INDISTINCT SOUND REDUCING DEVICE, HEARING AIR USING THE SAME, EARPHONE FOR AUDIO, EAR PIECE AND ELECTRO-ACOUSTIC TRANSDUCER

摘要

PROBLEM TO BE SOLVED: To provide an indistinct sound reducing device, etc. that can sufficiently reduce indistinct sound in an external acoustic meatus while preventing oscillation when negative feedback is performed by using a microphone for external acoustic meatus.;SOLUTION: An indistinct sound reducing device has a sound output unit 40 having an opening portion 48 formed therein, a sound collecting unit 50 having an opening portion 54 formed therein, a sound guide unit 60 through which the opening portions 48, 54 intercommunicate with the space in the external acoustic meatus, and a negative feedback unit for performing negative feedback from the sound collecting unit 50 to the sound output unit 40. The internal space of the sound guide unit 60 is compartmented into spaces 100, 101 and a common space 102 by a separation unit 61. The separation unit 61 is formed so that the common space 102 has a predetermined length L2. The sound output from the opening portion 48 propagates through the space 100 and the common section 102 into the external acoustic meatus, the sound in the external acoustic meatus propagates through the common section 102 to the opening portion 54, and the sound output from the opening portion 48 propagates through the space 100, the common space 102 and the space 101 to the opening portion 54.;SELECTED DRAWING: Figure 2;COPYRIGHT: (C)2016,JPO&INPIT