8ft by 10ft ISO Booth (DIY) PLZ HELP

Hi all, my first post:-) This all can get very complicated I know, but ideally I want to keep things simple. My first question is: If I make a plywood 8ft by 10ft room, with a sloped ceiling. If I use fiberglass on the inside walls, can I cover this with carpet or is that defeating the object of having the fiberglass? I just want to make sure the booth looks nice inside. Could I have the outer wall plywood, then insulation, then MDF and then carpet??? Or is this completly wrong? Can you recamend a material to cover the fiberglass completly.. but it needs to look nice and professional. I hope someone can shed some light Cheers

Hi Singing-lad, and welcome! There is an announcement at the top of the forum about what to do to assure getting as many responses as possible. The announcement leads to this post (click here). Actually, several people, who are experts on this forum, will not reply if you don't do what is written in that post. Many others who are very helpful, will not reply out of respect for the moderators' wishes. But anyway, I'm in a good mood this morning! So, to give you brief, basic, rough outlines of answers to your questions:

If I make a plywood 8ft by 10ft room, with a sloped ceiling.

Why plywood? It's more expensive and less massive the drywall in most places of the world. Why 8 x 10? What height? Is that based on a known good room ratio, or is it just a guess?

If I use fiberglass on the inside walls, can I cover this with carpet or is that defeating the object of having the fiberglass? I just want to make sure the booth looks nice inside.

Forget the carpet. It doesn't have much use acoustically, especially on top of fiberglass. Just build some frames around your fiberglass, and stretch acoustic cloth over it, carefully and neatly. You could use mineral wool (rockwool) instead of fiberglass, if it happens to be cheaper in your area. Both will work fine. The acoustic cloth will hide the frame and insulation, and make it look decent.

Could I have the outer wall plywood, then insulation, then MDF and then carpet??? Or is this completly wrong?

Forget the carpet. Forget the MDF. Forget plywood. Use drywall, as it is denser and cheaper, and easier to work with. Carpet is too thin to be of much use acoustically. Use thick, abundant fiberglass, mineral wool, acoustic foam, or some other tried and proven insulation. Don't use stuff that your pal once heard about from his second cousin's sister-in-laws best friend, who one dated a guy whose bother who swept the floors in a studio, and saw how they built it.... You didn't explain what you are trying to achieve (read the post I linked to above), but assuming that you are like most people here, you want two things for your booth: isolation, and acoustic treatment: They are not the same thing. Exact opposites, in fact. The best possible treatment you can have is to not have a booth at all, meaning zero isolation, and record in the middle of a huge open field, with no walls or roof at all. You cannot beat that for treatment. And the best possible isolation you can have is the worst possible treatment: Huge, thick, extremely massive high density reinforced concrete walls, several feet thick, surrounding a perfect cube room with flat, smooth parallel walls, floor and ceiling. Fantastic isolation, but worst possible room treatment design. So these two don't really go together very well, unless you make a special effort to design them to work together! Basically, for isolation your wall needs to be built of two separate "leaves": the "inner leaf", and the "outer leaf". You do NOT want a wall with 3 leaves, or 4, or more, as that will actually REDUCE isolation, which is contrary to popular belief and does not sound logical, but many things in acoustics do not sound logical until you dive into the underlying science. Then it makes sense. You want walls with two leaves ONLY. Never one, never three, unless you have no other choice, understand the consequences, and are prepared to live with them. For maximum isolation, the two leaves of your wall must not touch at all, and not be connected in any way. So they have to be built on two separate frames. In your case, you have a concrete outer wall, so you'll be building a simple stud frame and putting drywall on that for your inner leaf, but you will put drywall on only ONE side of the studs, not on both. (If you did it on both sides, you would have 3 leaves). The gap between the two leaves needs to be as large as you can possibly make it, at lest several inches, and needs to be filled with good insulation, such as fiberglass or mineral wool. You build the ceiling the same way: two leaves, separate from each other. The our leaf ceiling only rests on and only touches the outer leaf walls, and the inner leaf ceiling rests on and only touches the inner leaf walls. You are building a "room within a room": The only part that they have in common is the floor. Apart from that, they are totally separate and totally disconnected. So, the above is your isolation, not your treatment. Now comes your treatment, which goes on the walls and ceiling of the room (and not the floor: forget carpet). There are many ways of treating your room, but for a small room you will need LOTS of absorption. Fiberglass insulation is good, rockwool is good, proper acoustic foam is good, egg crates are stupid, pointless and a fire hazard, and have no useful effect at all on acoustics, carpet is probably useless for your case (it can be useful, for SOME things, but not for this), all other types of foam are useless, since they are mostly closed cell, which has no useful effect on acoustics. Forget old mattresses, sofa stuffing, egg crates, carpet, and all the other useless stuff that you find on the internet, perpetuated by ignorant people. Forget all of the myths and legend that you might have heard about acoustics: Instead, read as much as you possibly can on this forum, which is packed full of solid, scientifically based information and recommendations, and before you even buy one stud or nail, design EVERYTHING about your booth, and check it a dozen times with the experts here. Did you consider HVAC, for example? Power? Lights? Cables? Window? Door? Weight? If you don't design very carefully, according to sound acoustic principles, and don't think your entire construction sequence through carefully, you WILL run into problems at some point, and your booth will likely be a flop: It won't isolate, and will sound terrible. Every now and then people drop in here after they have already finished their room, to say "Look what a wonderful job I did! Let me teach you how to do it right, the way I did it!": They post several photos, then get upset when the experts here start telling them about all the things they did wrong, and why their room sounds so bad. They usually stick around for half a dozen posts, trying to defend the indefensible, then sadly they disappear, because they don't want to learn, and don't want to be told that they screwed up. Don't be one of them. I almost was. That's why I'm still here, months later, still learning, and not yet building. And very, very glad I found this place before I started.

Can you recamend a material to cover the fiberglass completly.. but it needs to look nice and professional.

Acoustic cloth. Google it. Many sources. However, it might not be a good idea to treat all of your walls and ceiling 100% with fiberglass: That could leave your room sounding very "dead", which is NOT good. You do need to keep some "liveness" in there. The trick is to get it just right...

This all can get very complicated I know, but ideally I want to keep things simple

. Good luck with that! "Acoustics" and "simple" are two words that don't go together very well.... :) Read the thread that I linked to above, complete the missing info, and get started on your journey into the wonderfully confusing world of small-room acoustics and home studio construction! Search this forum for "vocal booth", and you'll find many threads by people who DID build them successfully, Learn from them. Hope that helps! - Stuart -

You may want to look up the meaning of the word "brief".

xSpace wrote:

You may want to look up the meaning of the word "brief".

Well, I didn't want to take up a lot of space by giving him the long, detailed version! :) - Stuart -

Thank you for your brief explanation :-) :wink: You shed alot of light. I should have been abit clearer of my goal. Basically I am wanting to build a small vocal booth, just for recording vocals,, Really I think it will need to be abit small than I first thought maybe 8ft by 5ft. I am wanting to make a booth which is ok for recording vocals...cancelling out computer fan noise etc. I am wanting to make these booths and sell them... obviously a long way off at the mo, need to do alot more research. But I am just wanting to offer a cheaper alternative to the really expensive "pro" booths. My worry is, is that I know booths ideally should be as non parallel as possible. The problem with this is,, it's not very appealing for my intended customer,, who I think is really going to want "the pro look box sound booth" (as far from the real thing as that may be. I was interested with the leafs, does that mean I have an outer shell (1st leaf) made of drywall and then a 4 inch air space, then a 2nd leaf made from Rocksilk or mineral wool (held up by thin battons) covered in muslin or some other thin material. I'm going to install a Solid wooden door with a perspex window, triple pained with the middle pain lying at a slant. The thickness of each pain of perspex will be different. What is the best way to isolate the door?? Obviously on a budget, without using 2 doors with an air seal?? Lighting wise, I am going to have 4 spots coming out of the floor board... in each corner. Any ideas for a possible way of getting an XLR lead and a jack lead into the booth without making too much space for sound to get in? in the mean time I shall door more reading, but hope someone can help :-) cheers for all ur help

singing_lad wrote:

in the mean time I shall door more reading, but hope someone can help :-) cheers for all ur help

Dooring more reading is in line because the doors are going to be the most lethal sonic leak areas in this booth, assuming you get a wall panel that has enough mass to overcome a solid core door.

Can you recamend any articles which may help?? Do u mean the wall needs to be strong enough to hold a solid door? Sorry, im just trying to learn remember. I feel alittle out of my depth here.

Everyone feels out of their depth here ;) It's the only barometer to let you know you are still learning. As soon as you "know it all" a bigger name will come along and blast you out of the water! And learning is what you need but will not get in a few days. Even for what you might think is a small project that you can bang together in a few hours, and then make it a repeatable procedure, you are in an area that comes up here @ johnlsayers.com that has multiple answers for many reasons. The main criteria, you require a viewing window, a passage in/out, air in/out and the ability for this container to hold in more sound then it leaks out. Seems easy enough, until you make it transportable. Then the actual design can be the thing that makes it less appealing as a product to mass produce. You could build a knock down type or a completed booth that could be moved, like an outdoor shed ;) Here is what I will suggest, and I may get called out for it but I am beyond caring when it comes to forum searching. Go to http://www.google.com/coop/cse/ and set up a personal search engine. You can have it perform a search on multiple engines, forums, etc. Like mine searches johnlsayers, recording.org, hometheatershack and a few others. Trust me, the added multiplicity will help you define better questions, and defining better questions is a direct reflection from the acquisition of knowledge. Good luck, Brien

singing_lad wrote:

Thank you for your brief explanation :-) :wink:

I can give you the long version too, if you want? :)

I am wanting to make these booths and sell them... obviously a long way off at the mo, need to do alot more research. But I am just wanting to offer a cheaper alternative to the really expensive "pro" booths.

There's a reason that the "pro versions" are not cheap. It relates to them having decent acoustics! Unfortunately, "decent acoustics" and "cheap" are not words that you normally find together... :)

My worry is, is that I know booths ideally should be as non parallel as possible.

Why do you know this? Is it something that you just read about somewhere, or do you understand the acoustic reasoning behind non-parallel walls? It occurs to me that if you plan to build and sell a product, then you will probably want to understand the principles on which your product works. I don't know if you have read the Master Handbook of Acoustics, by F. Alton Everest, but if not, then I highly recommend it. It will give you a good understanding of the basics of acoustics, and will help to answer questions about when and where and why you need parallel or non-parallel walls. Vocal booths and iso booths actually can have parallel walls successfully. And on the flip side, a booth with non-parallel walls does not guarantee any degree of success at all. Parallel or non-parallel can only work as well as the entire overall design allows.

I was interested with the leafs, does that mean I have an outer shell (1st leaf) made of drywall and then a 4 inch air space, then a 2nd leaf made from Rocksilk or mineral wool (held up by thin battons) covered in muslin or some other thin material.

Nope. "Two-leaf" means that you have mass, then air, then mass. In the manner you described your booth originally (which is totally different from the way you are describing it now) you made no mention of the need for it to be portable and self-contained, so the assumption was that it would be part of a home recording studio or something similar, which would already provides one leaf, so the booth itself would only need one leaf. If you want to make it portable and self contained, that's a different kettle of fish entirely. Then you have no choice but to make the booth itself two-leaf, and live with the consequences of the reduced isolation of a three-leaf or four-leaf wall, since most likely the booth will be used within other rooms, which already have one or two leaves. So, you need to figure out how to build your booth in such a way that you have a layer of dense, massive material on the outside, then an insulated air gap, then another layer of massive material on the inside (and only then do you have your interior acoustic treatment - isolation and treatment are two totally different things). This is a two-leaf system: Mass-Air-Mass, normally abbreviated "MAM". More correctly called "Mass-Spring-Mass" (MSM). Next: if you want good isolation for your booth, then you have to decouple the outer leaf from the inner leaf. That means that you cannot attach the two leaves on either side of the same "thin baton" frame, since the frame will simply transmit sound from one side to the other. You need to physically separate the inner leaf from the outer leaf, all around the entire booth, ceiling included, so that no part of the inner touches the outer, anywhere. There are ways of doing that, but it isn't easy or cheap, which is why pro booths cost money. And if you need to make the booth portable, it has to also be extremely sturdy, from a structural point of view, so you cannot use flimsy materials to build it. Also, both leaves must be sealed hermetically, absolutely airtight, if you want to maximize isolation. If there is a small gap where air can get out or in, then so can sound.

I'm going to install a Solid wooden door with a perspex window, triple pained with the middle pain lying at a slant. The thickness of each pain of perspex will be different.

Perspex? That's pretty useless, acoustically. It has less than half the density of normal window glass, which is already less dense than the kind of glass you need for a good studio window. So you'd have to make your perspex REALLY thick in order for it to be effective. Probably something like two inches thick for each pane of perspex would be effective... Three panes? That's also pretty useless acoustically. Three panes is three leaves, which means reduced isolation at low frequencies. Three leaves is a bad idea in acoustics, unless there is no choice, but here you certainly do have a number of choices. And a slanted pane? Why would you want to do that? Despite the myths and legends that you might have read floating around the internet, slanting your glass has no useful effect acoustically (especially on the center pane in a 3-pane system!). Slanting glass can actually reduce isolation, not improve it. You need to maximize the airspace between the panes, and slanting the glass does the opposite. So does introducing a third pane.

What is the best way to isolate the door?? Obviously on a budget, without using 2 doors with an air seal??

What is the best way to drink a glass of water, without using any water or a glass? In other words, you can't. If you want isolation for your door, it must have an extremely good seal, and it must be massive. You cannot do that on a budget. Once again, there is a reason why pro booths cost lots of money. Try looking on the internet and pricing the cost of a good acoustic studio door, and see how it is made: That's how you need to make your door, if you want good isolation. You cannot wish away the laws of physics just because they make your booth expensive. The laws of physics apply to your booth, just as much as they apply to the expensive pro booths. The laws won't go away for you, just because you want to make yours cheaper. You can have "cheap", or you can have "good isolation": Pick only one.

Lighting wise, I am going to have 4 spots coming out of the floor board... in each corner.

Well, acoustically there's nothing wrong with that. How you do that aesthetically might be a different matter. I don't know if I'd like to work in a booth where I have lights shining up at me from the floor, but if that's what you think will sell more booths, then go for it! It makes no difference acoustically, as long as the lights and wiring do not penetrate the inner leaf at all.

Any ideas for a possible way of getting an XLR lead and a jack lead into the booth without making too much space for sound to get in?

Only one cable for a mic? Won't you also need cables for things like headphones, instruments, speakers, amps, MIDI, networking, etc.? Won't you need cables for power, too? Won't you also need ventilation and cooling? Putting people inside a small airtight container is not a good way of prolonging their life! People need to breath, and people emit heat. You need to cool your booth, and provide a supply of fresh air. You need to extract the stale air. And you need to do that without damaging your sound isolation.

in the mean time I shall door more reading, but hope someone can help :-)

You said that you wanted to build top quality portable isolation booths with good isolation, just like the pro booths, only cheaper. I hope I've managed to outline some of the challenges that you will face in doing that. If you ask me, then you actually can build a booth that is every bit as good as a pro booth, but you won't be able to do so for much less money than they do, since the same laws of physics apply to both yours and theirs. Or you can build a booth much cheaper, but it won't be as good as the pro booths. Don't get me wrong: many people do build successful booths for less that it would cost to buy one, but they do so after careful analysis, and understanding, and design: they build what they need and can afford, and are comfortable with: They are aware of what they are getting for their money, and they can live with that. I'm not trying to discourage you from trying to build a great booth, or form trying to build a cheap booth. I'm just pointing out that a cheap booth wont be a great booth, and a great booth wont be a cheap booth. Sorry to be so outright blunt about all of this, but I think it's better that you see the truth upfront, in all its sad glory, than to pussyfoot around the bush, trying to break it to you gently, while the truth slowly sinks in. It's better that you have the information in advance, all at once, so you can decide which path makes more sense for you: cheap booth with limitations, or great booth but not cheap, or maybe even somewhere in the middle: reasonably good booth, for a reasonable price. - Stuart -

A heavily massed inside out wall would be as effective as any mass/spring/mass build for what is being purposed. Easier to do, portable and easier to seal overall. And doesn't take near as long to say it :)

A heavily massed inside out wall would be as effective as any mass/spring/mass build for what is being purposed. Easier to do, portable and easier to seal overall.

Really? So how much mas do you suggest to get the kind of isolation that a good professional booth gives? Lets see now: With pure mass law, you get a 6 db increase for each DOUBLING of mass. A single sheet of drywall will give you an STC of perhaps twenty-something. So I guess maybe a foot or so of drywall would do the trick... Or maybe an inch of lead plate.... :)

There are options beyond what you say and what I say. Even the best numbers are only a guideline so it is important to who so ever should take on a project to know that they are free to move in several directions. Flexibility may be another word to review.

OK I see, Basically (if that is possible :-)) I am just wanting a "sound booth" to go in the same room as the computer etc,, (more of a hobby studio). Thats what I mean by,, it doesnt need to be right up there with Sony standard booths. It's making me think that the more important thing for this project is that the booth acousticly sounds good, obviously if I can keep some sound from entering the booth then great,, but I am not really after building a really pro booth (as wrong as that may be).. I see my clients as being more of the hobby producer that just wants a "sound booth". At the same time tho I dont want to rip them off and supply a shed that doesnt isolate or have good acoustics. Is a "dead" room/booth completly useless? I was thinking 8ft by 5ft Drywall, with rocksilk on each wall and on the slanted ceiling, wooden floor? As I said before, a window in the door, double pained... As for electrics inside, I was thinking of having an XLR, Jack, Headphone lead with maybe an extension lead or block. But how to get these leads in and to seal the gap I don't have any idea as yet?? maybe someone could give me a clue? I think its easy to get lost in the deep science of acoustics... but I am after creating something simple, better than just recording vocals in the studio room,, but obviously nothing like what they would use at a Sony studio (or wherever). I have my books on order ;-)

You only regret in time only having 1 mic input. XY, AB and near far technics all require 2-3 mics

for vocals?

for vocals?

The title of the thread says it is an iso booth, not just a vocal booth. While "iso" can indeed just be vocals, usually it also implies instruments and/or amps. - Stuart -

I started to understand that the more people chipped in :-). I am thinking because I am wanting to produce something cheaply that really this could only be a vocal booth. (Im sure thats open to argument... can you tell I'm getting into this forum lol). I'm not suggesting all vocal booths are cheap, but I'm saying the best bet for my product would be a vocal booth,, with more focus on the acoustic's... rather than isolation.

can a dead room be ok for recording vocals... maybe treated walls and ceiling but a hard wood floor?

I'm not suggesting all vocal booths are cheap, but I'm saying the best bet for my product would be a vocal booth,, with more focus on the acoustic's... rather than isolation.

That makes sense! As long as you define the purpose, and design for that purpose, then you most likely will get what you want! And it seems that you now have a good definition: For your case, isolation is not top priority, but a good sounding booth for vocals is. OK! progress! :)

can a dead room be ok for recording vocals... maybe treated walls and ceiling but a hard wood floor?

As a general rule, you don't want it too dead, since it is uncomfortable to work in a really dead space. Most people recommend making it a little bit live. Leaving the floor hard is a good idea: With a hard floor, you probably do want to make your ceiling fairly dead. If it turns out that the booth is still too live after you are done, you can always put a thick throw-rug on the floor, as the final touch. But if it is too dead, then ripping up carpet would be sad... Have you searched the forum for "vocal booth" yet? There are several good threads here by people who have done what you are trying to do, and I'm sure you'll get some good ideas from those. - Stuart -

Ok sounds good. Iv tried searching the forum for sound booth but it comes up with 1000's of matchs which just mension sound booth. Do you have any links to any articles or previous threads on what i am after? Hopefully if i can see some peoples ideas for door sealing etc. I cant wait to get started on this but like has been said its best have the plans down 100%, rather than doing it all wrong.