Sign up for daily updates

Help keep this education resource going strong!

More information

News Watch

Selected Documents

Research Links

Alerts

Press Releases

FAQs

Publications & Products

Photos & Graphics

Videos

Allied Groups

Issues/Locations

Documents Home
View PDF, DOC, PPT, and XLS files on line
RSS

Add NWW documents to your site (click here)

Low-frequency noise: a biophysical phenomenon  

Author: 

Abstract: Complaints on low-frequency noise were till recently fairly unexplained, but audiological research shed light on the mechanisms that enable perception of frequencies below the threshold of average normal hearing. It was shown that exposure to low-frequency sound may alter the inner ear. This results in an increase of sensitivity to low-frequency sounds, and as a result, previously imperceptible sounds becomes audible to the exposed person. Interactions between inner-ear responses to low and higher frequencies furthermore account for perception of low-frequency sound, as well as the property of the hearing system to perceive so-called difference tones.

... In Figure 2 the sensitivity curves of the inner and the outer hair cells are shown, along with the noise spectrum of a Dutch wind turbine. It is seen that noise above 50 Hz can be heard by the average normal hearing person. Noise below 5 Hz is not audible for anyone. The region in between is not audible, unless the sensitivity of a persons outer hairs cells are altered. ...

Frequencies lower than about 20 Hz cannot be heard by the average person, but they can be sensed as vibrations, as most people will have experienced when standing near e.g. a subwoofer. A minority of people, however, are able to hear these frequencies as well. ...

Legislatory control of noise necessarily rests on noise-level standards for the average person, as these standards cover the majority of people. The ear of the average person is generally assumed to have a frequency-sensitivity characteristic according to the dBA-standard. When this standard is applied in the assessment of noise, as a weighting, the amount of low-frequency noise produced by public infrastructure seems small. The unweighted low-frequency level, however, can be considerable. For wind-turbine noise, this is shown in Figure 4. A growing number of people suffer from LFN-induced enhanced hearing sensitivity for low frequencies, with enhancements of 20 dB or more. ...

Presented at Congres Geluid, Trillingen, Luchtkwaliteit en Gebied & Gebouw 2012 [Noise, Vibration, Air Quality, and Field & Building in The Netherlands], 6–7 November, 2012

Download original document: “Low-frequency noise: a biophysical phenomenon”

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

Get the Facts
HOME ABOUT PRIVACY CONTACT DONATE
© National Wind Watch, Inc.
Use of copyrighted material adheres to Fair Use.
"Wind Watch" is a registered trademark.
Formerly at windwatch.org.

Follow Wind Watch on Twitter

Wind Watch on Facebook

Share