Abstract: On one surface of a piece of wooden sheet, a cloth or paper is adhered to make an adhered sheet. An approximately V-shaped notch is provided on the adhered sheet, the adhered sheet is wetted to be softened, and a lubricant which acts to keep water is impregnated thereinto. Edge portions of the notch are overlapped, and the adhered sheet is tentatively molded in an approximately horn shape by a first hot press molding. The adhered sheet is then dried, impregnated with thermosetting resin, and half-dried. The adhered sheet is subject to a second hot press molding. A moisture-proof agent is applied on the adhered sheet, a center hole for a voice coil and periphery are removed to make a speaker diaphragm having a predetermined dimension and shape.

Abstract: On one surface of a piece of wooden sheet, a cloth or paper is adhered to make an adhered sheet. An approximately V-shaped notch is provided on the adhered sheet, the adhered sheet is wetted to be softened, and a lubricant which acts to keep water is impregnated thereinto. Edge portions of the notch are overlapped, and the adhered sheet is tentatively molded in an approximately horn shape by a first hot press molding. The adhered sheet is then dried, impregnated with thermosetting resin, and half-dried. The adhered sheet is subject to a second hot press molding. A moisture-proof agent is applied on the adhered sheet, a center hole for a voice coil and periphery are removed to make a speaker diaphragm having a predetermined dimension and shape.

Abstract: On one surface of a piece of wooden sheet, a cloth or paper is adhered to make an adhered sheet. An approximately V-shaped notch is provided on the adhered sheet, the adhered sheet is wetted to be softened, and a lubricant which acts to keep water is impregnated thereinto. Edge portions of the notch are overlapped, and the adhered sheet is tentatively molded in an approximately horn shape by a first hot press molding. The adhered sheet is then dried, impregnated with thermosetting resin, and half-dried. The adhered sheet is subject to a second hot press molding. A moisture-proof agent is applied on the adhered sheet, a center hole for a voice coil and periphery are removed to make a speaker diaphragm having a predetermined dimension and shape.

Abstract: On one surface of a piece of wooden sheet, a cloth or paper is adhered to make an adhered sheet. An approximately V-shaped notch is provided on the adhered sheet, the adhered sheet is wetted to be softened, and a lubricant which acts to keep water is impregnated thereinto. Edge portions of the notch are overlapped, and the adhered sheet is tentatively molded in an approximately horn shape by a first hot press molding. The adhered sheet is then dried, impregnated with thermosetting resin, and half-dried. The adhered sheet is subject to a second hot press molding. A moisture-proof agent is applied on the adhered sheet, a center hole for a voice coil and periphery are removed to make a speaker diaphragm having a predetermined dimension and shape.

Abstract: A lighting device incorporates therein a loudspeaker including a diaphragm detachably fastened at an outer peripheral edge thereof to a cup-shaped frame. The diaphragm is made of a light-transmissive material. The lighting device has a light source such as a circular fluorescent lamp disposed in a space defined between the frame and the diaphragm. Light emitted from the circular fluorescent lamp passes through the light-transmissive diaphragm.

Abstract: A diaphragm for a loudspeaker is described, which essentially consists of a polyolefin resin such as propylene homopolymer or copolymer with an ethylenically unsaturated copolymerizable monomer or a 4-methylheptene-1 resin and short fibers of potassium titanate. The titanate fibers have an average fiber length of 10 to 30 microns and an average diameter of 0.1 to 0.5 micron.