I recently attended a tradeshow and was surprised to meet a number of building professionals who didn’t realize that a sound masking system must be properly adjusted for each facility.
Unfortunately, there are vendors who contribute to this misperception by suggesting that their sound masking systems are basically plug n’ play. Or that by installing loudspeakers differently, such as facing directly downwards, systems can somehow defy the laws of physics and the sound won’t be affected by the qualities of the space into which it’s distributed.
So, it seems that tuning is a good subject to address in a post...
The reality is that no sound masking system produces the ‘right sound’ from the moment it’s powered on. After being installed in a facility, it needs to be tuned to meet a particular sound masking spectrum or curve.
Ideally, the curve is specified by a project’s acoustical engineer or referenced from an independent party, such as the NRC – not by the sound masking vendor (who may be tempted to provide a curve and tolerances that are easy to adjust for or that meet what their loudspeakers are physically capable of producing, rather than what’s been proven to be most effective in terms of improving speech privacy and noise control). The sound masking system’s job is to meet the desired curve as closely as possible throughout the space in which it’s installed.
It’s important to understand that the curve doesn’t define what the system’s volume and equalizer settings should be, but rather the measured output within the client’s space. Regardless of the system’s ‘out of the box’ settings, how small its zones are, how its loudspeakers are installed, and so on, the masking sound interacts with elements of the workplace interior, furnishings and other variables. In order for the sound to meet the desired curve, the system must be tuned to each unique space.
The tuning process is handled by a qualified technician after the ceilings and all furnishings are in place, and with mechanical systems operating at normal daytime levels. Because conversations and activities can prevent accurate measurement of the masking sound, it’s done prior to occupation or after hours.
Basically, the technician uses a sound level meter to measure the masking sound. They analyze the results and adjust the system’s volume and equalizer controls accordingly. They repeat this process as often as needed until they meet the curve, within the specified tolerances, at each tuning location. Ideally, the system should be tested, adjusted and documented in small zones of 1 to 3 loudspeakers.
Admittedly, tuning can be a time-consuming process because a professional masking technician won’t just measure in one or a small handful of locations within the space and call it day. They’ll ensure that the curve is met as closely as possible across the entire space so that the system’s benefits are experienced consistently by its occupants.
Tuning is essential to providing you with the core benefits you’re paying for when you purchase a sound masking system. Simply put, poor tuning equals poor masking.
Stay tuned for more on this subject...pun intended!