Reference thresholds for the ER-3 A insert earphone

Laura Ann Wilber, Barbara Kruger, Mead C. Killion

Research output: Contribution to journalArticlepeer-review

53 Scopus citations


Several recent studies have demonstrated that the ER-3A insert earphone may sometimes be directly substituted, without recalibrating, for a TDH-39/MX-41AR earphone. However, most available data have not been reduced to a form suitable for establishing a revised estimate of the reference threshold levels. This article reports such a data analysis performed on the results of five recent studies. The mean data from the five studies are typically within 1 dB of the provisional reference threshold SPLs given by the ER-3A manufacturer for calibration in a (HA-1) 2-cc coupler. After converting the mean data to equivalent Zwislocki-coupler-type ear simulator SPLs at each of the reported audiometrie frequencies (125,250, 500,1000,2000, 3000,4000, 6000, and 8000 Hz), agreement within 1.5 dB was seen with the revised estimate of minimum audible pressures given by Killion [J. Acoust. Soc. Am. 63, 1501-1508 (1978)]. Either the manufacturer's provisional SPLs or the average results from this study may be used with little noticeable difference for most purposes.

Original languageEnglish (US)
Pages (from-to)669-676
Number of pages8
Journaljournal of the Acoustical Society of America
Issue number2
StatePublished - Feb 1988

ASJC Scopus subject areas

  • Arts and Humanities (miscellaneous)
  • Acoustics and Ultrasonics


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