Abstract: An active adaptive noise control system in ducts is proposed，which adopts a motional feedback loudspeaker not only as an noise controlling actuator but also as a detecting sensor. By analysing each acoustical path, identification based adaptive linear neural networks is made. This kind of identifing method can be achieved expediently, and it would’t bring disturbance to working environment. The estimated result of each acoustical path agrees well with its real acoustical character, respectively.

Key words: Active noise control, Motional feedback loudspeaker, Neural networks identification