A comparison of in inaudible windfarm noise and the natural - - PowerPoint PPT Presentation

A comparison of in inaudible windfarm noise and the natural environment noise whilst monitoring brainwaves and heart rate

Steven 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?