Studio in old garage

[Lateralus07]

I'm looking to build a soundproof studio in an old garage for recording and jamming. The budget is about 1500-3000$, although if recommendations can be made that come close to that, over or under, then they will be considered, the build may just be held off for awhile. The garage is pretty far from airtight, and the windows in the garage door are broken. There will be a drumset, and a 4x12 cab at most. Although the cab can be turned down if needed, the drummer plays very loudly. At 3 feet, I figured a worst cased scenario of about 125 decibels on loud snare rim shots. The goal isn't to actually create a 100% sound proof studio, but to reduce the sound from escaping to the neighbors at a disturbing volume. The closest neighbor is only about 25 feet from the front of the garage, so I recognize the task may be difficult or impossible. My current plan is to use the back half of the garage. The rectangular base measures 22'3" x 14' (6.78 x 4.27 meters) and 9'2" (4.27 meters) high at the highest point and it tapers down to 8' (2.44 meters) at both ends of long side, 3' from either side. The photos aren't the best given the current state of the garage, but it's the best I can currently do. Please note the shelf in the corner of the garage will be removed. All of the labor will be done by myself and a few friends. Most if not all of the tools will be borrowed from family, so that leaves building materials as the only expense.

Step 1: Outside seal
It is a two car garage, and I plan to only use the back half. I didn't measure the depth of the garage, because the height in the front half of the garage is limited by the garage doors. The usable portion of the garage is 14' x 22.25'. My current plan is to put insulation in between the studs in the garage, and cover it with drywall on walls 2,3, and 4, in addition to building a wall (side 1) cutting the front half of the garage from the back half with a layer of drywall on either side of the frame with insulation in between. I then plan to put a roof reaching the 9'2" height and perhaps taper it down on the ends with insulation between two layers of drywall. This is the initial plan to seal up the current garage, as the garage is old and not airtight as you can see in the pictures. The purpose of this first step is to make an airtight space that will serve as the "outside room" in which the interior room will be built and decoupled from. From what I've read, the most efficient way to make a soundproof room is to have several airtight layers of material decoupled completely with air between.

Step 2: Inside room
The second step then is the inside room which will consist of a floor laid on the concrete. Regarding the floor, I plan to use 2x4s for floor joists and place insulation between them, with plywood or other for the floor. The walls on all four sides of the inside room would consist of an outside layer of drywall, a layer of insulation and an inside layer of drywall.

This is my current plan. I plan to use caulk to seal the spaces between the drywall. I have several questions regarding how well this plan will work as well as details regarding the build.

Firstly, would I need to make a second ceiling for the interior room? I had planned on building only one as I thought it would be sufficient enough, but this is not my area of expertise.

Will the insulation along walls 2,3, and 4 in step 1 be useful considering the current exterior wall on the outside of the garage is not airtight? I have a feeling that insulation would be virtually useless unless there was an airtight seal on the outside of the insulation.

Is there a need to put insulation between the floor joists? The floor is concrete and I've read that it won't transmit much sound as it will be transferred into the ground.

Is there a particular way to seal the floor with the concrete to make it airtight, or is that not required?

How should I go about ventilation? I know very little about this, but I am willing to learn. I plan to have a space heater and air conditioner in the room, but I also need fresh air coming in and out.

Regarding the actual drywall and insulation, is there a particular type that is recommended, and/or significantly better at stopping sound transmission than regular drywall/insulation? Would you recommend more than one layer of drywall in different parts of the design?

Electric and lighting is already wired in the garage and only needs rerouting, but is there a particular technique to installing outlets and light sockets to not compromise the sound proof nature of the room?

Is there a particular type/brand of caulk that will work significantly better than another?

I found these decoupling clips that seemed useful, do you recommend them? Found here:
http://www.fullcompass.com/prod/263814- ... AgyG8P8HAQ

Another plan I had involved using cement bricks for outside walls. I assumed this would be more efficient, but probably more expensive as anything beyond woodwork likely means paying a contractor.




Any input would be greatly appreciated. If the plan needs major changes or it is unrealistic, please say so and leave recommendations for the cheapest alternatives possible. I will update the post if I think of anything else.

[Soundman2020]

Double-post:

http://www.johnlsayers.com/phpBB2/viewt ... =1&t=20523