This paper discusses the importance of the spectral distribution of the energy in the sound to the dB(A) level of the usual passby test. A described technique obtains reproducible "real-time" spectra from the nonstationary sound field. Doppler effect and source frequency shift are quantified in relating these spectra to the tread pattern repetitions. Inverse square law fitting is viewed through the two-source-microphone relation which changes during the spectral window period. Spectra are shown for 6, 12, and 50 ft (1.83, 3.66, and 15.2 m) passby microphones and for a microphone carried on the truck.

  • Corporate Authors:

    Society of Automotive Engineers

    400 Commonwealth Drive
    Warrendale, PA  USA  15096
  • Authors:
    • Miler, R C
    • Thrasher, D B
  • Publication Date: 1974

Media Info

  • Features: Figures; References; Tables;
  • Pagination: 8 p.

Subject/Index Terms

Filing Info

  • Accession Number: 00095778
  • Record Type: Publication
  • Report/Paper Numbers: SAE No. 740608
  • Files: TRIS
  • Created Date: Jul 2 1975 12:00AM