The Sound Masking Blog
6Jul/12

Pay Me No Mind

Unobtrusive Sound MaskingOne unusual part of being involved in the sound masking industry is that we don’t want customers to notice our product. I guess there aren't too many other businesses out there who want to fade into the background, but going unnoticed is actually central to our technology’s success.

Of course, I’m not referring to our desire to engage in promotional or educational activities. And I don’t mean that you shouldn’t be told there’s a masking system in your space or that you won’t notice its impact (you certainly will), but rather that the system shouldn’t call attention to itself.

The sound produced by a masking system is always audible (otherwise it couldn’t do its job, which is to cover up conversations and noise). But a lot of engineering and design work has to go into making it as unobtrusive and comfortable as possible. Otherwise, it could become a source of irritation rather than the solution to it.

The first thing we do to remain invisible is produce a sound that’s truly random. The masking signal also has stable volume over time so that occupants perceive the sound as being at a constant level. In other words, there isn’t any ‘information’ in our sound – no noticeable patterns or variations that could draw attention to it. We also provide a proper masking spectrum. If the sound was missing sufficient low frequencies, for example, it would sound hissy.

We also strive to ensure consistent coverage and volume levels across the facility. That way, occupants can move around their space without noticing the masking. One way of achieving this is to install the loudspeakers in an upward orientation above the suspended ceiling, so that the sound reflects from the deck and disperses across a wide area. Alternatives such as loudspeakers cut into the ceiling tile would provide a much narrower area of coverage and we’d have to use many more of them.

We also ensure proper loudspeaker spacing. If too far apart, there would be ‘dead spots’ between them. For this reason, we also recommend that the system be installed throughout the space, and in both open and closed areas. If customers were to try to spot treat, occupants would notice the sound as they entered and exited masked areas.

System zoning and adjustment capabilities also play a key role. If the loudspeaker criteria were met, but we couldn’t adjust the sound in fine increments in local areas, the masking levels would vary across the space. That’s why we provide control over zones of one to three loudspeakers. Each of these small zones offers independent equalization and volume control in half-decibel increments.

Another way to make the masking sound seem like a natural part of the space is by ensuring that occupants can’t determine its source. That’s another reason why we prefer to install our loudspeakers invisibly above the suspended ceiling, rather than using cut throughs.

And there are even more steps that we take to remain unnoticed. For instance, there’s a ramp-up period for already occupied facilities, which slowly introduces the masking sound so that occupants can easily acclimatize to their new acoustical conditions. From that point, any volume adjustments made in response to anticipated occupancy rates are handled gradually using a programmable timer. These volume changes occur in half-decibel steps over long periods. If we implemented ‘responsive’ or ‘reactive’ adjustments that changed the volume frequently and relatively quickly, occupants would soon notice them and they’d become a source of irritation.

So, in large part, the success of sound masking depends on its discretion. The great thing is that the same functions that make the system unnoticeable also ensure its effectiveness.

Cheers,

Niklas

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