| 摘要 |
PURPOSE:To attenuate unrequired vibration rapidly by arranging a porous structure, consisting essentially of ceramics, as a sound absorbing material closely to the rear side of a diaphragm. CONSTITUTION:At the back side of cone type diaphragm 2 with edge 1 at the circumference and one-body dome type diaphragm 3, sound absorbing material 10 is provided on pole 5. To obtain this sound absorbing material 10, a powdery, granular, or lumpy ceramic material such as alumina and carborundum is mixed with a binder, such as a glassy substance, meltable at a high temperature and the mixture is sintered. Therefore, the sound absorbing material has sufficient sound absorbing performance because of its porosity and never vibrates against sound pressure; and ceramics are essentially used to decrease Q, so that unrequired vibration is attenuated rapidly. |
