| 摘要 |
A dynamic type unit is provided to minimize hum and a howling sound by correcting a wavelength of a frequency generated in driving a diaphragm with an exact sinusoidal wave. A dynamic type unit comprises a main magnet(11), a diaphragm(15), a moving coil(14), assistant magnets(21, 24, 27), and assistant plates(32, 33, 34). The main magnet forms a basic magnetic field circuit. The diaphragm and the moving coil form a vibrometer. The assistant magnets are installed in a top, a bottom, and a side of the main magnet. The assistant plate is attached in one surface of the assistant magnet. One surface of the assistant magnet is faced with the main magnet. A dimension of the assistant plate is equal to a dimension of the assistant magnet. |
