Providing Speech Privacy Through White Noise Sound Control Systems

The American Society of Testing Materials (ASTM) has approved the use of the Speech Privacy Index (PI) to calculate and measure the acoustical quality of a space. Rather than measuring the acoustics of each of the design elements in the space, the Speech Privacy Index measures the acoustics for the entire interior environment. The PI determines how much of a conversation at point A can be understood at point B.

The most effective method of increasing speech privacy in the office is through the use of a sound masking system. Sound masking, (white noise and pink noise) is cost effective and has a typical return on investment of 4 to 6 months.

Sound Masking is an electronically generated broad band, low level background sound that is precisely contoured to cover, or mask conversational intelligibility and unwanted background noise. The addition of sound masking to a space is acoustically equivalent to tripling the distance (radius of distraction) between people.

Sound masking can increase conversational privacy by as much as 100%. As a system, it works by slightly raising the ambient background sound at the listener’s ear and increasing privacy levels by reducing the signal-to-noise ratio. In effect, a sound masking system works the opposite of a hearing aid.

Margenau Associates, Inc. utilizes a “site specific” computer tuning process that assures the maximum degree of speech privacy at the lowest possible background sound. This process precisely fills in one-third octave band attenuation deficiencies for the specific application, then produces and contours an exact computer generated sound-masking spectrum for optimum performance. The MAI modeling program allows a user to evaluate the combined effect of any changes to the space.