| 摘要 |
PURPOSE:To obtain both satisfiable output sound pressure and directivity by fitting a flat cross-shaped diaphragm provided with a voice coil to the top surface of a magnetic circuit having four L-shaped magnetic gaps. CONSTITUTION:On the top surface of a plate 12 having a cross-shaped pole piece 13 stood stop, four rectangular top plates 15 are arranged on four rectangular magnets 14. Between those plates 15 and pole piece 13, a magnetic circuit 17 having four L-shaped magnetic gaps 16 is constituted and on this circuit 17, a flat cross-shaped diaphragm 18 is arranged. On the reverse surface of the diaphragm 18, a spiral printed voice coil 19 is formed opposite to the gaps 16. Consequently, the large area of the diaphragm is secured because of the long sides of the diaphragm 18 to obtain large output sound pressure, and directivity in both lateral and longitudinal directions is improved because of the short sides. |
