Loudness

loudness

[′lau̇d·nəs]

(acoustics)

The magnitude of the physiological sensation produced by a sound, which varies directly with the physical intensity of sound but also depends on frequency of sound and waveform.

Loudness

 

a quantity that characterizes auditory sensations for a given sound. Loudness depends in a complex way on sound pressure (or sound intensity), frequency, and form of vibrations. Where frequency and form of vibrations are constant, loudness increases with an increase in sound pressure. Where sound pressure is the same, the loudness of pure tones (harmonic oscillations) of different frequencies is different—that is, at different frequencies sounds of different intensity can have the same loudness. The loudness of a given frequency is evaluated by comparing it with the loudness of a simple tone of 1.000 hertz (Hz) frequency. The sound pressure level (in decibels [dB]) of a pure tone of 1,000 Hz frequency that is as loud (audially) as the tone being measured is called the loudness level of the given sound (in phons). Loudness for complex sounds is rated on an arbitrary scale in sones. Loudness is an important characteristic of musical sound.

loudness

The intensive attribute of an auditory sensation, in terms of which sounds may be rank-ordered on a scale extending from soft to loud; depends primarily on sound pressure, but also on the frequency and wave form of the sound stimulus; expressed in units called sones; 2 sones is just twice as loud as 1 sone.

Loudness

boiler factory

proverbial source of noise and confusion. [Am. Culture: Misc.]

breaking of the sound barrier

boom of plane heard exceeding speed of about 750 m.p.h. or Mach 1. [Aviation: Misc.]

Concorde

supersonic jet of British-French design. [Eur. Hist.: EB, III: 66]

Joshua

Jericho walls razed by clamorous blasts from his troops’ trumpets. [O.T.: Joshua 6]

Krakatoa

volcanic explosion on this Indonesian island heard 3000 miles away (1883). [Asian Hist.: NCE, 1500]

Olivant

Roland’s horn, whose blast kills birds and is heard by Charlemagne, eight miles away. [Fr. Legend: Brewer Dictionary, 772]

sonic boom

shock wave from plane breaking the speed of sound. [Aviation: Misc.]

Stentor

Greek herald with voice of 50 men. [Gk. Myth.: Espy, 39]