| 摘要 |
PURPOSE:To enable higher harmonic distortions produced in the reproduced sound pressure of the speaker to be removed by using the specific ferromagnetic material to a part or the whole of the magnetic circuit members forming a magnetic gap. CONSTITUTION:A center pole 2 and a magnet 3 are disposed on a disc-form yoke 1 and further a ring-form plate 4 is disposed on the magnet 3. A voice coil 6 is positioned in the magnetic gap 5 between the pole 2 and plate 4. Ferromagnetic materials 8, 9 including Ti, Nb, V or Al are provided on the upper outside circumferential part of this pole 2 and the inside circumferential surface of the plate 4. When audio current flows in the coil 6 to generate an AC magnetic field 7 around the same, the respective portions of the pole 2 and plate 4 near the gap 5 are magnetized even by the magnetic field 7 with the DC magnetic field by the magnet 3 as a center. This AC magnetization curve forms the minor loop linearized by the ferromagnetic materials 8, 9 of magnetic domains of small sizes, thereby reducing sound pressure distortions. |
