Patent ID: 9094748
Filing Date: 2015-07-28
Classification: H04R

Abstract:
1. A dynamic microphone unit comprising: a diaphragm vibrating upon receiving acoustic waves; a voice coil fixed to the diaphragm and disposed in a magnetic gap, the voice coil vibrating together with the diaphragm; a magnetic circuit generating a magnetic field in the magnetic gap; and a rear air chamber communicating with a back side space of the diaphragm via the magnetic gap, wherein a member forming the magnetic circuit includes holes formed therein for connecting the back side space of the diaphragm with the rear air chamber, and wherein the magnetic circuit is formed by a magnet, a yoke and a pole piece that are fixed across the magnet, and a ring yoke to which the yoke is fixed and whose inner periphery surface faces an outer periphery surface of the pole piece to form the magnetic gap together with the pole piece.