Abstract: A noise reduction system includes an enclosed system in which undesirable acoustic noise is generated by one or more associated noise-generating subsystems, and an acoustic resonator mounted on an exterior wall of the enclosed system, with an opening being defined through the exterior wall to allow for the passage of sound pressure waves from within the enclosed system to the acoustic resonator. The acoustic resonator includes a neck connected to the exterior wall at the opening and through which sound pressure waves from the enclosed system travel, at least two branches extending off from the neck, and a resonator connected to a distal end of each of the at least two branches.

Abstract: A system and method of reducing noise in an enclosure is disclosed. The method includes receiving at least one reference signal; receiving pressure signals from no more than two substantially orthogonally placed pairs of acoustic sensors, where one pair of acoustic sensors is in the x-direction and one pair of acoustic sensors is in the y-direction, and where the acoustic sensors are placed in a plane which is substantially parallel and in proximity to an inner surface of the enclosure; using the pressure signals and the reference signal to generate an output signal to minimize energy density at a location of the acoustic sensors; and sending the output signal to an acoustic actuator.