Studio Construction

Goal: Convert 16' x 24' garage into a useful recording space. Here is what I started with.

Floorplan
Includes a control room, tracking room, and closet which can also be used as a second booth. My original design was to split the garage equally into two rectangular rooms. On the advice of John Sayers, I altered my floorplan to what you see below with some changes I made during construction.* Turns out, it was good advice. I only lost a little recording space and gained a closet.

* I decided not use windows between rooms to and added a tv to the Tracking Room with video monitoring. This was done mainly to save costs and make construction easier. It has turned out be a good decision because I can look forward instead of having to turn my head to make eye contact with the talent and they can turn off the video monitoring if it makes them more comfortable. No complaints yet. Also the front of the Control Room was changed so the speakers are not sofit mounted. Many feel there are definite benefits to sofit mounting, but I found out that it's a bad idea for Mackie HR824s. Keeping the speakers on stands also allows me some flexibility in placement. There is also no bass trap in the left rear of the room (it just took up too much space).

A note about Soundproofing:

This studio is not sound proof. I decided early on after doing my research that I was better off going for a reasonable level of isolation between rooms. Why? Real soundproofing is expensive. It requires a true room in a room design(essentially airtight) including ceiling and floated floor, extra attention to acoustical treatment (if the sound doesn't leave the room, it just bounces around inside it) and extra HVAC considerations (so much for airtight) and making one mistake can screw the whole thing up. Fortunately for me, I don't have too close neighbors and I am happy let those low bass frequencies escape so I don't have to worry about absorbing them.

General Construction

Interior walls are "inside out"* to conserve space with two layers of drywall where possible with at least one layer being 5/8" firecode, which is denser than standard drywall.
*Inside out means that you essentially build two walls and flip them so that the finished sides are facing each other, leaving the exposed frame on the inside of the room. You can then place acoustical treatments between the studs saving a good amount of space. In my case each room is effectively 8" wider than they would have been otherwise.

All gaps in seams have been plugged with acoustical caulking or in one or two spots expanding foam insulation.

The ceiling (see pics) is a grid dropped 4" filled with Guilford of Maine FR701 fabric covering 2" 703 with a 2" air space. The finished the ceiling is 92."

The floor (see pics) is a snap together laminate on top of Quiet walk barrier on top of a 3/4" plywood subfloor filled with fluffy insulation for the purpose of damping and insulation. Each room has it's own independent floor to decouple as much as possible from the other rooms. They are not floated because I figured it was about an 80% chance I was going to screw that up.

All Materials were purchased locally (Lowes, JoAnn Fabrics, Walmart) except for the OC 703 (sensiblesoundsolutions.com), Guilford of Maine Fabric (sensiblesoundsolutions.com), and acoustical caulk (Interior Supply Inc, Dayton Ohio - had to drive an hour to get a case of it).

The initial work was done by contractors (electric to panel, HVAC, closing in garage wall and extorior). The rest is 100% DIY. One thing I learned about contractors is that you can't expect them to understand the needs of studio construction. Make sure you do your homework to know what you need ahead of time and pick someone who is open to new ideas.

Control Room (See Pics)

This is a RFZ (Reflection Free Zone) design. The idea here is keep the mixing position free of reflections that could smear the stereo image. The front walls angle out at 12 degrees so there are no immediate reflections bouncing off the walls to the mix position to confuse the stereo imaging. Instead sound is directed into the back wall. The walls are also filled with 2" rigid fiberglass (OC 703 ) and covered in burlap. They are set up so that I can convert them into slot (helmholtz) resonators if I feel it's needed. The back wall (orange area) is 6" deep (3" 703 and 3" air space to improve bass trapping) Since the room is fairly short so I opted to absorb as much sound as possible to prevent reflections from behind. In a larger room, I might have opted for using diffusion to keep a livelier sound.

Tracking(Live) Room (See Pics)

As described above, all walls are made "inside out" to save space. All the acoustical treatment is mounted between the studs, which is currently all absorption with 703 covered in burlap. 50% of the wall space is setup to convert into slot resonators to keep it livelier and improve bass trapping. That was the original plan. It works pretty well the way it is though so I'm not in a hurry to finish the job. I did build several bass traps to place in corners.

The walls are also non-parallel to prevent flutter echo and standing waves. I'm really sold on this concept now. Before I did any acoustical treatment to the room it was sounding pretty good. No flutter echo at all, just a pleasant quickly decaying reverb. The only problem with this design is that calculating the room modes is extremely complex whereas a rectangular room is pretty easy to do. You don't know how it will work for sure until it's built.

Storage/Booth (See Pic)

Not much to talk about here. It's a closet, but I highly recommend one for every studio to get odds and ends out of the way. I don't know if it will ever be used as a booth but I've got wires in place for a headphone feed and two mic sends. There isn't as much absorption in here, just one wall done up with scraps left over from the rest of the studio. The floor is the same as the other rooms, but the ceiling is standard grid tile. There is also an extra conduit in place to run video lines if needed.

HVAC
The studio has Central Air/Heat with the furnace located in the other half of the building. Feeds from the system are flexible fiberglass lined tubing (see pic). The idea being to absorb and stop reflection of the sound from HVAC. I think the idea is sound but it doesn't work as well I had hoped. The runs from some registers are just too short and direct for it to work effectively. The longer runs to the Control Room are almost silent. Of course as luck would have it the noisiest lines are in the Tracking Room, which is otherwise the quietest. Needless to say, the the HVAC is turned off during recording.

Wiring
To supply electric and communications, I had a trench (see pic) dug and run from the house. The electrical is split from the outside before the house mains panel, so the studio has it's own panel.

On the communications side, there are 2 network lines: one being a spare in case a client brings a laptop, the other connects my workstation to home network so I can back up files to a computer in the house. There is also a cable line and capability for extra phone lines in place.

The electrical and communications lines are run in separate conduit to minimize the chance of interference.

On the audio side, there are 12 mic sends, 4 returns (Canare Star Quad and Neutrik connectors from Markertek) connecting the Control Room and Live room as well as 4 headphone lines and audio/video lines for the TV. The storage room has cabling (unfinished) for two mic sends and 1 headphone line for future use.

What's Left to Do?
I need to appply a finish to the doors. I can't decide whether to stain or paint them. I hate the burlap fabric (looks cheap, and it is!) on the walls so that will have to be replaced with something nicer. Then I need to put in the trim moldings to complete it.

Leftovers
When I was close to done, I realized I had extra 703 (mostly in scrap pieces) so I made these nifty absorbers. The big ones go in the corners as bass traps. The little one can double as a gobo. There is also a smaller one yet that works as a gobo, but can also be mounted on a speaker pole. In a room where mics have to be setup close to a wall, I can put directly behind the mics to absorb reflections off the wall.

Tips on working with 703
When handling and cutting always wear latex/rubber/vinyl gloves, long sleeves and a dust mask meant for use with fiberglass insulation. It will make you itch like crazy if you aren't dressed properly. A thin razor type blade will cut through like a hot knife through butter. It does take a longer blade though than you find in the typical boxcutter. The little fibers that become airborne are the only problem when you're handling the stuff otherwise it's very easy to work.

Also, 3M Super 77 spray adhesive works great to attach fabric. Use it only in a well ventilated area. The vapors are strong. You can buy it at Lowes for about $8 a can. If you like to spend money, go to Staples and pay double.