Speaker diaphragms, manufacturing methods of the same, and dynamic speakers

A dynamic speaker including an approximately horn-shaped speaker diaphragm of a piece of wooden sheet, and an approximately dome-shaped cap covering a center hole formed in a center portion of the speaker diaphragm,

• wherein a cloth or paper is adhered on one surface of the wooden sheet;
• an adhered sheet including the wooden sheet and the cloth or paper is made into an approximately horn shape by overlapping edge portions of an approximately V-shaped notch formed in advance;
• a constituent material of a moisture-retaining material which is impregnated when forming the adhered sheet into the approximately horn shape is remained inside the adhered sheet;
• the edge portions of the approximately V-shaped notch of the adhered sheet are adhered with thermosetting resin, and the thermosetting resin is attached over entire front and back surfaces of the adhered sheet;
• and
• a moisture-proof agent is applied to cover the thermosetting resin on the entire front and back surfaces of the adhered sheet.

A manufacturing method of a speaker diaphragm where a speaker diaphragm is manufactured from a piece of wooden sheet, comprising:

• a lubricant impregnating step of wetting and softening the wooden sheet, and impregnating a lubricant which acts to keep water in the wooden sheet;
• a first pressing step of tentatively molding the wooden sheet in a predetermined shape;
• a first drying step of drying the wooden sheet tentatively molded in the predetermined shape;
• a thermosetting resin impregnating step of impregnating thermosetting resin into the wooden sheet dried in the first drying step;
• a half-drying step of half-drying the wooden sheet impregnated with the thermosetting resin;
• a second pressing step of molding the wooden sheet half-dried in the half-drying step in a predetermined shape by heating and pressing;
• and
• a moisture-proof agent applying step of applying a moisture-proof agent to the wooden sheet molded in the predetermined shape.