Background on the room. It's a FROG, so that helps tremendously from the jump. The attic does pass completely over the entire house which helps in wiring and such, but not for soundproofing. Three of the wall are exterior. The one adjoining wall has the door to the hall, the second bathroom and the master bath on the opposite side of the wall.
Pics for reference (all pics are from before purchasing the home) -
Room over garage. The window is a bump out, where the foose ball table is. The right hand wall is the projection screen wall. The back wall looks over the backyard. The left wall has the door to the hall and adjacent to the bathrooms.
From the doorway/hallway. The wall with the TV's on it is the side exterior wall. That's the projector screen wall. The wall on the left is the backyard wall. The wall to the right that the guy is looking at is the window/bump out.
This is the adjoining wall. The wall that the yankees uniform is on is the second bathroom. The closet you see butts to the master bath shower. The closet is demo'ed right now and is going to be a wet bar.
So there's the background.
Plans. I spoke with John I think at The Soundproofing Company. He advised me to stagger stud the adjoining wall and go with three layers of drywall and GG and no clips because the staggered wall would be my decoupling. Definitely plan on sealing the room in completely so I'll caulk all butted drywall joints as well and will do the flex duct fort he ventilation to squash sound through the vents. I'm guessing the exterior walls just need a healthy dose of insulation. Definitely caulk and seal the hell out of the ceiling/wall joints. I believe since I am creating a sealed room I need to add in a return/exhaust for the HVAC. And since the room is over the garage I figured not worry about the floor.
In a nutshell, that's what I had in mind. I plan on having a pretty massive substage which is my biggest concern.
Let me know what you think and TIA. appreciate all the help I can get.