Normal hearing threshold determined by manual and self-recording techniques.

Data are presented relating to the thresholds of three different samples of normally hearing subjects, which indicate that the British standard and recommended ISO reference zero for audiometers is insufficiently stringent by approximately 3 dB over the frequency range 0.5 to 6 kcps. Determinations of threshold, made with the same audiometer and the same earphone placement, by a conventional manual method and by a self‐recording method showed the latter to give an average threshold more sensitive than the manual usage gave by less than 1 dB. The inaccurate nature of current procedures for audiometer calibration employing a single subjective correction for all receivers of a particular pattern is stressed.