| 摘要 |
PURPOSE:To expand a reproducing band with simple structure by using one magnetic circuit so as to drive two nodes of a rectangular flat diaphragm. CONSTITUTION:In Figure, 17 is a cylindrical coil bobbin supported by a damper 9 and a voice coil 10 is wound on this coil bobbin 17. The diameter of this coil bobbin 17 is almost the same as an interval L between two node lines l1 and l2 produced on the rectangular flat diaphragm 1 in the primary resonance frequency f1 and the upper ridge of this coil bobbin 17 is fixed by the nodes l1 and l2 of the rectangular flat diaphragm 1. Since one magnetic circuit is used in this way and the coil bobbin 17 drives the two node lines l1 and l2 of the rectangular falt diaphragm 1, the primary resonance mode is eliminated and a flat sound pressure frequency characteristic is obtained up to the secondary resonance frequency f2 producing the secondary resonance mode, thereby expanding the reproducing band. |
