Patent attributes
A speaker and a magnetic circuit for a speaker, in which the high quality sound is obtained, are provided using a structure which is thin, light-weight and symmetrical in the vibration direction. In three sheets of layered magnets, the first magnet of the first layer and the third magnet of the third layer are arranged in the magnetic directions which repel each other, and the polarity of second magnet of the second layer is arranged perpendicularly to the polarity of the first and third magnets of the first and third layers at the top and bottom thereof. A voice coil wound near the center of a voice coil bobbin is arranged to oppose the second magnet of the second layer of the magnetic circuit composed of the three layers, and the same vibration systems composed of the diaphragms and edges are connected to both the ends of this voice coil bobbin. Accordingly, the speaker which has a vibration system that is symmetrical with respect to a center axis X-X perpendicular to the direction of a center axis of a voice coil is obtained.
