| 摘要 |
PURPOSE:To ensure the holding and to improve the characteristics, by holding a speaker unit case with tapered or radius plane having smaller diameter backward to a front recess of ear through the elasticity of ear shell. CONSTITUTION:A dynamic speaker unit 10 consisting of a voice coil and diaphragm plate located in a magnetic gap is contained in a case 12 made of light metal such as aluminum and hard plastic together with a sound absorbing member 13. The case 12 has smaller diameter backward with tapered or radius plane. The front surface of the case 12 is covered with a cover 14 having perforated elasticity or acoustic transmission such as foamed urethane, and the diameter of the cover is made greater than the case 12. The case 12 is inserted to an external ear shell (b) between the ears (e) and (f) to hold it with the elasticity of cartilage and muscline so that the cover 14 opposes to the ear (a). Thus, the acoustic energy hardly goes externally and the ear speaker can be held the ear shell surely. The acoustic characteristics can be improved. |
