AE700 & 20m HDMI cable - noise

Discussion in 'Projectors, Screens & Video Processors' started by Lapinou, Nov 11, 2004.

  1. Lapinou

    Lapinou
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    I tried to connect my AE700 to my PC with a 20m (lindy) HDMI cable (with a DVI adaptor).
    The good news is it works, 1280x720, but there is pretty bad noise visible in dark picture areas (blue scintillating dots). This noise pretty much disappears if I lower the resolution, but it makes having a digital connection a bit useless.
    I guessing this means that the signal strength is just not strong enough to push 720p bandwidth through 20m of cable.
    Is there anything else it could be, I've tried connecting the projector and PC to a common earth, but no luck. Just thought I'd ask before putting the 20m cable up for sale on ebay and ordering a 10m one.
     
  2. explicitlyrics

    explicitlyrics
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    HDMI-DVI cables are not great at distances, it seems that there is nothing really that can be done about this, short of spending stupid amounts of money on a cable. 5-10m seems to work with most people, although there are still reported problems with the DVI-HDMI anyway....
     
  3. xevito

    xevito
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    Anyone know where to get one in a town centre? Swindon mainly
     
  4. explicitlyrics

    explicitlyrics
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    you probably could get one from a high street, far better and cheaper off the net though really. tvcables.co.uk have served me well for my component and TOSlink needs but for DVI/HDMI maybe best trying Lindy as lots of people recommend them. :)
     
  5. xevito

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    Ah ha - but I want it tmrw - guess I could run off VGA until then.

    Suspect I will be stuffed without the right cables
     
  6. Lapinou

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    Just as an endnote, in case anyone else had the same woes.

    I finally managed to get a noise free connection between a PC and the 700 with the 20m HDMI cable (at 1280x720). The key it seems is to adjust the pixel clock (basically video bandwidth) down (using custom timing with Powerstrip) until you reach a 'sweet spot' where the noise disappears. I reached mine at 68 Mhz (Pioneer say it should be 76Mhz in the manual), which means that I have a refresh rate of 55hz instead of 50 or 60hz.
    Oddly, I would have thought that further reductions in the pixel clock (and vertical refrelsh rate) would change nothing, but further reductions made the noise return. It really looks like you have to hit a 'sweet spot' for projector to get optimal signal strength.
     
  7. Pecker

    Pecker
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    You could also buy 2x10m leads and connect together with a little gizmo that boosts the signal.

    I understand these work a treat - best to check the hardware forums (next to projectors, I think).

    Steve W
     
  8. David_of_Surrey

    David_of_Surrey
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    I often wonder if it would be better to have all the equipment at the back of the room closer to the projector (which is the device you want the best image/connection for) and accept poorer TV picture

    or maybe have the equip 1/2 way with shorter video cables to each
     

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