| 摘要 |
PURPOSE:To obtain a high-quality speaker for the high-pitched tone by blocking virtually the back part of the folding diaphragm via the cavity magnetic pole with groove. CONSTITUTION:Grid magnetic pole 10 in the front and cavity magnetic pole 11 with groove at the back sandwiches permanent magnet 12 between at their side adge parts, thus forming the magnetic field within the excited opposing cavities. Thus folding diaphragm 13 is held by holding frame 15 in non-contact to poles 10 and 11. For pole 10 the range partitioned by dotted line 16 features the grid form with outside radiation of radiation sound of + or -PO; while pole 11 forms comb-line groove 17 in the range partitioned by dotted line 16' to then form the cavity. Projection part 18 of pole 11 is opposed to grid 19 of pole 10, which forms the shortest cavity magnetic path with the magnetic flux density of 5-6 gauss. The cross-sectional area of each part of these magnetic poles is decided so that no magnetic saturation is caused by the inflow and pass of the main magnetic flux. Plural number of groove 17 of pole 11 are inserted in series to diaphragm 13. In this constitution, a high- quality and high-tone speaker is obtained with the wide-angle dispersion of more than 60 deg. possible up to 15Hz on the horizontal plane. |
