A few years back, I realised I was spending a small fortune renting rehearsal studios. The old shed/garage in back of my triplex offered a potential space for conversion into a practice and recording studio. The arrival of my son also meant that we needed our musical gear out of our flat to make room for the nursery. I spent about 18 months researching the project.
Budget, available space and requirements effected the process. An additional 2 feet in each direction would have been nice, as well as the budget to add acoustic rubber to all the surfaces beneath the drywall/sheet rock and vapour barrier. Oh well, next studio
(above, left)The studio had to be physically unconnected to the shed exterior to
prevent sound being transmitted in or out through the walls.
The structure was built out of 2 x 6 lumber, screwed in place(no nails), and acoustically insulated with 6" rock wool. The interior sheetrock was attached to the walls with z-channel strips. Power was supplied from an existing 25 Amp circuit and most of the outlets were quad(4 socket) boxes. It's foundation was comprised of six 8" cement pilings.
and the sheet rock(above, right). Vapour barrier
seams were taped with contruction tape.
The final result was a secure room 7 feet wide and 15 feet long. It cut sound well enough that I could record a folksinger without getting exterior noise, and the neighbours couldn't hear the speed metal drummer from 40 feet away(at ten feet, vibration was more noticeable than the snare hits).
You could use a similar process to build a good studio in a spare room or basement. In that case, you'd probably rest the structure on a series of thick rubber pads(hockey pucks?) to absorb sound vibrations.
Please remember, these articles are for information only. Use them at your own risk and peril. Consult your local officials as to building code restrictions, especially regarding electrical installation. Your mileage may vary, but it worked for me.