Echo Eliminator™ Acoustical Glossary
This glossary of acoustic terms has been provided with a brief definition and description, for the most part in non-technical terms to help remove some of the mystery surrounding acoustics and soundproofing. While the explanations may not be totally correct in their literal interpretations it is hoped that the plain language approach will provide a better understanding of the terminology frequently used in the field of acoustics.
ACOUSTICS: The science of Sound. Its production, transmission and effects.
ACOUSTICAL: The properties of a material to absorb or reflect Sound (adjective) Acoustically, (Adverb).
ACOUSTICAL ANALYSIS: A review of a space to determine the level of reverberation or reflected sound in the space (in seconds) influenced by the building materials used to construct the space. Also the amount of acoustical absorption required to reduce reverberation and noise.
ACOUSTICAL CONSULTANT: A professional usually with an engineering degree who is experienced in providing advice on acoustical requirements, and noise control in a variety of situations.
ACOUSTICAL ENVIRONMENT: The acoustical characteristics of a space or room influenced by the amount of acoustical absorption, or lack of it in the space.
AIRBORNE SOUND: Sound that reaches the point of interest by propagation through air.
ARCHITECTURAL ACOUSTICS: The control of noise in a building space to adequately support the communications function within the space and its effect on the occupants. The qualities of the building materials used determine its character with respect to distinct hearing.
ARTICULATION CLASS: A single number rating used for comparing acoustical ceilings and acoustical screens for speech privacy purposes. AC values increase with increasing privacy and range from approximately 100-250. This classification supercedes Speech Privacy Noise Isolation Class (NIC) rating method.
ARTICULATION INDEX (AI): A measure of speech intelligibility influenced by Acoustical Environment rated from 0.01 to 1.00.The higher the number the higher the intelligibility of words and sentences understood from 0-100%.
ABSORPTION: The properties of a material composition to convert sound energy into heat thereby reducing the amount of energy that can be reflected.
AREA EFFECT: Acoustical materials spaced apart can have greater absorption than same amount of material butted together. The increase in efficiency is due to absorption by soft exposed edges and also to diffraction of sound energy around panel perimeters.
ASSISTIVE LISTENING DEVICE: An electronic device that provides amplification of sound to a hearing impaired person. Device include personal hearing aids, magnetic induction loops, FM radio systems and infrared systems. All have advantages and disadvantages and some may be dependent on good acoustical environment for optimal performance.
ATTENUATION: The reduction of sound energy as a function of distance traveled. (See also Inverse Square Law).
A WEIGHTING: An electronic filtering system in a sound meter that allows meter to largely ignore lower frequency sounds in a similar fashion to the way our ears do.
AMBIENT NOISE/SOUND: Noise level in a space from all sources such as HVAC or extraneous sounds from outside the space. Masking sound or low-level background music can contribute to ambient level of sound or noise.