SPEAKER, SPEAKER SYSTEM, AND SPEAKER CONTROL METHOD

摘要

PROBLEM TO BE SOLVED: To provide a speaker system or the like with high linearity. SOLUTION: The speaker system 1 comprises an amplifier section 20, a speaker section 30 and a feedback circuit 40. The speaker section 30 drives its diaphragm in response to a drive signal received from the amplifier section 20. A light emitting element and a light receiving circuit to optically detect the displacement of the diaphragm are placed in the speaker section 30. The light receiving circuit detects a change in the position of the diaphragm from an emitted position of a reflected light from the light emitting element via a cap fixed to the diaphragm and converts the change into an electric signal to provide an output of the signal to the feedback circuit 40. The feedback circuit 40 generates an error signal on the basis of the electric signal and feeds it back to the amplifier section 20. The amplifier section 20 amplifies a signal corresponding to a difference between the input signal from a signal source 10 and the feedback signal from the feedback circuit 40 and supplies the amplified signal to the speaker section 30.