A speaker includes a yoke defining a receiving cavity therein, a first magnet received in the receiving cavity of the yoke, a second magnet received in the receiving cavity of the yoke and opposite to the first magnet, a first coil surrounding the first magnet, a second coil surrounding the second magnet, and a diaphragm drove to vibrate by both of the first coil and the second coil. A shape of the first coil is approximately a horse's hoof and defines a first linear side, a flexuous side and a pair of first arc sides coupled with two ends of the first linear side and two ends of the flexuous side.