Surround sound system
US4392019A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Dec 19, 1980 |
| Grant date | Jul 5, 1983 |
| Priority date | — |
| Expiry date | Dec 19, 2000 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04S2420/11
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
A system for surround sound utilizes three audio channels two of which are either in phase of 180.degree. out of phase for all angles of elevation and azimuth of the incident sound and which can be decoded to give good quality stereo reception. The third channel contains the signal indicative of the "front-back" information and this signal is chosen to yield the best quality of surround sound reception consistent with minimum interference to the quality of mono and stereo reception for a given type or range of program material. Preferably, the third channel is phase shifted by 90.degree. with respect to the phase of the other two channels. The three audio channels can be derived directly from three directional microphones or can be derived from the Ambisonics `B` format in which case an encoding matrix of the following form is used: ##EQU1## where .SIGMA., .DELTA. and T are the signals in the three audio channels and W, X and Y are the input signals to the encoding matrix.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.