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Expired Canadian patentCanada

Surround-sound system

CA 1330200 C · Owner: Lucasarts Entertainment Company · Inventors: Holman, Tomlinson

CIPO record

Overview

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Its claims, description and drawings are in the Canadian Patents Database.

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Abstract From the Canadian patent

Spectral imbalance (alteration in timbre) when playing home video versions of motion pictures is overcome by re-equalization according to a unique correction response curve which compensates for the equalization for playback in large theater-sized auditoriums inherent in motion picture soundtracks. Surround-sound home playback of motion pictures is enhanced by employing main channel loudspeakers that produce generally direct sound fields and surround channel loudspeakers that produce generally diffuse sound fields. In addition the reproduced, surround-sound channel is further enhanced by decreasing the interaural cross-correlation of the surround-sound channel sound field and by reducing …

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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

  • Granted June 14, 1994. A Canadian patent filed before October 1, 1989 lasted 17 years from grant, so its term ended June 14, 2011.
  • We check Canadian rights only. A patent in its family in another country could still be in force: check its family on Google Patents.
FiledSeptember 27, 1989
GrantedJune 14, 1994
Term endedJune 14, 2011
Patent numberCA 1330200 C
Classification (IPC)H04S3/02 +1 more

Timeline

Timeline From CIPO dates

19901993199619992002200520082011Application filedSep 27, 1989Patent grantedJune 14, 1994Term endedJune 14, 2011

Sources & verification

Everything on this page comes from the CIPO record linked above. Contains information licensed under the Open Government Licence – Canada.