Dowson S P, McNeill H A, Torr G R
Division of Radiation Science and Acoustics, National Physical Laboratory, Teddington, Middlesex, UK.
Br J Audiol. 1991 Dec;25(6):419-22. doi: 10.3109/03005369109076618.
Coupler measurements were made to compare the performances of new-style Model 51 cushions and old-style MX41/AR cushions fitted to TDH39 earphones. In addition, the calibration, using an artificial ear, of TDH39 earphones fitted with Model 51 cushions was compared with the calibration, using a reference coupler, of the same earphones fitted with MX41/AR cushions. It is concluded that the two cushion types can be taken as identical when fitted to TDH39 earphones, except at 6 kHz where differences in earphone sensitivity of up to 2.8 dB were observed. Likewise, output hearing levels of TDH39 earphones measured using a reference coupler and an artificial ear were found to be similar, except at 6 kHz where differences of up to 6.4 dB were observed. The data support the decision by ISO to declare the Model 51 equivalent to the MX41/AR cushion, thereby requiring TDH39 earphones to be calibrated using a reference coupler whichever cushion is fitted. However, they also highlight once again the ill-defined performance of TDH39 earphones at 6 kHz.
进行了耦合器测量，以比较安装在TDH39耳机上的新型51型耳垫和老式MX41/AR耳垫的性能。此外，还比较了配备51型耳垫的TDH39耳机使用人工耳进行的校准与配备MX41/AR耳垫的同一耳机使用参考耦合器进行的校准。得出的结论是，当安装在TDH39耳机上时，除了在6 kHz处观察到耳机灵敏度差异高达2.8 dB外，这两种耳垫类型可视为相同。同样，使用参考耦合器和人工耳测量的TDH39耳机的输出听力水平也被发现是相似的，除了在6 kHz处观察到差异高达6.4 dB。这些数据支持了ISO宣布51型耳垫等同于MX41/AR耳垫的决定，从而要求无论安装哪种耳垫，TDH39耳机都要使用参考耦合器进行校准。然而，它们也再次凸显了TDH39耳机在6 kHz处性能定义不明确的问题。
