The Listening Room Experience

This track is recorded at a mobile home site where many residents have sold up and moved out because of the wind farm.  The track starts with a car on the road interspersed with turbine noise which dominates as the car fades away. Not all the turbines were audible or intrusive.

The track includes some periods of rumbling / roar, thumping, lashing and also more typical wind turbine noise. Listen again and see if you can hear the difference in noise character.

This track provides contrast. It starts with a car passing on a main road which partially but not totally masks the turbine noise. The peak to trough variations recorded were previously considered impossible by industry experts. Furthermore, the peak to trough variations were considered to reduce over distance. This clip provides significant contrast with what is a quiet environment absent the wind farm noise. Many characteristics are evident including the sudden drop in noise between peaks.

The extract below was measured under typical, high wind shear, conditions likely to lead to EAM. There is very little wind at ground level but the turbines are generating AM with a 10dB peak to trough difference as well as lower frequency EAM.
 

The noise from the Kessingland turbines can again be seen to clearly dominate the sound environment in the area. The graph below is another example of EAM measured approximately 600m from the turbines. Throughout the period road traffic noise can be heard and contrasts with the EAM from the turbines. The modulation peak to trough is regularly in the region of 10dB(A). Noise in the 200Hz third octave frequency band is dominant throughout and largely dictates the low frequency character of the EAM. The nature of the sound varies throughout the period both in frequency content and in modulation depth, increasing from a peak to trough range of approximately 3dB(A) to a peak to trough range of approximately 10dB(A) in a time frame of 4 seconds.

The extract below was measured two and a half hours later, the turbines are still generating EAM. The peak to trough range is approximately 9dB(A). Noise in both the 200Hz and 250Hz third octave bands is dominant. Wind conditions at ground level are very still apart from a couple of occasions when leaves can be heard rustling in the wind.

These measurements were recorded externally in the rear garden, screened by the house from the turbines.  The matching internal is further down.

The measurements were made in an external amenity area location in a remote rural area approximately 1km from the wind farm. The site remains anonymous as requested by complainants and due to potential litigation. The graph compares a period when the turbines are not operating with a period just under half an hour later when the turbines are operating. There is approximately a 7dB increase in background noise level and the character of the soundscape is significantly altered.  Note: this is 'typical' wind farm noise and would not be categorised as AM.

Measurements taken approximately 800m from the nearest turbine (8 turbines in total).

One of the first windfarms in the UK the Delabole wind farm has recently been redeveloped. The original wind farm was identified in ETSU-R-97 as causing noise complaints. The measurements below shown that the redeveloped wind farm is generating EAM. The location of the wind farm at Delabole, within close proximity of the coast and surrounding hilly landscape, indicates a high likelihood of EAM occurring.

The measurements below were recorded under meteorological conditions and at an angle from the turbines that would not be expected to result in worst case EAM. This suggests that in downwind inversion conditions noise impact could be much worse. Noise levels were measured at a distance of approximately 400m from the turbines at a nearby caravan site. Modulation phases in and out during the period, at the beginning of the period the peak to trough range is approximately 6dB(A) and has a greater proportion of lower frequency noise content. At the end of the period modulation increases unexpectedly from approximately 2-3dB(A) peak to trough to 6-9dB(A) peak to trough. Towards the end the peaks are dominated by a greater proportion of higher frequency noise content.