A speaker system having a structure in which the room surrounding the first diaphragm and the room adjacent to the second diaphragm are acoustically coupled. The second diaphragm has coating on a surface. Applying the coating to the second diaphragm enhances the reliability and performance of the speaker system. Besides, the diversely definable geometry of the diaphragm allows an electronic device employing the speaker system or the speaker module to have flexibility in design.