Calibration data for a circumaural headset designed for hearing testing.

Standard reference threshold levels for the new Telephonics circumaural headset using TDH−39 and TDH−50 earphones have been measured. Because the circumaural headset cannot be mounted meaningfully in the same suspension with a conventional supra‐aural assembly, it was necessary to perform loudness balancing at threshold. The circumaural headset, furthermore, cannot be calibrated on the standard, NBS‐9A coupler. Thus, it was necessary to develop a new coupler and to refine a new coupler measurement procedure. Data on the comparative attenuation and the subjective voltage and power sensitivities of the two headset designs are reported. Objective data from coupler measurements are also reported. Implications of these findings are discussed and reference‐threshold sound‐pressure levels for the two headset types using both the TDH−39 and the TDH−50 earphones are reported. In general, it was observed that the clincial use of the new Telephonics circumaural headset affords significantly greater attenuation of ba...