Overview
EN ISO 389-5:2006 (CEN endorsement) defines reference equivalent threshold sound pressure levels (RETSPLs) for pure tones in the extended high‑frequency range 8 kHz to 16 kHz. It provides standard RETSPLs and calibration specifications for air‑conduction audiometers when used with specific earphones and ear‑simulator/adapter combinations. The standard supports uniform, traceable audiometer calibration for extended high‑frequency audiometry.
Key topics and technical requirements
- Scope: RETSPL values of pure tones from 8 kHz to 16 kHz for calibration of air‑conduction audiometers.
- Specified earphones: Values are given for specific models:
- Etymotic Research ER-2 (with ER1-14A eartips) - RETSPLs (dB re 20 µPa): 8 kHz 19; 9 kHz 16; 10 kHz 20; 11.2 kHz 30.5; 12.5 kHz 37; 14 kHz 43.5; 16 kHz 53.
- Sennheiser HDA 200 (closed circumaural) - RETSPLs (dB re 20 µPa): 8 kHz 17.5; 9 kHz 19; 10 kHz 22; 11.2 kHz 23; 12.5 kHz 27.5; 14 kHz 35; 16 kHz 56.
- Dependence on measurement setup: RETSPLs depend on earphone model and the ear simulator + adapter used (e.g., IEC 60318‑1, IEC 60711, IEC 60318‑2, ISO 389‑2 adapters).
- Calibration notes and tolerances:
- Values are arithmetic means of laboratory medians and rounded to the nearest 0.5 dB.
- Sennheiser HDA 200 shows temperature dependence (notably at 12.5 kHz); recommended calibration temperature 21 °C to 25 °C.
- Headband force for HDA 200: 10.0 ± 1.0 N with specified positioning (earphone separation 145 mm, headband height giving 130 mm center distance).
- Eartip insertion for ER‑2: insert deeply so outer end is flush with bottom of the concha.
- Supplementary info: Annex A explains derivation from multiple laboratory investigations; Annex B lists RETSPLs for the legacy Koss HV/1A earphone (for information).
Applications and users
- Calibration laboratories performing traceable audiometer calibration in the extended high‑frequency range.
- Audiometer and earphone manufacturers implementing calibration procedures and specifications.
- Clinical audiology and occupational health services requiring validated extended‑high‑frequency hearing tests.
- Research laboratories studying high‑frequency hearing or validating test equipment.
Related standards (normative references)
Keywords: EN ISO 389-5:2006, RETSPL, audiometer calibration, 8 kHz to 16 kHz, extended high-frequency audiometry, Etymotic ER-2, Sennheiser HDA 200, audiometric standards.
