PURPOSE: To oscillate reproduced natural sound with high fidelity by providing plural sets of speakers each with a specified voice coil inserted between a magnetic gap where the magnetic poles of a center pole, a yoke and a center piece are arranged to be homopolar counter electrodes.
CONSTITUTION: Between magnetic gaps 4 where a center pole 1a, a yoke 3a and a pole piece 2a act as N-poles, a counter clockwise voice coil 5a and a clockwise voice coil are inserted, and between magnetic gaps 4 where a center pole, a yoke and a pole piece act as S-poles, a counter clockwise voice coil 5a and a clockwise voice coil are inserted. Then the counter clockwise voice coil 5a is combined with a cone 7, and magnets 6 are provided by facing so as to joint-S-poles so that the magnetic poles of the pole piece 2a and the yoke 3a are N-poles and that the center pole 1a is also an N-pole. thereby, the eddy current or inversion of magnetic lines of force is generated and the magnetic liens of force forms an eddy current in the shape of an ellipse so that the voice coil oscillates freely in the whole area when a voice current is made to flow.
HAMAO NORIMITSU
YAMAKI SHUSUKE
