Delay Times on Amps

Discussion in 'AV Receivers & Amplifiers' started by john87, May 26, 2002.

  1. john87

    john87
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    I fail to see why they are needed - at least I didn't at first but after thinking about it, at the cinema surely it would be impossible to have delay times that suit everybody, and this is over much greater distances - 20+ metres (just a guess.)

    Cut the size of a room right down and why are they needed (even in bigger homes)?
     
  2. lynx

    lynx
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    I don't know why they are needed but i'll take a total stab in the dark here,could they be saftey devices ie ensure there is no internal or external short circuits before energizing relays to the output devices.As i said,total conjecture probabaly wrong. :)
     
  3. john87

    john87
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    No, they are made so that sound reaches your ears at the same time - if the speakers aren't equal distances from you.
     
  4. lynx

    lynx
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    Sorry i missunderstood your point.I thought you were refering to the delay between powering up and a signal being sent to the speakers. :blush:
     
  5. trfmnd

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    Delays are used to time align speakers and also to delay the time it takes for the surround sound to get to you in order to ensure that the first sound you hear is from the front array. Delayed surrounds enhance the spatial quality too. A lot of domestic rooms are set up with the surrounds closer than the LCR, say behind a couch. It's important to make sure all sounds arrive at your ears at the same time, then you can add delays to the surrounds for personal taste over and above what they might have needed in the setup. There's some technical papers on the dolby site relating to the ITU 775 spec for setting up mixing rooms that may give you more insight. www.dolby.com
     
  6. Bonesy

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    anyone want to comment on John's question -

    how can a 400 seater cinema offer a sweet spot to everyone?
    (well, I guess they don't).
    So how can you have a THX certified cinema?
     
  7. micb3rd

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    A cinema has a bigger sweetspot because it has more speakers than a home 5.1 ssystem, they oftern has a set of surrounds down the side walls and some at the back.
     
  8. Bonesy

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    thanks for the response,

    I guess there's still seats not in the sweet spot though.
     
  9. john87

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    I realise this - I was just wondering why it mattered, when you have a large cinema with speakers 10s of metres away from people.


    Yes but the front array can be 40+ metres away, or as little as below 10.

    Just something to think about :)
     
  10. MarkTaylor

    MarkTaylor
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    Delay adjustments are not just for speaker positions, far more important to me is the ability to adjust for the delays in the video image being displayed introduced by video processing circuits, de-interlacing, scaling etc.

    Mark
     
  11. Ekko Star

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    I always thought the delays were a bit like a reverb effect.

    Not quite sure if this right but this is what I have always believed.

    If you have a large room or hall with not much acoustic damping around any sound tends to echo quite a bit.

    Introducing a delay allows the timing from all the speakers to appear more in sync in order for a much tighter clinical sound ie sweet spot.

    I think this becomes even more important as without this feature the natural echo introduced in larger rooms also introduces a sort of unsynchronised lip sync effect with the video image being viewed.

    I think cos in a cinema hall you usually have carpeting, seating, draping that all tends to dampen the sound anyway so they can get away with less use of a delay. This I suppose would help in enlarging the perceived sweetspot.
     
  12. Reiner

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    Speaker delay settings are to compensate for the distance between listener and speaker, i.e. the rears might be closer to you than the fronts and thus their sound would reach you too early.
    The same applies for the center, if in line with the fronts it's actually closer to you.


    Delay adjustments are not just for speaker positions, far more important to me is the ability to adjust for the delays in the video image being displayed introduced by video processing circuits, de-interlacing, scaling etc.

    This is the audio-delay feature which you currently find only on a handful of amps, like e.g. the new Denon AVC-A1SR or the Onkyo TX-DS989 (with 2nd upgrade).
    Speaker delay is usually limited to the center & rears and thus would be of no use in this application.


    I always thought the delays were a bit like a reverb effect.

    That's IMHO the job of the (cinema) equalizer.


    I guess there's still seats not in the sweet spot though.

    Unless you sit smack in the middle - no.
     

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