No sound from rear speakers in pro logic mode.

Discussion in 'Archived Threads 2001-2004' started by Tan_U, Oct 30, 2001.

  1. Tan_U

    Tan_U Stunt Coordinator

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    I have a couple of problems. I have a Harmon Kardon AVR110 with JBL NSP1 speaker package. I'm watching cable T.V. and theres no sound coming from the rear in pro logic mode but it's fine in 5 channel stereo mode. The other problem is that the speakers are humming, is this because I'm watching cable?
     
  2. PaulKH

    PaulKH Second Unit

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    Pro Logic receiver mode doesn't guarantee anything from the rear speakers. The signal from your cable must include the encoding to indicate which portion of the signals should go to the rears. Little content on cable has pro logic encoding. Some commercials, a few shows, but not much.
     
  3. Rick_Brown

    Rick_Brown Second Unit

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    As long as your cable is providing a stereo signal and as long as the program you are watching is in stereo, you should hear something from the surrounds, even if much fainter than the fronts. I suggest that you re-check your setup.
     
  4. NathanP

    NathanP Supporting Actor

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    Yes, but many show are encoded with Dolby Surround. I.E. The Simpsons, and that should work fine.
    Sometimes DPL I will screw up on rears, make sure to keep them a bit louder than usual.
     
  5. Jeremy Anderson

    Jeremy Anderson Screenwriter

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    It's possible that your cable company isn't sending a stereo feed... in which case everything will come from the front. I have digital cable, and about half of the channels are not stereo (and you can tell).
     
  6. Sean Conklin

    Sean Conklin Screenwriter

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    quote: As long as your cable is providing a stereo signal and as long as the program you are watching is in stereo, you should hear something from the surrounds, even if much fainter than the fronts. I suggest that you re-check your setup.[/quote]
    Rick, this isn't true. The stereo signal MUST be encoded with Pro-Logic for your receiver to send ANYTHING to the rears. If you want all your speakers to have sound from a non PL signal you must force the receiver to process the signal, hence 5 Channel Stereo!
    Just because you set your receiver to PL doesn't automatically mean your going to hear anything from your rears, faint or otherwise.
    If you are watching TV and you have your receiver set to Pro-Logic, and the signal you are getting is "encoded" with PL, then you will know if you can hear your mains and center but not necessarily your rears, it just depends on the material.
    I have watched PL on TV and the rears are dead, then on pops a commercial and all of a sudden my system is Alive!
    Most PL on TV is weak at best and even though a show might be in PL doesn't mean your going to hear anything from your rears, it just depends on the show.
    Commercials actually have the most active PL on TV(Usually)
    Tan: I wouldn't be worried about this, I wouldn't count on too many shows to be in PL, As long as your surrounds are working in digital PL or 5.1(DVD) I wouldn't worry about it.
    I'm still upset that the NFL is not broadcast in PL!!
    ------------------
    Sean
    "I was thinking of the immortal words of Socrates who said.......I drank what?"
    [Edited last by Sean Conklin on October 31, 2001 at 01:29 PM]
     
  7. Sean Conklin

    Sean Conklin Screenwriter

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    quote: It's possible that your cable company isn't sending a stereo feed... in which case everything will come from the front. I have digital cable, and about half of the channels are not stereo (and you can tell).[/quote]
    Not only that but if your receiver is set to PL, and you are getting a non PL signal or mono, the only speaker you will hear is your center speaker.
    Setting your receiver to stereo when no PL is present will give you the best sound.Or 5 channel stereo would be good too!
    Also a broadcast can be in stereo, and not contain PL.In which case if you set your receiver to PL, only your center speaker will work, if this happens, set receiver to stereo or 5 Channel stereo.
    ------------------
    Sean
    "I was thinking of the immortal words of Socrates who said.......I drank what?"
    [Edited last by Sean Conklin on October 31, 2001 at 01:36 PM]
     
  8. Alex F.

    Alex F. Second Unit

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    Just a correction to a statement I read above: Audio in the surround channels CAN sometimes be obtained from sources that have not been Pro-Logic encoded.
    A P-L decoder will send out-of-phase information to the surround speakers. This requires a stereo source, from which the decoder will derive the "difference" signal. This can often be heard as hall ambience in classical-music recordings. This surround sound, usually unintended, is on many other recordings as well. On some television programming this can result in a "buzzing" noise (it doesn't mean your P-L decoder is faulty--it's the out-of-phase information being reproduced).
     
  9. Sean Conklin

    Sean Conklin Screenwriter

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    Alex, I can agree with that. Although the unintended sound from the surrounds is likely to be useless!
    ------------------
    Sean
    "I was thinking of the immortal words of Socrates who said.......I drank what?"
     
  10. Rick_Brown

    Rick_Brown Second Unit

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    "Rick, this isn't true. The stereo signal MUST be encoded with Pro-Logic for your receiver to send ANYTHING to the rears. If you want all your speakers to have sound from a non PL signal you must force the receiver to process the signal, hence 5 Channel Stereo!"
    Sorry, this is not the case. Simple test: put on a stereo music CD, engage PL - voila! You hear the surrounds. I'll leave the question about whether the sounds that are heard is a pleasant experience to others. The original question in this thread was that Tan_U was hearing "no sound coming from the rear in pro logic mode " when watching TV, and it still stands that if his TV program is being received in stereo he should hear something from the rears in PL.
     

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