Framing questions

hi, I've been sneakin around in here for quite a while and really found tons of useful information. I still, however, got many questions about how to build my little studio right - so I think it's time for my first actual post: I'm planning to set up a studio in the basement rooms of an apartment house which used to be rehearsal rooms till a lawyer's office opened in the first floor. Now we intend to build a studio whose tracking room will also be used as a rehearsal room (drums, bass, ...) - therefore the main goal is sound proofing (which of course means a room-in-room construction). For now I'm only thinking about soundproofing the tracking room - the control room will be planned later. To the location of the tracking room within the house: The tracking room is exactly below - and the same size as - the inner courtyard of the house - that means that all existing walls in the room are outer walls of the house. The lawyer's office is exactly above the control room. There's also an elevator shaft in the future tracking room which is, in collaboration with the pipes, a perfect sound transmitter to the upper floors I guess. After reading the thread about floating floors, I've decided not to float mine since the studio is located in the basement which is great for my effective room height. Due to the concrete socket (some kind of duct cover) next to to the elevator shaft, I think it's best to give up this space and build an angled wall in front of the shaft with a hatch to use the space behind for storage. The angled wall will also help me to reduce LF room modes due to inappropriate room dimensions (almost squared). Most of the questions I have right now are concerning the framing: I've read much about framing but still wonder how the first horizontal stud on the floor is connected to it exactly: is it just screwed onto the floor or do have to put some kind of damping material between the floor and the stud (in the case of having a "non-floating floor" and - just wonder - in the case of a floating floor)? In my case the existing concrete floor is quite coarse. Do I have to burnish the floor somehow or should I put some material (no idea which one) between the floor and the stud. If I'd build a doulbe frame wall, how is the outer wall of the two connected to the ceiling? The new ceiling will rest on the inner framed-wall, but the outer framed-wall, due to decoupling, mustn't be attached to the new ceiling. So I could attach it to the existing ceiling - but how could that be done for the wall in front of the wall between tracking and control room? Looking at my sketch you see that the existing ceiling construction (all concrete) is quite weird. Do you have a suggestion how to frame here? ...would really be thankful if somebody could help me with this basic questions so that I can go on planning. Not to forget my budget: ~ 6000$ for getting the tracking room "quiet" To prevent misunderstandings according my location: it's really Austria not Australia Thanks Chris