| 摘要 |
PURPOSE:To improve sound pressure specially in a low froquency sound range by composing a sounding body with the aid of laminating a piezo-electric porcelain plate and a diaphragm and arranging the piezo-electric transducers of inverse characteristic and of concentric circle on an identical surface. CONSTITUTION:The piezo-electric transducers 11 and 12 having the concentric circle and the invers characteristic are arranged on the identical surface. The transducer consisting of the piezo-electric porcelain plate 11 is displaced to lift the transducer consisting of the piezo-electric plate 12 to an upper part in a graphic and the transducer consisting of the piezo-electric porcelain plate 12 is displaced to exhaust air to the upper part in the graphic. Therefore effect appears in the low frequency sound range and that makes the frequency characteristic of the sound pressure flat. Simultaneously to that, the resonance frequency of the transducer consisting of the piezo-electric porcelain plate 12 appears to fills up the intermediate collapse of first and second resonance frequency of the transducer consisting of the piezo-electric porcelain plate 11. As the result, the flat resonance frequency characteristic can be obtained extending from 330 to 2 kHz.
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