ACTIVE NOISE REDUCTION IN HEADPHONE

摘要

PROBLEM TO BE SOLVED: To provide active noise reduction in a headphone.SOLUTION: An active noise reduction headphone comprises: a rigidity cup-shaped shell having an inner surface and an outer surface, in which the inner surface encloses a mold cavity achieving an opening part and further pick ups a sound in at least three positions distributed at a constant interval on the outer surface; a microphone constructed so that a first electric signal for reproducing the picked up sound is provided; an active noise control filter constructed so that a second electric signal is provided on the basis of the first electric signal; and a speaker which is arranged at the opening part of mold cavity and is set so that the sound is generated from the second electric signal. The active noise control filter has a transfer characteristic which is set so that noise transferred passing through a shell beyond the internal surface from the outer surface is reduced by the sound generated by the speaker.SELECTED DRAWING: None