Earphones in extended high-frequency audiometry and ISO 389-5

Area of Science:

• Audiology
• Acoustics
• Hearing Science

Background:

• Standardized audiometric equipment calibration is crucial for accurate hearing assessments.
• Existing reference equivalent threshold sound pressure levels (RETSPL) may not cover all commercially available earphones, especially in the extended high-frequency (EHF) range.
• The ISO 389-5 (2006) standard provides guidelines for the 8 to 16 kHz range, but requires updated data for specific earphone models.

Purpose of the Study:

• To determine common reference equivalent threshold sound pressure levels (RETSPL) for earphones used in the extended high-frequency (EHF) range.
• To provide data for updating calibration standards for audiometric equipment.
• To facilitate future revisions of international standards like ISO 389-5.

Main Methods:

• Hearing threshold sound pressure levels were measured up to 20 kHz using the Sennheiser HDA 200 audiometric earphone.
• Measurements were compared against the ISO 389-5 (2006) norm and existing research data.
• A cohort of 223 otologically normal subjects aged 5-25 years participated in the hearing threshold determination.

Main Results:

• Measured hearing thresholds demonstrated good agreement with previous studies.
• The data collected provides specific RETSPL values for the Sennheiser HDA 200 earphone in the EHF range.
• The findings validate the methodology for establishing RETSPLs for new audiometric earphones.

Conclusions:

• The study's results are pertinent to the international standard ISO 389-5 for audiometric equipment calibration (8-16 kHz).
• The generated data can inform future updates to RETSPL values for both circumaural and insert audiometric earphones.
• Accurate EHF RETSPLs are essential for reliable hearing screening and diagnosis in audiology.