This International Standard applies to sources which radiate discrete frequencies or narrow bands of noise. The spectrum of the source can include broad-band components upon which the prominent discrete frequencies or narrow bands of noise are superimposed. These methods are often complex and time-consuming 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.
SIS SS-ISO 3742:1989 history
1989SIS SS-ISO 3742:1989 Acoustics — Determination ofsoundpower levels ofnoise sources — Precision methods for discrete-frequency and narrow-band sources in reverberation rooms