A speaker includes a vibrating unit, and a magnetic circuit unit. The vibrating unit includes a diaphragm, an elastic plate coupled with the diaphragm, and a voice coil electrically connecting to the elastic plate. The vibrating unit is mounted to and positioned by the magnetic circuit unit. A projection of the diaphragm on the magnetic circuit unit is disposed within an outline of the magnetic circuit unit. The speaker has no frame or any structure with a frame configuration, which makes the magnetic circuit unit larger and more powerful.