| 摘要 |
PURPOSE:To increase the output of a horn speaker, and to miniaturize a device, by abutting the cooling side of an electronic cooling element at the inner peripheral plane of the base of a diaphragm, providing a large number of radial grooves at the front plane of a center pole, controlling the heating of the center pole, cooling a movable coil compulsorily, and permitting a large current to be conducted. CONSTITUTION:Since a leakage magnetic flux is cut off by the oscillation of a movable coil 10 in the forward and backward direction, an eddy current in a direction to stop the oscillation of the movable coil 10 is conducted at the front plane of a center pole 6, and intends to heat the center pole 6. And since the large number of radial stripe grooves 7 are formed at the front plane of the center pole 6, those stripe grooves suppress the generation of the eddy current, thereby the heating of the center pole 6 is suppressed. Therefore, the movable coil 10 can be maintained at a comparatively low temperature, even when conduction through the coil continuous for a long time. Furthermore, in the horn speaker, by performing the conduction to an electronic cooling element 10 simultaneously with the conduction to the movable coil 10, and setting the contact plane with the diaphragm 8 of the electronic cooling element 10 at a low temperature, the movable coil 10 can be cooled.
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