Hi, I need to make a roughly 6'x9' booth sound more dead than average and have a limited budget.

The reason I need it to be pretty dead is that I'll be recording ADR and would like actors to be able to yell, scream etc with the sound of the room as removed as possible.

The room is a room-within-a-room, so I don't have to worry about isolation much.

Any suggestions are very welcome, thank you!

Rockwool RW3 100mm in timber frame faced with flame-proofed hessian?
(ProRox SL 930 in some territories I think). It's what my vocal "booth" is made of.

Make it thicker if you want. A layer of RW45 / 920 on the inside?

+ head height, a ceiling and some way for the talent to get in and perhaps out.

If you search on here for "vocal booth treatment" you'll get dozens of threads over many years.

TLDR is that dampening high frequencies is easy but sorting out lower frequencies and boxiness or boominess is much harder.

Good ventilation is important but tricky also.

Build it inside out. Frame it with 2x6 put two layers of drywall on the outside, insulate with Rockwool Safe N Sound, add a layer of thin poly batting and cover with fabric. Your walls become the sound treatment on all 4 sides and above.

problem with a "booth", only 6'x9', is that if you give it any sort of solid wall you're going to have wicked modal issues right where you don't want them (boxy / boomy). I suspect. If the booth walls are more porous, and depending on its location relative to the studio walls (& their construction / treatment), less so. The enclosing volume can act as a bass trap for the booth. You'd think. You're going to have to balance isolation against this consideration. And cost. Obv.

Ultra Touch cotton insulation is about the best material for total absorption (and it works to pretty low frequencies in 4 inches). The problem is: It's a little heavy and very floppy.



-tINY

this is a question for the acoustics forum. i can guess at what they will say:

use a lot of mass. there is no substitute for mass. that means layers of drywall, mass loaded vinyl, etc.

use roxul or the other brand they recommend that i don't remember. owens corning 703 apparently changed their formula and is not as good as it used to be.

something like this might work:

outer wall: three 1/2" drywall slabs, for 1.5" total thickness. drywall (at least in the united states) is incredibly inexpensive. use two 1/2" drywall layers if you can't afford three.

inside that wall: line it with mass-loaded vinyl. this will add hundreds of dollars to the cost, so you might have to skip this on a budget.

inside walls: 3" thick of roxul on all walls and the ceiling. if you needed to do a lot of bass trapping, even thicker roxul would be recommended. but it is for voices, and the cheap and readily available stuff at home depot is 3" thickness.

cover the roxul with guilford of maine cloth. if that's too expensive, select something cheaper.

floor: carpet with padding underneath.

float the floor. get auralex u-boats to do that.

that might be an acoustics forum-approved solution. they are very fussy over there! it might not be "acoustically correct", but it's in the direction of the problem you are trying to solve.

ventilation is going to be a real consideration. unless you are building something you can't be in for more than ten minutes at a time, you are going to need ventilation. getting quiet ventilation that also excludes sound well is very difficult. the whisperroom products do a quality job of it. but once you open sound to the outside, sound can get in. quality ventilation increases the difficulty by 4x. the door is also an area of difficulty. it's going to be the most mass-light part of the walls by far. heavy industrial doors cost a lot of money. you can build your own thick door, but getting an airtight seal is going to be difficult. if you could get a lighter, less-costly industrial door with an airtight seal, and then bulk up the inside of it with roxul and drywall, that might work.

You lost me at "booth," and again at "dead."

Any box is going to sound like a box. And you want neutral, not dead. For both reasons, the BOX must go.

Rooms can sometimes be made to sound good; boxes cannot.

Yup, they'll tell you to spend more money than you've got on something you don't need.

Not sure that is quite fair. Typically you get an answer to the question as asked. Which is the best way is a different question than which is the cheapest. No doubt skewed to standard practices but what would you expect?

I'm completely redoing my studio and I saved a lot by doing a bit of research and asking questions. A lot of the answers I got was a bunch of source materials that I had to read to figure the answers for my application. It ends up being a bit of work in educating yourself. Often times the right answer is not as simplistic as some of the responses in this thread. Too many details are missing in both questions and answers.

I did put a smiley on there. See? There it is again.

In fairness, it's up to the OP - suggestions are what was asked for. And this is low-end.