Sound masking is the addition of unstructured sound to an environment created by special digital generators and distributed by normally unseen speakers through an area that fills in the sound spectrum and makes the structured sound of human speech less intelligible and to reduce distractions.
Like light, sound is a wave and spreads out in all directions from a source. Hard surfaces reflect it, walls block it, and soft surfaces absorb it. Other sounds can cover it up. But unimpeded, sound can travel pretty far.
The ABCs represent the three ways you can improve your acoustic environment and achieve necessary privacy levels. Absorption of sound waves by using a high-NRC-rated ceiling tile or acoustic wall panels, Blocking by using high-STC-rated panels, partitions, walls, windows, etc. Covering by adding a source of unstructured, low-level background sound, known as sound masking or white noise. Covering provides the greatest increase in privacy per dollar invested.
Sound cancellation electronically alters an incoming sound wave to minimize or eliminate it altogether. The sound wave is picked up by a microphone, analyzed by a microprocessor, and then a speaker placed in the path of the sound wave broadcasts a mirror image (exact opposite) frequency, thus flattening out the wave and canceling out much or all of the sound. Sound masking, on the other hand, works on the principle that when background noise is added to an environment, speech is less intelligible. This is what a “white noise” system does to mask sound. It “fills in” the sound spectrum around you with barely perceptible “unstructured” noise. Your brain will tune out unstructured noise as it searches for the structured variety. The goal of any speech privacy system is to add enough sound to an area to cover up speech, yet still be quiet enough to be almost imperceptible. Good, well-tuned, quality sound masking systems will produce sound that your mind naturally tunes out. The more uniformly the sound masking system accomplishes this throughout the treated area, the more “invisible” the sound becomes.
In office spaces, the background noise level is generally low. Hence, people unintentionally overhear conversations – a difficult situation for all concerned. To address this problem, sound masking systems emit a soft, inconspicuous background sound with the use of a loudspeaker system. The ambient sound level becomes more uniform and otherwise noisy distractions are muffled by the sound masking.