decibel

decibel
(dB)
   a customary logarithmic measure most commonly used (in various ways) for measuring sound. The human ear is capable of detecting an enormous range of sound intensities. Because of this great range, and because our perception of sound is not linear, it makes sense to measure sound on logarithmic scales. Informally, if one sound is 1 bel (10 decibels) "louder" than another, this means the louder sound is 10 times louder than the fainter one. A difference of 20 decibels corresponds to an increase of 10 x 10 or 100 times in intensity. The beginning of the scale, 0 decibels, can be set in different ways, depending on exactly which aspect of sound is being measured. For sound intensity (the power of the sound waves per unit of area) 0 decibels is equal 1 picowatt per square meter; this corresponds approximately to the faintest sound that can be detected by a person who has good hearing. A quiet room has a normal sound intensity of around 40 decibels, ten thousand times louder than the faintest perceptible sound, and a thunderclap may have an intensity of 120 decibels, a trillion times louder than the faintest sound. For sound pressure (the pressure exerted by the sound waves) 0 decibels equals 20 micropascals (µPa) RMS, and for sound power 0 decibels sometimes equals 1 picowatt. In all cases, one decibel equals about 0.115 129 neper and d decibels equal d(ln 10)/20 nepers.
   See also dB-.

Dictionary of units of measurement. 2015.

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  • Decibel — Décibel Pour les articles homonymes, voir Décibel (homonymie). Le décibel (dB) est une unité logarithmique de mesure du rapport entre deux puissances. C’est une grandeur sans dimension en dehors du système international[1]. Elle est utilisée… …   Wikipédia en Français

  • Decibel — Basisdaten Entwickler KDE / supported by NLNet and basysKom Aktuelle Version …   Deutsch Wikipedia

  • décibel — [ desibɛl ] n. m. • 1932; de déci et 2. bel 1 ♦ Métrol. Unité, égale au dixième du bel, servant à exprimer le rapport de deux puissances (acoustiques, électriques, etc.), notamment d une puissance donnée par rapport à une puissance de référence… …   Encyclopédie Universelle

  • decibel — DECIBÉL, decibeli, s.m. Unitate de măsură a intensităţii sonore, egală cu o zecime dintr un bel. – Din fr. décibel. Trimis de dante, 13.09.2007. Sursa: DEX 98  decibél s. m., pl. decibéli; simb. dB Trimis de siveco, 10.08.2004. Sursa: Dicţionar… …   Dicționar Român

  • Decibel — Saltar a navegación, búsqueda Decibel puede referirse a: decibelio en inglés, nombre de la unidad de comparación de magnitudes; a la rock progresivo y del rock en oposición, a Decibel, el framework de comunicaciones en tiempo real de KDE 4.… …   Wikipedia Español

  • dècibel — m 1. {{001f}}fiz. jedinica za mjerenje razlika u snazi (simbol dB), najčešće u elektronici; u akustici mjeri razlike u pritiscima u mediju koji prenosi zvuk (jedan decibel je približno najmanja razlika intenziteta zvuka koju može zamijetiti… …   Veliki rječnik hrvatskoga jezika

  • decibel — 1928, from DECI (Cf. deci ) + BEL (Cf. bel) (n.) …   Etymology dictionary

  • decibel — s. m. Décima parte do bel, unidade de medida que serve, em acústica, para definir uma escala de intensidade sonora (símbolo: dB). [A voz média tem por intensidade 55 dB.] …   Dicionário da Língua Portuguesa

  • decibel — o decibelio sustantivo masculino 1. Área: física Unidad que se utiliza para medir la intensidad de un sonido …   Diccionario Salamanca de la Lengua Española

  • decibel — m. Fís. decibelio …   Diccionario de la lengua española

  • decibel — ► NOUN ▪ a unit of measurement expressing the intensity of a sound or the power of an electrical signal. ORIGIN from DECI (Cf. ↑deci ) + bel, a unit (= 10 decibels) named after Alexander Graham Bell (1847 1922), inventor of the telephone …   English terms dictionary

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