Speaker, speaker system, stereo speaker system, and on-vehicle stereo speaker system

摘要

A speaker includes a vibrating body having an annular valley portion recessed rearward and a diffuser having an annular or arcuate base part, which is positioned so that an end of the base part on the side of the vibrating body is opposed to the valley portion. The base part is provided, at the end on the side of the vibrating body, with one or more recessed parts from which distance to the vibrating body is larger than a distance of the other portion of the end to the vibrating body, each of the recessed parts being formed in any one of a sine-wave shape, a triangular-wave shape and an arc shape.