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Prologic Etc.

Discussion in 'AV Pre-Amp/Processors & Power Amps' started by RichardG6PAJ, Apr 12, 2005.

  1. RichardG6PAJ

    RichardG6PAJ
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    Hi,
    I'm new to all this, so I'm hoping you can give some sound advice. (pardon the pun).
    I am assembling a cheap surround sound system, Consisting of a Panasonic DMR-E55EB DVD recorder, a Packard Bell Digital Digital Theatre Processor fed into a Phillips A3.610 5.1 Channel Speaker System. My problem is with the PB Sound Processor. As yet I have no instructions with the unit and can not find any info on the net. The dvd unit is connected to the processor via an optical cable and the processor is connected to the speakers/amplifier via six phono plug terminating to a mini din plug. Using the test button on the processor I get white noise through all 5 speakers. So everything appears to be connected ok. The sub woofer is also working. When I play a dvd (recorded from tv) the processor switches to pro logic, but sound only comes from the centre speaker. The only way I can get sound to come from all speakers is to switch the processor to what it calls BYPASS mode. The sound quality is excellent. But not sure why when in the prologic mode I only get sound from one speaker. When sound comes directly to the unit from a broadcast (BBC, ITV etc) I again get sound from all speakers, but the processor does not switch to prologic mode, I can however scroll through some of the processors DSP modes ( cinema, theatre, live, matrix etc.).
    If you have any constructive comments I would appreciate it.
    Thanks
    RichardG
     
  2. MarkE19

    MarkE19
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    When pro logic only outputs sound through the centre channel it normally means that the audio is only in mono. Pro Logic can not create surround sound from a mono source, but needs to be fed a stereo source. I would suggest that you check the settings of your DVD recorder to make sure it is recording a stereo audio track.

    Mark.
     
  3. u32t5645

    u32t5645
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    Richard, I’m going thru the same learning curve. I experience the exact same thing you described with a Primare processor. For that processor the ‘bypass’ means all processing and formatting of the input signal is bypassed and instead routed straight thru to the DACs and amps. Bypass is “the most faithful possible reproduction of stereo or multi-channel sources.” Presuming ‘bypass’ is the same for your kit, if you are hearing 5.1 surround sound in bypass mode then your source signal is all of those discrete channels.

    My understanding is (anyone, please correct me if I am wrong here!!!) ProLogic is a scenario that takes 2-channels only (often stereo) and reformats it into quasi-5.0 surround. Since the source signal is only 2 discrete channels it is not technically a true 5.0 (or 5.1) format, but it will use the 5.0 resources on the backside so you will hear it thru all those speakers. It is not clear to me if ProLogic generates the .1 channel or if that is derived elsewhere in your equipment’s processing, i.e. anything below the set frequency goes to the sub. I think if you input a mono source on L/R stereo inputs for ProLogic processing, you should still get something out of all 5 speakers.

    Somewhere I read that with 5.1 discrete channels input into ProLogic processing, the default will be into the center channel only…and I read why but I’m going thru information overload in my learning curve and I forgot?!?!? Sorry… Anyway, the Primare processor does the same thing as your processor.
     
  4. RichardG6PAJ

    RichardG6PAJ
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    Hi,
    Thanks to Mark & u32t5645 for taking the time to answer my query.
    Firstly, Mark, I checked the soundtrack on the recorded disk and apparently the track is recorded in Dolby 2.0 stereo. So it should be ok. Also I tried switching the recorder to a broadcast channel, which was shown as Nicam Stereo I then switched the processor to prologic and still the sound comes only from the centre channel.

    To u32t5645, thanks for your comforting words, I think. I haven't yet experienced true surround as I haven't any surround sound source material, I intend buying some this coming weekend. However I am still at a loss as to why the prologic setting isn't working and the worst thing is that the processor automatically switches to prologic when I play a recorded disk, so I then have to switch to bypass to get anything out of the other speakers.
    I will keep reading and asking people who know.
    Once again, Regards and Thanks

    RichardG
     

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