Hat with sound playing function

A hat with sound playing function, the hat comprising:

• a hat body;
• a brim extending from the hat body and having a supporting layer and a decorating layer covering a surface of the supporting layer;
• and
• at least one slim speaker between the supporting layer and the decorating layer, the at least one slim speaker includes a capacitive double-diaphragm speaker comprising:
• a conductive plate having a plurality of through openings;
• a first electret diaphragm on a lower surface of the conductive plate, the first electret diaphragm having a first film body and a first electrode layer, wherein the first film body has static charges and the first electrode layer is formed on a lower surface of the first film body;
• a plurality of first spacers between an upper surface of the first film body and the conductive plate;
• a second electret diaphragm on an upper surface of the conductive plate, the second electret diaphragm having a second film body and a second electrode layer, wherein the second film body has static charges and the second electrode layer is formed on an upper surface of the second film body;
• and
• a plurality of second spacers between a lower surface of the second film body and the conductive plate.