A speaker is provided in the present disclosure. The speaker includes a magnetic circuit system, a vibration system and an auxiliary system suspending the vibration system above the magnetic circuit system. The magnetic circuit system comprises a yoke, permanent magnets assembled on the yoke, and a magnetic gap near the permanent magnets. The yoke comprises an upper surface for assembling the permanent magnets, a lower surface opposite to the upper surface, side surfaces connecting the upper surface and the lower surface, and communication conduits extending through the upper surface and the side surface to communicate the magnetic gap and the space outside the speaker.