Patent ID: 8144917

Claim:
A dynamic type unit with a multiple magnetic field system, which comprises: a main magnet adapted to constitute a basic magnetic circuit; a diaphragm and a moving coil which are adapted to constitute a vibration system in the basic magnetic circuit; and at least one auxiliary magnet mounted at least one of an upper portion, a lower portion and a lateral portion of the main magnet in such a fashion as to be spaced apart from the main magnet, wherein the total value of a magnetic flux density of the auxiliary magnet is 25-100% of a magnetic flux density value of the main magnet, and wherein the magnetic flux density values of the upper and lateral auxiliary magnets are 25% of the magnetic flux density value of the main magnet, respectively, and the magnetic flux density value of the lower auxiliary magnet is 50% of the magnetic flux density value of the main magnet.