Multichannel feedforward active noise control system with an optical laser microphone and a distant air-conduction microphone for noise reduction in a real system

Abstract

A conventional feedforward active noise control system suffers from degraded performance of noise reduction due to the causality constraint caused by processing and propagation delays. To address this issue, we propose a multichannel feedforward active noise control system that combines an optical laser microphone and an air-conduction microphone. The proposed system relaxes the causality constraint by acquiring vibration information at the speed of light using the optical laser microphone and enhances coherence using the signal of the air-conduction microphone. Experiments using a laser Doppler vibrometer and an electret condenser microphone demonstrate superior noise reduction compared to the conventional system.