Acoustics — Reference zero for the calibration of audiometric equipment — Part 4: Reference levels for narrow-band masking noise
声学——测听设备校准用参考零点第4部分:窄带掩蔽噪声参考电平
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.