Quantifying acoustic sources through sound power measurements

Characterizing the level of acoustic energy radiated from a machine is an important task for manufacturers of consumer goods. Several measurement methods and standards exist for measuring the sound power level of an acoustic source. For those engineers without a detailed background in acoustics and noise control, it can be difficult to determine which measurement method is best for their application, or which standard to follow. This article discusses the seven most common sound power measurement standards and presents the governing equations behind these methods. Example sound power data is shown for four sources using the precision grade free field method. Finally, the pros and cons of each measurement type are discussed as a guide for choosing the best method for your application.