Sound Masking Terminology You Need to Know

American Sound prides itself on installing world-class, professional sound and video equipment. One aspect of our business is high-quality sound masking technology. Whether protecting confidentiality is a matter of preference or mandated by law, sound masking is an excellent good solution. Today’s blog from American Sound explains sound masking terminology you need to know.

ABCs of Acoustics

The ABCs of acoustics stand for:

  • A Absorb Sound
  • B Block Sound
  • C Cover Sound

A combined approach to absorb, block, and cover sound is the best way to ensure speech privacy in your building. Sound masking technology provides Cover Sound by generating white noise with overlapping acoustic signals that make speech in another room unintelligible. The noise from Cover Sound is similar to air circulating in a room.

Articulation Index

The articulation index represents a quantitative measurement of the intelligibility of speech in a given location. A value of 1 means all speech can be understood, while a value of 0 means no speech can be understood. Acceptable speech privacy is when the articulation index is 0.2 or lower for sound masking. American Sound will strive to hit this mark with every install.

Privacy Index

Privacy index is the inverse measure of the articulation index. Sound masking technology must achieve a privacy index of 80% or greater, either by itself or in combination with sound blocking or absorbing.


Appropriate sound masking technology needs multiple channels, or unique output signals, to achieve a privacy index of 80% or greater. For example, one channel may cover sounds with a higher pitch while another covers sounds with a mid-range pitch. Our technicians will adjust the channels on sound masking technology to achieve optimum results. Once we achieve the right results based on your building’s acoustics, the technology will be barely noticeable to ordinary people.


Directional describes the distribution pattern of sound coming from a speaker or sound source. Highly directional speakers project sound across greater distances, and they work well to cover speech coming from another room. Speakers may also use the ceiling to disperse sound to cover speech in the same room. Speakers with wide dispersal patterns radiate sound directly into a room. American Sound will determine the best system for your building based on the materials, shape, and size of each room where you need sound masking.

Decibel Tolerance

Decibel tolerance measures the uniformity of the sound emitted by sound masking systems. The smaller the tolerance level, the better the uniformity of the system. The best sound masking systems, like the ones we install, have a decibel (dB) tolerance of less than 1 decibel. In essence, this level of tolerance means you can’t tell there are different channels emitting various frequencies and decibels of sound that cover the sounds of speech coming from other rooms or across the same room.

Professional Sound Masking Installation by American Sound

Sound masking helps to ensure the privacy of patients and clients in the healthcare, legal, and financial industries. It also reduces distractions and provides privacy in boardrooms and conference rooms. Contact American Sound or call (859) 261-9024 for more details on our world-class sound masking technology.