Some regulatory authorities in Australia have recently proposed low frequency noise assessment criteria for wind farms based on C-weighted noise levels. This involves the specification of an outdoor night time trigger level of 60 dB(C), above which further investigation may be required. While the accuracy of noise model predictions of A-weighted noise levels is well established for wind turbines, less information is available on the accuracy of low frequency noise predictions. This paper presents an analysis of approximately eight months of low frequency noise measurements at a location near a wind farm, conducted using appropriate windshields and at locations away from extraneous noise sources. The measured low frequency noise levels are compared to predicted levels to assess the accuracy of conventional noise modelling techniques for low frequency wind farm noise. Changes in low frequency noise levels with wind direction, wind speed and wind shear are also analysed.
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