Sound-field characterisation and implications for industrial sound-intensity measurements

Sound-field characterisation is of vital importance in evaluating and improving the reliability of sound-intensity measurements. This paper examines indicators of the sound-field characteristics and the consequent implications for sound-intensity measurements. Results illustrate how the coherence between sound pressure and particle velocity can classify sound fields as diffuse multi-source, direct, or direct-plus-reverberant from one source. The measurements were conducted in a power station, which is typical of many commonly encountered multi-source, reverberant environments confronting the noise-control engineer. The value of sound-pressure/particle-velocity coherence is consistent with the form of acoustic field implied by the sound-power, vector-sound-intensity, and sound-pressure measurements. Some practical difficulties of sound-intensity measurement in complex environments are discussed, as is the identification of these by coherence and the standard sound-field indicators. © 1992.