Useful information

Low-frequency noises and infrasound from wind turbines and other sources

On the invitation of the Ministry for the Energy Revolution, Agriculture, the Environment and Rural Areas (Ministerium für Energiewende, Landwirtschaft, Umwelt und ländliche Räume) in Schleswig-Holstein (MELUR), the workshop Infrasound and Wind Turbines (Infraschall und Windkraftanlagen) was held in Kiel on 3 June 2016. The presentation by our speaker, the geophysicist Bernd Dörries, given during this workshop, can be found here: Vortrag Infraschall und tieffrequente Geräusche an WEA (1 MB).

Between 2013 and 2015 the Landesanstalt  für Umwelt, Messungen und Naturschutz Baden-Württemberg (LUBW), together with Wölfel Beratende Ingenieure GmbH, took measurements of low-frequency noises and infrasound on wind turbines, among other things. The results were published in a report in February 2016. In this way, LUBW aims to contribute to greater objectivity in the discussion. The report is addressed to interested citizens, administrations and professionals. You can find the report here: Low-frequency noises including infrasound  (15.3 MB).

Revision of Part 1 of Technical Guideline for Determining the Sound Emission Values of Wind Turbines

Edition 2 of EN 6140011, published in 2007 and applicable to measurements on wind turbines, was revised for the 2013 Edition 3. The transition period for using Edition 2 ended on 12 December 2015. Measurement analyses were extensively revised for Edition 3. The Technical Guideline published by Fördergesellschaft Windenergie und andere Erneuerbare Energien e. V. (FGW) on this topic is currently undergoing revision. Moreover, the new analysis method is undergoing a round-robin test. We are actively involved in both processes.

Revision of DIN 45680: Measurement and assessment of low-frequency noise immissions in the neighbourhood, published 2007

Working Group NA 001-01-02-11 of the Acoustics, Noise Reduction and Vibration Technology (NALS) Standards Committee is currently revising the above standard. The two drafts presented so far found no consensus in the profession. A third draft is now being aimed for. We have been active in this process since 2016.

Room acoustics audio samples

We are aware that when designing an auditorium, acoustics is only one aspect. This is why we are happy to work to your design specifications. However, you can’t fool physics. In the following audio samples you can listen to a speaker in an auditorium with 3 s reverberation time and in one with 1 s reverberation time. You decide …

Audio sample in a reverberant room with three seconds reverberation time (3.44 MB)
Audio sample in an insulated room with one second reverberation time (3.28 MB)

The sound difference is best heard if you use a speaker or earphones.

Audio samples for wind turbines

The perceptibility of even the smallest sound level increases or decreases is discussed time and again. The discussion rotates around the following questions:

  • May a rating level calculated to one decimal place be correctly mathematically round to a whole number before comparing it with the immission guide value?
  • Must a facility fall below the immission guide value by 6 dB, 10 dB or even 15 dB, before it is acoustically irrelevant in the terms of TA Lärm (Technical Instructions on Noise Control)?

In order to complement the abstract and legalese-dominated discussion with subjective impressions, we have normalised the following noises, recorded during an emission measurements campaign on a 2 MW class wind turbine, to a variety of sound levels. In a direct comparison, you can listen to the effect of a change in sound level. For as authentic a playback possible, use high-quality earphones or an external loudspeaker.

If you would like to listen to the playback of an absolute sound level – e.g. 45 dB(A) for the immission guide value in mixed-use areas at night – you must set your loudspeaker to the required level beforehand with the aid of a sound level gauge.

A final note: Humans do not have a long-term acoustic memory. Sound level differences can therefore generally only be assessed by comparisons.

Audio samples

Wind turbine noise 0dB (80 KB)

Wind turbine noise -0.5dB (80 KB)

Wind turbine noise -1dB (80 KB)

Wind turbine noise -2dB (80 KB)

Wind turbine noise -3dB (80 KB)

Wind turbine noise -4dB (80 KB)

Wind turbine noise -5dB (80 KB)

Wind turbine noise -6dB (80 KB)

Wind turbine noise -10dB (80 KB)

Wind turbine noise -12dB (80 KB)

Wind turbine noise -15dB (80 KB)

Seminars

We happily provide in-house seminars on the topic of sound (e.g. sound control, architectural and room acoustics) for architects, engineers and planners. Please contact us.

Presentations

Daga 2015 in Nuremberg
Infrasound and low-frequency noises on wind turbines (Fabian Küke)
Download (PDF)

Daga 2014 in Oldenburg
Measurement of low-frequency noises on wind turbines (Michael Stalder)
Download (PDF)