为遮隔来自外部的噪声,市场上出售许多种耳机。大多是用来堵在两耳上的耳罩,使外来噪声变小。也可以说是一种防御型、消极型的。对较大音响虽有效,对小的音响则效果较小。 法国国立科学研究所工学音响研究室研制一种新型防噪声耳机。称噪声对抗型耳机。它能测出外来噪 To shield the noise from the outside, many kinds of earphones are on the market. Mostly used to plug the ears in the earmuffs, the external noise smaller. Can also be said to be a defensive, negative type. Although effective for larger speakers, smaller speakers are less effective. France National Institute of Science and Engineering Laboratory of sound research and development of a new type of noise-proof headphones. Known noise-resistant headphones. It can detect external noise