The Influence of Source Size, Location, and Number upon Power Flow Attenuation Achieved with Duct Active Noise Control Systems

Results are presented that show that the ability of an active system to control plane wave sound propagation in ducts is greatly influenced by system geometric variables. For a single control source system, the location and size have an important effect on the system performance. The introduction of a second control source can enhance the performance of the single control source system, with unconstrained multiple control source optimization possibly providing the best result.