Thank you for your reply
Yeah I know. The construction site looks like that the first day I walked in that's mean It's already start before I join the team. I'm working with another 2 persons which are Engineer and Architect/interior.
This is the layout they gave me on the first day
MUSIC ROOM1.jpg
Talking with Engineer and Architect is another issue. They work mostly on living space. Sometime they don't understand and ask question that I know what I have to use but quite hard to explain to them such as
Why do I have to use 2 layers of gypsum?
Can I use another insulation beside Rockwool?
Can we prevent impact from outside by using thin rubber under wooden floor?
and blah blah blah
In my opinion due to the weight of second wall thin rubber sheet wouldn't do anything and Building wall method it's standard like tested and succeed formula.
You are totally right: he should stop for a few months until the design can be completed correctly.
I'm not so sure I can hold it for that long maybe 1-2 month because construction workers will cost him everyday. Now they're working on his showroom/garage for his antique cars and collections (which is located opposite side of this building) I have to get my plan ready before the showroom complete.
but now I'm still working on layout
And this is current layout
MIP layout2 06-03-2014_1.jpg
I took out that curtain as you recommended and change it to ISO booth. I think it's ok to use it as storage too.
From the plan they've given me I think this is the best it could go but I'm not 100% happy with it. I might try corner CR later but I have to discuss with engineer about avoiding those pillars around control room and sound lock.
In case I can't make corner CR Here is the current control room design
MIP CR 06-03-2014.jpg
Positioning the speakers at a 40-degree angle. Is this OK?
Normally I prefer 60-degree but in this case I'd like to place engineer's seat around middle of the side window so he can see Live room as much as possible. Positioning the speakers at a 40-degree angle will get acoustic axis crossed behind his seat
Ray tracing check 30 degree from acoustic axis. Is it enough?
I also checked 45" It's OK as well
Normally I would check 90 degree but I can't get it right. I've tried 60-degree speaker positioning and RFZ around 90 degree CR become too many sided wall and engineer seat way up front only see half of live room.
Back part of the room will be insulation cover with fabric. If I use Steel stud how can I attach fabric to Steel stud? For timber stud just use stapler does it work with metal frame too?
HVAC. I don't see any provision for HVAC in there, and that is critical for studios
Owner said that he's going to use split type in control room but for live room, booth and waiting section should be duct type. Duct plan is giving me headache

Avoiding sound leak through ducts, Noise in the duct, balancing air in with air return, Duct size and
I'm not HVAC guy. I Think i'll coordinate with HVAC company later.
Ken