A four particle velocity sensor device

In a sound field disturbance of pressure, particle velocity, density, temperature, and energy occur. In this paper acoustic disturbances in air are considered. In the majority of papers on acoustics only changes in the sound pressure are reported while in this paper results on the particle velocity are reported. Since particle velocity is a vector, while the pressure is a scalar, more information can be obtained when using a particle velocity sensor instead of a pressure sensor (microphone). Four particle velocity sensors are combined to one (small) device. In a reverberant room the four autospectra and the six cross spectra are determined. Interpretation of the measured results gives information of the free field (sound field without a contribution of reflections) as well as of the reverberant field