Directional microphone assembly
US5878147A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Dec 31, 1996 |
| Grant date | Mar 2, 1999 |
| Priority date | — |
| Expiry date | Dec 31, 2016 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04R2410/07
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
A microphone capsule for an in-the-ear hearing aid is disclosed. The capsule can include a top plate having first and second spaced openings defining front and rear sound inlets, and a directional microphone cartridge enclosing a diaphragm. The diaphragm is oriented generally perpendicular to the top plate and divides the directional microphone cartridge housing into a front chamber and a rear chamber. A front sound passage communicates between the front sound inlet and the front chamber, and a rear sound passage communicates between the rear sound inlet and the rear chamber. Front and rear acoustic damping resistors having different resistance values are associated with the front and rear sound passages. The acoustic resistor pair provides a selected time delay, such as about 4 microseconds, between the front and rear sound passages. The use of two acoustic resistors instead of one levels the frequency response, compared to the frequency response provided by a rear acoustic damping resistor alone.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.