Patent ID: 6091828
Filing Date: 2000-07-18
Classification: H04R

Abstract:
A dynamic microphone having a microphone case; a microphone unit having a first magnetic circuit having a first magnetic gap, a first diaphragm at an upper portion of said unit having a first voice coil for outputting acoustic signals therefrom; and a vibration detection unit having a second magnetic circuit with a second magnetic gap and a second diaphragm at a lower portion of said unit spaced from said first diaphragm with a voice coil, said dynamic microphone comprising:a first housing having a main section for housing said microphone unit herein, and a secondary section smaller than said main cylindrical chamber, the first housing having a bottom at the end of the secondary section, and a sleeve extending from said bottom, the first housing being mounting to said microphone case, said first magnetic circuit having a first cylindrical magnet, a side yoke around said first cylindrical magnet, and a tail yoke under said first cylindrical magnet;a spacer for forming an air chamber within said microphone case below said unit;said vibration detection unit having a housing with a ceiling, and an opening at the lower end thereof, said second magnetic circuit having a second cylindrical magnet, a ring yoke under said second cylindrical magnet, a second side yoke around said ring yoke, and a top yoke on said cylindrical magnet; and a film under said second side yoke along said opening, the film having a semicylindrical cross section, said second diaphragm held by said film under said ring yoke, said vibration detection unit being mounted inside of said sleeve; anda pathway for allowing pressure transfer from said air chamber to said first magnetic gap through a first opening at said sleeve, a second opening at said bottom, and a third opening at said tail yoke.