Patent attributes
In the speaker of the invention, a circular outer magnet type magnetic circuit 8, and a diaphragm 13 to which a circular voice coil 14 driven by the circuit is fixed are held on a rectangular frame 1. The circular outer magnet type magnetic circuit 8 is configured by: a yoke 9 in which a rectangular flange 9b is disposed in one end of a circular center pole 9a; a plate-like magnet 10 which has a circular center hole 10a, which is placed with forming a circular annular gap around the yoke center pole 9a, and which has a rectangular outer shape that is substantially identical with the outer shape of the yoke flange 9b; and a circular annular pole piece 11 which is substantially equal in inner diameter to the magnet center hole 10a, in which the outer diameter is substantially equal to short side dimensions of the yoke flange 9b and the magnet 10, and which cooperates with the yoke flange 9b to clampingly hold the magnet 10. A circular magnetic gap 12 is formed between the yoke center pole 9a and the pole piece 11. The magnet 10 is split into two portions in a center area in the longitudinal direction.
