Patent ID: 7653209

Claim:
A speaker apparatus comprising: a permanent magnet and a magnetic circuit, the magnetic circuit including an annular inner flux applicator and an annular outer flux applicator, the inner flux applicator and the outer flux applicator being arranged coaxially around a central axis and having a magnetic gap therebetween; a voice coil arranged in the magnetic gap around the central axis, the voice coil being supported such that the voice coil can vibrate when the inner flux applicator and the outer flux applicator produce magnetic flux in the magnetic gap; and a diaphragm coupled to the voice coil, the diaphragm being supported such that the diaphragm can vibrate when the voice coil vibrates, wherein at least one of the inner flux applicator and the outer flux applicator includes an annular first member having a first surface that faces toward the magnetic gap, the first member satisfying L 1 >W 1 where L 1 is a length of the first surface in a direction parallel to the central axis and W 1 is a width of the first member in a direction orthogonal to a central axis; an annular second member that is magnetically coupled with the first member and arranged on an outer side of the first member, the second member satisfying W 2 >L 2 where W 2 is a width of the second member in a direction orthogonal to a central axis and L 2 is a length of the second surface in a direction parallel to the central axis; and L 1 >L 2 .