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Digital audio optical vs. RCA on STB

Discussion in 'Home Theater Projects' started by Carl333, Jan 4, 2007.

  1. Carl333

    Carl333 Member

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    My STB has a digital audio output. I presently am using a cheapie RCA connection from my STB to my 7.1 receiver. A salesperson suggests that I use a Digital Audio Optical Cable to my receiver for overall better performance instead.

    Is he right? Will I get noticable better surround sound and video ? Are these cables expensive for a short run?

    If RCA is the way to go, should I replace my cheapie with something else I may have lying around? I have a cable yellow (thick wire) red and white (thin) and a blue, green and red cable set (heavy). I keep getting confused which one is component and composite video.

    tks
     
  2. Stephen Tu

    Stephen Tu Well-Known Member

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    Certainly you should use digital audio connection; that's the only way to get Dolby Digital from your STB. Much cleaner channel separation than via analog. Big difference for DD 5.1 broadcasts on HD channels, premium movie channels. On non-DD broadcasts, improvement won't be that noticeable (so if you have only analog channels, may not want to bother).

    There are two types of digital audio connectors though, one is coax & uses RCA connectors, the other is optical (aka Toslink). Your cable STB might have both types available or just one. The RCA jack is typically color coded orange on the STB, marked "digital" or "SPDIF" if available. If you are already using this for audio (single RCA connector between your STB & receiver), & your digital indicator is lighting up, there's no need to change anything. If you are using the red/white RCA analog pair, you should switch to digital.

    The cables are inexpensive if you order from some place like www.monoprice.com. If you try to buy them from local electronics store they tend to be outrageously expensive as the mark-ups are huge & they often carry only "boutique" over-priced brands like Monster.

    As for video, changing just the audio connection would obviously make no difference whatsoever to the picture. The red/green/blue cable set is the component video, and certainly should be used if you have HDTV & HD STB.
     
  3. Carl333

    Carl333 Member

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    Thank you for the explanation. Monoprice sells the digital optical cable at $2.66. Your so right about the inflated prices. I found a local store that has a 3 ft. cable that was reg. priced at $34.99 but on special at $14.99 and its not a Monster cable at that. I can wait for shipping time to Canada from Monoprice so I'll go the $14.99 route.
     
  4. Jeff Gatie

    Jeff Gatie Well-Known Member

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    Just use a video cable (yellow RCA, 75 Ohms) for the coax digital audio connection. Don't spend a fortune on a "Digital Coax Cable", there is no such thing. The SPDIF specifications were written to use a cheapo 75 Ohm video cable. I use two cheapies that came with a DVD player and VCR. They've been in use 6 years and not a dropped bit yet. I also have a Walmart special optical that cost me around $10. That's been going for 8 years.
     
  5. Carl333

    Carl333 Member

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    My STB has a digital optical out. I just bought a optical cable and hookd it to my optical in on my receiver. The STB manual says "that the output is for use with high quality digital sound decoding systems" I just bought a Pioneer 7.1 THX, DD, DTS blaa, bla, bla receiver. Was my purchase a waste of money?
     
  6. Jeff Gatie

    Jeff Gatie Well-Known Member

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    You didn't waste your money on the digital connection, but depending on how much you spent for the optical cable, you may have paid too much. If the package says "Monster", you paid too much. [​IMG] If you paid $40 or more, you paid too much. Return it and get the 9.99 cheapie at Walmart.
     
  7. Carl333

    Carl333 Member

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    Jeff, there is such a thing as a digital coax cable. Now totally confused? I can't post the link because I need 10 replies.

    Sorry, extreme newbie just trying to learn.
     
  8. Jeff Gatie

    Jeff Gatie Well-Known Member

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    Well, they call them "digital" coax, but the SPDIF interface specification says you only need a 75 Ohm RCA terminated coaxial cable to transmit digital coax audio. Another name for a "75 Ohm RCA terminated coaxial cable" is "video cable", something that is given for free with almost every video component sold. All the special "ESPECIALLY MADE FOR DIGITAL AUDIO!!" crap is marketing bullshit so they can charge twice the price of a video cable.[​IMG]
     
  9. Carl333

    Carl333 Member

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    It that think yellow RCA cable that is bundled with a white and red thin wires, coax 75 ohm?

    Edit. I just checked the wire and it is printed coax RG59. Looks like I have the correct cable.

    thanks
     
  10. Jeff Gatie

    Jeff Gatie Well-Known Member

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    Yup, that's the one. Yellow RCA is 75 Ohm video (and digital coax audio [​IMG] ).
     
  11. Carl333

    Carl333 Member

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    thanks Jeff
     

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