Abstract
Active control of sound fields is an emerging technology which has a great potential to become superior to many passive low frequency noise control methods. It is based on fundamental physical principles which include acoustical coupling of sources, destructive wave interference, and control of enclosure modes. The implementation of active noise control requires placing secondary sources and microphones into the controlled field. Most systems use adaptive filters to control the secondary sources to achieve maximum noise reduction. The engineering applications will require developing optimization techniques for secondary sources and controlling microphone locations. Also new types of robust actuators and controlling sensors will be needed. A brief summary of existing and future applications is provided.