Studio design in old garage

[Lateralus07]

I'm looking to build a soundproof studio in an old garage for recording and jamming. The budget is about 3000$, although if recommendations can be made that come close to that, 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.

[GraGra]

Your garage is almost identical to mine! Ive been in the planning stage for about 2 years now but Ive picked up a lot of good info from this forum.

Don't bother with the floor - to do it right is extremely expensive, and the method you're thinking of will probably do little to reduce sound transference, and instead probably create some troublesome low frequencies "resonances' within the room. Assuming your garage is built on a good solid concrete slab, that should do a decent enough job here.

You definitely need a second ceiling. There needs to be an airtight gap between the inner and outer 'shells' - this gap acts like a spring to absorb the sound energy as it passes through. And the inner shell must be completely separated from the outer shell (except for the concrete slab). This means no part of the frames may touch at all - if they do, the vibrations will be transferred through the wood to the other shell, bypassing the effectiveness of the airtight 'spring'.

Cheers, Graeme

[Lateralus07]

Thanks, if I were to do what I listed above with two ceilings, how much sound leakage should I expect?

[GraGra]

This is where you get to the 'how long is a piece of string' part of the design. Please understand Im not the expert here, just passing on what Ive learned so far..

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.

So your gonna need 50-60dB noise reduction at a guess. Not impossible if you use the appropriate meterials and methods.

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.

For the 'outside room' or 'outer leaf' as its known, you only want sheeting on one side of the studs. I'd be removing the current boards on the outside and replace with OSB/cement sheet. A layer of each might work well, with Green Glue sandwiched in between. That's assuming your current frame can support that much mass, which you'll need an engineer to assess for you.

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.

Yes that's the gist of it, however two decoupled layers with one airgap is best. This is whats called a 'two-leaf system'. Adding more layers and airgaps does not improve performance - oddly it actually decreases performance...

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.

Once again, you only need drywall on one side of this wall. Otherwise you end up with more leaves and more airgaps, which is not optimal.

I plan to use caulk to seal the spaces between the drywall.

Yep, use lots of it and seal it up good.

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?

Regular drywall is fine. Dont be fooled by expensive stuff. All that matters is mass and thickness. The heavier and thicker the better generally. 16mm (5/8") drywall seems to be the best value. And yes use at least two layers. Theres a product called Green Glue (which isnt actually glue) that you sandwich between the layers which dramatically increases their effectiveness.

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

You wont need decoupling clips if youve already built a decoupled two leaf system.

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.

Yes and yes!

[Soundman2020]

Hi there "Lateralus07", and Welcome!

Graeme has already answered most of your questions, but I'll add some more detail to that.

The budget is about 3000$

That's on the low side for what you are thinking of doing. Building a studio usually costs more than you imagined. You should probably increase your budget.

There will be a drumset, and a 4x12 cab

Yep. Loud. Probably around 120 dB, peak.

but to reduce the sound from escaping to the neighbors at a disturbing volume.

You should put a number on that. Take your sound level meter over to his place while you play loud music inside your place, and measure the level. Turn down the volume a bit at a time until your neighbor says the level is acceptable. Check what the reading is in your meter. Subtract that from 120. That's how much isolation you need.

so that leaves building materials as the only expense.

... and the HVAC system. That can be quite pricey. You will likely also need some type of building permits, inspections, and other documentation along the way. That also costs money. It's all those little items that can add up to a lot of money...

My current plan is to put insulation in between the studs in the garage,

You need to seal the outer-leaf air-tight first.

and cover it with drywall

That would already create a two-leaf system, so adding other walls after that would create a three-leaf system, which would be lousy for isolation of low frequencies...

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.

Yes, but the "outside room" must be a single-leaf. What you are proposing makes it a 2-leaf.

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.

Nope. It looks like you've been reading the wrong information. What you need is a 2-leaf wall, and just one single air gap. Each time you add another leaf and another air gap, you re-tune the system to a higher resonant frequency, which obviously means that the low-frequency isolation will suffer. Optimum isolation is attained with a two-leaf wall. You might need to build up each leaf from two or more layers of massive building materials, such as drywall, OSB, MDF, plywood, etc, but there's no air gaps in between the various layers that make up a leaf.

Regarding the floor, I plan to use 2x4s for floor joists and place insulation between them, with plywood or other for the floor.

That would be a bad idea. Here's why:

http://www.johnlsayers.com/phpBB2/viewt ... f=2&t=8173

The very best floor that you can get for a studio, is what you already have: a bare concrete slab. Nothing beats that. If the concrete is in bad shape, or looks ugly, then just lay laminate flooring on it (over a suitable underlay, of course).

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.

Adding that to your existing two-leaf outer-wall, you would then have a four-leaf wall, which is ever worse than a three-leaf wall for isolation of low frequencies.

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.

For the ceiling, the same rules apply as for the walls: two-leaf only. So you have your outer leaf (the roof) and your inner-leaf (the actual ceiling). That's it. Nothing more. The roof is part of the outer leaf, and sealed to that. The ceiling is part of the inner leaf and sealed to it. The outer-leaf and the inner-leaf do not touch at any point.

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.

Right. You have the correct basic idea. You need to have one duct that brings in fresh air, and one duct that removes the same amount of stale air. Each duct needs to have a pair of "silencer boxes" (also called "baffle boxes") on it, to stop sound getting through but still allow the air to flow. You need to do some math here to calculate how much air flow you need, how fast it needs to move, and what size ducts you need.

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?

5/8" Fire-Rated drywall is usually the best. It's a bit heavier than ordinary drywall.

Would you recommend more than one layer of drywall in different parts of the design?

Probably. You can determine that by doing the math, to see how much mass you need to get the level of isolation that you want.

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?

Yes: Do not make holes in the wall, the way you normally do! Instead, use surface.mounted ducts and fixtures:

http://www.calcentron.com/Pages/fram-tr ... aceway.htm
http://www.legrand.us/wire-cable-manage ... eways.aspx

I found these decoupling clips that seemed useful, do you recommend them?

If you build a proper fully-decoupled 2-leaf MSM wall, then you do not need clips.

Another plan I had involved using cement bricks for outside walls. I assumed this would be more efficient, but probably more expensive

Correct. It would be much better for isolation, but would increase the cost quite a bit.


- Stuart -