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Sound Level in Stereo to 5.1/6.1/7.1 Conversion

Discussion in 'AV Receivers & Amplifiers' started by felix_li, Apr 3, 2005.

  1. felix_li

    felix_li
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    Hi Fans,

    AV amps can convert stereo to 5.1/6.1/7.1 and the back channels (as well as the centre) are somehow derived from the original signal.

    Does anyone have an idea what percentage of the front channels (L+R) will become the back channels in different matrix, e.g. IIx, DD 5.1?
     
  2. JBL 4645

    JBL 4645
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    The percentage do you mean the crosstalk errors try going to Dolby hear is the page for technologies

    http://www.dolby.com/consumer/technology/tech_overview.html

    Look though this you will find some answers…and in a nutshell Dolby pro-logic creates more crosstalk with centre channel information filtering into the surround channel I have done an A&B test and preferred the Dolby pro-logic as it keeps to the original Dolby stereo playback… :)

    Ashley…
     
  3. eviljohn2

    eviljohn2
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    It really depends on who mixed the sound and what sort of source you're using.

    Originally, it was something like anything common to both channels and in phase was sent to the centre channel. Anything common to both channels and out of phase was sent to the (then mono) surround channel. Naturally more modern algorithms are far more advanced and take into account characteristics like transients, vocal tones and so on. There really is no simple answer - for example; in football the surround channels get plenty of crowd action whilst for Radio 4 most of the sound would come from the centre channel, neither of which work on a simple percentage basis. :)
     
  4. felix_li

    felix_li
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    Hi JBL & EvilJohn,

    Thanks for your answers.

    I know that for "normal" movie material, the surrounds are normally act as "effect speakers" which the main (L+R+C) will take at least more than 70% of the total loading (except for some special scenes, I think). But in the stereo to the surround channels conversion by the AV amp., what likely will be the conversion ratio to the surround, e.g. the surround also act as "effect speakers" (a tiny/small portion of the main) or at an around 1:1 conversion...) so that I can decide the "relative sizing" of speakers I should go for this kind of listening mode.
     
  5. chedmaster

    chedmaster
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    the surround speakers arent meant to output anything the front ones do, in theory they have their own dedicated channel (for stuff "behind you")
     

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