Directional loudspeaker system
US4823908A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Apr 28, 1986 |
| Grant date | Apr 25, 1989 |
| Priority date | — |
| Expiry date | Apr 28, 2006 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04R2217/03
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
A parametric loudspeaker utilizes nonlinearity of air relative to ultrasonic waves for producing an audio frequency having super directivity, and to thus provide a limited listening area public address system subject to a large listening area by safeguarding listeners by the provision of a framework for intercepting powerful ultrasonic waves and an acoustic filter. The depth and energy consumption of the parametric loudspeaker are reduced by the use of a reflective plate. Arbitrary directivity is obtained by the provision of a mechanism to move an ultrasonic wave radiator or the reflective plate. The parametric loudspeaker and any other loudspeaker may be combined.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.