Construction and Calibration of an Improved Bone‐Conduction Receiver for Audiometry

The construction of an acoustically shielded bone conduction unit is described. The masses and springs have been proportioned for optimum purity of wave form at low frequency, and for extension of the high frequency range to over 12,000 cycles. The precautions taken in preparing an acoustical loudness‐balance calibration are described, and the reproducibility of observations is considered. Methods of specifying the response of production units are shown.