Methods: We conducted comparative studies on the acoustic property including frequency response affected by different sizes, length of the sound bore, vent of hard earmould.

• 方法：在其它条件不变的情况下，对同一耳不同长度的耳模，改变其声孔、气孔形状、口径及加用阻尼等进行测量，并对其声学特性进行分析。