MEASURING METHOD OF ACOUSTIC IMPEDANCE AND ACOUSTIC ABSORPTION COEFFICIENT

PROBLEM TO BE SOLVED: To provide a simple and accurate measuring method of the stable acoustic impedance and the acoustic absorption coefficient of a material in the installed state on a cite, without requiring a special apparatus or a large scale facility. SOLUTION: The measuring method of the acoustic impedance and the acoustic absorption coefficient includes: a step of disposing near an object to be measured two far-near microphones 2a, 2b at a predetermined far and near distance or an acoustic pressure-particle velocity sensor; a step of irradiating sound waves, the acoustic pressure level of the microphone or the sensor of which is made to the predetermined value, according to the acoustic absorption coefficient of a material, from a sound source ensured with diffusibility to these two far-near microphones 2a, 2b or the acoustic-particle velocity sensor; a step of measuring the acoustic pressure between the far-near microphones or a transfer function of the acoustic pressure between the acoustic pressure-particle velocity; and a step of calculating the acoustic impedance and the acoustic absorption coefficient based on the measured values. COPYRIGHT: (C)2010,JPO&INPIT