On the Measurement of Sound Power using a Cubical Arrangement of Microphones in a Small Rigid Sphere

Recently a new acoustic measurement device, the SonoCat, has become available. The probe consists of 8 MEMSmicrophones, embedded in a small rigid sphere. By accurately calibrating the amplitude and phase mismatch betweenthe microphones, the probe is able to measure the sound intensity accurately. In this paper, we will explain the methodthat has been used to derive the sound intensity from the measured pressure signals and how the effect of the presenceof the sphere has been accounted for. In addition, we will show experimental results, obtained in the anechoic room ofthe University of Twente, comparing the sound intensity, as measured by the probe, with a benchmark sound intensityprobe. The accuracy and precision of the new probe will be discussed.