View PDF, DOC, PPT, and XLS files on line

Add NWW documents to your site (click here)

Sign up for daily updates

Keep Wind Watch online and independent!

Donate $10

Donate $5

News Watch

Selected Documents

Research Links


Press Releases


Publications & Products

Photos & Graphics


Allied Groups

Wind Turbine Noise at Grays Farm, Deeping St Nicholas  

Author:  | Filings, Noise, Regulations, U.K.

Witness Statement of S. Jane Davis in support of Friends of the South Pennines and the Todmorden Moor Restoration Trust.

1. Sound Pressure Wave Modulation recorded at Grays Farm


This slide illustrates the characteristic peak to trough trace of amplitude modulation recorded in the bedroom of our house in July of 2008. In terms of the severity of what we have suffered over the past two and a half years this level of modulation would rate as 6 on a scale of one to ten (where 1 is least and 10 is the worst)

The lowest to the highest point exceeds 10dB, and this is just in a period of 1 minute. The maximum variation for and individual thump or whoosh is 8dB (A).

Modulation generally occurs at a frequency of one beat per second.

2. The unsuitability of the LA90 (10min) Descriptor for measuring turbine noise pollution


This is an illustration of the failure of the descriptor LA90 (10min) used under the guidance given from ETSU-R-97. The peak to trough range of modulating sound pressure waves produced by modern large turbines is far greater than that from the small to medium size turbines on which ETSU-R-97 was based. Consequently the larger peak to trough variation changes the characteristics of the sound and hence it is more noticeable and intrusive. The LA90 (10min) descriptor does not reflect this and therefore a substantial decibel penalty (10dB (A) or more) would be warranted to reflect the nature, or characteristic of the sound.

3. The failure of external background noise to mask turbine noise when experienced within a dwelling


This slide shows sound measured from the turbines inside and outside our house simultaneously. The lower trace (A) is the internal measurement and shows the spiky peak to trough modulation. The upper trace (B) is the outside measurement and generally only records the upper part of the modulation due to masking from external noise sources (background noise). This shows that while a limited amount of masking does occur externally, internally the full modulation is experienced. The structure of the house significantly reducing the effect of any external background noise indicating a significant contribution to the turbine noise from lower frequency ranges. [Note, the spike at (C) is due to un-related internal noise.]

This material is the work of the author(s) indicated. Any opinions expressed in it are not necessarily those of National Wind Watch.

The copyright of this material resides with the author(s). As part of its noncommercial effort to present the environmental, social, scientific, and economic issues of large-scale wind power development to a global audience seeking such information, National Wind Watch endeavors to observe “fair use” as provided for in section 107 of U.S. Copyright Law and similar “fair dealing” provisions of the copyright laws of other nations. Queries e-mail.

Wind Watch relies entirely
on User Funding
Donate $5 PayPal Donate


Get the Facts Follow Wind Watch on Twitter

Wind Watch on Facebook


© National Wind Watch, Inc.
Use of copyrighted material adheres to Fair Use.
"Wind Watch" is a registered trademark.



Wind Watch on Facebook

Follow Wind Watch on Twitter

National Wind Watch