John Sayers' Recording Studio Design Forum Archive

Greetings from Minne-snow-ta.

I am trying to figure out the best way to build a 4x5x7 vocal booth. I would like to build it so in the future it could be disassembled without to much damage. If not, so be it. I want it quiet, it will only be used to do voice work and edit. My house is a 2,000 sq foot tri-level and the booth would be situated in a lower level (small) bedroom. The bedroom is 11x9 and the ceiling is a popcorn finish and the ceiling itself is 7.5'. Since the room is on concrete and has carpeting with carpet pad, my thought is I won't need a booth floor and I would just put the walls directly on the carpet.

As for outside noise, my neighbor is rather lazy so he isn't doing much yard work. Two houses away, more of an issue. I do get a fair amount of traffic along the opposite side of my house. I chose this room because it is away from the AC outside and the furthest point from the laundry room.

Major concern is noise isolation from outside the booth and not a dead sounding booth. My wife does run a daycare out of the house, so that will cause some early mornings and late nights, but I hope that if she has them on the second level opposite of my booth (in the kitchen), I will still be able to work.

My thinking at the moment is 2x4 walls with two layers of sheet rock (I'm not sure the best way to do this), roxul insulation and fabric covering that. I haven't figured out the ceiling yet.

I have spent hours and hours researching and as you know, it's like trying to drink water out of a fire hose.

Other thoughts I toyed with, going with 2x6's and 2x4 staggered joists, or putting another piece of sheet rock on the inside (maybe using a channel?).

Cost? As low as I can keep it.

I'm trying to remember any other items I need to cover, so I cover all the posting rules.

So to recap:
Lower level bedroom on concrete with carpet and pad
4x5x7 vocal booth
Sound isolation of most importance, but not a dead booth
In-home daycare
Proper technique for walls
Is it okay to build directly on carpet?
Suggestion on ceiling
Price is an issue, trying to keep it low

Whew! That took longer than I planned. I thank you in advance for your help.

Mike

Hi Mike, and Welcome!

Here's something that might interest you:

http://www.johnlsayers.com/phpBB2/viewt ... =1&t=14147

I won't need a booth floor and I would just put the walls directly on the carpet.

Correct: You won't need a floor, if you build it correctly.

However, setting it on carpet is out. Carpet will not provide the air-tight seal that you need, since it is porous. In order to obtain isolation, you need the best possible seal you can, and carpet is not it. So either you'll have to cut out a patch of carpet where the booth will go, or you will have to lay a sheet of plywood on top of the carpet, and build your booth on that.

Carpet is bad for another reason: Lousy acoustics! If you really want your booth to sound bad, then put carpet on the floor. And if you want to make sound even worse, then carpet the walls and ceiling too...

And apart from anything else, you'd wreck your carpet anyway by standing all that huge amount of mass on it...

Major concern is noise isolation from outside the booth

You should try to put a number to that, in terms of how many decibels of isolation you want. What once person considers "good isolation", then next guy might say is "really lousy isolation", while a third guy might call it "extreme overkill". Numbers clarify that.

and not a dead sounding booth.

Well, on that point, you lose. There's no choice here, since you say that it has to be very small (just 4x5x7), so there's no other option, acoustically. You can make it sound dead, or you can just leave it sounding terrible. For such a tiny space, those are your only two choices. In fact, even when treated to be "dead" it will still sound somewhat "boxy", and "closet-like". It's just the nature of the laws of physics, applied to sound waves in very small spaces. Very small spaces cannot sound good. Sound waves need large spaces if you want them to sound good.

I haven't figured out the ceiling yet.

Same as the walls. The door also needs to be built the same way, and so do your ventilation silencer boxes, and the window (if you have one), and the electrical and signal pass-throughs.

My thinking at the moment is 2x4 walls with two layers of sheet rock

Two layers of drywall as a single leaf will give you about 30 dB of isolation between you and the room around the booth. Obviously, that will be higher with respect to levels in other rooms, at other points in the house, and also with respect to the world outside your house. But you still need to figure out if that is enough, or not Loudest human singing can put out an SPL of about 90 - 100 dBC. 30 dB of isolation would bring that down to around 60 - 70 outside the booth, which is about the same level as normal to loud conversation. If you only sing softly (romantic ballads, for example) then that would be more like 70 - 80 dBC inside, meaning 40 to 50 dBC outside.

I have spent hours and hours researching and as you know, it's like trying to drink water out of a fire hose.

Yup! And if you have only spent "hours" on it, then you've really just been taking a few tiny drops from the fire hose... I don't mean that facetiously, but seriously: acoustics is a huge subject, and just a few hours of investigation won't get you very far. Just scratching the surface.

or putting another piece of sheet rock on the inside (maybe using a channel?).

That would increase your isolation yes, provided that you used proper resilient channel (RC-1), and not just ordinary hat channel, which looks very similar but is totally different acoustically. Or you could use hat channel provided that you mount it on RSIC clips, or some other type of good acoustic resilient clip. However, doing that would eat up a lot of space, as you'd then have to put your acoustic treatment on top of that inner leaf of drywall, but you don't have any space to waste! You'd lose a minimum of 8 inches in width, 8 inches in length, and 4 inches in height. Probably more...

So you could go that route if you need more isolation that a single leaf can provide, but you'd need to expand the footprint to compensate for the lost space. In fact, I'd expand the footprint anyway, as large as possible, to reduce the typical tiny-room "boxy" sound.

Cost? As low as I can keep it.

Wouldn't that be nice! But in the world of acoustics, "low cost" is not part of the vocabulary...

So to recap:
1. Built on concrete with carpet and pad
2. 4x5x7 vocal booth
3. High sound isolation,
4. Not a dead booth
5. In-home daycare
6. Proper technique for walls
7. Low cost.

That's a great list, by the way! Pick any two items from it: you can have those, but not the others. Which two would you like?

Is it okay to build directly on carpet?

Nope.

Suggestion on ceiling

Same as walls: 2x4 joists, with two layers of 5/8" fire-rated drywall on top, thick insulation in the joist, fabric cover.

Whew! That took longer than I planned.

Yup! Welcome to the world of acoustic design! That will be your reality from now on: EVERYTHING will take much longer than you planned, and will cost a whole lot more than you planned... It goes with the territory...


- Stuart -

First thank you for the kind welcome, I love what you've done with the place.

Here's something that might interest you:

I have looked that thread over a couple of times and will do so again.

On the floor, I will put down some plywood, not a problem.

I would like to try to achieve in the mid to upper 50db range inside the booth.

yes, provided that you used proper resilient channel (RC-1), and not just ordinary hat channel, which looks very similar but is totally different acoustically. Or you could use hat channel provided that you mount it on RSIC clips, or some other type of good acoustic resilient clip. However, doing that would eat up a lot of space, as you'd then have to put your acoustic treatment on top of that inner leaf of drywall, but you don't have any space to waste! You'd lose a minimum of 8 inches in width, 8 inches in length, and 4 inches in height. Probably more...

Boy you are right, that is A LOT of space that will get eaten up. Dang.

In fact, I'd expand the footprint anyway, as large as possible, to reduce the typical tiny-room "boxy" sound.

I might be able to go another 6" on the sides, other than that I'm stuck.

Wouldn't that be nice! But in the world of acoustics, "low cost" is not part of the vocabulary...

We'll just keep that between you and me, my wife can find out later.

That's a great list, by the way! Pick any two items from it: you can have those, but not the others. Which two would you like?

1) High sound isolation
2) Proper technique for walls

Hey there Mike,

Mike981 wrote:I would like to try to achieve in the mid to upper 50db range inside the booth.

Have you got a Db measurement for your loudest sound outside the booth (ie: traffic noise, kids running around, wife-yelling-at-you-for-how-much-you-spent-on-this-crazy-acoustic-nonsense? this will dictate what kind of construction you need in your booth.

Soundman2020 wrote:Two layers of drywall as a single leaf will give you about 30 dB of isolation between you and the room around the booth.

Green Glue might also be of use to you in this construction. Whilst it is pretty expensive, the amount you would need is not going to be a huge expense. I have used it and can tell you it works as advertised.

Mike981 wrote:1) High sound isolation
2) Proper technique for walls

good chioce, and the only realistic one for a useful room

all the best,

Steve

Thank you Steve.

I am getting close to start framing my booth. Since I am building this modular I am wondering if there is a material I should put between the modules before I connect them.

Thank you again.

Mike981 wrote:I am wondering if there is a material I should put between the modules before I connect them.

by that i'm guessing you mean for the purpose of sealing the modules airtight?

If so then you'll want some acoustic sealant/caulk. Doesn't harden over time like ordinary silicon. Green Glue make an acoustic sealant, although you'll find there are other brands available.

Maybe post up a few pics of the modules as you build so we can see any possible issues with the construction before you bolt everything together

all the best,

steve

Will do, thanks Steve.

Quick question on the 2x4 framing for the modules for my 6(L)x4(w)x7(h) voice booth. I have noticed in others pictures and diagrams in the corners, some seem add another perpendicular 2x4 in the corners. Is this necessary?

Thank you.

Generally, yes, but it depends on what you are trying to do!

It would be good if you design your booth in SketchUp and post that here, so we can understand what it is that you are planning, and maybe help you to improve it.


- Stuart -

Stuart I am going to really try to figure out SketchUp, so I can explain my plan better and help your frustration level.

Basically I am building five modules (including the ceiling). Two sheets of 5/8 drywall on the outside and Roxul on the inside with cloth covering that.

I hope this file works, I struggled with uploading the actual file and went with a PDF (sorry about that). I tried to give a top view diagram of my booth location in the main room and the actual booth (between three small walls). As I mentioned above, I am doing a rather basic studio design with five modules. My problem is the top/ceiling module. By the way, the main room ceiling is 91" and my total booth height will be a few inches less than that.

My thought was to build the top module and then with help lift it up and place the top module on the walls and then secure it from inside. My concern is that since I am building it between three walls (and the ceiling) I will not be able to seal the drywall from the top to the walls. There just isn't enough room, so there will be a gap.

I plan on applying acoustic sealant on all the joints inside, do you think that will be enough? Also would it make sense to put Green Glue where all the modules connect to each other?

Again I'm sorry about the PDF.

Mike981 wrote:Again I'm sorry about the PDF.

just quickly Mike as I'm about to head out the door.....but if you go to 'file', 'export', '2d graphic' in sketchup, it'll copy what you see on the screen as a JPEG which you can then put directly in your post without the need for a link.

cheers.

steve

I hope to get the walls up tomorrow and proceed from there. All walls are in the garage and I am bribing my son and his friend to come over and help carry them down stairs. Beer and brats when all walls are connected.

Now I need to order some Cambric fabric (found some on Ebay) to cover the Roxul S&S and start work on the baffle boxes.

Hey,

I know that this is an old thread, but I read about the 4/5/7/etc design a few years ago here (as sort of an ideal small configuration). Now that I have a space that I could build this, I read that this size is too small for reasonable sound, is there a threshold size for a vocal type of iso booth? Like would 7/8/9 start to be decent?

Thanks,

Matt