• The effect of fequency tolerance on audiometer accuracy 

      Guelke, R. W.; Floyd, J. D.; Van Zyl, F. J. (Health & Medical Publishing Group, 1977)
      Investigations into the methods used to calibrate audiometers reveal that the 6000 Hz frequency is particularly liable to yield inconsistent results when calibrated in the usual way. It is shown that the TDH39 telephone ...