Active Reduction of an Enclosed Sound Field: An Experimental Investigation

Many experimental investigations into the active control of sound have concentrated on the simplest sound field, a one dimensional wave propagating along a duct, where a simple control strategy can be used because cancellation at one point guarantees cancellation downstream of that point. A simple controller can be implemented by measuring the sound upstream with a unidirectional sensor and using a feedforward controller with a delay and phase inversion to drive the cancelling source