高周波帯域の純音域値検査用受話器の試作について

抄録

Regarding the earphone used in audiometers standardized by JIS or ISO, it was impossible to examine the hearing of high frequency over 8, 000Hz. In this respect “Rudmose” high frequency audiometer was used together with the open-air type condenser earphone and high frequency generator or the amplifier.
The hearing of high frequency was examined by “Rudmose” ADF-4 system and the combination of MX-1E with a remodelled old audiometer. The results showed that ADF-4 was unable to suit for precise test of the hearing of high frequency because the structure of the earphone made the continuative frequency test impossible and the tone signal was difficult to hear. The combination of MX-1E and a conventional audiometer was also examined, but concerning the open-air type, the dip near 13, 000Hz couldn't be removed. There, the insert-type condenser earphone which lessened the distance between diaphragm and tympanum was used with the trial high frequency audiometer. It was confirmed that this earphone was practical because the high frequency sound was easily produced, and the output calibration was possible with 0.2cc coupler, and no dip was produced in the high freqency range.