Phonoscopy: An acoustical holography technique for plane structures radiating in enclosed spaces

Abstract

The present paper provides a modification of near-field acoustical holography (NAH) enabling reconstruction of sound fields in a room in order to study plane structures radiating in enclosed spaces; the new technique is called phonoscopy. A description of the measurement laboratory is given; a single microphone scanner is used to measure the pressure on the hologram plane. Three examples of measurement are presented: a point source located on a rigid wall, a homogeneous wall, and a window mounted in a wall. Maps of the velocity of the structure and of the acoustic intensity radiated are given. The accuracy of phonoscopy is demonstrated by comparison with the accelerometer methods (for measuring vibration velocities) and the two-microphone technique (for measuring acoustic intensities). Some K-space spectra are also presented and analyzed, giving more information about the physics of the vibrator.