I’m almost embarrassed to say. I actually hired someone to do a thorough analysis report of the room and recommend treatment. It’s Realacoustix stuff, so pretty high end, kind of like RPG. He does audiophile listening rooms and home theater stuff generally.
There’s 4 of the 47" x 20" x 10" BassBox (corner bass traps), 2 of the 24" by 24" x 4" FAST diffuser/absorber. 2 of the 24" x 48" x 4" FAST diffuser/absorber panels, and 4 of the RealAB 24" x 48" x 4" absorber panels. They’re custom fabriced/colored as well. You can’t see the 24" x 24" ones in that pic, they’re on the ceiling - or the 2 big ones on the back wall. All that was $4800 including shipping and tax.
There’s actually more in the design I didn’t do yet, 8 more ceiling bass traps and a 2nd subwoofer (yes, a 10’ by 10’ room is a huge pain for bass management of the nodes!), but I only wanted to spend this much so far.
I’m sure you can get good results with a cheaper Auralex foam solution.