Hi, I'm new here so please be gentle! I am looking to build a drum practice room, that basically follows the same sound isolation principals as a recording studio. I have read Rod Gervais very knowledgeable book, but have a question, that hopefully this knowledgeable community can help me with.

Just a bit of background first:
Studio will be located in a steel framed building (similar to an industrial building) that has a brick outer wall and 100mm (4") solid block inner wall with 100mm cavity filled with glass wool.
The studio sits upstairs above a workshop in a dormer (sort of not a full height room, it's half a floor and goes into the roof)
I will likely have some questions regarding the roof and suspended floor construction, but I'm not at that point yet.

My first question is regarding the walls. As mentioned earlier, the walls are brick and block construction that are tied together. I have a contradiction between 2 things I should not do, and need to know which is the least worse. I have a very basic diagram below showing a cross section of the building. The studio sit's above the joists, with the wall on the right. The contradictions I have are as follows; no holes in any walls, and the classic 4 sheets of plasterboard diagram:

plasterboard-construction-jpg


Wall construction is as the below very basic diagram. The black and purple structure is a stud wall with 2 sheets of Sound Plasterboard/Drywall. My original thought was to construct like option 1, as this follows the principles of the drywall layout, with 2 non connected structures. When building the structure, I noticed I need weep vents, which are tiny (10mmx10mm) vents above the doors and windows. I estimate there are 8 of these around the room walls. They are there to allow any condensation to collect and run out of the building, rather than run in.

wall-construction-jpg

So that led me to consider option 2, which is continue the block construction up to the roof, in an airtight manner, and move the stud wall in. But this contradicts with the plasterboard positioning layout, as I will now effectively have 3 walls.
I should add that I would render/skim and brick or block walls to ensure they are airtight and follow the normal procedure of sealing every gap/join.
I hope Iíve managed to explain the problem I have. Any advice would be appreciated.

Thanks