How to make a collapsable sound isolation booth?

April 6, 2012 6:58 PM

Help me build a sound isolation booth -- that's collapsable. I'd like to build a small soundproof room (about 4x4x8 feet) that can be disassembled for shipping and reassembled without huge amounts of effort or crowbars.

No windows, and one door -- or one entire wall will swing on hinges to act as a big door, if that's not impractical. The sound isolation doesn't have to be as good as a professional recording studio, but more is better.

So I guess the two main questions are - what sound isolation technologies to use, and how to fasten the walls, floor, and ceiling together so that they can be detached and re-attached relatively easily without compromising the soundproofing too much. It's ok if it takes hours to disassemble / reassemble, as long as the process is not destructive.

I probably don't need ventilation because nobody will spend a long time in there with the door closed, but I welcome suggestions for ventilation methods that don't compromise the sound isolation too much.

I've just started researching isolation methods and materials like homasote, green glue, absorbent foam and batting, "floating" walls with vibration-absorbing brackets, and so forth. I don't understand them well enough to choose! Please advise.

posted by moonmilk to Home & Garden (11 answers total)

I think you are on the right track, just cover the walls in some sound absorbing egg crate and use some well placed hinges to tie it all together.

For isolating it from vibrations, I would recommend just isolating the microphone from the stand that it is on. Seems way easier.
posted by gjc at 7:04 PM on April 6, 2012

Response by poster: To clarify, the most important property of this thing is that people outside shouldn't be able to hear a singer inside, nor vice versa. Recording quality is a lower priority.
posted by moonmilk at 7:24 PM on April 6, 2012

I don't think you need to worry about floating walls, since you can make the whole thing float (and if it's on the ground it's moot). Floating walls are more if you have a superstructure (like a house) that you need to isolate from. If it's just a box on the ground, it's just going to be the walls/ceiling with maybe some special stuff under the floor.

I would just make a 4x4x8 room (this is actually quite small for a person, so beware of claustrophobia), use double layers of the thickest sheetrock you want to afford, staggering the seams (whatever the technical term is...) with green glue between them. Two tubes of green glue per 4x8 sheet of rock is the figure I've heard, but that could have been Big Greenglue speaking, so research and vary your mileage accordingly.

If you need to isolate from the floor/ground, leave the floor beams exposed and set the whole thing on a bunch of isolators. You can also tack on 2x2s if you make a full floor/walls with insulation or whatever, and set those on the isolators. The floor itself should probably have some underlayment. It's pretty much a lbs/sqft thing, and you can get lead sheets and stuff, but Mass-loaded vinyl (MLV) is a standard.

For ventilation, it would have to be baffled, so some kind of ceiling module, and there is premade stuff, too.

You should also caulk the inside seams whenever you assemble it. This might be a mess or take a long time to dry, maybe something like the beam isolators above (Sorbothane could be another option) as gaskets where the walls meet. You could have screws that tighten down on the gaskets for both some acoustic isolation and sealing.

Lastly, consider building the thing so that none of the walls are parallel. It'll just be a better space that way for a (little?) bit more complicated construction.
posted by rhizome at 8:19 PM on April 6, 2012

Consider using thick styrofoam for the walls. It's cheap at Home Depot and is light. I don't see any reason to use heavy materials, especially if you want it collapsing.
posted by bprater at 10:42 PM on April 6, 2012

With respect to previous commenters, there is an enormous difference between muffling a sound and making a room soundproof. If you really expect a listener outside the room to hear *nothing* coming from inside, forget any structure that you could ship. You would need walls made of something far heavier, like concrete, to accomplish that kind of isolation.

This company makes isolation booths for singers, drummers and audio testing. Even their premium product line is only able to reduce sound levels by 75%, and the cost of a 4x4' room is over $6,000.

I believe what you are asking for is impossible to accomplish within your stated requirements. Maybe you can provide more details about how this booth will be used?
posted by stephennelson at 11:33 PM on April 6, 2012

Response by poster: Thanks for the feedback! stephennelson, I understand that perfect isolation isn't possible and even partial isolation is expensive. So I will clarify my clarification:

The goal is to keep vocal sounds from leaking between inside and outside the room, as much as is practical given the constraints of packability and reasonable price.

That said, the products from whisperroom.com are pretty close to what I need, and possibly within my budget. I'd still like to build my own for aesthetic reasons, but maybe that would be silly. So I'm gonna change the focus of my question a bit:

Could I build my own collapsable isolation room - with no windows, no ventilation, and a hinged wall for a door - from studs, sheetrock, green glue, foam, etc. - for a few thousand dollars and a few dozen hours labor - that would at least approach the isolation capabilities of whisperroom.com's standard booth? (About 40-50dB at vocal range) Could I perhaps even do a bit better than that, since I can fairly easily make a double wall, like their enhanced booth (about 50-60dB)?

If not, then I should probably just buy a booth.
posted by moonmilk at 7:22 AM on April 7, 2012

You'll need some kind of ventilation or it'll be like locking yourself in a fridge.

I think it will be way easier to make a well fitting door in one of the walls, rather than putting the wall on hinges. That way you can construct a rigid box, instead of having to over-engineer an open ended box that won't flop around.
posted by bonobothegreat at 9:50 AM on April 7, 2012

Response by poster: I don't expect people to stay in with the door closed for long periods, but you're right, probably better to have ventilation anyway.

Good point about the door.
posted by moonmilk at 11:31 AM on April 7, 2012

Best answer: I would say it is possible. Construct a frame of 2X6s around the edges and 2X4s in the middle. Most rooms are made with a single stud that holds both the inside wall and outside wall, but you will want each side on its own stud, isolated as much as possible from the other side. Stagger the studs so that the boards of the interior walls line up along the inner edge of the 2X6, while the outer studs go along the outside edge of the 2X6. This creates an air gap inside the wall that will reduce sound transmission.

Hang sheetrock from the vibration dampening rails you mentioned earlier, then affix another layer of sheetrock on top of the first using green glue. Repeat this on the other side of the frame to form the outer wall.

You will want tight seams where the walls meet. I think the best thing to do here is line the edges with thick, heavy, rubber weather stripping, then tighten the walls together with lag bolts to compress that rubber and eliminate air gaps. The same goes for the floor and ceiling.

The door poses the biggest problem, as it will need to be tightly fitted and weatherstripped too. There are companies that sell doors for recording studios, this might be your best bet. If you have staggered the studs inside the wall, making it extra thick, you might have enough room to employ a double door, one opening out and the other opening in. If you have done a good job, it will be pitch black inside the room, so leave a flashlight or lantern inside!
posted by stephennelson at 10:52 PM on April 7, 2012

Response by poster: Thanks, stephennelson - that looks like a good way to go. Green Glue makes a rubber tape that's intended for floor joists, but might make a good removable grommet for where the walls are bolted together; or perhaps their sealing caulk would be better. I'm not sure which would make more mess when the walls are separated for transport.

There will be lighting in the room, yes! Probably an LED ceiling fixture.
posted by moonmilk at 9:19 PM on April 8, 2012

I don't think you want to add ventilation. Any hole you make that allows air to travel into the box will also allow sound out. You could have a little portable fan inside if you need to move the air around a bit. You don't have to worry about someone running out of oxygen in a 4x4x8' space unless you're locking them in there for hours at a time.
posted by echo target at 8:29 AM on April 11, 2012