Small, semimoveable practice booth for vocal/acoustic guitar

Hi all, I'm trying to figure out how feasible it would be to build an isolation/practice booth within some (what I think are) fairly strict limits. I play acoustic guitar, and have recently started practicing vocals. In the past, I've just played guitar fairly timidly while at home, so as not to annoy neighbors or landlords. However, now that I've been doing some vocal classes and actually had a chance to play and sign at "real" volume, I've realized how important it is to actually be able to do this at home. I'll list what I'm hoping to have, but I know that, as with all things, you can't always get what you want. I live in San Francisco, so floor space is at a premium. I am almost always limited to what I can fit in my bedroom. I think the maximum external dimensions would be roughly 4'x6'. 4'x6' is the max I could fit in my current space, and I think I can reasonably expect to have a similarly size room if/when I move again, which leads me to the next part. To be safe (I've lived in some places with low ceilings), I'd like to keep the height as low as reasonably possible. I'm 6'2", so I'm guessing between floor, ceiling, 7' would be the minimum. I'm not sure what the minimum interior space would be (I list my questions at the end), but at the very least I need to be able to stand and play a guitar. Ideally, I'd like to be able to sit as well, but this is not a requirement. I also seem to move every year or so, so it's important that it be constructed in such a way that I can disassemble it with (preferably) no damage. This is another reason why I'd like to minimize the height, as it makes it easier to maneuver the pieces up stairs and through narrow hallways. Along the same line, I'd like to try to keep each "part" under 75lbs or so, so that I can reasonably move it by myself. However, this would be more of a nicety, not a requirement, as I could probably enlist some friends' help to move if needed. I know the forum guide asks that we have an objective measure of the noise level, so I hope I don't draw too much ire by saying that I don't (yet) have a sound level measurement device. Currently, I'm in behind-the-garage apartment, which already has a subjectively(boo, I know) decent level of isolation. I can hear footsteps, and I can hear my landlords when they raise their voices, but otherwise it's pretty quiet. However, knowing I'll likely move within a year, and will most likely be an an apartment building at some point in the future, my feeling is that sound reduction is the most important thing. I know that if I don't feel comfortable practicing, I won't, which would defeat the purpose of building it in the first place. As I mentioned, I will be playing acoustic guitar and singing, but that's it. I don't need to accommodate anything amplified. I have a more baritone voice, and at the loudest, it would be something like choral singing. No screaming. Ideally, I'd like to plan the isolation for a "worst case scenario" of living in a place with only a single layer of drywall on either side of the studs which separate my room or apartment from another. Using numbers pulled from various decibel example tables, this would mean reducing me singing at 70dB (this might be a high estimate) to about 40dB (quieter than a normal conversation). I don't know if this is possible with the space/build requirements I have (I'm still trying to calculate the STC of various leaves), but I figured the more information I can provide, the better. The only reason I record at home is to help myself practice (I have access to studio space through a local music school if I'm ever inclined to make any sort of quality recording, and I only do this for enjoyment anyway). This would lead me put the sound quality of the space way down on the list of importance. I realize that bad enough acoustics could be detrimental to practicing, so I'm not assuming that it isn't important at all; just that sound fidelity/liveness/deadness is probably less important for my situation. I would like to add some kind of ventilation, but it doesn't have to be quiet, just keep from leaking out a lot of sound. I would say my max budget would be about $2000. Ideally it would be closer to $1000-$1500, but I look at it as an investment if it works well for what I want. I'd say my priorities are, in order of importance:

Size (it has to actually fit in my room) Sound Isolation Modularity (ability to knockdown and rebuild) Cost Sound quality

I've searched the forums quite a bit, and I think my main questions at this time are:

Is any part of this wildly unrealistic? What's the minimum interior size I would be looking at? What sort of modular designs have people had success with? I found some threads about modular building, but I didn't find a whole lot of feedback about the methods. Do I have to worry about weight? Has anyone had experience with the DAWBOX plans? They are designed to be modular, but I don't know if the plans would be a helpful resource.

Thanks much!

Hi Chris, and welcome! :) So basically you need a semi-portable booth that will fit in an average apartment, and gives about 30 dB of isolation, when combined with existing walls/floors/ceilings? I think that is do-able, with caveats.

Is any part of this wildly unrealistic?

I don't think so. It should be do-able.

What's the minimum interior size I would be looking at?

You are going to need some type of framing, of course, to hold the thing up, but that can probably be 2x3, meaning that you'll lose 2-1/2" from the framing thickness. Then you need to allow for the thickness of your outer leaf (on the outside of the booth), which I would suggest making from MDF, screwed and glued to the framing. The sections of framing can then be bolted together, so that the booth can be disassembled easily by unbolting. So you'd lose the thickness of the MDF. I'd suggest 5/8" MDF, but you could probably also go down to 1/2" if you really have to. That makes the structure about 3" or so thick. The ceiling would be the same: framing with OSB on the outside, screwed and glued, and the ceiling frame bolted to the wall framing. Caulk to seal the gaps. Interior lined mostly with insulation, but perhaps also a slats on one side ("slot wall"), angled slightly, for better acoustics inside. I would also cover the entire outside with good quality carpet, mostly for protection in transportation. That would give you somewhere around 25 dB of isolation, and combining that with the room around your booth, should get you where you want to go. The good thing is that you don't need to isolate yourself FROM the room, but rather to isolate yourself from other rooms, beyond the one the booth is in. That makes it a whole lot easier. So as long as you can set up your booth at least 5" away from the walls of whatever room it is in, the combined isolation of both booth+room should be enough. However, I'd say that you are estimating a bit on the low side with your 70 dB singing! It's probably more like 90, maybe more... Before you settle on the final plan, I would definitely get a sound level meter and rest yourself, to see how loud you are!

Do I have to worry about weight?

Yup! :) It will be heavy. MDF weighs about 10 kg/square meter for 1/2", closer to 14 kg/m2 for 5/8".... Don't forget you will also need ventilation! That's a really small box in there: you need fresh air, so you'll need a fan and a small silencer box to handle that. - Stuart -

Soundman2020 wrote:

That would give you somewhere around 25 dB of isolation, and combining that with the room around your booth, should get you where you want to go. The good thing is that you don't need to isolate yourself FROM the room, but rather to isolate yourself from other rooms, beyond the one the booth is in. That makes it a whole lot easier.

Ah, you're right! It didn't even occur to me I'll have the normal isolation from the room itself. That does make the numbers look much better.

Soundman2020 wrote:

However, I'd say that you are estimating a bit on the low side with your 70 dB singing! It's probably more like 90, maybe more... Before you settle on the final plan, I would definitely get a sound level meter and rest yourself, to see how loud you are!

You're spot on. I finally got a sound level meter, and singing at pretty much the loudest I would was 87 dB.

Soundman2020 wrote:

Do I have to worry about weight?

Yup! :) It will be heavy. MDF weighs about 10 kg/square meter for 1/2", closer to 14 kg/m2 for 5/8"....

Looking at the 2010 CA Building codes, I see for "Residential: Private rooms and corridors serving them", the psf is 40. Does it make sense to use this, along with the footprint of the booth, to get the max weight and work backwards for materials? That is, say I have a 4'x5' space, then the max live load would be 4x5x40=800lbs, so I could have up to 800lbs of materials. Or is there another number I should use, or additional considerations? Thanks much for you help, I greatly appreciate it!

I've started to sketch out some basic designs for this. As sheet rock and plywood come in 4x8 sheets, I'm trying to design it to use materials most efficiently. The walls are made up of two sections each, making it easier to both carry by myself when it's moved, and to make it easier to maneuver up stairs and hallways. This picture only shows sheet rock on the side, but I'm thinking about doing plywood and quietrock. This would give me a weight of a little under 100lbs per whole wall, plus the weight of the framing. The corners will likely be joined with wood screws, and the plywood on the top (and bottom) should also help keep the walls in place without having to add too much hardware.

I'm looking at the corners more, and trying to decide on a good way to join the separate "panels". I could get some lag bolts and bolt through the 2x4's on the corner, but then I would have a bolt, or at least a head, sticking out on the outside. Not a huge deal, but it would make it more difficult to cover (I think). I thought of L-brackets, but every several moves, I'm worried they would start to have some give. Another thought was to use hinges to join them, and the pin as a way to make it so I can easily break them apart. I think the tricky thing here would be getting everything to line up well enough for all the hinges and pins to fit.

This picture only shows sheet rock on the side, ...

Oh no!!!! You cut your head off to fit inside!!!!! That's probably a bit extreme!!!! :) Seriously, the basic plan looks fine, but I would modify the corner framing to make it possible to bolt the sides together easily.

but I'm thinking about doing plywood and quietrock.

Why do you need the quietrock if you already have the plywood? What matters acoustically is the amount of mass (kg/m2), not so much how it is made up. So use the least expensive materials that will get you the mass you need for the amount of isolation you want.

I'm looking at the corners more, and trying to decide on a good way to join the separate "panels".

Modify the framing so that you have facing 2x4s on the corners, that mate on the wide faces. Glue a s trip of rubber to one of those, for the seal that you need between the frames, then put a few bolts through, so you can tighten them to put pressure on the rubber and get a good seal plus good mechanical integrity, while still making it easy to remove the bolts and take the thing apart, when you need to. Same plan for the roof: framing, rubber seals, bolts. - Stuart -