no double stud wall, i figured that would be too much overkill for just vocals and small amps. i didnt have enough room too. theres a bar to the right that you can't see and if i made it any bigger you REALLY have to suck it in to walk by.
also alot of research i did shows that its more about whats INSIDE the booth, such as a large bass trap on the wall behind the singer and proper absorbtion on the walls and ceiling. however i will be doing double 5/8 drywall on the outside with green glue, and i think just a single layer on the inside, because of what ive read the double drywall will keep it quieter in the control room but double dry wall inside the booth will cause more reflections (a single layer will allow the sound waves to go through the inside wall easier ) nessecitating in more treatment on the inside "phew"
that was a mouthfull.
this is kinda my "practice" room before i go build my real studio in my dads basement.
btw once its done it will be 5 x 5'6" x 7'4" plenty of room for me, a guitar, and a mic stand or two or a small or large amp, i'm pretty sure i could fit 3 people around for omni vocals if i needed.