Overview
EN ISO 389-2:1996 is an internationally recognized standard that addresses acoustics related to the calibration of audiometric equipment. Specifically, it defines reference equivalent threshold sound pressure levels (RETSPL) for pure tones when using insert earphones, with a focus on the Etymotic Research ER-3A earphones coupled with ER-3-14 ear inserts. This standard supplements ISO 389:1991 (soon to be ISO 389-1), which focuses primarily on supra-aural earphones.
The standard provides essential calibration reference levels required to ensure accuracy and consistency in audiometric testing, particularly when using insert earphones. It acts as a cornerstone for professionals in audiology and electroacoustics aiming for precise hearing threshold measurements.
Key Topics
- Reference Equivalent Threshold Sound Pressure Levels (RETSPL): Establishes baseline sound pressure levels for pure tones delivered via insert earphones, essential for accurate hearing assessments.
- Audiometric Calibration: Provides the reference zero point for calibrating pure-tone audiometers, ensuring measurement consistency across devices and laboratories.
- Insert Earphone Specifications: Applies to Etymotic Research ER-3A earphones with ER-3-14 foam ear inserts, detailing coupling methods and acoustic coupling conditions.
- Acoustic Coupler and Simulators: Defines coupler types compliant with IEC 126 and occluded-ear simulators per IEC 711 for measuring sound pressure levels accurately.
- Frequency Range: Covers a wide range of audiometric frequencies, from 125 Hz up to 8,000 Hz, with interpolated values for select frequencies.
- Measurement Methods: Based on empirical data from international studies using hearing threshold techniques and established coupling devices.
Applications
- Audiometer Calibration: EN ISO 389-2 is essential for laboratories and clinics calibrating audiometers equipped with insert earphones to meet international accuracy standards.
- Hearing Assessments: Ensures that hearing threshold tests using insert earphones reflect proper reference sound pressure levels, reducing occlusion and interaural effects.
- Audiology Research: Provides standardized calibration parameters facilitating consistent research data across studies involving insert earphone audiometry.
- Equipment Manufacturing and Quality Control: Helps manufacturers calibrate and validate insert earphone audiometric devices, improving device reliability.
- Noise Impact Studies: Supports investigations on how noise affects human hearing by ensuring precise baseline calibration in audiometric evaluations.
Related Standards
- ISO 389-1: Reference equivalent threshold sound pressure levels for pure tones and supra-aural earphones (re-issue of ISO 389:1991).
- ISO 389-3: Reference levels for pure tones and bone vibrators.
- ISO 389-4: Reference levels for narrow-band masking noise, complementary to RETSPL data.
- IEC 126:1973: Standard for acoustic coupler used in calibrating earphones coupled by ear inserts.
- IEC 711:1981: Specifies occluded-ear simulators to simulate ear canal acoustic conditions.
- ISO 389-5 to ISO 389-7: Additional parts covering extended frequencies, short-duration signals, and hearing thresholds under various listening conditions.
Keywords: audiometric calibration, reference equivalent threshold sound pressure level, RETSPL, insert earphones, ER-3A earphones, ER-3-14 ear inserts, audiometer standards, pure-tone audiometry, IEC 126, IEC 711, hearing assessment calibration, audiology standards.
