Hybrid passive-active absorption of a microperforated panel in free field conditions

J Acoust Soc Am. 2007 Jun;121(6):EL251-5. doi: 10.1121/1.2739112.

Abstract

Although hybrid passive-active absorption in impedance tubes has been widely analyzed, its study in more realistic conditions remains to be accomplished. This letter describes the practical measurement of the passive-active absorption coefficient in a free field. The passive absorber consists of a microperforated panel backed by an air cavity and a wooden panel. A multichannel active system controls the sound pressure in a reduced cell behind the absorber. Measured absorption coefficients between 200 and 400 Hz account for 0.2-0.4 and 0.72-0.75, in the passive and active cases, respectively, and above 500 Hz both are comparable.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Hearing*
  • Humans
  • Noise
  • Reproducibility of Results
  • Sound*