Pelmear, P. L. and Hughes, Brenda J. (1974). British Journal of Industrial Medicine, 31, 304-309. Self-recording audiometry in industry. A study of initial and repeat audiograms of 118 drop forge employees using fixed frequency self-recording audiometry showed that the mean of the differences at the test frequencies 0 5, 1, 2, 3, 4, and 6 kHz ranges from 0 47 dB to + 0-61 dB. The largest standa...