A comparative study of feedforward control of harmonic and random sound transmission into an acoustic enclosure

This paper describes an analytical and experimental investigation which com pares the feedforward control of harmonic and random sound transmission int o an acoustic cavity. A rectangular enclosure is considered that has five a coustically rigid walls and a flexible plate on the remaining side through which a plane acoustic wave is transmitted into the enclosure. The control systems are designed to reduce the acoustic potential energy inside the enc losure when the incident sound is either harmonic or random. Three control configurations classified by the type of actuators are investigated both th eoretically and experimentally. They are (i) use of a single point-force ac tuator, (ii) use of a single acoustic piston source and (iii) simultaneous use of both a point-force actuator and an acoustic piston source. It is sho wn that the configuration of both acoustic and structural actuators is desi rable for the active control of both harmonic and random sound transmission into a coupled structural-acoustic system whose response is governed by pl ate and cavity-controlled modes. (C) 1999 Academic Press.