scope:

This International Standard specifies the special requirements that are necessary for accurate determinations of the sound power when discrete frequencies or narrow bands of noise are radiated by a source. This International Standard applies to sources which radiate discrete frequencies or narrow bands of noise. The spectrum of the source may or may not include broad-band components upon which the prominent discrete frequencies or narrow bands of noise are superimposed. These methods are often complex and timeconsuming for measurements on sources which primarily radiate discrete frequencies below 200 Hz. For such sources measurements in a free field as described in ISO 3745 are likely to be more appropriate.