Audiometric zero for air conduction using manual audiometry.

Thresholds of hearing of 76 subjects in the age range 18-24 years were measured using manual audiometers. Particular attention was paid to the otological selection of subjects. In spite of precautions the testers introduce some variation in results, and it is suggested that tester variation might account for differences between various manual audiometry studies and automatic audiometry studies. When tester variation is included there is no significant difference between results of this manual study and that undertaken with automatic audiometers by Robinson, Shipton, and Hinchcliffe, except that our average threshold is higher at 0.5 kHz. We support their main recommendation for adjustment of standards at 0.5 and 6 kHz.