Abstract: A diaphragm for electro-acoustic transducer comprising a core member of honeycomb structure made of either a thin film of a metal or a high molecular material, and a skin member bonded to at least one side of this honeycomb core structure and being prepared by the use of aromatic polyamide fibers having a high tensile strength, a high Young's modulus and a high Young's modulus-to-weight ratio and reinforced by a thermo-setting resin. Such diaphragm has a high Young's modulus, an improved mechanical strength and a wide frequency range of piston motion, and presents reduced distortion throughout a wide frequency range, and has a superior transition characteristic, whereby a good sound reproduction characteristic is obtained.

Abstract: A vibrating member made of a thin metal plate and adapted to be used in an acoustic transducer such as a loudspeaker or microphone is diffused at least partially with an inorganic substance to improve the acoustic characteristics thereof, particularly the high frequency range.

Abstract: A composite diaphragm for a speaker comprises a boron layer formed on a metal foil such as titanium foil, in which a layer of a low melting point metal such as aluminum or magnesium is interposed between the metal foil and the boron layer to provide high rigidity, high elasticity and high bonding strength between the metal foil and the boron layer.

Abstract: A diaphragm for use in a loud speaker is constructed of a substrate formed into a diaphragm configuration from a thin plate or a sheet composed of an organic or an inorganic substance, and a coating layer made of boron, or, an alloy of which a major component is boron or a chemical compound of boron, being provided onto at least the surface of said substrate.