Active device for attenuating the sound intensity

Claim 1

An active device for attenuating the sound intensity in a determined region by emitting antinoise waves, said device comprising: a set of sensors capable of determining the signals and directions of incident waves emitted by distant noise sources; means for processing the noise signals b(t) from the incident waves as determined by said sensors, and for generating signals cb(t) corresponding to antinoise waves; said generating means including a set of electroacoustic sources connected to said signal processing means, said sources being capable of emitting antinoise waves in the same direction and in the same sense as the incident waves, the set of sensors being placed such that the incident waves reach the set of sensors prior to the determined region, wherein the electroacoustic sources are installed in a location proximate to the determined region and, the antinoise waves emitted by the electroacoustic sources combine to form resultant antinoise waves having a radius of curvature approximating that of said incident waves and in which each electroacoustic source is controlled such that the acceleration of a contained diaphragm of the electroacoustic source is proportional to the derivative of the antinoise signal cb(t).