Frank T, Chaffinch J O, Svitko C S
Ear Hear. 1986 Aug;7(4):273-5. doi: 10.1097/00003446-198608000-00009.
Coupler output levels were obtained for six repeated placements of a TDH-49 earphone in a P/N 51 cushion on a NBS 9A coupler and a B-71 and B-72 bone vibrator on a mechanical coupler from 250 to 4000 Hz using experienced (N = 9) and untrained subjects (N = 9) who were later trained. The largest minus the smallest coupler output levels across the repeated placements were determined for each subject and transducer at each frequency. The coupler output level differences were similar across subject group for each transducer at each frequency and were not reduced by training. The median and mean differences for the TDH-49 were less than 1 dB, consistent across frequency, and the highest range score never exceeded ANSI tolerance levels. The median and mean differences for the B-71 and B-72 were higher than for the TDH-49 but did not exceed ANSI tolerance levels and were frequency dependent corresponding to the high frequency resonance slope of the vibrator. However, for some subjects, the differences exceeded ANSI tolerance levels for both vibrators, especially for the B-72 at 250, 2000, and 4000 Hz.
在NBS 9A耦合器上的P/N 51耳垫中，以及在机械耦合器上的B - 71和B - 72骨振器上，使用有经验的受试者（N = 9）和未经训练的受试者（N = 9）（这些未经训练的受试者后来接受了训练），从250至4000赫兹对TDH - 49耳机进行了六次重复放置，以获取耦合器输出水平。针对每个受试者和每个频率的每个换能器，确定了重复放置过程中最大耦合器输出水平减去最小耦合器输出水平的值。每个频率下每个换能器的耦合器输出水平差异在不同受试者组之间相似，并且训练并未使其减小。TDH - 49的中位数和均值差异小于1分贝，在各个频率上保持一致，且最高范围得分从未超过美国国家标准学会（ANSI）的公差水平。B - 71和B - 72的中位数和均值差异高于TDH - 49，但未超过ANSI公差水平，并且与振器的高频共振斜率相关，具有频率依赖性。然而，对于一些受试者，两种振器的差异都超过了ANSI公差水平，特别是B - 72在250、2000和4000赫兹时。
