Loudspeaker having a laminate diaphragm of three layers
 A loudspeaker having a diaphragm including first and second layers and a core sandwiched between the layers, the core being firmly secured to the inner surface of each layer so as to form a unitary structure therewith, a drive assembly causes the diaphragm to vibrate in accordance with a varying electrical input signal fed thereto, and a support is provided for supporting the diaphragm and drive assembly. The layers are formed of materials through which the velocity of propagation of a longitudinal wave is greater than 5000 m/sec, and the core is formed of materials having a shearing elastic modulus Gco which exceeds the value ##EQU1## WHERE E.sub.f is the longitudinal elasticity of each of the layers, PA1 t.sub.f is the thickness of each of the layers, PA1 t.sub.c is the thickness of the core, and PA1 l is the length across the surface of the diaphragm. 
Sony Corporation
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inventional inventional inventional
Atsushi Jun Masaaki
Matsuda Kishigami Nishimura