Patent ID: 8306251
Filing Date: 2012-11-06
Classification: H04R

Abstract:
1. A narrow directional microphone comprising: an acoustic tube having a metallic cylindrical body; a unidirectional microphone unit arranged in a rear end part of the acoustic tube with a predetermined gap provided therebetween as a sound wave passage; and a unit positioning means which positions the microphone unit coaxially with the acoustic tube and provides the gap uniformly between an inside diameter of the acoustic tube and an outside diameter of the microphone unit, wherein the unit positioning means has a ring base plate which is arranged in a front surface peripheral edge part on a front acoustic terminal side of the microphone unit and is formed into a washer shape, and a plurality of leg pieces connectingly provided integrally with an outer peripheral edge of the ring base plate at approximately equal angular intervals in a circumferential direction and extending in an outer radial direction; the unit positioning means is formed of a metallic plate spring material; and the leg pieces are bent approximately at right angles from the outer peripheral edge of the ring base plate and are arranged in the gap.