Patent ID: 7426278

Claim:
A public address system allowing uniform sound coverage over a zone to be addressed, comprising: an array of electroacoustic sources ( 1 ), each electroacoustic source ( 1 ) diffusing a version delayed by a delay ( 3 ), filtered by a filter ( 4 ), and amplified by an input signal amplifier ( 5 ) of the system, wherein said array is essentially rectilinear and vertical, in that the angles θ formed by the axes of emission of the electroacoustic sources ( 1 ) and the normal line to the array are such that θ n >θ n−1 , where n is the index of the electroacoustic sources ( 1 ) numbered in increasing order from top to bottom of the system, and in that the delays ( 3 ) work with the angles θ such that the system generates a wave front ( 6 ) of the shape corresponding to the desired sound coverage of the zone to be addressed, wherein the angles of inclination θ of the electroacoustic sources ( 1 ) are chosen such that for each of the electroacoustic sources ( 1 ), the distance d separating the center of said electroacoustic source from the point of intersection between the axis of emission of said electroacoustic source and the desired wave front is minimal, and wherein the delays ( 3 ) are essentially R n =R n−1 +(d n−1 −d n )/c for n>1, R n being the delay in seconds linked to the nth electroacoustic source, R 1 being any value, c being the speed of sound in m/s, the distances d being expressed in meters.