Yes Virginia, there is a right way to build a home studio.
Before hosting CoolToys TV, I spent years studying to become one of the best home theater designers I could be. It turns out that recording studios follow the same rules. Home Studio design became a nice addition to my business. I was inspired to write this in a hotel room, two rooms away from the elevator. 6 AM the elevator started going non-stop and I can hear it clearly.
Basically there are three things to worry about when designing and building a room. Room Noise, Echo and outside noise. I’ll tackle them one at a time in the order that you are likely to build the room in. And I’ll use terms that will make you sound like a pro when you order materials or call a guy like I used to be. I don’t build home theaters or studios any more. Occasionally I get called in to listen to a room and figure out the problem, but I am expensive so that is only once or twice a year.
Isolation
Isolation is what the hotel I am staying at needs right now. If they had properly isolated the elevator I wouldn’t hear the whir of the motor as it goes up and down every 1 to 3 minutes. My home studio needed isolation for my wife to voice audio books because we live near an airport and the jets flying over were messing up her work.
Isolation is the toughest problem of any room located near anything that generates noise. One flaw in my studio is the garage door opener. It is bolted right to the frame member that runs into the studio. Even a pro can miss something.
There are companies like Acoustiblok that specialize in acoustic isolation. Basically you are trying to limit the physical connection between you and the noise source. When the sound of the jets hits a single pane window, the window vibrates and acts like a speaker. A double pane window is better because the sound is changing mediums twice. It hits glass, then air, then glass again. Even so sound gets through.
Sound Sneaks In
My home studio is “double walled”. Some builders call this an apartment wall. Basically you build a wall in each room with 1 or 2 inches between them. Because there is a shower and a water line in the wall next to the recording studio, a double wall was required so I could use the shower while she worked. This is the most basic form of isolation.
Both walls are also insulated with a mineral wool insulation. This is the trick of very high end builders. They fill the interior walls of the house with insulation. It makes the house quieter. Most people will describe the house as “higher quality” and “warmer” when this is done. The best will even use different thicknesses of wall board on each side of the wall. The different thicknesses each transmit sound differently, adding to the acoustic dampening of the house.
The next method to consider if your sheetrock is not up is isolation tracks. These come in all forms. The term the pro’s will use is “decoupling”. By using an isolation track, your sheetrock has less direct contact with a solid surface like the wood stud. Basically rubber blocks or metal tracks with rubber blocks are attached to the wood studs (avoid metal, it rings). The sheetrock is then screwed onto the tracks or blocks. This method takes a lot more skill, and isn’t always affordable or even necessary.
Weight Matters
The weight or “total mass” of a wall is a big factor in how much noise gets in. Loaded vinyl barrier is one way to increase the mass of your walls. This stuff weighs about one pound per square foot and is quite difficult to install without tearing it due to the weight. We put in in the ceiling of the garage below the recording studio and under the floor in the studio.
Weight can be added in other ways as well. 2×6 walls have more weight than a 2×4 wall, and a 2×6 staggered stud wall adds weight and increases isolation. There is wall board material that has extra weight added that is just for sound isolation. It is off course heavy and very expensive. I have seen some people simply add a layer of this to the walls without doors in a bedroom and the difference is noticeable.
Sound is Like a Mouse.
Even with all of the great insulation, sound can still leak into a room. Like a mouse it can squeeze into the tiniest gap and make it to the next room. One simple rule is to never have electrical outlets on both sides of a wall in the same stud bay. I also silicone fill or foam fill every wire hole in the bay that has an outlet on the studio side. The final step is to use a heavy clay and seal the back side of the electrical outlet and the front side after the sheetrock is up.
Every seam needs to be sealed as well. With the loaded vinyl barrier, this can be a challenge because lining it up during installation is difficult. You should install it loosely so it has a little “dip” in each stud bay. Then you need to tape the gap between layers.
Once the sheetrock or wall board is up all of the edges need to be sealed there too. You will be amazed at all the little gaps. Especially around the bottom where the baseboard will hide them. Trust me when I say it isn’t easy, but get it right and the room will “feel” much better.
Doors and Windows
All of the detectable sound in our home studio comes from three places. The door to the hall, the French doors to the balcony and the window. Each of them is treated slightly differently. The studio door could have been a sealed double door. Instead we made a short hallway with thick carpet and insulated the adjacent area. The window has a plug in it that you can see in many of the newer CoolToys® TV episodes.
Exterior doors are always a challenge, French doors are the worst. With most doors the easy solution is to double them up with exterior sealing doors. Late Night Union Singer Christian Erik did this for his home studio and editing room. Each has double sliding doors. Turn off the microphone and you can barely hear the drummer destroying the drums.
We handled the French doors with a couple of curtains. One is a simple photographers muslin. We use that mostly to create a “key light” when I video record in the room. Since it wasn’t intended as a video recording room, there is also a very heavy blackout curtain. This is made from an acoustic blanket covered in black fabric. It acts as a “negative” so the room isn’t too bright for audio recording.
Room Noise
It all starts with the room. Every room has natural noise. There are a lot of causes and your breathing is one of them. Sound is very predictable. A 60hz bass note is about three feet long. While studying to become a THX certified home theater designer, the instructor set up a great demo. He put a speaker three feet from the wall, and aimed it at a wall 18 feet away. The class room was 21 feet across.
He then had X’s on the floor and had everyone stand on an X. Then he turned on the speaker and played the 60hz note. Only a few of us could hear anything. We were standing in the “lull”. This is the place where the wave bounces off the wall and cancels itself out. Very much like backwash at the beach at high tide. The sound is crashing into itself at opposite sides of the wave so there isn’t anything to hear but the crash.
Next we would walk very slowly to the X in front of us. As we did that we hit a point called the “peak”. This is where the two waves lined up and effectively doubled the perceived energy. Basically the 60hz note was near deafening. He then turned off the sound and said “Design a room wrong, and half of the seats get no bass. Worse yet, the other half get too much, and that is why you are here”
Standing Waves
The biggest enemy of a designer is the “standing wave”. This is where the audio has a specific peak and lull Room noise is solved with two things. Shape and absorption. This class I was taking that day was called “Room Shape and Modes”. Modes are the cause of a standing wave or the result. It is a Chicken and egg question that really doesn’t matter. If you have room modes, you have standing waves.
Most great theaters have a semi domed back wall and are wider at the back. Sort of an odd trapezoid shape. This prevents those “standing wave” from having anyplace to build itself. This isn’t always possible at home, so a man named Bolt created the Bolt Ameoba. Essentially a simple formula to limit room modes. The formula is simple, 16x9x21 is the ideal room and as you tweak those dimensions the line creating the perfect room looks like an Ameoba.
As we got smarter about this another man, Bonello created a “window” calculator that allows you to figure this all out even more accurately. With home studios, the room dimensions are usually pretty set before you build so both of these tools aren’t of much help. The basic rule is don’t use a square room. 12x12x8 is about as bad as it gets. If that is your room, add a false wall somewhere to change the acoustic shape. Even some old cubicle panels from an office supply store can help.
Echo
The real problem with square or rectangle rooms is echo. Room modes are in fact nothing more than echo. The problem is that if you eliminate all echo, you get a “dead” room. People who aren’t trained tend to get disoriented and nauseous in rooms like this. When the door closes and they hear their heartbeat it makes them nervous. When you build a home studio the right way, it should be warm and comfortable. It shouldn’t feel like a tomb.
A room with no echo is an anechoic chamber. They are great for testing microphones, speakers and hearing. If you have every had a hearing test in a booth, that booth is an anechoic chamber.
The trick to dealing with echo is finding the right balance. Fortunately this can be done after the room is built. More importantly it can be changed depending on what you are doing.
Striking a Balance.
When a room is finished the truly hard part begins. If you did it right, you kept the sound out and prevented most of the problems the room itself can create. You can never solve for all of them so the fine tuning begins.
Foam, fiberglass and carpets are all great ways to tone down the echo in a room. In my studio there are two 2’x4′ foam panels on the front wall. There is also a 50″ studio monitor in there on a tilting mount. It has to be adjusted based on the height of the person using the room and the microphone placement. You can hear the echo of the flat screen with a little practice.
I mounted the acoustic foam panels to 2’x4′ foam board and used OnCommand® velcro hangers so I could move them if they didn’t work out.
The wall behind me also has a heavy grey background cloth that dampens voice very well along with two more of the foam wedge panels. The side walls have 2’x4′ photos that are wrapped over Acoustic Fiberglass panels. I didn’t want to just have foam wedges around the room. My wife is also a photographer, and she sells the acoustic panels with photos in 1″ and 2″ thicknesses.
Try and Try Again
The floor is reclaimed wood with two oriental rugs covering the middle of the room. The final echo to deal with is the ceiling. Up there I uses carpet tiles in a pattern with a solid area directly above the two microphone spots, and then opening more space as you go to the front. I glued them to the ceiling with 3M panel spray.
Getting the ceiling right was the hardest. I started with a 50% pattern like a checker board and ended up taking some down over the cameras and adding more over the microphones. I used 3M double sided tape until I knew where I wanted the panels for sure. The take won’t leave a mark if you take it down in less than a week. The spray is gonna stay.
Now that you have your home studio built, get a small computer in there and start hosting live shows with Fan2Stage!