Image Number 3 for United States Patent #6522759.
A reduced-size speaker for generating sound waves in wide low frequency audio region includes a cylindrical main body which is open at the top and bottom surfaces, a top lid being provided on the top surface of the main body and a circular ring-shaped base, which has a hole in its center, being provided on the bottom surface of the main body. A circular sound pipe is provided approximately in the center of the top lid and extends from the upper surface of the main body through the inside of the main body. A disc-like film is provided over the opening of the hole of the base, which is located at the outer side with respect to the main body, the disc-like film being held between the base and a circular ring-shaped bottom lid. A disc-like sound generator is provided in the opening of the hole of the base, which is located at the inner side with respect to the main body, with a circular ring-shaped damper provided in between. A plurality of supporting members are attached to the bottom lid in order to mount the speaker on a mounting surface.