Patent ID: 7769192

Claim:
A speaker system comprising: a magnetic circuit; a cylindrical shaped voice coil unit generating oscillation in the magnetic circuit; an oscillating plate extending in a circular conical shape from a outer peripheral surface of the voice coil unit, a dust cap connecting to the oscillating plate covering an open face of the voice coil unit on a side surrounded by the oscillating plate; a plurality of linking members connecting to the voice coil unit, each of said linking members extending toward a center axis of the voice coil unit; and a detection unit comprising: a first component part fastened to the linking members, said first component part positioned at the center axis of the voice coil unit closer to the voice coil unit than the dust cap; and, a second component part positioned facing the first component part, said second component part is independent of the voice coil unit such that the first component part is held between the second component part and the dust cap; wherein the detection unit optically detects the oscillations of the voice coil unit by means of a light that courses between the first component part and the second component part.