IMPROVING LOUDSPEAKER PERFORMANCE FOR ACTIVE NOISE-CONTROL APPLICATIONS

Actuator performance plays an important part in active noise and acous tic control. The loudspeakers that are normally used as actuators in m any active noise and acoustic control applications add significantly t o the dynamics of the control loop and can be detrimental to the contr oller's performance. By compensating a loudspeaker with a technique si milar to motional feedback, the loudspeaker performance is enhanced fo r applications such as control of acoustic enclosures. A method to com pensate a loudspeaker easily and reliably in order to approximate cons tant volume velocity behavior over the piston-mode frequency range is presented and demonstrated. This decouples the actuator from the syste m being controlled and reduces the impact of the loudspeaker dynamics over the control bandwidth. Experimental results of the proposed metho d using a 5-in (127-mm) loudspeaker are included.