Wind Noise Reduction for Microphones Behind Small Ports

Author(s):

W.C. Kirkpatrick Alberts II and Gregory W. Lyons

Abstract:

Single and multiple microphones in small or handheld devices (such as mobile phones) are often single-port and without windscreens, acting like bare microphones. In a typical outdoor situation, bare microphones can be subject to strong, impulsive wind noise. The significant computational power of mobile phones can sometimes be used for sophisticated signal processing reduction or removal of wind noise. When battery conservation is paramount and computational processing resources are severely limited, alternative wind noise reduction (WNR) strategies must be used. This report details an experimental effort to determine materials and configurations to passively reduce wind noise on microphones inside a ported enclosure. Bare microphones, rough surface treatments, and porous materials were investigated for their WNR capabilities, and it is found that porous metal in place of the port significantly reduces wind noise over a broad frequency range at multiple wind speeds.