| 摘要 |
1,152,377. Sound generator. NIPPON GAKKI SEIZO K.K. 22 Dec., 1966 [5 April, 1966; 3 May, 1966], No. 57577/66. Heading G5J. [Also in Division H4] A sound generator, for use in an electronic musical instrument, comprises a diaphragm 1 which is adapted for flexural but not reciprocating movement by being mounted such that its periphery is clamped between a pair of frame plates 2, with a layer of precompressed cushioning material 3 located between the diaphragm and the plates. The flat diaphragm 1 is made of foamed polystyrene (specific gravity 0À03) and the cushion is made of polyurethane foam, rubber or foamable synthetic rubber. The precompression is effected by means of a separate spacer 4 or a spacer integral with one plate (Fig. 5, not shown), its length being chosen in dependence on the desired compliance. The thickness of the cushion is less than half the normal amplitude of vibration of the diaphragm. An electromagnetic driver 15 is attached to the centre of the diaphragm. |
