A speaker of the present invention arranges the grooves on the dome, which forms a leakage passage that helpful for the air current to circulate between the grooves and the voice coil, and therefore, the air current in the voice coil can timely circulate through the leakage passage between the voice coil and the dome. The inner and outer air pressure difference of the voice coil can be effectively decreased after the amplitude of the vibrating system increases, and the influence on the performance of the speaker imposed by the unbalance of the inner and outer air pressures of the voice coil is avoided.