Carter N L, Upfold G
National Acoustic Laboratories, Chatswood, Australia.
Am Ind Hyg Assoc J. 1993 Jun;54(6):307-12. doi: 10.1080/15298669391354711.
The Real Ear Attenuation at Threshold (REAT) of E-A-R (slow recovery) from earplugs was determined, using three methods of presentation of the test tones during a single fitting of the earplug. The three presentation methods were (a) sound-field listening; (b) TDH49 earphone mounted in the shell of a circumaural earmuff; and (c) TDH49 earphone in a Model 51 cushion. Thresholds were tested once under each condition. Test frequencies were .125, .25, .5, 1.0, 2.0, 3.0, 4.0, 6.0, and 8.0 kHz. Comparison of the REAT values measured by the three methods indicated that the mean REAT obtained by the reference (Sound Field) method could be reliably estimated by both earphone methods for frequencies up to and including 4.0 kHz. However, the Sound Field REAT values of individual subjects could not be predicted reliably from their REAT determined by either type of earphone presentation. It is concluded that TDH49 earphones in standard audiometric earcushions could be used to check the overall effectiveness of slow recovery foam earplugs in the workplace. Further research is necessary to ascertain whether the audiometric earphone/earcushion test could be modified to achieve satisfactory reliability in assessing earplug fitting in individual workers.
在耳塞单次适配过程中，使用三种测试音呈现方法测定了E-A-R（慢回弹）耳塞的阈值处真实耳衰减（REAT）。这三种呈现方法分别为：(a) 声场聆听；(b) 安装在环绕式耳罩外壳中的TDH49耳机；(c) 置于51型耳垫中的TDH49耳机。每种条件下阈值测试一次。测试频率为0.125、0.25、0.5、1.0、2.0、3.0、4.0、6.0和8.0千赫兹。三种方法测得的REAT值比较表明，对于高达并包括4.0千赫兹的频率，两种耳机方法均可可靠地估计由参考（声场）方法获得的平均REAT。然而，无法根据通过任何一种耳机呈现方式确定的REAT可靠预测个体受试者的声场REAT值。结论是，标准听力测试耳垫中的TDH49耳机可用于检查慢回弹泡沫耳塞在工作场所的整体有效性。有必要进行进一步研究，以确定听力测试耳机/耳垫测试是否可以改进，从而在评估个体工人的耳塞适配情况时获得令人满意的可靠性。
