If you listen carefully at Soundstage 11, in the Culver Studios, Culver City, CA, you can almost hear the echoes of Clark Gable, Vivian Leigh, and Olivia de Havilland filming “Gone With the Wind” in 1939.

That’s an exaggeration, of course, but this historic soundstage is not only still in use, it’s better than ever, thanks to an air conditioning system upgrade. That upgrade makes it one of the most comfortable and also one of the quietest soundstages in Culver City and Hollywood.

Other blockbusters filmed at Culver Studios over the years include the original release of “A Star Is Born,” “Spellbound,” and “Citizen Kane.” More recent films include “E.T.,” “City Slickers,” and “Air Force One.” It has also been home to well-known TV shows, including “Lassie,” “The Andy Griffith Show,” and “Batman,” along with such recent hits as “Mad About You.”

According to Ken Kenyon, hvac technician at Culver Studios, what makes Soundstage 11 unique in the film and television industry is that, unlike most other soundstages, its new a/c system is so quiet that it can continue running with taping underway.

Previously, the old air conditioning system had to be shut off during taping because the noise generated by the equipment interfered with sensitive recording equipment on the set.

Kenyon says that in the past the set would be “subcooled” for a few hours prior to taping. While taping, the system was shut off until the scene was over. By then, the hot lights made the set too warm for actors and actresses and, at times, for the audience and equipment such as computer-controlled light dimmers. When taping stopped, the air conditioning system started once again, repeating the cycle.

Silent Air

About four years after Col-umbia TriStar TV moved into Soundstage 11 to tape “Mad About You,” it was decided that the air conditioning system was in line for upgrading. The system had to be quiet enough to operate continuously during the show’s taping. This became the primary objective for an upgrade to “silent air.”

To take on the challenge, Culver Studios called on the Los Angeles, CA office of The Trane Company. Joe Kountzman, general manager of Southern California Trane Service, assembled the design/build team of Dale Au of D’Autremont-Helms and Associates mechanical engineers (Los Angeles) and acous-tical consultant Mark Schaffer, P.E., associate principal with McKay Conant Brook Inc. acoustical consultants (Agoura Hills and West-lake Village).

(Schaffer now has his own firm, Schaffer Acoustics Inc. of Pacific Palisades.)

Also on the team were Lee Schulz from Wheeler & Gray, Inc. structural engineers (Los Angeles), and contractors E.W. Thorn Refrigeration (Sun Valley) and Darrow Heating & Air Condition-ing (North Hollywood).

Schaffer said of Soundstage 11, “The obvious challenge was keeping the studio cool and comfortable, and doing that quietly so that when the cameras are rolling and the microphones are on, operating the air conditioning system would not be a problem.

“To determine exactly what was meant by the term “silent air,” we visited other soundstages at the Culver Studios to find one that was acceptable. One such stage had a measured background noise criteria rating of NC-18. And so NC-18 became our goal for Soundstage 11.

“What made this a challenge was the tremendous amount of air we had to deliver to the studio. Normally, the square footage area of a stage this size would require only about 35,000 cfm of conditioned air. Dale Au’s calculations, based on the studio’s requirements, showed that to keep the set cool during taping µ with all the stage lights on µ we would have to deliver 80,000 cfm.

“On the supply air side, we designed the air handling system for very low velocity to minimize turbulence, which is what creates noise in ductwork. We also used long-radius elbows and lined all the ducts to attenuate any residual noise.”

The Heart of the Matter

The heart of the new air-handling system for Soundstage 11 is two Trane Modular Climate Changer® air handlers, each equipped with two Trane Model Q™ fans. Schaffer remarked, “The Q fan is compact and moves a lot of air, and does so quietly.”

The air handlers are mounted external to the building. The cool supply air is distributed through exterior wall penetrations into four 60- by 60-in. plenums running the length of the inside ceiling. Each of the four main air plenums has eight 32- by 32-in. duct drops to distribute the air as needed over the sets.

In addition to cooling the set, the cooling load is often increased by those TV programs taped before a live audience. Another critical air distribution point is to the computer-controlled stagelight dimmer control room, which must be maintained at 70°F.

Return air to the air handlers is drawn through what Schaffer calls a sound attenuating “plaque” that is built into the exterior wall of the building. In essence, nearly the entire wall is a return air plenum. According to Schaffer, the plaque forces the return air to make a turn, the equivalent of a lined elbow, and puts the air in contact with more sound attenuating liner before it returns to the air-handling unit.

In addition, outside air economizers are used to reduce energy consumption when possible. The economizers also purge the soundstage following use of special effects such as smoke.

Playing a supporting role to the air handlers is a chiller plant with two Trane centrifugal chillers and an ice storage system. The chillers are operated only during nighttime hours when utility rates are at their lowest.

The chillers produce 23° glycol solution that is circulated in 18 ice storage tanks to produce ice. During the day, the chillers are shut off and all air conditioning is provided by the melting ice and by operating chilled water circulating pumps. This results in significant energy savings when compared to a conventional system with chillers operating while peak rates are in effect.

Is It Quiet?

The design goal was to achieve a noise criteria rating of NC-18. According to Kenyon, when the new air handling and air conditioning system was first started, the noise level was actually less than the goal, coming in at NC-17 with the air conditioning system delivering the full 80,000 cfm.

Kenyon noted that, after some minor ductwork sealing, the air handling system achieved an even lower NC-15, resulting in the quietest soundstage that he is aware of.

As a result of the improved air conditioning system, taping at Soundstage 11 means less sound editing, and it goes much faster and costs the producers less money µ big advantages in the TV and film industries.

Kenyon said, “For certain, this is the quietest soundstage owned by Sony Entertainment, the parent company of the Culver Studios. And the tenants at Soundstage 11, Columbia TriStar TV, are ecstatic. We used to get a lot of phone calls in our department complaining about the hvac. I still get calls, but now it is from people who say ‘Thank you!’

Sidebar: Getting Things Under Control

Each Trane air handler and chiller has its own microelectronic controls for on-site control.

Overall monitoring and control of the system and individual pieces of equipment are accomplished through a Tracer Summit® building automation system designed to provide advanced operating strategies for energy savings, continuous monitoring of equipment operating conditions and the space temperatures on the sets, as well as advanced diagnostics.

Trane calls this combination of building automation and equipment an Integrated Comfort™ system, citing the advantage of factory-installed and tested controls specifically designed to work with its air conditioning equipment. Hvac technician Ken Kenyon can monitor and control the entire system from the soundstage, from the office, or from a remote location using a laptop computer with dial-up capabilities.

Sidebar: Trapping Sound in Short Order

Mark Schaffer of McKay Conant Brook Inc. stated, “My calculations showed that we would have to install sound traps, which are special sections of ductwork that have very thick internal sound attenuating baffles. They provide a lot of attenuation in a very short distance of duct.”

Schaffer designed the sound traps, which are specially shaped and custom built, so that they could be conveniently installed in the existing structure. He credits Darrow Heating & Air Conditioning for its work in the construction and installation. E.W. Thorn Refrigeration handled installation of the air handlers and chilled water piping.

The air handler fan motors are equipped with variable frequency drives such that only enough air is distributed to meet the cooling load. This feature not only contributes to low noise, but also saves considerable energy.

Publication date: 09/25/2000