ABSTRACT
Radiated sound power is widely considered to be an intrinsic property of a source which may be used as a quantitative 'label' of acoustic output. Although it is true that source sound power is generally far less influenced by the nature of the immediate surroundings than the associated sound pressure, it is not totally independent of these surroundings, as illustrated in Sections 9.2 and 9.5. The principal practical importance of sound power is that it is the fundamental quantity upon which a prediction of the potential effect of a source on any operational environment must be based. In addition, it constitutes the basis for comparison between the acoustic performance of products from different suppliers; it is one of the two major acoustic quantities which are controlled by legislation and regulations; and its dependence upon the physical and operational parameters ofa noise-generating system provides a basis for source identification and characterisation.
