Comparability of Two Commercially Available Artificial Mastoids

The new ANSI Standard S3.13-1972 for an artificial headbone lists in its appendix suggested threshold values for audiometric bone conduction calibration using a Beltone artificial mastoid. Two sets of comparisons were recently made between the Beltone 5A and the Brüel & Kjær 4930 artificial mastoids. The average values of these comparisons are given to provide numbers which may be related to those in the ANSI appendix when using a Brüel & Kjær artificial mastoid.