| 摘要 |
PURPOSE: To improve a sound quality by cancelling magnetic fluxes induced between a voice coil and upper/lower part plates through an AC magnetic flux cancelling means so as to minimize the bending of sound pressure. CONSTITUTION: A speaker is composed of a DC magnetic field generator including magnets 112 and 115, the upper and lower part plates 113, 114, the voice coil 123, etc., to make the magnetic path of a DC magnetic field. This speaker is provided with the AC magnetic flux cancelling means 130, which generates AC magnetic fluxes with a 180 phase difference between with AD magnetic fluxes induced between the voice coil 123 and the upper/lower part plates 113 and 114. Thereby the generated induced magnetic fluxes are cancelled to minimize the bending of the sound pressure to improve the sound quality. In addition an induced current is reduced at the upper/lower part plates to reduce a heat loss and a hysteresis loss. |
