| 摘要 |
<p>Permanent magnets (2, 3) each having N poles and S poles magnetized alternately in stripe are respectively arranged on the front and back sides of a diaphragm (1), and a conductor circuit (4) is wired on the diaphragm (1) along the stripe magnetic poles of the permanent magnets (2, 3). Consequently, an effect for preventing generation of an echo can be attained. The diaphragm (1), the permanent magnets (2, 3), the conductor circuit (4), a spacer (5), and iron plates (6, 7) are contained in a baffle (8).</p> |
