| 摘要 |
[Problem] To achieve, when earphones are used, a frequency characteristic balanced in a broad band while making it easy to listen to sound from the earphones with external noise reduced and reducing sound leakage that may displease people therearound. [Solution] A sound guide tube is equipped with an ear tip, or a sound guide tube that fits the shape of an ear hole is used, thereby enhancing sound isolation. An internal space of a housing storing an electro-acoustic transducer and an external space are not acoustically communicated with each other. The internal space of the housing is sectioned into three spaces of a front space, an inner space, and a back space by the electro-acoustic transducer and an intermediate housing. The front space and the inner space are communicated with each other by a communication portion having a relatively small tubular space. The inner space and the back space are communicated with each other by a communication portion having a relatively small tubular space. |
