Directional microphone
US3940575A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Mar 3, 1975 |
| Grant date | Feb 24, 1976 |
| Priority date | — |
| Expiry date | Mar 3, 1995 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04R1/38
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
A pressure gradient directional microphone of the moving coil type in which the acousto-mechanical function of the transducer is achieved by a vibratile diaphragm the major area of which is of coneiform shape and the central portion of which is of dome shape and of significantly smaller area and provides a surround for attaching the coil. One side of the diaphragm is exposed to the sound field surrounding the microphone, and the other side is exposed to two cavities, one of relatively large volume behind that portion of the diaphragm which is of coneiform shape, and a second behind the dome portion which is sufficiently smaller that it is unnecessary to provide any phase-shift action for any sound pressure generated therein. The diaphragm is secured at its periphery to a support ring having a plurality of openings formed therein which serve as acoustic ducts from the ambient into the larger cavity.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.