Signal correlation by wind between two 90mm-windscreened microphones

摘要

The authors previously conducted an experiment outdoors and found correlation between output signals of two microphones 1-meter distanced along a prevailing wind direction, and couldn't find a relation between varying wind speed signals of the same distance. The relations were considered, with frequencies under 200-Hz targeted. The quiet outdoor measurement might have some acoustical noise. But if wind-affected noise was dominant in the measured microphone signals, what was the difference between the correlations of microphones and of hotwires. Spatial size might be a contributory factor. The windscreens used were 90-mm in diameter, which corresponds to the spatial wave-length of 30-Hz at 3-m/s wind speed or air flow. Meanwhile, the hotwire size was 2-mm, and the streamline in varying wind direction might not penetrate the two hotwires. Bare microphones and the 200-mm windscreened same ones at this time are used to investigate correlations of microphone wind-noise signals, and the noise source is considered.