| 摘要 |
PURPOSE:To inhibit the reproduction of unnecessary input signals without changing the constituting parts other than the diaphragm, etc., improve the quality of the reproduced sound, by selecting the size and material of the dust cap glued on the upper surface of the diaphragm. CONSTITUTION:A diaphragm 12 is fixed to a frame 9 coupled with a magnetic circuit 4 and a voice coil 13 is coupled with the central part of the diaphragm 12, and the coil 13 is inserted into the magnetic gap 15 of the magnetic circuit 4. Then, a dust cap 16 is glued on the upper surface of the diaphragm 12 and the inner diameter d1 of the cap 16 is set in such a way that the inner diameter d1 and the effective vibrating diameter d0 of the diaphragm 12 satisfy a relation, d1=0.4-0.8d0. Moreover, a material having a large internal loss and a small specific resonance is used for making the cap 16, and the sound pressure generated at the central part of the diaphragm 12 is absorbed by the cap 16 by covering a part of the diaphragm 12 which resonates at a frequency higher than the high frequency with the cap 16. In this way, the reproduction of unnecessary input signals is inhibited and the necessity of any filter circuit, etc., is eliminated, and thus, the constitution of the sound synthesizing device is simplified. |
