so called "dolby digital" from tv cable box

Discussion in 'Playback Devices' started by KyleCT, Sep 20, 2005.

  1. KyleCT

    KyleCT Stunt Coordinator

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    I have my receiver set up to my cable box so that it accepts both analog and digital audio. I know the DD 5.1 works because for some HBO movies i get 5.1 sound (even though for most HBO channels i only get DD 2.0 which is lame).

    Then there are channels like espn (and usa playing jurrasic park right now) where it says it is dolby digital but it is only playing out of my center speaker. I cant even switch it to pro logic, its stuck on 1 channel DD. I can switch it to stereo mode so its only the two fronts playing a "DD" signal (which im not sure is even a stereo signal). At least with those HBO channels i can switch it to Pro Logic 2.

    Is this normal? I feel like its just advertising, like the tv station say its broadcast in dolby digital (which it is) but it seems to only be one channel!! I would just like to know if this is normal or if i dont have it set up right. Thanks
     
  2. ChristopherDAC

    ChristopherDAC Producer

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    It's a little surprising that you'd only be getting one channel, but not impossible. After all, Dolby's first mass-market digital product was AC-2, a 192kbps fixed-rate encoder for stereo sound via satellite TV [today's "Dolby Digital" is AC-3, a closely related system with more flexibility, which is being upgraded to "Dolby Digital Plus" or Extended AC-3 to provide better quality at lower bitrates]. Television broadcasting in stereo, though, has become standard, so you might well have something set up wrong. On the other hand, if both channels are the same [dual mono], the ProLogic matrix engine will send them both to the centre speaker as a mix.
     
  3. Paul D G

    Paul D G Screenwriter

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    Well, Dolby Digital is just a sound format, it can be 1 channel or 6.1, etc.

    I would think, however, a channel like ESPN is broadcasting in stereo, but not every cable channel does.

    You might want to verify you are getting these in stereo thru the analog outputs.

    It's worth mentioning that my old cable provider, COX, sent the coax signal in MONO. The only way to listen to a show in stereo was to use the RCA jacks. This was incredibly annoying to have to turn on my receiver just to watch a show in stereo. It's one thing if you're watching a movie, or a show where you want better sound. But not when you're just watching a sitcom, etc. My point is, there may be some stupid reason your cable provider is sending some of these channels in mono.

    -paul
     
  4. KyleCT

    KyleCT Stunt Coordinator

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    i have cox as well. my cable box is hooked up to my reciever through both coax and rca. if there is a digital signal the DD light on my reciever lights up, if there is an analog signal it just goes through RCA. just wierd that some channels are full DD 5.1 and some are just 1 channel. so is cox to blame?
     
  5. John Garcia

    John Garcia Executive Producer

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    The format broadcast is determined by the channel broadcasting, it has nothing to do with your cable company. It will vary from show to show and movie to movie.
     
  6. ScottCHI

    ScottCHI Screenwriter

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    yep, i have comcast and very few of my cable channels are actually capable of DD5.1. a couple of my HBOs and a couple of my Showtimes. and EWTN for some reason! maybe one or two more. my understanding is that it is because of cable bandwidth issues. why this seems to vary from market to market, i'm not certain, exactly.

    my receiver detects (almost) everything else as DD2.0 and i have it setup to use DPLII in this case.
     

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