| 摘要 |
PURPOSE:To increase the reproducing band, by providing a reinforcement beam along the longer side and on the surface of a diaphragm having a sandwich structure in that the surface material is bonded on both surfaces of a flat and rectangular core material. CONSTITUTION:The surface materials 2 and 2' are bonded on both surfaces of a flat and rectangualr core material 1 to obtain a base material. Then reinforcement beams 3 and 3' are bonded on the lower surface of the base material along the longer side of the base material to obtain a flat and rectangulr diaphragm 4. The diaphragm 4 is supported by a frame via an edge member, and at the same time a coil bobbin is attached at the center of the lower surface of the diaphragm 4 to drive the diaphragm 4. Owing to the reinforcement beams, the rigidity of the diaphragm is icreased to increase both the primary and secondary resonance frequencies. This results in an increase of the reproducing band. |
