I have decided it is time to build my own voiceover booth. Long story short, there are enough projects and products for which I need a quiet place to record that it justifies a dedicated booth. I can’t do what I need to do in my house. I have spent weeks researching online and have collapsed in on myself with information overload; it’s crazy. Since this is a popular subject on the Internets, I thought I would write the guide I wish I could have found with all the relevant information in one place.
Table Of Contents
- What is my goal for this booth?
- What are the considerations?
– You cannot make it soundproof– Environmental– How does sound work?– Materials aka Budget– Equipment
- The Plan for The Structure
– The Base– The Walls– The Ceiling– The Door– Sealing it all up
- The Plan for The Wall Treatment
- Why Aren't I Using...
– A blanket and PVC booth?– A box booth? A Shield?
- I'm Not A Carpenter
- In the end, if it works, it works!
- Other posts in this series
Author’s notes: I have written this post after having designed my booth and purchased the materials, but before actually building it. I wanted to document what went into this project that helped me come to my design conclusions. This is part one of a series. Part two will be the actual build process, part three will be first impressions and modifications, and part four will probably come a month or two later after I’ve put it through its paces. Once the booth is complete I will be coming back to this post to create a video, followed by blog/video posts for the other parts. I just wanted to get this text version out into the wild to start generating interest.
What is my goal for this booth?
The simplest way to answer this is by answering another question: what am I going to record, specifically, in this booth? In my case, the answer is, specifically, the spoken word. Not singing vocals for a song, not an instrument, not an amplifier, not drums, just my speaking/reading/acting voice. The booth needs to make that sound good.
When you research voiceover booths it frequently gets lumped in with vocal booths. Functionally they are very similar. However, what is written about them is usually more focused on musical applications and environments, and that’s not my project. So to me, they are different. You will find tons of posts and videos on home recording studios and sound dampening. This is not a studio. It’s a small booth, but some principles transfer.
My other goal is portability. I want to be able to take this booth apart and easily move it, either to another part of the garage, or maybe someday into the house when Son #2 finishes college and enters career mode. This means it is going to be lighter in weight which means lighter materials. To some of you that will translate to less sound blocking properties, and you are technically correct. But I don’t need much.
What are the considerations?
Whenever you jump into a DIY project of any kind, you filter it through your own context. Remember that. Filter all of your own research through your own context and needs, and that will help inform what you need to consider. These are the ones I think will apply to anyone looking to build their own voiceover booth.
You cannot make it soundproof
Just understand that going in. To make something truly soundPROOF takes combinations of both highly dense (mass) materials, softer absorbing materials, layers of walls that are not connected to each other, gaps of air to trap sound, it is a major undertaking.
To that end, your are going to come to a compromise that will seem to the outside observer (aka sound hipster know-it-all) like it can’t/won’t work. But, it just has to work well enough for your goals. Most of the rest can be fixed in your recording software.
- Where do you live? In an urban area? A suburban neighborhood? Rural property?
I live in a cul-de-sac off of a dead end road in a suburban development. There is very little traffic. Kid’s play in their back yards, but I don’t think that there are very many kids close by. The house is about 1/2 mile uphill from the Columbia River so there is cargo ship traffic that occasionally blows a horn. Along the river are train tracks that are very active. Along the train tracks is the I-5 freeway.
However, there are lots of trees and a number of houses between me and all of that so most of that sound is dampened. Even so, if you are in a room on that side of the house, or in the garage, and very quiet you can hear the freeway, and you can definitely hear the train whistles. Oh, and military helicopters that fly between Portland and Ft. Lewis near Tacoma tend to fly above I-5, along with other private aircraft. But that isn’t very often.
- Who do you live with? Honestly, this is probably the biggest consideration when building something in your home.
My wife works from home as a medical biller, which means she is on the phone often. Son #2 is doing distance learning and finishing up his Masters degree in Education (proud dad!), so he is talking to online classes often.
We all love movies (and games) so it is common for the TV to be in use at any time of the day, and we have a decent home theater setup in our open plan two-story home.
Then there are the appliances like the washer and dryer, the dishwasher, the HVAC, and a Roomba.
Oh, and we have two large dogs who rather enjoy the stairs. (Check out#alicethestbernard on Instagram).
Did I mention that both upstairs and downstairs are wood laminate flooring, along with the stairs themselves? It is very easy to be in the living room downstairs (with the TV off) and hear the TV in the master bedroom that isn’t turned up very loud, very clearly, just bouncing through the halls and stairwell. Sound travels in this house.
In this context it brings up my most important consideration; personally, I do not want to be heard. There is no closet I could use where I couldn’t be heard and I couldn’t hear others. We have a great 5’x5’ walk in closet that would be perfect. The problem is, I can hear everything from the rest of the house in there. Plus, that’s where our clothes live, and its in the master bedroom where my wife tends to hang in the evening hours when I’d be free to record anyway.
- Do you have a garage or a basement?
A number of people I found talking about DIY vocal booths were using them in their basements. Of course, you can get away with that. Five sides of you are already insulated with concrete and planet earth! I do have a fully finished garage. In the evening hours is it around 34db in there. That’s pretty quiet. This is where I will be building my booth.
How does sound work?
The short answers are theses.
- Sound is produced by vibrating air. Vibrations are energy, so sound is energy.
- Low frequency sounds are made up of a lot of energy while high frequency sounds are made up of little energy.
Think of it this way. Imagine you are standing next to a pond and you have a pile of rocks ranging in size from ones you can barely lift, down to little pebbles. When you toss the large rocks into the pond they make large/long waves (low frequencies). To stop the large rocks from hitting the water would take a very dense piece of material to reflect the rocks, or enough of a soft material to absorb them. To stop the pebbles wouldn’t take much at all.
This is what you are dealing with when it comes to building a booth. It doesn’t take much to stop high frequencies because they aren’t made of a lot of energy. You can’t stop the low frequencies completely because they are made up of a lot of energy. In fact, look again at the above pic from my phone. Notice all of the low frequency still coming in to the garage (the left end of the graph). The human ear can’t really hear that, but it’s there. The rest of the mid an high frequency is down at or below 20db.
You remember how your friend in high school put 20” subs in his 1989 Honda CRX, and whenever he came to your house, you could always hear the bass booming, but you never heard much else? This is what we’re talking about. All of the high and most of the mid frequencies were blocked by the materials of the car. The bass just went on through.
So guess what I did? I got in my car which is actually in my garage, with my recording gear and my db meter on my phone. My phone registered in the high 20dbs, and the noise floor in my recording software didn’t even register (lower than -60db). I recorded a few things as a test, and you cannot tell that I am in my car, in my garage. Here is a sample.
Once I did this, I knew that all I had to do was to build a booth out of materials that would give me equal to or better sound dampening as my car. Any low frequencies from trains or trucks I can roll off in my software. Dogs barking and kids playing, not so much. But I can record at night when there is less of a chance of that happening.
Also, when looking at materials for this project, they have a rating called STC which means the materials were tested in a lab for how well the deal with sound transmission, reflection, absorption. The higher the number the better at blocking sound it is. 60 would be great. The best overall results are achieved by combining methods and materials.
Now that I know what kinds of sounds I want to try to keep out, and where I can most safely build my booth so that my own noise doesn’t bug others in the house, their noises won’t bug me, and my neighborhood won’t be a major problem, what kinds of materials will give me good enough results?
Remember, I’m in my finished garage which means all of the walls are insulated and have 5/8” sheet rock on them. I’m not building a room to contain or keep out home theater system noise. I’m not dealing with people upstairs walking or stomping on the floor. I’m also not in a basement which would be nice. I am building a box inside of a box, a term you will come across while researching this subject. I need to keep out highs and mids (which is pretty easy), and will do what I can to alleviate lows knowing it is impossible to block them all out within reason.
After tons of reading, based on my needs, I concluded that a combination of lighter materials would give me enough of a combined STC rating that would do the job.
Here’s the thing. There is this threshold around 45-50 STC where in order to even get a couple of points higher, you have to spend a lot of money and do a lot of work. My goals are voice recording and portability. Sheetrock, wall gaps, staggered studs, just, no. If I were building a permanent room inside my garage, or if I were going to modify an existing room, maybe. Those might happen someday if this somehow turns into a career. But as I’m just getting started, what I have planned should do well enough.
All of that being said, the most important equipment in a voiceover booth is not the mic, it is what is around the mic. It’s the wall treatment. You could have a $5,000 mic, but if the space it is in sucks from a sound perspective, it’s still going to sound bad.
Mike over on Booth Junkies bought a $3,500 booth called a Whisper Room. When he finished building it and he put his best mic in there, it did not sound good. Why? No wall treatment! Sure it kept most sound out of the booth so it was quiet, but it didn’t sound good inside the booth. That's not the fault of the booth, it just means more money needs to be spent.
This is another area where you could spend tons of money and get the wall treatment that all of the cool kids have. Or you can go low-tech and low-money and get the results that are close enough (remember that STC threshold).
That said, I bought the 3rd gen Focusrite Scarlett 2i2 Studio which comes with their 2i2 interface, a condenser mic, and headphones. Some might poo-poo this as a cheap bundle kit and mic. But you know what? For my speaking voice, it sounds pretty good.
I’m a Mac guy so I will be using my MacBook Air (2018) to record on and an older Mac Mini on which to edit. The Mac will sit in a pocket on the outside of the booth with the USB-C wire running into the booth where the audio interface, keyboard, mouse, and monitor will be. The laptop will save the audio to a networked drive which is where the Mini will access and edit what was recorded. You don’t want to edit in the booth. It takes 3-5 minutes of editing for every one minute of audio you record once you get the hang of it. If you’re recording a 30-second commercial or maybe a podcast tag, sure you could get away with that in the booth. But if you are doing narration or an audio book, that’s hours and hours and you won’t want to do that standing in your booth.
Remember, I’m not multi tracking a band, I’m recording one track, my voice, with little to no effects on it (compression and EQ). That doesn’t take much power to do. I mean, I could do all of this on my iPad if I really wanted to.
The Plan for The Structure
Here is what I’m going to build. The booth will measure about 4’x4’x7’10” externally, and about 3’6”x3’6”x 7’3” internally. Remember, I want to be able to move this into a standard room in my house someday so the height has to fit.
I want the booth to be as big as possible which is partially why the walls are thin, but I also want to make as few cuts when building as possible. Most building materials come in 4’x8’ sheets, or 8’ sticks of wood, so 4’ will be the max. This gives me enough room to reasonably stand and move.
I talk with my hands, and if I ever get to do animation work, when you physically act the part you are playing, it comes out in the performance, so I need some room to move at least my arms.
The base is going to be 2x4 sticks with 1/5” plywood top and bottom and a channel for future ventilation. (Yes that is a weird thickness for plywood, I’ll explain later.)
While I’m not going to implement a ventilation fan immediately, I want to include airflow in the build process. I will want air to be blown in from the bottom and pulled out from the top of the booth. I’m going to drill a 2 1/2” hole in one of the 2x4s in the base on one side for air to go through. In the base itself I’m going to put 2” rigid foam insulation and place it closest to what will be the floor of the booth. This will leave a gap of air at the bottom of the base. I’m going to then cut holes between the chambers in the framing of the base to direct air in a kind of maze pattern, and then a whole up into the booth itself for air to enter it.
The purpose of the maze is that the more surfaces sound has to bounce off of, the more energy it loses (less noise). You have to be concerned with not just sounds being made outside entering the hole, but also the sound of air being pulled through a hole. Make a two-inch circle with your lips and inhale. Go ahead, I won’t look. There was some sound, right?
I will also cover the hole into the base with two offsetting pieces of chicken wire because I don’t want little critters to find their way into the garage nesting in the booth, gnawing on the wood. That’s a fun sound! Inside the booth on the floor I will put some mesh over the hole to that stuff doesn’t fall down into there.
I’m going to put caulking instead of glue between the plywood (throughout the project) and the framing. Glue dries solid, solid = rigid, and rigid transmits vibrations (sound). Caulking is more flexible.
Additionally, I will be using these floor floaters. The 2x4s sit inside the U shape. They are a rubber compound that isolate vibrations (low frequency) coming from the floor, in this case the concrete in my garage. I might cut them into more of an L shape so that I don’t have to cut holes in the plywood on the bottom of the base. I can use the cut-off pieces under the center 2x4 in the framing for the base. They are about 1/4” thick.
The walls will be a piece of 2” rigid foam insulation framed in 1”x3” wood, and 1/5” plywood. This design was inspired by Eric Strebel’s DIY Whisper Room project. In reality, the 1x3 is actually 3/4” x 2 1/2”. I couldn’t find true 1”x2” furring wood. But, the 1/2” difference is going to provide a bit of an air gap and trap if I sufficiently seal the frame.
Like me, you might read those specs and wonder how in the world 2” of foam and 2/5th of an inch of plywood are going to stop any sound? Well, think about it. There are three components at play.
- The plywood is going to slow down a lot of the high frequencies. High frequency, low energy, doesn’t take much.
- The 2” rigid/solid foam itself has an STC around 35-37. That’s significant.
- Then there is the air which I could put all on one side of the foam, or I could leave a 1/4” gap on each side of the foam in the wall, which is probably what I will do. Since I’m building a box inside of a box (finished garage), this will do. The foam will act as a sort of trampoline reflecting the sound.
Yes, I could use thicker MDF, OSB, or particle board, or even thicker plywood. But the weight get’s crazy. One sheet of MDF weighs about 50lbs and I would need two for each wall. Plus, when you cut into these composite materials, they release VOCs which are bad for anyone, but are especially bad for my wife who has a condition called CIRS. So those are out.
With 1/4” plywood, the price goes from about $15/sheet to $22 and higher. Going from .2” to .25” of material for $7/sheet (10 total) is not worth the STC gain which would be minimal anyway.
Why didn’t I go thicker walls with a different kind of insulation? Because again, weight, and because the money spent on the other options (Owens Corning 703, that much mineral wool, etc), don’t gain me enough STC for the dollar and effort. Bang for your buck. Er, silence the bang for the buck.
The ceiling will mirror the base in terms of the maze and holes for a future ventilation fan and airflow, but instead of 2x4s I will use the 1x3. It’s basically the same as a wall, but a lid.
Concerning the ventilation, basically, I want to put a 2” hose in the hole in the lid, maybe off of a smaller shopvac, and then connect that hose to something the size of a desk fan (I’m imagining lots of tape) that sits on the floor next to the booth, not making any contact with the booth. It’s a small space, it won’t need that much volume of air moving constantly. It will get warm in there the longer I’m in it to be sure. I just need enough air moving in there so that I can breath and not overheat. Time will tell.
Remember how I said I wanted to make as few cuts as possible? Well, a door is way more complicated than one would think, especially when you are considering sound. A door means gaps and gaps means sound leakage. So instead of a door in a wall, I’m making a door that is a wall.
Three of the walls will sit on the base with the lid sitting on the walls. The fourth wall will be attached with hinges to one of the side walls, and when it closes it will overlap with the opposite wall, the base, and the lid, closing off the booth.
The door will stay closed by means of four “double roller” door catches spread along the opening side of the door so that all of the tension of keeping it closed doesn’t rest in one spot but is instead distributed, in theory.
There will be a basic handle on the inside and outside of the door to open and close it. The double rollers and the handles mean it is simple to open and close from inside and outside.
The paranoid safety-nerd in me wanted something simple like this so that if, for some reason, I passed out in the booth, it could be opened from the outside without worrying about latches or locks or anything on the inside. I also didn’t want to get trapped inside by a stuck latch. I know, I’m weird.
Oh, and no window. Again, I don’t want to do a bunch of cutting and trim work, and honestly I don’t need a window. Some do because it’s more of a psychological thing. They need to see out or need someone to see in. Just give me my booth, a mic, and a script, and I’m good.
Sealing it all up
The places where the walls meet each other, the base, and the lid, are going to have a strip of yoga mat material in them to seal up these connections. The walls, base, and lid will be “pulled” together by a series of hasps or latches located inside the booth, so that it doesn’t just fall apart like a house of cards. I’m also going to be using 1/2” dowel pieces in the base, lid, and walls. They line everything up and help keep it together before the hasps are engaged.
When the hasps pull the parts together, the yoga mat material will be compressed and fill those gaps. Apart from the ventilation holes, it should be a pretty tightly put together booth.
There will also be a sealed hole where an extension cord and the USB cable passthrough one of the walls. Spray foam will work for that seal.
The Plan for The Wall Treatment
While it may sound counterintuitive, it is possible to over treat the walls of your VO booth. You can put so much stuff on the walls that it produces a dead, boxy sound. It doesn’t sound natural and you end up having to take stuff off of the walls to reintroduce some live flat surfaces.
What you don’t want is two flat surfaces opposite of each other. Side to side, top to bottom, front to back, one side needs some kind of treatment. You need something to take the edge off overall, but then you need to stagger your treatment.
Inside the booth, I’m going to do two things.
- The bare plywood walls and ceiling will be covered with a loosely attached canvas drop cloth material that is typically used for painting projects. It’s light in color and it’s thick without being heavy. I will probably use the leftover yoga mat material for the floor along with a small area rug for the floor. Something comfortable to stand on. That’s the overall coverage.
- Instead of buying sheets or tiles of acoustic foam ($$$), I’m going to make my own custom bats of mineral wool insulation that is specifically rated for sound reduction.
While I couldn’t find an STC rating for this material, the manufacture gives an NRC rating which is another way to measure the same function.
“NRC is measured on a scale that ranges from 0 to 1. An NRC of 0 means that the product absorbs no sound. An NRC of 1 means that the product absorbs all sound. The higher the NRC, the better the product is at soaking up the sound.” (Source.)
- This stuff has an NRC of 1.05, which means it will do a very good job absorbing sounds across all frequencies.
- I will probably put one 42”x42” (the internal width of the wall) on the wall behind me, covering the top half of the wall, and then stagger more around the rest of the surface area. I could also use the material to make bass traps for the corners. I can make three bats and have a little leftover.
- It’s possible I will add this to the entire interior. What I like about this material is that it gives me options. I can always add more. Yes, I will lose a little space in the booth, but it will be worth it for the cost/effort.
Why not go the route of moving blankets inside the booth? I totally could have, but again, bang for the buck. A bag of this insulation that covers a total of 50sqft was about $50. Those blankets start at $20 each and I would probably need two layers of them to get the same results.
Why aren’t you using…
"Corby, there are so many prefabricated options out there. Why not a different kind of booth? Why a booth at all?"
See my own considerations above. But, if you are considering using other options, add these thoughts to your considerings (new word).
A blanket and PVC booth?
A blanket booth will keep out low-volume nose to a decent degree. But if anyone in any room nearby is on the phone, for example, there is no point. If the TV is on, the dishwasher running, chances are you will hear all of it. Unless you are using a dynamic mic which is much less sensitive, and not recommended for voiceover work, it won’t block enough sound out for my purposes. Nor will it keep people from hearing me do my thing. The same considerations apply to the box booth and the shield.
And for good measure, just stay away from something like this based on cost alone.
A Box Booth? A Shield?
With a box booth and a shield, the only sound being address is that coming from behind the mic. The problem is that the mic is the least sensitive to what is behind it and most sensitive to what is in front of it. Everything behind you in the room and neighboring spaces will still come through.
Unless you are already in a very quiet environment, these will do nothing for you. And again, the most important part of recording your voice is what is around the mic.
Also, I Am Not A Carpenter
While I have built two decks in my life almost all by myself, and installed laminate flooring in two houses (mostly all by myself), all I have is a circular saw, a jig saw, and a drill. I need to keep this simple. Cut, drill, caulk, done.
I will be adding a simple shelf and a couple of color changing LED lights. I hope to record a bunch of course videos in the booth so there is a video friendly component I will address in the future.
In the end, if it works, it works.
Even if it doesn't conform to sound nerd culture standards. Every area of life has a level of, shall way say, snobbery. (Sorry if that sounds harsh, but that's how it comes across.) Coffee snobs, smartphone snobs, clothing snobs, car snobs.
Voiceover is no different. Mic snobs, gear snobs, DAW snobs, booth snobs, training snobs. It can be disheartening and discouraging to live by the snobbery of others. Be open to all information and advice, but don't feel like you can't start or try or learn just because you can't afford Brand X or don’t have the resources to do Method Y (why? because we like you!).
Take stock of your environment. Consider what you can and can't control in that environment. Do what you can do with what you have, or can afford now and do it well. Plan ahead for when you can do more or different.
- Remember, I’m recoding the spoken voice.
- I’m building a box in a box. If I can match the sound quality and characteristic of sitting inside of a car in a garage, I will be totally fine.
- I want the booth to be portable (and modifiable to be honest, if I decide to change something) which means it needs to be light and easy to put together and take apart.
- The condition inside the booth is the most important component of the booth. The walls just need to keep my noise inside of the booth and other noise outside of the booth.
I wrote this in April of 2020 and am publishing it in December of 2020. I didn't feel like I had the right to post this until I got my first paying gig using what I've promoted and built.
Well, it happened. While I did record my demos and some "favor" projects in this booth in June, I got my first paying gig in November. So, I hope you look forward to the rest of the posts!
Also, the finished product ended up being about 95% of what I wrote above. I made some modifications along the way. I already know what I would do differently next time and I will try to document that at the end of the series.
Other Posts In This Series
- DIY Voiceover Booth Build Part One: The Plan (this post)
- DIY Voiceover Booth Build Part Two: The Build
- DIY Voiceover Booth Build Part Three: First Impressions and Modifications
- DIY Voiceover Booth Build Part Four: Time Will Tell
- DIY Voiceover Booth Build Part Five: The Next Build