Measurements with two different directional microphone systems were made for the purpose of locating and identifying radiated noise sources on a high speed electric train travelling at speeds between 160 and 250 km/h. An acoustic mirror with 7 microphones positioned in the focal plane was used to measure higher frequency noise, while a linear array of 14 microphones was used for lower frequencies. Data recorded with the array were processed so as to allow the main lobe to either (1) focus dead ahead, or (2) be electronically slewed to track moving sound sources. Both wheel/rail and aerodynamic sound sources were investigated with the mirror and the array. The results of these measurements demonstrate the versatility and usefulness of directional microphone systems for locating and analyzing noise sources on moving vehicles.

  • Corporate Authors:

    Deutsche Forschungs-u Versuchsanst f Luft-u Raumft

    Brunswick,   Germany 

    National Aeronautics and Space Administration

    600 Independence Avenue, SW
    Washington, DC  United States  20546
  • Authors:
    • Bechert, D W
    • KING, W F
    • Grosche, F R
    • Stiewitt, H
    • Martin, A
  • Publication Date: 1979-7

Media Info

  • Pagination: 106 p.

Subject/Index Terms

Filing Info

  • Accession Number: 00336258
  • Record Type: Publication
  • Source Agency: National Technical Information Service
  • Report/Paper Numbers: DFVLR-MITT-79-15
  • Contract Numbers: BMFT-TV-77230
  • Files: TRIS
  • Created Date: May 21 1981 12:00AM