The invention discloses a
woofer comprising a round flat-panel-shaped vibrating diaphragm, the vibrating diaphragm comprises a rigid ball top located at the center position and a ring folding part located at the edge position, and the ball top is of a flat-panel-shaped structure. The
woofer further comprises an outer shell, the vibrating diaphragm is combined on the upper lateral face of the outer shell, wherein a plurality of voice coils arranged in a distributed mode are combined on the surface, close to the outer shell, of the vibrating diaphragm, the voice coils drive the vibrating diaphragm to vibrate in a balanced mode, each
voice coil corresponds to an independent
magnetic circuit system, and the
magnetic circuit systems are contained and fixed in the outer shell. According to the structure, the thickness of the
woofer is reduced, and therefore the woofer of the structure can be applied to thin-type electronic devices and is favorable for
thinning of the electronic devices.