Subjective perception of wind turbine noise

The evaluation of wind turbine noise impacting upon communities is generally related to external noise environments and has a problem with separating wind turbine noise from ambient noise (which includes the presence of wind) which is not normally the case for general environmental noise. Subjective testing of wind turbine noise to examine amplitude modulation and subjective loudness has tended to use large baffle speaker systems to produce the infrasound/low-frequency noise and one high-frequency speaker - all as a mono source. Comparison of mono and stereo recordings of audible wind turbine noise played back in a test chamber and a smaller hemi-anechoic space provides a distinct different perception of amplitude modulation of turbines. A similar exercise compares use of high-quality full-spectrum headphones with the two different sound files applied to just the ears is discussed.