ISO 389-8:2004 Preview
Acoustics -- Reference zero for the calibration of audiometric equipment -- Part 8: Reference equivalent threshold sound pressure levels for pure tones and circumaural earphones
ISO 389-8:2004 specifies reference equivalent threshold sound pressure levels (RETSPLs) for pure tones in the frequency range from 125 Hz to 8 kHz, applicable to the calibration of air conduction audiometers equipped with a particular model of circumaural earphones (SENNHEISER HDA 200).
Some notes and references on the derivation and the test conditions used to determine the recommended reference levels are given in Annex A and the Bibliography.
The sound attenuation of the earphone is given in Annex B. For speech audiometers of types A-E and B-E, the correction figures of the earphone for a free-field equivalent output are given in Annex C.