Mike!
First off, to be certain, your acoustic treatments are going to do nada for any insulation. Unless you make some sort of meaningful 'room' enclosed, heat will find its way around your treatments.
Unless of course, you choose to build walls.
I was thinking, you would only have to frame and insulate about 3' below outside grade to get 90% effectiveness of insulation as if you went all the way down to the floor. Three foot is about where the frostline is around here. THAT way, you wouldn't have to mess with your 'dry basement treatement' installed at the bottom of the walls.
You would still loose probably 5-6 inches off of those walls though.
Still, you might consider that, and perhaps building some 'traps' into the walls by not drywalling some panels, and insulating them in a way that works for trapping and some temp gradient. Cover those parts of the wall in fabric, maybe with a layer of polyfill over the fibreglass to keep it from puking fibers at you...
My thought being, as a homeowner, you would be improving the value of your home, framing and finishing wall down there AND insulating part of the basement. Plus, for a fact, insulation added effectively to your home is some of the fastest payback money spent on a house.
Its doable, but it'd cost you beer, and the pleasure of you pounding your hands with a hammer as much as I do....
Of course, importing treatments just for the sound seems a lot less painful though....hehehehe
DF
