Sound masking systems actually utilize pink noise, which is “shaped” with frequency filters applied by the acoustic/audiovisual system designer. White noise is technically equal noise per octave and is a misnomer related to sound masking systems.
Music has long been identified as inappropriate for sound masking where speech privacy is a concern. It is not consistent in terms of frequency or sound level, and it is difficult to achieve agreement of music format by space occupants.
How has sound masking technology improved in recent years? What kinds of capabilities and features are today’s systems offering?
The industry has made great strides in technology to enhance the use and performance of sound masking systems in recent years. Most significant is the ability to adjust and control each and every loudspeaker in a system–often many hundreds of them, located above a suspended acoustic ceiling–remotely from a single laptop computer.
This has been a big timesaver. Computer programs allow for individual frequency adjustments per individual or zones of loudspeakers so that the resultant background sound generated in a space can be customized to the specific location, size, and function therein.
Some manufacturers are even offering packages of sound masking integrated with their ceiling panels. The difficulty with this approach is that if there is no acoustical consultant to guide the project, the client or end user may be getting more or less system than they need. An acoustical consultant can best determine, by technical calculation and their broad base of experience, where and when a sound masking system is appropriate—and what the expectations will be.
Where do sound masking systems fit into the overall acoustical design of a healthcare facility?
In the early days of sound masking systems, which were developed specifically for open plan offices with no full-height partitions, some thought it was a panacea for all noise problems. Now, 20 years later, the use of sound masking allows us to be more creative, and to carefully utilize sound masking systems where they are appropriate.
The key point for laymen to understand is that in order for a sound masking system to be effective, it needs to be located within the space requiring privacy, not the space generating the sound. Furthermore, some acoustically sensitive spaces, such as large conference or training/presentation/audioconferencing rooms, require low background sound levels and good interior room acoustics in order to function properly. Increasing the background sound level via adding a sound masking system is simply not appropriate.
Good acoustical design requires a combination of controlling sound and vibration from the HVAC/air distribution system, room finish material selection, and developing partitions to meet the privacy needs of the client/end user as determined by early establishment of acoustical criteria during programming sessions with the end users. Sound masking systems should only be a component of the total package.
Ryan Bessey, PE
Acoustical Engineer, Stantec, Toronto
How should a sound masking system best be integrated into a space?
Sound masking should be located within the same space as the “listener” in order to mask noise coming from other areas such that it isn’t intelligible. It’s advisable to consistently use sound masking throughout a particular area so that it is not noticeable as users come and go from the space.
What are some options for where to locate the system?