Impact on hearing aid targets of measuring thresholds in dB HL versus dB SPL

Gabrielle H. Saunders, Donald E. Morgan

Research output: Contribution to journalArticle

21 Scopus citations

Abstract

Audiometric measurements are traditionally made in dB HL, which by definition are specified relative to the sound pressure level (SPL) in a coupler. Real-ear dB SPL is then estimated by applying an average ear transform to the coupler value. However, individual variation in ear canal acoustics and variations in transducer placement strongly influence the dB SPL of signals arriving at the eardrum. In this paper, data from 1814 ears are presented, showing that the distribution of eardrum dB SPL for a fixed signal level varies across ears and across frequency by as much as 40 dB. The impact of this variance upon hearing aid targets computed with the NAL-NL1 fitting algorithm is examined by comparing the targets obtained from using an average transform with those obtained when audiometric data in dB SPL are obtained by applying individually measured real-ear-to-coupler difference (RECD) values to dB HL thresholds. The impact can be considerable.

Original languageEnglish (US)
Pages (from-to)319-326
Number of pages8
JournalInternational journal of audiology
Volume42
Issue number6
DOIs
StatePublished - Sep 2003

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Keywords

  • DB SPL versus dB HL
  • Hearing aid fittings
  • Real-ear measurement

ASJC Scopus subject areas

  • Language and Linguistics
  • Linguistics and Language
  • Speech and Hearing

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