News To Me: Optical Inferior to Coax: Except Glass...

Discussion in 'AV Receivers' started by Arthur S, Aug 21, 2005.

  1. Arthur S

    Arthur S Cinematographer

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    A serious player on another Forum said that optical is inferior to coax because it has to go through another process.

    The discussion then went on to say that if you use an optical cable that is made of real glass strands (as opposed to the ordinary plastic strands), optical is as good as coax.

    This is all news to me.

    What do you think?

    Thanks
     
  2. Phil A

    Phil A Producer

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    This has been covered many times and there's probably somehing about it here: http://www.hometheaterforum.com/htfo...hreadid=120328

    Do a search. Dolby Digital signals are delivered in packets so I'd be hard pressed to think that there really can be much if any in the way of differences. With 2 channel PCM on a CD, optical cables can induce more jitter but are not prone to RFI or EMI like a coax cable. So the answer might not be the same for every situation.
     
  3. Kevin C Brown

    Kevin C Brown Producer

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    I have come across similar arguments:

    1) Coax is better because it does have higher bandwidth (data rate capacity).

    2) Coax is better because optical has extra conversions (optical to electrical to optical to electrical), and is therefore more likely to have higher induced jitter.

    3) No RF/EMI interference for optical. (But coax is 75 ohm shielded coaxial cable, anyway.)

    I have used both with no complaints, but I always default to coax if I have a choice.
     
  4. JeremyErwin

    JeremyErwin Producer

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    Using optical is often the simplest way to eliminate ground loops
     
  5. Phil A

    Phil A Producer

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  6. Chu Gai

    Chu Gai Lead Actor

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    A serious player on another Forum said that optical is inferior to coax because it has to go through another process.
    So what? Does the serious player understand that the data on CD's is interleaved to begin with and needs to be reconstructed before it gets processed by the DAC? If there are bad conversions you'll have data loss that can't be reconstructed and then have dropouts. What you will find though between the two flavors though is that levels might be different and that in itself can lead to perceived sound quality differences. I'm sure such a serious player has taken the time to measure the output levels using test tones and a VOM, right?

    The discussion then went on to say that if you use an optical cable that is made of real glass strands (as opposed to the ordinary plastic strands), optical is as good as coax.
    There are less attenuation losses with glass as opposed to plastic, but that's only an issue if you're running very long lengths. Glass, though, does give you bragging rights. Comparatively inexpensive glass toslink can be found at MCM.

    This is all news to me.

    What do you think?

    Use the type of connection that best meets your needs or potentially addresses a problem. The serious player probably needs to go out and laid more often. Maybe it'll clean out his ears.
     
  7. John Garcia

    John Garcia Executive Producer

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    I prefer coax simply because I know it's not going to get knocked out of the socket. [​IMG]
     
  8. Kevin C Brown

    Kevin C Brown Producer

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    It won't get "broken" either. Coax cables are much more robust than optical. One other problem with optical, is that you can get dust in the connectors which can kill the signal.

    Good point about ground loops. [​IMG] But more than likely, if you have a ground loop from cable TV or a satellite connected up wrong, changing just the connection from the DVD player to the receiver or pre/pro isn't going to fix the problem.
     
  9. Lewis Besze

    Lewis Besze Producer

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    I keep hearing about how the the coax is more robust and has tighter connection.
    I don't see how that makes any difference to most people at all.Unless you move equipments in and out like a reviewer from it's place therefore unplug things often, or just like to play with your cable like a lasso[sp?], it shouldn't make any difference how beefed up the connection or the cable is.
     
  10. Cees Alons

    Cees Alons Moderator
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    Millions of yards of optical fiber connections are used in offices, across the country, buried beneath your streets, etc. for the Internet as well as cable transmissions.

    What do you think? They are all inferior?

    Truth is: fiber connections between AV-modules are so short, as compared to all other professional use, that the chance of losing even one packet of data is virtually zero. This includes the conversion to and from light. Glass or plastic.

    When used for digital audio, they're electronically at least as good as coax. And I wonder about mechanically. Sure glass can break. But so can metal strands and soldered connections.


    Cees


    PS: Do I count as a "serious player" on this here forum? [​IMG]
    C.
     
  11. John Garcia

    John Garcia Executive Producer

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    It depends on the quality of the connectors on the end of the cables. I've used optical cables that just don't "click" into their little socket and have had them pop out too easily when just moving the HD box slightly. Yes, it only happens when you move the unit, but that's still not good enough for me.
     
  12. Brian L

    Brian L Cinematographer

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    Arthur,

    Would this be the thread:

    http://www.stevehoffman.tv/forums/sh...ad.php?t=58991

    I like Hoffman's music forum, and do read the hardware stuff, but there really seem to be a lot of "true believers" that really push the credibility envelope. Not quite as many as at Audio Asylum, but you can't swing a dead cat without hitting someone in the head that thinks his new $500 interconnect is da bomb.

    Good comment there Chu....I notice that my 2CH system always sounds better after the misses and I get busy![​IMG]

    Brian
     
  13. John S

    John S Producer

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    I like opitcal better because the little red light is cool.... Otherwise just use the convienient connection of your choice... [​IMG]
     
  14. Philip Hamm

    Philip Hamm Lead Actor

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    You do to me, Cees. [​IMG]

    Use whatever is convenient and cheap. It doesn't matter.
     
  15. Cees Alons

    Cees Alons Moderator
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    And that's reciprocal, Philip! [​IMG]


    Cees
     
  16. Chu Gai

    Chu Gai Lead Actor

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    Tom Nousaine once conducted a test where he had several converters chained together and people, under controlled, level matched, and unsighted conditions were unable to differentiate between the chained setup and a straight through output. Of course one can argue that the system wasn't revealing enough, the listeners were unfamiliar with either the music or the setup, the moon was in Scorpio, they were stressed...the usual suspects [​IMG]
     
  17. FeisalK

    FeisalK Screenwriter

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    *LOL* I wonder what the system sounds like if you do get a hit... ;D
     
  18. Lewis Besze

    Lewis Besze Producer

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    Yeah it supposed to click if it doesn't then it's "broke", and shouldn't be used at all. My comment was for good functional connections.
     

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