Why do USB cables make such a difference?

Discussion in 'Sound Science' started by Cartma, Jul 17, 2017.
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  1. bigshot
    If a tree falls in the forest and no one can hear it, does it matter if you have a noise floor of -80dB? You keep quoting tests you've done yourself with no oversight, and I've already said that I don't believe that you've been totally honest in your tests. You've already burned that bridge. Get an impartial third party to oversee your tests and I'll listen to results of tests of your hearing ability. For now, I think you've been remarkably disingenuous with us.
    Last edited: Nov 11, 2017
  2. gregorio
    And I've also already explained all of this!

    In real life, are you really suggesting attaining an exceptionally low noise floor (either with an exceptionally well isolated listening room or using well sealed IEMs in a moderately quiet room) AND playing back at "very high levels"? No, you're talking about testing, about picking quiet passages, maybe even just note decays, which can be safely played at much higher level than normal to expose the noise floor. But of course that is testing, it is not "real life"! In "real life" consumers playback entire tracks, not only the very quietest parts and they do so at a comfortable level. And, what constitutes a comfortable level is relative to the noise floor, so if the noise floor is exceptionally low, the comfortable peak levels are also low. This is the complete OPPOSITE of your testing, which is a very low noise floor AND "very high levels of listening"! If consumers actually applied your test conditions to their everyday listening habits, it could potentially be dangerous/damaging, so how can you reasonably say "nothing extreme here"?

    To gain a good idea of the limits of human hearing requires a bunch of at least fairly extreme test conditions. And, I agree it's useful to do such tests and have this information but what I disagree with is calling it something which it obviously is not, "real life"!

    Sorry bigshot, I'm definitely with Amirm on this one. There are a great many claims in the audiophile marketing world and typically either no published measurements/specs at all or only an incomplete list of specs which don't tell the full story of a particular bit of kit's performance, often intentionally! I for one am very thankful for Amirm's work in measuring and publishing the actual performance of consumer kit, regardless of the fact that I disagree with him somewhat about what constitutes the "real life" audibility of artefacts.

    The AES, EBU, ITU and others have published a significant amount of tests and measurements of human hearing/perception and generic elements of digital audio but they publish precious little in terms of testing/measuring the performance of specific, individual pieces of consumer audio equipment. So, Amirm is filling an important information hole which is easily accessible by anyone.

  3. Darren G
    For the purpose of breaking a ground loop... note the Schiit Wyrd is just a USB hub, and makes no claims of isolation. The Schiit Eitr device is the one that provides isolation. A cheap sound card with optical out is probably your cheapest solution, though depending on your motherboard, there might even be a less expensive option that just exposes the MB headers as Coax and TOSLINK out for < $20. Some people aren't fans of optical, but that's a different story.
  4. bigshot
    I don't think I trust his findings any more than I do the manufacturers' sales sheets. AES at least has peer review and hopefully they have oversight to make sure things aren't fudged to make a point.

    It's really easy to do basic listening tests to find out if a piece of equipment achieves audible transparency. I do that with every piece of equipment I buy. If everyone did a simple controlled listening test to compare their equipment, the problem of coloration would be solved. However, I really don't think that is a very big problem. Every time I ask someone who argues that colored equipment exists to point out an example, they either point to high end stuff that has been deliberately colored and everyone knows it, or they point to a $20 DAC that's only noisy if you have bats' ears and can hear noise floors under -80dB. I have a $40 Walmart DVD player that is audibly transparent. Every computer I've ever owned going back to 1995 has been audibly transparent. Every DAP, every DAC, every player I've ever bought is audibly transparent. I don't think I'm doing anything special selecting these. It really isn't hard at all to find stuff that performs perfectly for human ears. Now transducers are a different story... But with transducers, you almost have to assume that they are going to be colored and apply room treatment and EQ to pull them into line. I find the headphones response curves published by various people on HeadFi to be very valuable. I think most of the discussion here about amps, DACs and players to be full of hot air. Even the people doing the testing don't seem to know that the numbers they call "horrible" are thoroughly inaudible. That doesn't instill confidence in me to the value of their testing.
  5. amirm
    First of all, you are completely wrong about peer review of Journal of AES. There is absolutely nothing in the peer review that vouches for either correctness or authenticity of the data in a paper. Nothing. My team at Microsoft was routinely in peer review loop of major organizations and that is absolutely how it works.

    What the peer review does is to catch fundamental mistakes with respect to science or as my PhD researchers would say, "something they taught you in college." If for example you didn't know what a fourier transform was, you get called on it. But if you ran a blind test and are reporting the results, as long as you don't outline protocol errors, the outcome whatever it is, will not get subjected to any review or correction. No peer review agency can ever do that as they would have to try to duplicate the experiments which simply is not practical. They will refuse however to accept non-scientific work like sighted listening tests, etc.

    So you can definitely "fudge" what you submit to AES. If you do, and someone re-runs the test and disproves what you have, you will be embarrassed and that is the guard against pulling such stunts. Same is true here seeing how I post under my real name and everyone from my family to friends, customers and professional colleagues read them. You might play fast and loose with your posts here but I don't have that luxury, nor is anything said here is worth the ethical misconduct.

    What is really going to get you is that there is published, peer reviewed, AES paper that shows audibility of resampling high-resolution audio to CD rate. See: Stuart Title Page.png

    In there they report on results of double blind tests showing audibility of digital filters to resample audio to lower rates:

    Stuart Conclusions.PNG

    Here is the statistical summary results, with the dashed line the threshold for 95% confidence (p < .05):

    Stuart Scores.PNG

    (Don't be confused about the percentage numbers on the left. See this article I wrote on that: https://audiosciencereview.com/forum/index.php?threads/statistics-of-abx-testing.170/).

    I assume you have not read the paper. In that case, you can read my digest of it which was *published* in the Widescreen Review Magazine here: https://audiosciencereview.com/forum/index.php?threads/high-resolution-audio-does-it-matter.11/

    So there it is: peer reviewed, published study using real music and with speakers, saying what you say is impossible. Or must be a lie.

    As I noted above, ton of my work and measurements has been published for the world to see including some of the major detractors. They have stood the test of time because they are credible and not isolated experiences.

    You don't like them because it goes against what you have learned to repeat online. So you are trying to protect your back side by crying "liar, liar."

    Time permitting, I will repeat one of these tests, take a video of it, post i there and then show you how you too can hear the difference. Or at least some readers can.

    Last edited: Nov 12, 2017
  6. amirm
    My reel to reel tape deck has 80 db signal to noise ratio and its tape hiss is definitely audible. Do you really have trouble hearing such a noise floor?

    We got digital as to be free of such noises. The silicon DAC box makers use is easily capable of providing far, far better performance. But when it is stuck in a box without competence, much of that headroom is lost.

    Here is a fresh of the press review and measurement of a $450 digital audio player, the Shozy Alien+: https://www.audiosciencereview.com/...of-shozy-alien-digital-audio-player-dap.2058/

    Here is how it does against my Samsung S8+ cell phone:


    Without this data if I polled 10 audiophiles which one has better performance they would ay the Alien+. Yet in test after test, it underperformed both my laptop and Samsung s8+.

    The AKM DAC in there is capable of far better performance. Poor design choices cause substantially higher noise floor. I like to shine a light on these issues as to weed them out. There is no reason whatsoever to live with -80 db in digital age and in this year and decade.

    80 db... Why don't we bring back horse and buggy while we are it????
    D2Girls likes this.
  7. Arpiben
    If you are interested in EMI and noise supression, you may have a look at those Murata`s papers:
    castleofargh likes this.
  8. bigshot
    With analogue tape, the noise floor depends on the tape speed and how hot you burn the signal into the tape. At 15ips at a good level, I generally can't hear tape hiss at normal listening volumes. It's perfectly fine. It's also quite listenable at 7 1/2 ips. Tape hiss is usually only audible in the dead spots between songs. But when I worked on tape, that was usually leadered up anyway. Analogue is capable of producing excellent high fidelity sound... it's just more work to maintain it because analogue has generation loss, so noise tends to stack up.
    Last edited: Nov 13, 2017
  9. GrussGott
    Having read the first 9 pages of this thread - which I would sum up as "I have selected a few facts and now believe I fully understand all audio and electronic phenomena and anyone who questions the finality of my conclusions must be delusional"*- so this seems like one of the worst threads on the site so I thought it'd be a good idea for me throw out my 2 cents. Which probably has already been said somewhere in these pages already.

    (1.) If it sounds better, then delusion or not I'm fer it
    (2.) if it sounds like blowhards pissing then I'm agin it
    (3.) I bought an Eitr and it sounds WAY better than without or via my optical input from my MBP

    The fact is, I don't know what's in that Eitr box. Could be well designed electronics doing good ear stuff or it could be a box of delusions or it could be machine elves. It really doesn't matter to me because it works and there is science to explain why that is, it's just that either nobody here or no humans know what it is.

    Some engineers at Cisco who design audio gear think USB cables make a difference because they scienced it out. There are also a few Google engineers (from both legacy tanberg and android) who say the same thing for the same reasons and have posted stuff somewhere. Could be the bathroom for all I know - they post a lot of sciencey stuff above the urinals.

    Anyway, it's something about chip sets and noise backing the chips up and the audio protocol doesn't ask for missed bits so filters have to fill in gaps and this causes audio quality degradation blah blah blah.

    The Eitr is a pretty sweet product that can help listening be better, is my point.
    Last edited: Dec 21, 2017
  10. D2Girls
    Haven't you heard, usb5 board from schiit audio is product of the year? :)
  11. gregorio
    1. That's your choice of course but IMO it's a poor choice. The problem with delusion is that just one simple piece of information, one new bias or one somewhat changed bias is all it takes to change or even completely dispel that delusion. So your "fer" spending money for something which "sounds better" for maybe just one instant or however long it takes for your perception biases to change? Personally, if I spend decent money on something I want better sound for longer than one instant, I want to know that I'm actually getter better sound and therefore whatever my biased perception is attempting to tell me from instant to instant, day to day can be dismissed as just a temporary delusion.
    2. Recording and reproduction technology is made by humans, according to the science known by humans. Whether or not there is something that science doesn't know or that humans don't know is irrelevant because we can only record what we know and can measure. If we don't know and can't measure something then we cannot record it and it doesn't exist on any of the recordings to which you are listening!
    3. I don't think anyone here is stating that USB cables don't make any difference, that's NOT what we're questioning. What we're questioning is if those differences are audible and if so why. The answer to this question is generally "no" but could potentially be "yes" if the DAC is effectively faulty. Your Eitr appears to be an example of the latter, a fix for a faulty DAC. If it were me, I would've returned the faulty DAC and demanded the manufacturer fix it at their expense or give me my money back. The VERY LAST thing I'd have done is spend another $180 with that company to fix their faulty device ... but that's just me, maybe that means I'm not a true audiophile/audiophool?

  12. castleofargh Contributor
    while your summarized quote does indeed fit with too many posts on both sides of the argument, what you do after is another emblematic aspect of going nowhere.
    your points (1.) and (2.) are saying that you follow your personal feelings no matter what is really going on. ok, so? at the end of the day we all do whatever we want with our ears. it's not the "how should I feel?" topic, we assume that you're going to do that just fine on your own. but here is an objective topic on how, how much, and why a USB cable can change something in the playback chain. so dismissing objective data means you have no interest in the topic.
    then in (3.) you want us all to know that you're happy with some magic box you bought. again, I believe we have appreciation threads for that kind of stuff. what's more, maybe it will come at as a shock, but it isn't a USB cable. ^_^

    then you proceed without really saying anything about how some people say stuff somewhere. we would prefer links or quotes with any data backing it up. then we could get somewhere.
    GrussGott likes this.
  13. GrussGott
    :smile: You're hilarious! If you actually want to know the science - and not just entertain us all with these posts - then interview some internetworking engineers who design USB connected audio products for a living - they have plenty of science-y stuff, but the answer to the question the thread asks is noise on the line overwhelms the receiver chip sets. Also, FYI, unless we're talking optical all cables are analog because electricity / conductor.

    But seriously - it would be trivially easy for you to get time in a lab at Google or Cisco; just show them three of your most certain posts. They'll spend HOURS with you.
  14. amirm
    The problem with that is if it is a false conclusion, the effect wears off. Have you noticed how often some folks go through audio tweaks? From one footer to another. From one cable to another.

    Well, I do. They advertise that all of their products are manufactured in US. That is actually false in this case. I have it on solid authority that they actually manufacture them by virgins on some tropical island (waterboarding was insufficient to get the name of said island from my contact). They apparently soak the component from juice of special variety of guava fruit juice that adds certain amount of sweetness to the sound. So there is no mystery there. If I had that juice I too could make all of my audio gear sound better.

    And folks sad there is nothing but useless commentary in this thread!!!
    GrussGott likes this.
  15. Strangelove424
    Does anybody in this thread have actual noise issues with USB? There's something I'd like to test. Just requires honesty, any USB cable, and black tape. No permanent change to cable. Must have noise present before hand. Thanks.
    bigshot likes this.
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