking at 2" min on walls, so I can get something with over a 1.x noise reduction in the bass range and evenly kill everything rather than taking too much highs but not bass.
For audio equipment it will likely be the Denon AVR-4308CI with 140Watts per channel in a 7.1 configuration and RBH or Energy speakers. Two subs, yet to be picked.
(Column will be covered in Dazian celtic cloth so they look full height and surround speakers will be placed in some columns)