Loudspeaker with motional feedback
US4727584A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Feb 14, 1986 |
| Grant date | Feb 23, 1988 |
| Priority date | — |
| Expiry date | Feb 14, 2006 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04R3/002
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
Improvements in a moving-coil loudspeaker system of the type incorporating motional feedback. An accelerometer mounted on the loudspeaker coil to develop the feedback signal is enclosed within an air-tight shield can to avoid low-frequency instability. High-frequency stability is enhanced by various means including use of a "trumpet" shaped speaker cone, an inverted (concave) dust cap, and theta-dependent cone variations such as providing clusters of holes through the speaker cone to alter the propagation of sound waves radially in selected sectors of the cone. Also disclosed is the use of weights placed on the loudspeaker coil in selected locations circumferentially with respect to the accelerometer to minimize instability effects.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.