A General Review of Sound intensity Measurement Errors for Finite Sources

As commercial acoustic intensity measurement devices are introduced to the market place, it is essential that the limitations of the two-microphone technique used in these devices are well defined. This paper presents an analytical study of measurement errors due to the finite difference approximation in the intensity formulation. Unlike previous studies which treated only ideal point sources, this study investigates errors associated with finite sources. The sources considered include a pulsating sphere, an oscillating sphere, and a general two-source model. Errors determined for measurements with these sources are plotted for typical measurement conditions. Errors are found to closely resemble those for ideal point sources with the exception of the general two-source model.