Acoustics

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Term Definition
Acoustics

Science dealing with the production, control, transmission, reception and effects of sound, and the process of hearing.

In the context of architecture and engineering, acoustics can be defined as the technology of designing spaces, structures, and mechanical systems to meet hearing needs through design so that "wanted" sounds can be heard properly and "unwanted" sounds, or "noise", can be attenuated or masked to the point where it does not cause annoyance.

All acoustic systems have three common elements: source, transmission path, and receiver. The source can be made louder or quieter and the path can be made to transmit more or less sound. The listener's reception of sound also may be influenced.

In building construction, these three elements are controlled through the use materials and the shape of enclosures. Generated sound radiates out from the source until it strikes a room boundary or other large surface. When the sound reaches the wall or other surface, it is partially absorbed and partially reflected, and a small portion is transmitted into adjoining spaces.

The ratio between the energy absorbed and the energy reflected by a surface will significantly affect what one hears within a space. If little energy is absorbed and much is reflected, intermittent sounds will be mixed together, making speech less intelligible, and steady sounds will accumulate into a reverberant field (echo), making the space noisy.

On the other hand, if much energy is absorbed but little is reflected, the room will sound "dead" and quiet to speech. This may work well for a private office, but not for a lecture hall, large auditorium, or music venue.

Acoustic design in buildings aims to find an optimal balance between these two extremes so that spaces are ideally suited for the functions they are meant to serve.