A new temporal method for the identification of source directions in a reverberant hall

The study presented here is related to the reduction of noise in factory halls. The type of factory hall considered here has large dimensions and contain several industrial machines, running 24 h a day. A method is presented to determine the angular directions which provide the main contributions to the sound levels at any point in the hall. These directions correspond to the sources and their images on the walls and on the obstacles. The method is based on the use of cross-correlation functions of sound signals measured on a microphone array. It is adapted to the constraints of the problem (short measurement time, no possibility to stop the machines, small dimensions of the array, etc.). Experimental results are shown first for several test cases carried out in a semi-anechoic room and in a rectangular room, and, then, for the case of a surface-planing machine in a cluttered hall.