ISO 389-4:1994 Preview
Acoustics -- Reference zero for the calibration of audiometric equipment -- Part 4: Reference levels for narrow-band masking noise
This standard was last reviewed and confirmed in 2015. Therefore this version remains current.
Specifies reference levels for narrow-band masking noise presented by air conduction 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 corresponding pure-tone frequencies. Data are given for noise bandwidths of one-third and one-half octaves.