it is drop ceiling, partialy tilted...
- aluminium skelet
- from 12cm height with 5cm of rockwool to ~50cm and 20cm of rockwool
- will cover it with perforated gypsum board (~5% of perforation)
Should work as broadband absorbtion (helmholtz type) with "bass trap" at the most thick part.
The rest will have to be in panels... wood frames filled with rockwool, covered with cloth.
In the corners, I'd use "superchunk" style, I find here: http://forum.studiotips.com/viewtopic.php?t=535
I have some 3D models (just for an eye, not acoustical), but currently I'm working on some changes that will take some time, but will post as soon as possible