Calibration of pressure-velocity probes and measurement of sound power and ear canal conductance

The appearance in the last decade of a new generation of p-u sound intensity probes, allowing the direct measurement of the air particle velocity, represented a great chance to advance a domain of acoustics not entirely studied yet. This topic can be best called Sound Energetics, a term including the study of sound energy generation, propagation and absorption as well as the study of the structure of the energy field of sound. Although this new kind of MEMS-designed probes, based on the anemometric transduction principle of double heated wires, can be properly used for innovative applications of Sound Energetics, it is still far from being a reference instrument in sound intensimetry. In particular, calibration is nowadays an open issue, even if some studies are already presented in literature. The author's main research activity has been just focused on a new approach of calibration of p-u probes using a progressive plane wave field as reference field for calibration. The thesis firstly introduces Sound Energetics and some of its typical quantities, followed then by a description of p-u probes calibration theory and main experimental methods nowadays used: particular relevance is given to the plane wave reference field, for which experimental data are collected and results are shown in detail. Finally, some example of possible applications are illustrated: a conventional measurement of sound power of a noise source in different environments, a study of energetic properties of simple one-dimensional fields and a forward-looking analysis of human ear canal sound conductance.