Evaluation of wind farm noise amplitude modulation synthesis quality

Wind farm noise amplitude modulation (WFN_AM) is a major contributor to annoyance and could cause sleep disturbance. In laboratory listening experiments assessing its annoyance and sleep disturbance potential, WFN_AM stimuli are commonly synthesised and can thus suffer from a lack of ecological validity. Here, five stimuli synthesis methods were compared with measured noise in terms of their perceived similarity. An ABX discrimination listening test and one-third octave band spectra were used for evaluation of the aural and visual similarity, respectively, between the synthesised and measured noise spectra. The results showed that synthesising WFN_AM using a simple method can be ecologically valid as listeners could not accurately differentiate between measured and synthesised WFN_AM. However, time varying features of WFN_AM do play a small but significant role in human perception and therefore hearing test evaluation of synthesis is recommended for obtaining the most ecologically valid synthesised WFN_AM.