High frequency Bekesy audiometry. I: equipment and calibration

A simple, straightforward and inexpensive conversion of the high-frequency (HF) range (up to 20 kc/s) of the Grason-Stadler E-800 Bekesy audiometer is described, incorporating as transducer a 1/2-inch condenser microphone loosely coupled to the ear canal by an adjustable headband, which provides also for a standard audiometric earphone-cushion unit on the non-test ear. A free field calibration is recommended. The system has a dynamic range of 135 db. Step-by-step instructions are provided for the conversion and for calibrations. Repeated calibrations of a prototype unit showed acceptable stability and validity. The HF E-800 audiometer could provide a valuable and cost-effective source of HF diagnostic information for the audiologist.