Light weight and low magnetic leakage loudspeaker

A loudspeaker, comprising:

• a yoke having a bottom part and a ring part fixed on the periphery of said bottom part;
• a primary magnet having a first surface and a second opposing surface, said first surface located in contact with said bottom part of said yoke;
• a first central top plate located on said second opposing surface of said primary magnet;
• a surrounding top plate located on said ring part of said yoke and maintaining an air gap with said first central top plate such that said primary magnet, said first central top plate, said surrounding top plate and said yoke forming a closed-loop magnetic circuit;
• a thin magnet located on said first central top plate, which repels said primary magnet, to lessen the magnetic leakage, the thin magnet having a thin magnet thickness of 1.5 mm or less;
• a second central top plate of high magnetic flux conducting material located on said thin magnet for reducing magnetic leakage above said thin magnet,
• a bobbin;
• a voice coil wounded on said bobbin and located within said air gap, wherein said voice coil may interact with said closed-loop magnetic circuit to produce a force, whose direction is perpendicular to the direction of the tangent of said voice coil and to the direction of said closed-loop magnetic circuit;
• and
• a diaphragm connected to said bobbin for sounding by said force.