Matrix Pro Logic Encoder?

Discussion in 'Computers' started by LeeH, Jun 27, 2003.

  1. LeeH

    LeeH Stunt Coordinator

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    I was wondering if there is a program out there that allows you to do matrix encoding on your pc.
    thanks,
    Lee
     
  2. Wayne Bundrick

    Wayne Bundrick Cinematographer

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    If you can't find anything you might be able to fake it yourself depending on the tools you have at your disposal. This is how Dolby describes a Dolby Surround encoder:

    The encoder takes the left and right inputs and passes them through untouched except for an all pass phase shift network in each channel which delays the signal from input
    to output by two cycles (720 degrees) at all frequencies. The Center channel input is first reduced in level by 3 dB and then sent to both the Left and Right channels before the all pass networks. The Surround channel is reduced in level by 3 dB, band pass filtered with a 100 Hz high pass and 7 kHz low pass filter, encoded with a Dolby B-type processor which is modified to have only 5 dB of noise reduction instead of the normal 10 dB, and then phase shifted 630 degrees. The result is a signal that is +90 degrees with respect to the Left, Center and Right channels. An inverted signal of the 630 degree surround signal is also created. It has a total phase shift of 810 degrees. The result of this is two surround signals, one +90 degrees and one -90 degrees with respect to the front channels. The -90 degree signal is fed to the Left channel output and the +90 degree signal is fed to the Right channel output. The net phase shift from left to right for a surround signal is 180 degrees, out of phase.
     

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