Stinson M R, Shaw E A, Lawton B W
J Acoust Soc Am. 1982 Sep;72(3):766-73. doi: 10.1121/1.388257.
At frequencies greater than 2 kHz the acoustic impedance at the human eardrum is an unreliable indicator of the behavior of the middle ear system because of the complicated configuration of the ear canal and tympanic membrane. The energy reflectance at the eardrum, however, when obtained from measurement of the standing wave ratio (SWR) in the canal, is relatively insensitive to irregularities in the anatomical layout at the higher frequencies. Measurements of sound pressure distribution in 13 normal ear canals have been analyzed in a critical manner to provide new values of SWR, with estimates of error, between 5 and 10 kHz. At the higher frequencies these values tend to be appreciably greater than those previously reported. At 8 kHz, for example, the new values of SWR range between 18 and 24 dB as compared with earlier values which are in the vicinity of 13 dB. The correspondingly greater values of energy reflectance (60%-78%, as compared with 40%) are more consistent with known properties (mass, size, vibrational patterns) of the human eardrum. These results are applicable to the development of network models representing the middle ear system.
在频率高于2 kHz时，由于耳道和鼓膜的复杂结构，人耳鼓膜处的声阻抗并不能可靠地指示中耳系统的行为。然而，当通过测量耳道中的驻波比（SWR）来获得鼓膜处的能量反射率时，在较高频率下，它对解剖结构布局的不规则性相对不敏感。对13个正常耳道中的声压分布测量结果进行了严格分析，以提供5至10 kHz之间新的驻波比值及误差估计。在较高频率下，这些值往往明显高于先前报道的值。例如，在8 kHz时，新的驻波比值在18至24 dB之间，而早期的值在13 dB左右。相应更高的能量反射率值（60%-78%，而早期为40%）与人类鼓膜已知的特性（质量、大小、振动模式）更为一致。这些结果适用于代表中耳系统的网络模型的开发。
