Low frequency active noise control

Abstract

A noise attenuation system (10) for an air induction system (12) includes an air inlet duct (16) having an open end (18) to draw in air and a loudspeaker (22) mounted within the inlet duct (16) and facing the open end (18) of the inlet duct (16). The air horn (24) is connected to the loudspeaker (22) to tune the sound output and increase the sound power from the loudspeaker (22) to optimize cancellation of noise generated by the air induction system (16) at lower frequencies. An open end (18) of the air horn (24) is positioned within a plane defined by the open end (18) of the air inlet duct (16). A microphone (26) is positioned near the air inlet duct (16) and is in communication with a controller (28). The controller (28) generates an input to the loudspeaker (22). The input to the loudspeaker (22) is out of phase with the noise detected by the microphones (26) to cancel a portion of noise emitted from the open end (18) of the air inlet (16).

Dependencies are inferred from the claim text.