This International Standard specifies reference levels for the calibration of narrow-band masking noise presented by air con-duction from an earphone in pure tone audiometry. The data are given in terms of levels to be added to the reference equivalent threshold sound pressure levels for the correspond-ing pure-tone frequencies when the masking earphone is placed on the appropriate acoustic coupler or artificial ear.
Data are given for noise bandwidths of one-third and one-half octaves.
Some notes on the derivation of the reference levels are given in the annex.