Multi-channel audio surround sound from front located loudspeakers
CA 2543614 C · Owner: Britannia Investment Corporation · Inventors: Polk, Matthew S. Jr.
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
A surround sound reproduction system uses a series of filters and a system of main and sup-speakers to produce phantom rear surround sound channels or a phantom surround sound effect from a loudspeaker system or pair of loudspeaker systems located in front of the listener. The sound system includes left and right surround input signals, and left and right front input signals. Left and right sub-speakers, and left and right main speakers are located in front of a listening location. Spacing between respective main and sub-speakers is approximately equal to ear spacing for an average person. The input to the left sub-speaker comprises the right surround signal subtracted from the left …
Read the whole patent
Listed from its CIPO record in Patent Yard's archive of Canadian patents past their term. Its claims, description and drawings are in the CIPO record and on Google Patents, and the Claude kit works from them.
Why it's free to use
- Filed October 25, 2004 and granted August 27, 2013. A Canadian patent filed from October 1, 1989 lasts 20 years from filing, so its term ended October 25, 2024.
- Certificates of supplementary protection extend only drug patents, and it isn't classified as one.
- We check Canadian rights only. A patent in its family in another country could still be in force: check its family on Google Patents.
Timeline
Timeline From CIPO dates
Sources & verification
Official CIPO records
Everything on this page comes from the CIPO record linked above. Contains information licensed under the Open Government Licence – Canada.