While the 2mm parallel vent reduced the occlusion effect more than15dB, the short 2mm vent decrease that about 20dB. Conclusion The occlusion effect is observed below 1000Hz and is regardless with the intensity of bone conduction.

• 普通的2mm平行通气孔可使该频带的堵耳效应平均下降15dB以上,短的2mm通气孔则可使堵耳效应降低约20dB。 结论堵耳效应不因骨导信号的强度变化而改变,主要集中在1000Hz以下的低频;