As the interior walls of my studio were being packed with insulation, my contractor began installing the fresh-air ventilation system. One factor that many people forget to consider when designing a studio is airflow. It’s not just about how quiet a system is, but how efficiently it works.
You may find it surprising — though it’s obvious upon reflection — that in creating a nearly soundproof room, you are also creating an airtight space: Wherever air can enter, sound will enter as well. If you were to install and run a heating/cooling system in an airtight studio without supply and return vents, you’d pressurize the room in a dangerous way very quickly. Therefore you must find a quiet and efficient way to move air in and out of the room so you can work comfortably.
But there are a number of issues that need to be addressed as you determine the climate-control requirements of your studio. Space is an important one, because HVAC systems can eat up a portion of your wall and ceiling area if you need to enclose them in soffits. Of course, you could get a portable air-cooling unit, but they can be relatively loud, while taking up floor space and requiring you to connect a duct to an exterior vent.
Factors you’ll need to consider when figuring out the proper size for your system include the number of people you will have in each room of the studio, the amount of space (and money) you can devote to the HVAC system, and, of course, local weather conditions. During my brief tour of the southeast this month, I was reminded of how hot and humid it can get in certain parts of the country. Consequently, the HVAC requirements for a studio in, say, Birmingham, Ala., where there is high humidity during much of year, are much different than in Reno, Nev., which has a much drier climate.
And consider that it’s not just humidity from the outside that you’ll battle. Humans expel water vapor when they breathe, and the more people you have in your studio, the greater the humidity you have to deal with. A five-piece rock band doing take after take of a song will quickly raise the temperature and humidity in your tracking room, and that’s not even considering the heat coming from the gear.
The same goes for your control room and vocal booth. Despite having fewer people in these rooms, they can become hot and uncomfortable quickly if you don’t have a way to bring in fresh air.
The best scenario is to install a system that is quiet enough that you can leave it on while you work, rather than sweating it out when you track or mix, and then turning the A/C on during the breaks.
On the Wall
Although my studio was being constructed from the ground up, I wanted to lose as little space as possible to ductwork and avoid soffits. I also wanted to have my climate control system completely separated from the rest of the house, both sonically and structurally.
The Music Technology Center at Diablo Valley College, where I teach an Intro to Pro Tools class, installed wall-mounted, single-room air conditioner/heaters that connect to an external fan. They’re surprisingly quiet, very efficient, and relatively affordable for personal studios. And all of the venting and duct work are tucked away in the ceiling.
A number of companies make these types of units, but for my studio we settled on the Mitsubishi Split Ductless system, which attaches to the wall (though there are systems that attach to the ceiling as well). Because the room will be airtight, we added two fresh-air ducts in the ceiling, each placed about 3.5 feet from the highest point in the room. A Broan HRV90 Fresh Air System, which will provide 75 CFM of airflow, connects to the studio using spiral metal ducts lined with Casco Coated Circliner II duct liner to keep the system’s sound to a minimum. (You can see examples of the lined ducts in the photos on this page.) The supply and return vents have Shoemaker 90-series double deflection grilles (10 x 10), which should be large enough to permit the required amount of air to flow without creating any whistling noise.
Installing the duct work turned out to be a bit tricky because insulation had already been placed in the ceiling and the layout of the trusses is complicated (to say the least). But after it was installed, the system was completely hidden from view.
Once the final finishing layers are added to the walls and ceiling, we will attach the A/C unit and complete the fresh-air outlet boxes by adding the grilles. Then we can fire up the system as I load in all my gear and begin the process of locating the various sweet spots in the room for recording drums, amps, and vocals.
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