Need to build a free standing vocal booths.

Hello all, first post so please be kind... or not hehe :lol: Preface: Unfortunately my noisy family that lives downstairs makes it very hard for me to work with my clients when recording vocals. So I want to build a vocal booth that hopefully will also be big enough for accoustic guitar. The idea: The idea is having a room that will go with the following. wall A: 5 foot Wall B: 6 foot Wall C: 6 foot Wall D: what ever the tangent is between wall A and wall C. Wall A and C are parallel. B and D will not be parallel. The whole Hight should be (including the supporting floor strut) of 8 foot. How I envision the wall structure is maybe a mess but it's an Idea and maybe you guys can tell me if it will work The followings are each layers from the exterior moving inward. Half inch Sheetrock Half inch Sheetrock 1/8 inch mass loaded vinyl 4x2 strut lined with mineral wool (or fiberglass) 1/8 inch mass loaded vinyl Half Inch Sheetrock Half inch Sheetrock 4x2 strut lined with mineral wool (or fiberglass) Some kind of fabric to cover the strut and mineral wool for the finishing. This would go for all the walls and the ceiling. If my math is right, that means the wall thickness would be 10 inches and 2/8th I would place 2 doors lined in with Mass loaded vinyl on wall C to get in and out. One door opening in the booth, the other opening outside of the booth for a better sound insulation. For ventilation I'm thinking of using 2 x 4 90 degree corners system In 90 degree , twist sideways 90 degree, twist sideways 90 degree, and out 90 degree. With a 80 mm computer fan to push the air in and to pull the air out on the second unit. Both units would be made out of wood and able to fit withing the 10 inch wall thickness. For the floor, the struts (frame) would rest on auralex U-boat and the frame would be filled with mineral wool (or fiberglass) with 2 layers of mdf with 1 layer of 1/8 mass loaded vinyl and 2 half inch Sheetrock sandwiched in between the 2 layers of mdf. Now my first problem is making the plans to make sure all the seems are covered with no gaps in it considering that wall D is at an angle, and taking into account the thickness of the wall. I also have to figure out how to pass the microphones wires, a wall mounted lcd screen with a web cam, and a ceiling mounted light with the electrical wiring and all. I would greatly appreciate any help you fine gents (and woman if there is) could provide with either the plan or suggesting an other way of doing this booth.

Hi "Media BCD", and welcome! :) If you search the forum for "vocal booth" or "isolation booth" you should be able to find lots of information. Your basic idea is OK, with some comments:

Half inch Sheetrock Half inch Sheetrock 1/8 inch mass loaded vinyl 4x2 strut lined with mineral wool (or fiberglass) 1/8 inch mass loaded vinyl Half Inch Sheetrock Half inch Sheetrock 4x2 strut lined with mineral wool (or fiberglass) Some kind of fabric to cover the strut and mineral wool for the finishing.

1) Forget the MLV (Mass Loaded Vinyl). It is very expensive, and you do not need it. also, you cannot use it as the first layer on your studs: the drywall (sheetrock) must be attached directly to the studs. 2) It's not worth putting that much mass on the walls unless you also decouple one leaf. You would actually get better isolation if you used just one layer of drywall on each side (16mm, not 12mm), and used resilient channel ("RC") on the studs inside the booth, to mount the innner-leaf drywall. 3) Use only 5/8" drywall (16mm), never 1/2" (12mm). 12mm is too thin, too flexible, and has poor resonant characteristics. 4) Instead of adding another frame inside the room, just build absorber modules that you can hang on the walls. OR build your inner-leaf "inside out" (search the forum to find out how to do that).

If my math is right, that means the wall thickness would be 10 inches and 2/8th

Probably, but it would also be extremely heavy: too heavy for your floor to support safely. Before you build anything at all like this, call a structural engineer to check your floor structure and tell you how much extra weight it can support safely, in addition to what it is supporting already. If you do not do that, and then there is some problem with the building (such as the floor collapsing, or even sagging down into your neighbor's room), then YOU will be responsible, not your insurance company. They will refuse to pay if you do something to overload the building structure. So getting a structural engineer is cheap, considering the possible huge expenses if anything goes wrong...

I would place 2 doors lined in with Mass loaded vinyl on wall C to get in and out. One door opening in the booth, the other opening outside of the booth for a better sound insulation.

The idea is correct (back-to-back doors), but once again forget the MLV: Just use ordinary solid core doors (not hollow core!), and if necessary add a layer of MDF for more mass.

For the floor, the struts (frame) would rest on auralex U-boat and the frame would be filled with mineral wool (or fiberglass) with 2 layers of mdf with 1 layer of 1/8 mass loaded vinyl and 2 half inch Sheetrock sandwiched in between the 2 layers of mdf.

You do not need that. That's a huge waste of money, and also of room height. Let the walls rest on the floor, then put down a layer of 2" OC-703 with two layers of 19mm plywood on top, screwed and glued together. Cut the plywood to leave about a 1/4" gap around the edge, up to the walls, then fill that gap with backer rod and acoustic caulk. That's all you need. - Stuart -

Hey Stuart thanks for the response :) very appreciated. I have been able to find some good plans with the help of John so I can use them as a reference, only I have to customize it a bit to get the window out of there and make it a bit smaller. The reason I was going for uboats is that the house itself is a ubber resonator. It's an old house that was built in a way that everything that happens downstairs (even in the basement) vibrates up to the last floor (where the studio is) so just placing the booth on the floor itself, without anything to decouple it from the floor, will result in the same thing happening as in my studio at the moment, where I hear everything from downstairs. If U-boats wont work, what else can I use to completely decouple the booth from the house?

so just placing the booth on the floor itself, without anything to decouple it from the floor, will result in the same thing happening as in my studio at the moment, where I hear everything from downstairs.

I think you missed the point of what I was saying: If you hang your inner-leaf drywall from resilient channel, then it is decoupled. If you place your floor on 703, then it is decoupled. Only the outer leaf remains coupled to the floor, which is fine since the floor itself is also the outer leaf... :) If you want to float your booth, then you should read this thread first (below), about how to do it right: viewtopic.php?f=2&t=8173 That explains all of the issues quiet clearly, and how to deal with them. It also mentions the calculations that you'll need to do in order to figure out where to places the rubber pucks, and how many of them you would need, and how much mass you would have to have bearing on each one, and the spacing between them, and the depth of the air gap, and the effect of the insulation, and all the other factors. That's a lot of calculations! :) Floating a floor, or an entire room, is nowhere as easy as people think. There's a LOT of math that goes into it, and you have to be certain that you get the math right. If not, then either the rubber is not loaded enough, so it does not float, or it is loaded too much, so it does not float. In both cases, you wasted a lot of time, effort and money, and ended up with a worse situation than not floating: you now have a resonant floor (think: "drum head"). Getting the calculations correct so that it does float is the tricky part... And getting them wrong is so very easy to do.

If U-boats wont work, what else can I use to completely decouple the booth from the house?

You do not need to decouple the entire booth from the house: you only need to decouple the inner-leaf. Hence, the suggestion to hang your inner-leaf drywall on RC, and set your floor on 703. If you can't get RC where you are, then another good alternative is to use ordinary hat channel on RSIC clips. As long as you use something that is specifically designed to acoustically decouple drywall, that's all you need. - Stuart -

Alright, thank you very much for your help will check this out promptly.