Active Noise Control in a Y-Shaped Duct: Simulation and Experimental Results

There are different approaches to active noise control (ANC). The time domain Filtered-X LMS adaptive control scheme is currently used in most applications. The purpose of this paper is to describe an experiment consisting of a Y-shaped duct with two loudspeakers attached to the two branches of the Y duct. One of the loudspeakers acts as the perturbation source and the other acts as the control source. Tonal noise control is investigated, and control implementation issues such as number of filter weights, value of step-size parameter, and sampling frequency are discussed. The reference signal is taken from the signal sent to the perturbation loudspeaker and the error signal is taken from a microphone that can be placed anywhere along the stem of the Y-shaped duct. Simulations and experimental results are presented. The setup is simple and may be easily implemented for leaching purposes.