A new era for applications of active noise control

The fundamental theories and methods of active noise control (ANC) have become well established over the last 30 years, so fewer academic research projects on ANC are funded nowadays. However, applications of the technology are entering a new golden era with greater numbers of companies investigating the applications of noise control in their products. One good example is the successful application of ANC on Apple's iPhone 5 to increase speech quality in communication by cancelling ambient noise. This paper discusses a number of ANC projects that we have conducted over the last ten years with emphasis on the various challenges encountered in the applications of ANC. Aspects covered include acoustical design methods, recently developed adaptive control algorithms, new control hardware and systems, and new applications. The projects discussed include active control of transformer noise, ANC in natural ventilation windows, and ANC in a communication chassis. Unlike our previous research, all these projects are funded by industry bodies, and their aims are not to perform academic research, but to develop commercial products.