optical vs. coaxial digital cables

Discussion in 'Archived Threads 2001-2004' started by Ryan T, Sep 20, 2001.

  1. Ryan T

    Ryan T Second Unit

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    Hi, I'm wondering if there are any major differences between optical digital and coaxial digital for movies and music. I'm going from A DVD to my A/V receiver. Right now I’m using optical, It sounds great but I’m wondering if coaxial is better or not.
    Ryan
     
  2. Neil Joseph

    Neil Joseph Lead Actor

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    Both are good. Coaxial has the advantage of having a more robust connection than optical, which can be damaged more easily. For this simple application of transferring the digital bitstream between the DVD player and the processor, both cables operate well below their maximum levels.
    orangeman
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    http://webhome.idirect.com/~orange1
     
  3. Andrew_Chan

    Andrew_Chan Agent

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    Only the physical layer is different, the raw data being transfer from DVD to the receiver is still the same. However, I find that optical cable are cheaper to buy, you can find a cheap one for $10 on ebay, but for cheap 75ohm coxial wire, the cheapest is $19
     
  4. Drew Eckhardt

    Drew Eckhardt Stunt Coordinator

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    Actually, coaxial cables are cheaper. Just buy the 75 ohm cables labled "video" instead.
     
  5. John Morton

    John Morton Stunt Coordinator

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    I experience a significant improvment by moving from a cheap optical to a good optical. I then experienced an even bigger improvment by moving to coaxial. Just my experience though!!
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  6. Robert Fellows

    Robert Fellows Stunt Coordinator

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    There is one less conversion, so go with the coax.
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    Bob
    p.s.: This advice is worth exactly what you paid for it...
     
  7. Andrew_Chan

    Andrew_Chan Agent

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    No way, I don't think there'll be an improvement when you buy a better cable. I used to use a cheap Composite cable for digital audio out, but when there are certain point inside a DVD movie where the cheap wire just don't have enough bandwidth and the audio just stop for 0.5 second, and that is with dolby digial, the problem occur more oftenly with dts sound(I assume dts has less compression and would require a even wider bandwidth) So, it's either you listen to the sound perfectly, or you won't hear it, that's the definition of "DIGITAL"
     
  8. Jim Burns

    Jim Burns Auditioning

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    It is hard to screw up a digital signal in only three feet, I know this because e I have done a lot of testing of cables with a NetWork analyzer, TDR and tearing of the ATSC bit stream.
    Coax is slightly better because there are two less transducers in the path (changing electrical energy to light and then back).
    From a marketing standpoint fiber is cool, think of the phone company and cable.
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    Jim Burns
    http://www.dtvconsultants.com/ www.imagingscience.com
    [Edited last by Jim Burns on September 22, 2001 at 10:46 PM]
     
  9. dougW

    dougW Stunt Coordinator

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    There can be a difference, and you can hear it. Optical goes through another step in decoding, so you cannot say they are the same, and a lot of how well an optical handles this is based upon the quality of the RX/TX optical signal decoder. This can cause the process to create a more "digital" sounding soundstage. Usually that's due to the quality of the optical transistor in the RX part as well as perhaps transistors that follow in the signal path. In essense, something happens during the decoding process by inferior optical decoders to take away the smoothness capable with a good quality digital coax.
    Low to mid-fi electronics are even more prone to this occurance due to the quality of components used.
    Lex
    CAT
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    Lexman's Theater
     
  10. Scott Gerenser

    Scott Gerenser Auditioning

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    Doug,
    While that may be correct (to a point) with PCM, it physically cannot be correct for Dolby Digital. That is because it is an encoded format, it is not just a digital stream that gets output in real-time. Due to it being encoded, along with error correction, if there were any dropouts/errors, it would result in an obvious blip, dropout, noise, etc. There would certainly not just be a "loss of smoothness," whatever exactly smoothness means. [​IMG]
    The optical transducer does not have an effect on the final sound, as it would be *very* unlikely for it to create a constant, steady stream of errors that just *happens* to be perfectly decoded as a "somewhat lower quality" sound as opposed to pure noise or no sound at all.
     
  11. Brian Bunge

    Brian Bunge Producer

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    No one has seemed mention the true benefit to optical over coax. That advantage is immunity to RF interference. While it probably isn't a big deal with a good shielded coax, RF interference can be an issue in some instances.
    Brian
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  12. Randy G

    Randy G Second Unit

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    Yeah, we know about the RF interference thing, but can it get rid of spousal interference?
     
  13. Brian Bunge

    Brian Bunge Producer

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