Digital Coaxial Cables

Discussion in 'Cables & Switches' started by Steve-O 2007, Dec 30, 2006.

  1. Steve-O 2007

    Steve-O 2007
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  2. Andy98765

    Andy98765
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  3. Steve-O 2007

    Steve-O 2007
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  4. clockworks

    clockworks
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    All the signals are sent together, down one cable.

    Obviously, the units at each end have to have coax digital sockets, and be capable of handling 5.1.
     
  5. Welwynnick

    Welwynnick
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    You do need a good quality cable for digital audio - video quality, not audio quality. RG59 cable doesn't define performance (just centre core diameter, really), but it's probably a good place to start. Shold be OK.
     
  6. Matt_C

    Matt_C
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  7. Chris Frost

    Chris Frost
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    High quality coax cable is designed to handle signals at much higher frequencies without too much loss. They're often rated for resistance (75 Ohms or 110 Ohms) which helps the transfer from device to device without introducing signal reflections.

    Freebie cables don't do this. They're OK for analog signals like you'd get from the L&R audio outputs on a CD player, but they're not going to do much for higher bandwidth digital signals like the coax output of a DVD player.
     
  8. edent

    edent
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    Nothing. If the 1 and 0 are getting through you'll hear 6.1 DTS-ES (or whatever you're passing through).

    The only slight risk is if the cable isn't that well shielded and picks up interference from the mains. Although I've got an old phono cable cable running next to mains, component video, speaker wire, telephone cable and ethernet and it passes the sound just fine.

    T
     
  9. Welwynnick

    Welwynnick
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    I believe that could mislead people who come for good advice and information. Digital audio is a high bandwidth signal and analogue is not. The requirements for SPDIF are much the same as for video, and rather different to audio. For example, the characteristic impedance for SPDIF and video cables should be as close as possible to 75 ohms - source and sink impedances should be well-matched to ensure good coupling and minimal reflection and standing waves. Whereas for analogue audio it hardly matters - output impedance is generally low, and input impedance is generally high. Core, dielectric and screen requirements are also different. While a good video cable can be used quite well for both digital and analogue audio, you cannot say the same for analogue cable. It would work, but not well.

    Nick
     
  10. edent

    edent
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    The max bitrate that a DVD will output for audio is 1.5Mbps - that's full DTS. Most AC3 bitrates are 443Kbps.

    You can take a few metres of bell wire and get the same digital[/] signal passed as an expesive "Digital Ready" cable.

    Try it for yourself, get a bog standard phono cable, some speaker wire and an uncurled metal coat hanger...
     

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