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A/V "Audiophile" Digital Cables - am I going crazy, or are they?

Discussion in 'Hardware' started by Yslen, 13 Feb 2011.

  1. floyd_washington

    floyd_washington What's a Dremel?

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  2. Siwini

    Siwini What is 4+no.5?

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    Can you coment on this cable vs this? Seems like you know what your talking about. Whats all this 15.8/10.2 GHZ nonsense?
     
  3. outlawaol

    outlawaol Geeked since 1982

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    This reminds me of that dumb buffoon on youtube that was spamming these 'Apple product DIY's' that involved just sticking your USB cable into a potato and seeing it 'charge'. Then showing video of it actually working. I wanted to strangle him so bad. Im sure Apple seen a fair amount of customers bringing in Apple cords/products that had potato goo all over them. I did my best to spam his videos with comments saying it was false, but the lemmings will run in herds right off a cliff....
     
  4. Yslen

    Yslen Lord of the Twenty-Seventh Circle

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    This is of course true, but its completely irrelevant in most cases. You'd need a lot of interference before the waveform is degraded that far. All you'd have to do is add some cheap shielding anyway and the problem would go away.
     
  5. ulfar

    ulfar holy s**t, i can change this?

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    yes, however,
    if a digital 0 is 0V- 0,8V analog and a digital 1 is 2-5,25V analog,
    the cable has to have a resistivity of 2,4 ohms since u=ri -> r=u/i -> (2-0,8 = 1,2)/0,5A = 2,4 ohm. based on what is known, this gives a cable length of approx. 28,5m since:
    ro = R x A/l, where ro is resistivity (1,68*10^-8 for copper), A = 0,2mm^2 and l is what we want.
    ro = R x A/l -> l = A / (ro/R) -> l = 0,0000002 (in metres) / ((1,68*10^-8) / 2,4) = ~28,5m.
    let's say that you can have a cable length of 14,5 m if the cable consists of 50% copper and 50% crap.

    further, let's say that you have the hdmi cable running next to the power cord:
    the electric field (E) produced by a 230V 50Hz cord ranges from 3-30V/m. E = U/d(distance between the two)
    30= U / d (0,01, one cm) -> U = 30 * 0,01 = 0,3V. not enough to distort, and besides, a simple cheap shield removes this.

    conclusion, don't but cables which consist of 50% crap, and don't buy the "gold plated, platinum core, tri-shielded, diamond encrusted, unbreakable, ???????? super cable of doom".

    ps, bs calculations are bs, but really really fun. ds.
     
    Landy_Ed likes this.
  6. memeroot

    memeroot aged and experianced

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    nice calculations but you're out by a factor of pf#
     
  7. Gryphon

    Gryphon What's a Dremel?

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    And your units are a bit out... You've said the current is 28.5 meters :)
     
  8. ulfar

    ulfar holy s**t, i can change this?

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    i = I
    l = L

    :p

    pf#? and where?
     
  9. specofdust

    specofdust Banned

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    The one that says 10.2Gb/s at 340Mhz is basically just boasting that it's an HDMI cable, since being able to transfer 10.2Gb/s at 340Mhz is a central requirement of catagory 2 HDMI cables. The up to 15.8Ghz nonsense would appear to be just that, nowhere in the HDMI spec are frequencies anywhere near that high used, however I suppose people like big numbers and 15.8Ghz is a bigger number than 340Mhz.

    You ask me they're both overpriced and gimmicky.
     
  10. sb1991

    sb1991 What's a Dremel?

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    That 15GHz number is complete BS, there's no way an HDMI cable would be able to transmit such a high frequency signal. Unless they've managed to include a high quality coaxial cable in there as well as the normal HDMI one...
     
  11. Landy_Ed

    Landy_Ed Combat Novice

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    Here's some more nonsense, by the majority view here

    Absent of "catagory 2" anything, btw.

    Oh, ulfar x9 on the power cables, take into account crosstalk on the hdmi ports inside the telly & potential amplification of other RF from the aerial amp, plus a cheapish UPS intended to attentuate power supply fluctuations - not imaginary ones - like main lights flickering darker & lighter than the average lux at non-peak times, then allow for the additional devices.

    Then take into account the relative cost of your time toing and froing to that place that sells the cheapo dodgy cables that don't seem to work in multiples, fuel, opportunity cost, wear on vehicle etc etc. I maintain my stance that there is a sweet spot on the cost of cables, like many other things, and if a supplier charges me £20 for a cable that in raw materials is worth £1 I have no issue with that because it would ultimately cost me more in time and effort to achieve the same thing and, with my gommy hands and bad eyesight, probably wouldn't work anyway!
     
    Last edited: 17 Feb 2011
  12. sb1991

    sb1991 What's a Dremel?

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    Nobody is saying that this is nonsense. Of course there are cables that are designed and tested to different standards, just as there are for ethernet cables. The point most people have been making is that there's no difference in the quality of the video/audio produced by a device connected via an expensive cable rather than a cheap one, as long as both satisfy the requirements of the source: an HDMI cable either can or can't carry a signal, there are no subtle losses in fidelity as can happen with an analogue signal. There's no mention of category 2 because (according to the website you linked)
     
  13. ulfar

    ulfar holy s**t, i can change this?

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    or you could just order online from a respected regular online vendor and buy ordinary hdmi cables for £5, and not use your vehicle to go to that store which sells the same cable for £20 :p

    the point is that some vendors try to take advantage of customers by basically lying and cheating. i understand that the price at your local vendor has to be higher due to rent, salarys and whatnot, but a 400% price difference is ridiculous. or trying to sell cables which supposedly give a better image and sound quality (since they contain adamantium and pyerite) when they obviously don't.

    i thought about implementing all the surrounding em-fields, even the power grid. but unless you live under high voltage cables (the ones supplying you neighbourhood), the biggest poluter would be a supply cable running one cm from the signal cable. and since the hdmi's are shielded, it doesn't matter anyway.
     
    Last edited: 17 Feb 2011
  14. Landy_Ed

    Landy_Ed Combat Novice

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    ulfar, I'm not arguing with you. You have directly supported my view that not all cables are equal purely on the basis of having HDMI printed on the label.

    The £5 cables from tesco are in every way inferior to the one I spent more money on (which, as it turns out, was this one), and cannot cope with the usage hence I get comms failures between devices unless there is just the one cable connecting tv and one device only. My circumstances may be peculiar enough to warrant my experience - I certainly don't suggest that there is a loss of fidelity as exists with analog (which in that scenario I agree is perceptible to a point but there is still a sweet spot) but a significant enough degradation of signal that the experience is compromised to a fairly extreme level. It is not imagined, and I very much discourage anyone from buying the cheap technica branded hdmi cables from Tesco.

    The salesman in the sony centre tried very hard to sell me a £100 cable. then an £80 one. then a £50 one. I went for the cheapest one in the shop that supported the 3d signal & two way comms between the bd player and tv he was selling me, and he discounted it because I was bartering (that thing we're not supposedly able to do in the UK). no doubt thosethe tv screen & equivalent bd player were available cheaper elsewhere with different brands on them, but I bought the aesthetic as well and do not in any way feel ripped off.

    I'm sure you can appreciate my desire to be able to use the things the day I got it rather than a week later, and after spending circa £1500 on a tv & bd, well, I figure what I spent is probably not such a bad thing to accommodate my impatience.
     
  15. megadrive

    megadrive What's a Dremel?

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    I'm 100% sold on having decent cables for analogue signals, even over short distances for Hi-Fi. Makes a more significant difference the better your kit is. Not settled on digital interconnects yet.

    Something that makes a surprisingly large difference is a mains conditioner such as http://whathifi.com/Review/Tacima-CS929/. I've bought 2 the picture and the sound of everything plugged into it is changed dramatically. I actually had to turn the brightness down on my TV it changed so much! How "conditioning the mains" makes a difference is beyond me though...
     
  16. Siwini

    Siwini What is 4+no.5?

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    You must have one messed up cable than.
     
    Last edited: 19 Feb 2011
  17. megadrive

    megadrive What's a Dremel?

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    Gotta hand it to the guys at What Hi Fi though, can't imagine a worse job than having to compare to similarly priced cables and then write a review on the differences!

    @ siwini

    I got cheap and decent of both analogue and digital cables. I can't be bothered comparing digital cables, just put decent ones on. Its easy to compare with analogue cables on my Hi-Fi, the CD player has 2 outputs so just flick through on the amp, the difference is very clear.

    and if your referring to the wiring in my house - well yeah its probably Victorian.
     
  18. joro78

    joro78 What's a Dremel?

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    Yeah m8. You miss to check some reliable vendors like Amazon first,then all the rest.There you can find everything and it will be the finest price ever.
     
  19. 13eightyfour

    13eightyfour Formerly Titanium Angel

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    I use 4 5M hdmi cables that i bought from ebay for £8 each, all work perfectly fine and after a friend bought a significantly more expensive shorter cable, we decided to test them.

    The conclusion was that i got 4 cables for less than his single one, and we couldnt notice any difference at all, Using computer input, Blu ray at 1080p, and general telly viewing.

    Not all cables are physically built the same, but the end result is imo.
     
  20. RichCreedy

    RichCreedy Hey What Who

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    for short runs i don't think it matters if it's a cheap cable, i also use cheap cables, and even my 3d bluray player has no issues
     

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