The Live Room and Mix Room require very different treatment.
To reduce Liveness, flutter echo etc. a 4 inch panel with a 4 inch gap behind is pretty decent. I would call it broad band.
Rooms within rooms is a phrase misplaced I would say. However you can create temporary macro acoustic areas and a little separation using Gobos.
The Abbey Road design may inspire you. Try to get them tight to the floor, many leave a big gap down there. And make sure the legs or wheels don't prevent them angling 90 to each other.
Courtesy of Fletcher
http://lib.store.yahoo.net/lib/merce...udio/abbey.pdf
DD