Hit the Floor Running
In his book Home Recording Studio: Build It Like the Pros (Cengage), Rod Gervais explains that no room is completely soundproof. All you can really do is minimize sound transmission by decoupling the structures, sealing any and all gaps, and being sure that your surfaces—walls, ceilings, floor, doors—resonate at little as possible (and at as low a frequency as possible).
Cheap to do? No. But it’s not outrageously expensive, either.
My room is being designed for tracking and rehearsing, rather than, say, mixing. Consequently, I’m working toward a space that is pleasing to play and record in—one that maintains a high level of isolation from the outside while keeping the sound of the drums and amps from annoying the rest of the house as well as the neighbors. So rather than spend the money on acoustical treatment once the room is built, I’m investing in the structural aspects. If you’ve looked into the cost of high-quality acoustical treatment, you know that it’s pricey, and treating a room adequately can begin to feel like a remodel once you get the bill.
This Old House
Meanwhile, construction continues—and what a difference six weeks can make. Since my last post, we found dry rot in parts of the house we hadn’t planned on remodeling, so the scope of the project has expanded, slowing the studio side of things down a bit. The good news is that the electrical in the rest of the house will get an upgrade, which will make recording in the older rooms much easier. (The house dates from the ’50s, and much of the original, ungrounded wiring was still in place.)
In my post from early June, I showed how the double walls looked after they had gone up. At that point, my contractor’s team was about to begin sheet-rocking the ceiling, which turned out to be an exercise in patience. It wouldn’t have been so much of an issue had the ceiling been flat, but this one is vaulted in a quirky way, with angles added to the surface area as a result of the layout of the walls (see Fig. 1).
The ceiling starts with three layers of 5/8-inch gyp board, with a layer of Green Glue between each. The sheetrock was attached using 20-gauge, steel-hat RISC-1 clips. Fortunately, once the pieces of sheet rock were cut into the various shapes for the first layer, the rest could be fashioned more easily by simply duplicating the cuts. In Fig. 2, you can see the pre-cut pieces. Once installed, the seams were filled and caulked, just as they were in the walls.
Soon, the space between the wall and ceiling will have backer rod installed before being caulked. Similarly, the space between the bottom of the drywall and the floor will have backer rod added and get finished off with caulk: The drywall is not allowed to touch the existing deck in order to prevent coupling with the floor.
In the last few days, we’ve begun building up the floor, starting with a layer of Gyp-Crete being poured onto the plywood deck. Gyp-Crete is relatively lightweight and used frequently for fire and sound control in homes, apartments, and hotels. I was surprised to see how quickly it was applied (the crew was done in just over an hour) and how quickly it dried (by the end of the day). The next morning, I returned to find a layer of protective paper on it, with workmen using my empty studio space to air-dry painted doors from the rest of the house. Fig. 3 shows the floor before the pour, and Fig. 4 is a close-up of the metal rail at the base that separates the Gyp-Crete from the walls. Fig. 5 shows how the Gyp-Crete looked a few hours after it was poured.
However, adding a layer of Gyp-Crete over the plywood deck is only the beginning of the sound-control measures we’re taking with the room. The studio floor straddles part of the garage, as well as a half-bath, a mudroom, a hallway, and a bit of the laundry room. (Yes, the laundry room!) Consequently, extra measures have been taken to keep the first-floor ceiling and the studio floor as physically decoupled as possible.
To help isolate the floor further, a layer of 2-inch Owens Corning 703 insulation is put down on top of the Gyp-Crete. Next a layer of 1/2-inch CDX with a full application of Green Glue is added. Both layers are kept 3/8-inch from the perimeter, where backer rod and caulk are added to isolate the flooring from the walls. The final layer will probably be an oak floor. We had oak in the former living room, and it sounded great with the drums.
The finishing layer for the walls and ceiling will be made up of a layer of fabric covered Owens Corning 702 insulation, which is then topped by a pattern of 1×8, 1×6, and 1×4 wooden slats, with a 2-inch gap between each. The layout is designed to offer a combination of absorption and diffusion that should yield a pleasantly musical space to work in. Gervais has had great results with this design in tracking rooms, and because of the unusual shape of my studio, we’re both confident that it will make for an exciting room. I’ll post some photos as things develop.
Exploring Music’s Hold on the Mind