Estimation of an open-loop compact adaptive passive noise control system with microstructures

An adaptive passive noise control system with high-aspect-ratio apertures in a thin perforated plate is presented. An implemented absorber forms an array of Helmholtz. resonators which consists of micro-order diameter apertures in a perforated plate and a tunable cavity gap. The simple open-loop control algorithm was employed as a control strategy in order to reduce extra hardware and realize the compact system. The developed adaptive passive noise control system employed high-aspect-ratio apertures in an absorber and adapted for a lower-frequency range without increasing the cavity gap. In the experiment, the compact system could absorb less than 1000 Hz frequency noise with a thin cavity gap, 23 mm. This paper reports the possibilities of 3 compact adaptive passive noise control system with taking into account of advantages of microstructures based on microelectromechanical systems technology. (C) 2001 Acoustical Society of America.