Lightweight, high insertion loss, active noise enclosure with air gaps

Preliminary experiments that demonstrate the control of noise using a lightweight, active enclosure with significant air gaps are discussed. The active enclosure consists of a lightweight, plexiglass box with piezoceramic actuators bonded to each side as active inputs. The control approach used is the filtered-x LMS. Global reductions of 7 to 20 dB are reported and mechanisms of control are discussed. ï¿_ï¿ï¿ 1995 Acoustical Society of America