| 摘要 |
The ear defender includes a selectively operating sound absorbent and is to be applied to the outside of the ear during use. In this connection, the defender consists of a spacing cushion 3 which is made of elastic and porous material, which covers, and bears against, the ear and which allows sound to pass through. The outside of the cushion 2, as seen relative to the ear, covers a perforated disc 1 which bounds an otherwise closed cavity 2 for the purpose of forming a resonator chamber. The spacing of the cushion, the thickness of the perforated disc 1, the number and size of the holes, and the volume of the resonator chamber 2 are adjusted in accordance with the desired absorption property for a particular frequency range. <IMAGE> |
