A speaker including a frame, a diaphragm fixed to the frame through a first edge, a voice coil, a magnetic circuit, and a suspension holder fixed to the frame through a second edge is disclosed. The first and the second edges are spaced apart, and substantially symmetrical in shape with respect to the space between them. The inner periphery of the suspension holder and the inner periphery of the diaphragm are fixed to a part of the voice coil which is located outside of the magnetic gap of the magnetic circuit. The magnetic circuit has a magnet provided outside of the bottom of the frame. The outer periphery of the magnetic extends at least beyond the center of the second edge. The magnetic gap of the magnetic circuit is disposed inside of the frame, above a bottom surface of the frame.
1. A speaker comprising:
a concave frame having a lower surface on a lower portion thereof, and an opening on an upper portion thereof;
a diaphragm having an inner periphery, an outer periphery, and a bottom surface, said diaphragm disposed in said opening of said frame and fixed to an edge of said opening by a first edge;
a voice coil on said bottom surface of said diaphragm;
a suspension holder having an inner periphery and an outer periphery, said suspension holder disposed inside of said frame at said bottom surface of said diaphragm and fixed to said frame by a second edge; and
a magnetic circuit including:
a yoke having a columnar protrusion extending from an upper surface of a plate member,
a ring-shaped magnet having an outer periphery, said magnet laminated on said yoke; and
a ring-shaped plate having an inner periphery, and an outer periphery laminated on said ring-shaped magnet;
wherein:
said first and second edges are spaced apart, and substantially symmetrical with respect to a space therebetween;
at least a portion of said magnetic circuit is disposed outside of said frame and below said lower surface of said frame;
said outer periphery of said ring-shaped magnet extends beyond a center of a width of said second edge;
said inner periphery of said ring-shaped plate and said columnar protrusion extend into said frame from said lower surface to an area within said frame midway between said lower surface and said opening, so as to form a magnetic gap between said inner periphery of said ring-shaped plate and said outer periphery of said columnar protrusion;
at least a portion of said voice coil is movably disposed inside of said magnetic gap; and
said inner periphery of said suspension holder and said inner periphery of said diaphragm are fixed to a portion of said voice coil which is outside of said magnetic gap.
2. The speaker of claim 1 , wherein said inner periphery of said suspension holder and said inner periphery of said diaphragm are directly fixed to said portion of said voice coil which is outside of said magnetic gap.
3. The speaker of claim 1 , wherein said inner periphery of said suspension holder and said inner periphery of said diaphragm are indirectly fixed to said portion of said voice coil which is outside of said magnetic gap.
4. The speaker of claim 1 , wherein said ring-shaped magnet is disposed below said lower surface of said frame; and said outer periphery of said ring-shaped magnet extends at least beyond an outer periphery of said second edge.
5. The speaker of claim 1 , wherein said magnetic circuit further comprises a plate-shaped top plate laminated on said columnar protrusion of said yoke.
6. The speaker of claim 5 , wherein said ring-shaped magnet is disposed below said lower surface of said frame; and said outer periphery of said ring-shaped magnet extends at least beyond an outer periphery of said second edge.
7. The speaker of claim 1 , wherein a lower part of a side surface of said frame includes a step section for receiving said second edge, and an air vent disposed below said step section.
8. The speaker of claim 7 , further comprising a dust filter disposed in said air vent.
9. The speaker of claim 8 , wherein said dust filter is disposed outside of said frame.