A Method of Assessing Acoustical Two-Port Properties of Earplugs

Per Hiselius

Research output: Book/ReportReportResearch


An experimental setup for objective measurements of high impedance objects in ducts, yielding the acoustical two-port properties of the object, is presented. The setup has been applied on earplugs. A frequently used experimental setup for measuring objective acoustical properties of earplugs is that of artificial ears. Great effort is spent duplicating the outer ear of a person. The insertion loss is considered to give the acoustical properties of the object. Such a setup, however, gives a ratio of the 'response of a system' to that of another system. The actual properties of the object are thereby embedded in a complicated artificial response. By instead fitting the test object in a duct, it's two-port parameters can be assessed, given the sound pressure level at both sides of the object for two sufficiently diiferent termination impedances.
Original languageEnglish
Publisher[Publisher information missing]
Publication statusPublished - 2002

Publication series

ISSN (Print)0281-8477

Subject classification (UKÄ)

  • Fluid Mechanics and Acoustics


  • flow impedance
  • dynamic flow resistance
  • objective measurement
  • equivalent circuit
  • insertion loss
  • earplugs
  • HPD
  • hearing protectors
  • protection
  • hearing
  • attenuation
  • two-port
  • four-pole


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