Editing Sound power (section)

{{short description|Rate at which sound energy is reflected or transmitted per unit time}}
{{Sound measurements}}

'''Sound power''' or '''acoustic power''' is the rate at which [[sound energy]] is emitted, [[reflected]], [[Acoustic transmission|transmitted]] or received, per unit time.<ref name=clinical>{{cite book|url=https://books.google.com/books?id=ElPyvaJbDiwC&q=sound+power+loudness&pg=PA94|title=Clinical Measurement of Speech and Voice|author=Ronald J. Baken, Robert F. Orlikoff|publisher=Cengage Learning|year=2000|isbn=9781565938694|page=94}}</ref> It is defined<ref>{{cite web | url = https://www.iso.org/obp/ui/#iso:std:iso:80000-8:ed-3:v1:en | title = ISO 80000-8(en) Quantities and Units - Acoustics | publisher = [ISO] }}</ref> as "through a surface, the product of the [[sound pressure]], and the component of the [[particle velocity]], at a point on the surface in the direction [[Normal (geometry)|normal]] to the surface, [[Surface integral|integrated over]] that surface."  The [[International System of Units|SI unit]] of sound power is the [[watt]] (W).<ref name=clinical/> It relates to the power of the sound force on a surface enclosing a sound source, in air. 

For a sound source, unlike sound pressure, sound power is neither room-dependent nor distance-dependent. Sound pressure is a property of the field at a point in space, while sound power is a property of a sound source, equal to the total power emitted by that source in all directions. Sound power passing through an area is sometimes called ''sound [[flux]]'' or ''acoustic flux'' through that area.