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The sound of silence: the active counter-noise in air ducts.

Le son du silence : le contre-bruit actif dans les conduits d'air.

Author(s) : BRISTER A.

Type of article: Article

Summary

Passive noise attenuators are efficient, except though at low frequencies. The principle of active counter-noise consists in creating variations of pressure equal and opposed to the vibrations of air pressure which cause noise. The installation of such a system in airducts consists of detection microphones, a digital filter which produces a counter-noise signal at loudspeaker level and a test microphone controlling the result obtained. The system has been tested: efficiency is good at low frequencies, especially for pure frequencies, and not so good at high frequencies, higher than specific frequency limits. Combined active-passive systems have been tested. J.L.

Details

  • Original title: Le son du silence : le contre-bruit actif dans les conduits d'air.
  • Record ID : 1995-0429
  • Languages: French
  • Source: Promoclim - vol. 24 - n. 6
  • Publication date: 1993/10
  • Document available for consultation in the library of the IIR headquarters only.

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