A diaphragm is disclosed in the invention, which comprises a one-piece diaphragm body and a plurality of mass blocks mounted on the diaphragm body. Each of the mass blocks substantially has the same radial distance from the center of the diaphragm. The mass blocks are divided into three or more arrays each of which includes one or more mass blocks. the arrays are distributed along the circumference direction of the diaphragm body, and the mass blocks in each array are distributed along the circumference direction of the diaphragm. The mass blocks are elastic and made of materials with internal damping, such as rubber, silicone or foam rubber. At least one of the mass blocks is connected to an annular roll fixed on the peripheral edge of the diaphragm body, and the mass blocks are bonded to the diaphragm body.