A range of steps can be taken to customize the look or improve the acoustics of open plenum space.Michael Robinson In the past, sound masking was often used as a after-the-fact acoustical solution when a trendy open plenum proved to be too noisy. But today, with the noise problem well known, sound masking is part of the design of a new building from the beginning.
“Ceiling design has become much more complex,” says Niklas Moeller, vice president of LogiSon Acoustic Network, which “introduces greater complexity in terms of masking as well.”
“Sound masking output must be uniformly distributed in any environment, regardless of the presence or absence of a suspended ceiling,” says Nathan Van Ness, product marketing manager for Biamp Systems. Direct-field emitters installed on the ceiling deck or walls are one solution, but “sometimes the nature of an exposed ceiling proves too challenging.” In that case, a network-connected system is preferred — which also allows the system to be fine-tuned from a laptop instead of from the top of a ladder.
Software-based programs “strike a balance of performance and comfort,” Moeller says. What’s a comfortable background sound? “Low frequency — no one likes hissy sound,” he says. “No repeating patterns. Uniform volume, like uniform temperature.”
Doesn’t the HVAC system already provide all the background sound needed? The answer is no, say experts.
“People often compare what they hear to the sound of an HVAC system,” Van Ness says. But running the ventilation system is not a sound solution: “A properly engineered sound masking system broadcasts very specific output with absolutely no fluctuations.”
Moeller agrees: “You can’t rely on an HVAC system to provide a consistent level of background sound.” The reason is that there is too much variation depending on the season, or on closeness to a vent.
In most open office spaces, a lack of ambient sound can lead to a “library-like scenario,” Moeller says, in which any voice at a normal volume carries too far. Sound masking “interferes with the listener’s ability to hear unwanted sound.”
David Lewellen is a freelance writer who covers facility issues.
Email comments and questions to edward.sullivan@tradepress.com.
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