Intensity measurements in various rooms: A new intensity probe

Abstract

The main advantage of acoustic intensity measurements is that in a reverberant room the direct and the reverberant sound field can be determined. This property has been tested using the Bruel & Kjaer p-p probe in four different rooms (anechoic, reverberant and two listening rooms). As compared to the results in the anechoic room, small deviations, which can be positive and negative, were found. The deviations can be explained using a model of early reflections. A new intensity probe consisting of a microphone and a sound velocity sensor has been tested and compared with the Bruel & Kjaer p-p probe. The sound (particle) velocity sensor contains the Microflown, a novel micro-machined sensor. This silicon-based velocity microphone operates on a thermal principle. The dimensions of the Microflown are on the order of a cubic millimeter. For symmetry considerations, however, the sensors were packaged in a quarter inch package. Experiments were done in the anechoic and in the reverberation room. A good agreement was found.