Open issues of active noise control applications

Interest in active noise control has grown significantly over the past decades, successful industrial applications include active control of sound in headsets, in industrial ducts and in propeller aircrafts, to name a few. To extend the upper limiting frequency and attenuation zone of active noise control systems, one of the solution is to use a multiple channel active noise control (ANC) system with several secondary sources and error sensors. Multi-channel ANC also has application to a wide variety of problems in manufacturing, industrial operations, and consumer products. In this paper recent developments in ANC technology are reviewed and the technical problems still standing in the way of widespread application are discussed Current research directions are outlined and the future of the discipline is examined.