Noise reducing device.

摘要

This invention is concerned with a device for reducing the external noise reaching the ear in extremely noisy places such as in the vehicle or construction sites. According to the present invention, the external noise is picked up by a microphone provided in the vicinity of an electro-acoustic transducer element, such as a headphone unit, provided in the vicinity of the wearer's ear, and the noise signal converted in this manner into electrical signals is produced as the acoustic signal by the electro acoustic transducer element. The transfer characteristics are controlled in such a manner that the produced noise signal prove to be an acoustic signal which is of the same frequency spectrum and opposite in phase with respect to the external noise reaching the wearer's acoustic meatus from outside to reduce the external noise reaching the acoustic meatus.