A longitudinal pressure wave in air or an elastic medium, esp. one producing an audible sensation

A disturbance or oscillation that transfers energy progressively from point to point in a medium or space without advance by the points themselves, as in the transmission of sound or light

A graphic representation of the shape of a wave, obtained by plotting deviation at a fixed point versus time

The distance, measured in the direction of propagation of a wave, from any one point to the next point of corresponding phase

The maximum deviation of a wave or alternating current from its average value

A surface of a propagating wave composed at any instant of all points having identical phase, usually perpendicular to the direction of propagation

The lowest frequency at which a vibrating element or system will freely oscillate

A vibration having a frequency that is an integral multiple of that of the fundamental frequency

A range of wavelengths or frequencies between two defined limits

An apparent shift in frequency occurring when an acoustic source and listener are in motion relative to each other, the frequency increasing when the source and listener approach each other and decreasing when they move apart

The number of cycles per unit time of a wave or oscillation

The SI unit of frequency, equal to one cycle per second

The predominant frequency of a sound as perceived by the human ear

The interval between two frequencies having a ratio of 2:1

A subjective response to sound indicating the magnitude of the auditory sensation produced by the amplitude of a sound wave

A unit of expressing the relative pressure or intensity of sounds on a uniform scale from 0 for the least perceptible sound to about 130 for the average threshold of pain

The sense by which sound is perceived, involving the entire mechanism of the internal, middle, and external ear and including the nervous and cerebral operations that translate the physical operations into meaningful signals

A range of frequencies from 15 Hz to 20,000 Hz audible to the normal human ear

The rate at which acoustic energy flows through a medium, expressed in watts per square meter

The difference between the actual pressure at any point in the field of a sound wave and the static pressure at that point, expressed in pascals

The amount of acoustic energy radiated by a source per unit time, expressed in watts

Sound intensity measured on the decibel scale, equal to 10 times the common logarithm of the ratio of the sound intensity to a reference intensity

An electrical instrument for measuring sound pressure levels

Sound pressure measured on the decibel scale

The acoustic power of a source measured on the decibel scale

The level of sound intensity high enough to produce the sensation of pain in the human ear, usually around 130 dB

Physical or mental weariness caused by prolonged exposure to loud noises

An increase in the threshold of audibility, at specific frequencies, caused by normal aging, disease, or injury to the hearing organs

The minimum sound pressure capable of stimulating an auditory sensation

The qualities or characteristics of a room, auditorium, or concert hall that determine the audibility of speech or fidelity of musical sounds in it

A structure over or behind and above a speaker or orchestra to reflect the sound toward the audience

A non-absorptive surface from which incident sound is reflected, used esp. to redirect sound in a space

One of a number of acoustic panels installed near the ceiling of a concert hall to reflect sound for improving the acoustic quality of music

A detailed study of the use of a building, the location, and orientation of its spaces, possible sources of noise, and the desirable acoustical environment in each usable area

The planning, shaping, finishing, and furnishing of an enclosed space to establish the acoustical environment necessary for distinct hearing

The application of absorbent or reflecting materials to the walls, ceiling, and floor of an enclosed space to alter or improve its acoustic properties

Airborne sound waves bent by diffraction around an obstacle in their path

The return of unabsorbed airborne sound after striking a surface, at an angle equal to the angle of incidence

The repetition of sound produced by the reflection of sound waves from an obstructing surface, loud enough and received late enough to be perceived as distinct from the source

A rapid succession of echoes caused by the reflection of sound waves back and forth between two parallel surfaces, with sufficient time between each reflection to cause the listener to be aware of separate, discrete signals