| 摘要 |
PURPOSE:To improve sound quality by mounting a motional feedback use sensor on part a circumferential surface of a voice coil bobbin and mounting a balance member on the circumferential surface except the mounting part of the sensor so as to vibrate smoothly the voice coil and the diaphragm. CONSTITUTION:A magnetic air gap 12 is formed between a pole 11 of a yoke 1 and a plate 3 and voice coil 5 is inserted into the gap 12. The voice coil 5 consists of a bobbin 5a and a coil 5b, a notch 17 is formed on part of a circumferential surface of the bobbin 5a and a motional feedback use sensor 10 is mounted thereon. Then in order to take a weight balance of the voice coil 5, a balance ring 27 is arranged on the circumferential surface except the mounting part of the sensor 10. Thus, the voice coil 5 is correctly and smoothly vibrated and then a diaphragm 7 is vibrated correctly and smoothly, then the motional feedback control of the speaker is properly executed. |
