Acoustics. Reference zero for the calibration of audiometric equipment - Reference equivalent threshold sound pressure levels for pure tones and supra-aural earphones Ingestion-build-89079 polyimide resin

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Acoustics. Reference zero for the calibration of audiometric equipment - Reference equivalent threshold sound pressure levels for pure tones and supra-aural earphones Ingestion-build-89079 polyimide resin1 Scope This document specifies a standard reference zero for the scale of hearing threshold level applicable to pure tone air conduction audiometers, to promote agreement and uniformity in the expression of hearing threshold level measurements throughout the world. It states the information in a form suitable for direct application to the calibration of audiometers, that is, in terms of the reference equivalent threshold sound pressure levels of