An integrated 3D sound intensity sensor using four-wire particle velocity sensors: I

Complete characterization of a sound field requires measurement of both sound pressure and particle velocity. In this paper, a new symmetrical four-wire sensor configuration is discussed which has a lower noise floor than its two-wire version and measures in two dimensions. With a pair of four-wire sensors, a fully integrated 3D particle velocity sensor is realized with smaller size than its predecessors. In this paper, a further investigation towards the directivity pattern of the sensor is done, revealing that a deviation is present between the expected and measured direction. Measurements of the directionality and possible solutions to the problem are presented in this first part, whereas the second part of this paper presents a more theoretical model of the deviation. Furthermore, a connection method is discussed enabling the use of the sensor for commercial purposes and measurements are presented showing the difference in performance resulting between a two-wire and a four-wire sensor configuration. (Some figures in this article are in colour only in the electronic version)