ISO International Standard

This document describes a method for the objective determination of the audibility of tones in environmental noise.

This document is intended to augment the usual method for evaluation on the basis of aural impression, in particular, in cases in which there is no agreement on the degree of the audibility of tones. The method described can be used if the frequency of the tone being evaluated is equal to, or greater than, 50 Hz. In other cases, if the tone frequency is below 50 Hz, or if other types of noise (such as screeching) are captured, then this method cannot replace subjective evaluation.

NOTE      The procedure has not been validated below 50 Hz.

The method presented herein can be used in continuous measurement stations that work automatically.