Robust control of a sensorless bass-enhanced moving-coil loudspeaker system

Moving-coil loudspeakers generally exhibit poor response in the low-frequency range because the diaphragms are unable to produce sufficient volume velocity. To alleviate the problem, this study focuses on enhancing the low-frequency performance of loudspeakers by means of modern control techniques. A self-sensing velocity observer is utilized for producing the cone velocity signal required by the controller. Feedback H-infinity robust control and feedforward H-2 model matching control are employed to simultaneously achieve robust stabilization and tracking performance. The proposed controller is implemented using a combined digital signal processor and operational amplifier circuitry. (C) 1999 Acoustical Society of America. [S0001-4966(99)02806-4].