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Whats the difference between Dolby Pro Logic and Dolby Surround Pro Logic?

Discussion in 'Home Cinema Speakers' started by monkeyboygokZ, Mar 13, 2005.

  1. monkeyboygokZ

    monkeyboygokZ
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    My TV is Dolby Surround Pro Logic, so im confused.
     
  2. Ian J

    Ian J
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    In the case of your TV there is no difference but different people use different expressions for the same thing.
     
  3. monkeyboygokZ

    monkeyboygokZ
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    So what exactly is Pro Logic anyway, is it only 2 channel? yeah I was confused as I had the real Dolby surround logo on my TV. Is Pro Logic 1, 2 channel Pro Logic 2, 5 channel? I guess my Tv is only channel as it has rear, left and right, front left and right and subwoofer.

    Also does anyone know how to change the internal speaker volume to match the external ones, I only ahve 2 external speakers, and my internal ones cover front lefr right and centre, but no matter the volume the external ones are FAR louder than the internal ones.

    There is a AV and a Scart volume control on the TV, but even at max it sounds the same.

    RF sounds about right.
     
  4. phillfyspoon

    phillfyspoon
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    pro logic is a processing technology to derive 5 channels of audio from 2 channel stereo. it isnt true 5 channel like dolby digital or dts.
     
  5. Jules Tohpipi

    Jules Tohpipi
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    Dolby Surround is an encoding system used to shrink four channels down into two. It's done at the mastering stage. So, a similar decoding ciruit was put into early AV amps etc to decode this signal.

    A few years later Dolby thought of a better, more enhanced circuit for decoding Dolby Surround. They called this Dolby Pro Logic. Amongst other things, it greatly improved channel seperation.

    As the encoding/mastering process remains unchanged, then VHS titles, etc will still carry the Dolby Surround logo - there was no change at the studio end. However, modern AV amps will carry the Dolby Pro Logic symbol, to show they are using the more advanced/efficient decoding circuit - over and above the original Dolby Surround decoding circuit.

    Dolby Digital and DTS are much more advanced digital systems that contain discrete channels of information, rather than the Dolby Surround technique of condensing four channels of info down into two (allowing transmission on two channel formats such as VHS and Nicam), and afterwards a decoder then attempts to reconstruct the original four channels as accurately as possible. The later Dolby Pro Logic decoders reconstructed the signal much more accurately - but the encoding process remained unchanged .i.e Dolby Surround.
     
  6. MarkE19

    MarkE19
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    And the DPL story continues.....

    DPL2 then came along and rather than just having 4 channels of output (front L/C/R and mono surround) it gave 5 channels, ie a stereo surround output.

    and then recently DPL2x was released. This gave a 7 channel surround for those with surround rear channels.

    Mark.
     

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