Can someone explain HK Logic 7

Discussion in 'Archived Threads 2001-2004' started by Robert_Dufresne, Apr 7, 2002.

  1. Robert_Dufresne

    Robert_Dufresne Stunt Coordinator

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    I keep reading about HK Logic 7 and how it is so

    wonderfull. Could someone please tell me what it

    is ???

    Thanks

    Robert
     
  2. Harold_C

    Harold_C Stunt Coordinator

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    Assuming it's what I think it is [​IMG] Logic 7 would be a generic matrix decoder designed to extract center back surround signals from the surround channels of any 5.1 channel recording (or even the Dolby Pro Logic derived surround chanels from a 2-channel recording). It basically ensures that, if you have center back speakers, something will be coming out of them.
    It's basically an alternate version of the Dolby Surround EX decoder that will distribute surround sound information to the surround array anytime the system is configured with a center back speaker or speakers. If you want, you can think of it as different flavor of Dolby Surround EX decoder for which no royaly is required.
    Depending on what mode is selected (usually not user adjustable) the matrix algorithms in these generic decoders can work better than the Dolby Surround EX decoders because they tend to distribute the sound more evenly (in terms of volume) among all of the available surround channels. Dolby Surround EX sometimes collapses the surround field a bit too much into the center back speaker(s), much in the same way that a Pro Logic decoder sometimes collapses the front soundstage too much into the center channel. This would be the case whenever there is a significant percentage of equal amplitude in-phase information shared by the surround channels. This would be interpreted as "center" information and sent to the center back channels, when you might prefer that it be distributed evenly among all the surround speakers for a more diffuse soundfield. Having the soundfield collapse into speakers behind you isn't what you really want when the intent of the soundtrack is to envelop you in a broad diffuse surround soundfield.
    I'd have to read the HK owners manual, but more than likely, Logic 7 is always active and will always extract center back information unless a flag embedded in the digital datastream activates a different extended surround decoder (i.e. Dolby Surround EX or DTS-ES). The Logic 7 would work (automatically) in conjunction with Dolby Digital 5.1, Dolby Pro Logic, or any other mode.
    I know that Rotel has a very good version of this type of extended surround decoder (called Rotel XS) in their new processors. From reading a number of owners manuals from other brands recently, it appears that most all of the 6.1 channel processors have something along these lines. They were developed because the officially licensed Surround EX decoders were initially limited to THX licensed processors, something that has just recently changed. One nice benefit is that these decoders work with the early Dolby Surround EX discs in which Dolby failed to set the Surround EX flag required to turn on the Surround EX decoder!
     
  3. Selden Ball

    Selden Ball Second Unit

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    Selden
    A minor addendum:

    It isn't a "generic" dematrixing.

    Harman-Kardon's Logic 7 is licensed from Lexicon (now also a part of Harman International). Lexicon's Logic 7 has been around much longer than the new movie rear channel standards.
     
  4. Robert_Dufresne

    Robert_Dufresne Stunt Coordinator

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    Thank guys , now I know
    Robert[​IMG]
     

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