A comparison of inaudible windfarm noise and the natural

environment noise whilst monitoring brainwaves and heart

rateSteven Cooper

23rd International Congress on Acoustics

• Sound system calibrated to playback 3-min sample of Cape Bridgewater Windfarm in bedroom (Signal 1) at same level as measured in the field

• 3-min samples of other noise sources normalised to have the same A-weighted Leq level as Cape Bridgewater Windfarm signal

• Playback of all signals were inaudible in the two rooms

Signal No. Description

1 Cape Bridgewater House 87 Bedroom

2 Bawley Point Surf Noise

3 Capital Windfarm

4 Taralga Windfarm

5 Capital Windfarm

6 Coal Mine Ventilation Fan

7 White Noise

Listening Room

Hemi-anechoic Room

Bawley Point Surf Noise Measurement

Listening Room

Hemi-anechoic Room

Conclusion

• Inaudible noise

• Direct response of brain – no thought process

• Promising – worthy of further study• Need for longer samples• Suggest one source at a time minimum 20 min exposure• Minimum break between tests 30 mins

• Is the real amplitude modulation in the low frequency that gives rise to the greatest effect?

• But why then a greater change in the standard deviation for the hemi-anechoic room? Smaller room or full spectrum?