Virtual Sensing Technique for Feedforward Active Noise Control

Abstract

Active noise control (ANC) is a promising technique to reduce unwanted acoustic noise, based on the superposition property of acoustic waves. When an anti-noise wave is elegantly generated to have the same amplitude and inverse phase of the noise wave, ANC can reduce the noise level at the desired location, where an error microphone is placed to monitor the error signal and make the whole system a closed-loop control problem. In the case when the error microphone cannot be placed at the desired noise reduction location, virtual sensing techniques are useful. In this paper, we examine a recently proposed virtual sensing technique in an experimental setup using the parametric array loudspeaker as the anti-noise source (also known as the secondary source). Experiment results show that improved noise reduction can be achieved at the virtual microphone location.