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Testing audiophile claims and myths

Discussion in 'Sound Science' started by prog rock man, May 3, 2010.
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  1. sonitus mirus
    There is not a lot separating 15kHz from 17kHz with regards to human hearing, as pitch is perceived logarithmically in relation to frequency. If put into reference with music scales, it would only span a couple of keys on a piano, provided the keys extended an additional 23 keys beyond C8.

    15kHz-17kHz.PNG [

    Try a tone generator using a tool like Audacity and see if the headphones behave similarly. There are simply too many factors to know for certain why any sound is present beyond 15kHz on YouTube videos. What you are hearing may actually be 17kHz, but from all of the information I have found, that sound is most likely not coming from the YouTube content that was playing.
     
  2. KeithEmo
    It's also worth noting that, at very high frequencies, it can be difficult to tell whether you're really hearing something or not.
    Therefore, if listening to a continuous sweep, or steps in order, it's easy to be misled as to at what point you can actually no longer hear anything.

    Unfortunately, there are also several limitations and issues with using separate files.
    Most audio players emit at least a small tick when they start playing a file - which provides a cue for when you might expect to hear something.
    Likewise, the audio generators in many editors are not perfectly clean, and so may add a small tick between sample frequencies they generate.
    These, again, may provide a clearly audible hint when the tone can be expected to start.

    There is a relatively easy way to compensate for this issue with a little planning.
    Create a series of test files, each containing five seconds of a single frequency, with the frequency SPOKEN AUDIBLY after the tone.
    Also create several files, using the same editor, containing five seconds of SILENCE, with that called out at the end of the file.
    Now play the files, one after the other, in random order.
    Any ticks or other "starting noises" present on the tracks with tones will also be present on the silence tracks.
    (By including the same cues on both tracks with tones, and tracks with silence, they no longer provide hinsts about when we should expect to hear tones.)

     
  3. castleofargh Contributor
    just in case, the video linked didn't give me the upper range signal, but some do. just play a random music video and chances are you'll get typical audio range spectrum.
    this one sweep works for me:



    or those test tones https://www.youtube.com/playlist?list=PLzFvCAfIq7a2SIBfDhpCytfJ4RHVb_KLY
    the traces in red are from playing 10 12 14 16 18 20khz single tones vids(firefox, no flash player. dunno if that matters or not but at least you know)
    osse.jpg
    16khz is just fine, 18khz is the one at lower amplitude and 20khz was a no show.




    to try older stuff, I went to get my favorite video clip in the universe, and it cuts off around 15khz, which is really sad because it audibly ruins an otherwise perfect song and perfect video.
     
    Last edited: Dec 24, 2018
    sonitus mirus likes this.
  4. gregorio
    No, they were in fact particularly good examples for the purposes of the test. The flaw in your reasoning, AS ALREADY STATED, is that you cannot make-up YOUR own "purposes of the test" and then cry foul because the test does not meet YOUR purposes. All tests have a scope and within the scope of this particular test, the test material used was entirely appropriate. If you've studied testing as you claim, how do you not know this? Maybe you do know but you're just misrepresenting it for some reason or maybe you were being "sarcastic" again?

    Ah yes, I was waiting for another of your "what if something exists", that doesn't actually exist! As inter-channel phase shift does not exist with 16/44.1 (or SACD), it's irrelevant whether humans can detect it down to 10 micro-secs, 10 nano-secs or 10 weeks. Again, this thread is titled "testing audiophile myths and claims", pretty much the exact opposite of what you're doing here, which is just repeating an audiophile myth without testing! Your "PERHAPS" has no factual, logical or scientific basis and if that's not bad enough, you presume to advise everyone else on applying logic and how to define "Pure Science". Maybe you were just being "sarcastic" again?

    Round and round and round we go!!!

    G
     
  5. KeithEmo
    You're quite right. AS LONG AS WE AGREE THAT, SINCE MEYERS AND MORAN ONLY USED A FEW SPECIFIC SACDS, AND ONLY USED A FEW SPECIFIC STEREO SYSTEMS, AND FAILED TO TEST OR DOCUMENT THE PERFORMANCE CHARACTERISTICS OF EITHER, WE CANNOT REASONABLY ASSUME THAT THEIR RESULTS APPLY TO OTHER STEREO SYSTEMS OR OTHER SACDs, then we are in perfect agreement. The test samples, and the choice of test systems, were perfectly appropriate for what they were hoping to prove. (They were hoping to prove that a sample of test subjects could determine no difference using certain specific "audiophile SACDs" and certain specific stereo equipment.)

    Since they used a few specific SACDs, and a few specific stereo systems, and failed to document the details of either, their results apply to the samples and equipment they used, but we have no way to determine how their results might compare to our own samples and equipment, or to generalize those results to any other equipment. Therefore, any claim or attempt to apply it to "all CDs", or "all SACDs", or "all stereo systems" is impossible. The error lies on the part of anyone attempting to use their results to support a general claim that "adding the CD quality signal loop would be inaudible in other circumstances, with other test samples, or with other listening systems". (WIthout doucmentation and measurements, we simply have no way to know how the SACDs and equipment they used compare to anything else, or whether they are "representative" of their respective classes in general.)

    Also note that, as usual, you didn't read what I wrote (or you have some difficulty with grammar). I DID NOT SAY THAT AN INTER-CHANNEL PHASE DIFFERENCE EXISTS WITH THE CD RECORDING PROCESS IN GENERAL. In fact, I agree with you that it does not. However, it's not impossible that that such a difference might be introduced by a simple flaw in their test equipment, or by a poorly written sample rate converter, or even by some weird error in the specific SACDs they chose to use. I merely pointed out that, IF such an issue existed, for whatever reason, it would be audible, BUT, SINCE THEY DIDN'T ADEQUATELY TEST THE PERFORMANCE OF THEIR TEST SETUP AND EQUIPMENT, we would have no way of detecting it later when we attemnpted to analyze the results.(That makes it "an example of how the limitations of their test might introduce an error" - no more and no less.)

    [I really am through responding here.... It seems clear that, rather than read and respond to what I actually write, you simply pick out a few key words, figure out some way you imagine you can prove they're wrong, and go from there. We aren't "discussing" anything... we are simply talking PAST each other.... which is a total waste of my time, and everyone else's.]

     
    Last edited: Dec 24, 2018
    TwoTrack likes this.
  6. analogsurviver
    Meyers and Moran test is flawed for all the facts cited. It "proves" only what they wanted to prove.

    But I DID SAY INTER-CHANNEL PHASE DIFFERENCE CAN EXIST WITH THE CD (PCM) RECORDING PROCESS IN GENERAL. Period.

    And I stand by this claim and I will, beyond any shadow of a doubt, present more than enough solid evidence that it can happen - with completely documented path, hardware and software that DOES fail in this regard.

    If it can fail in only one example I have unfortunately had the "privilege" to discover, that - by no means - means that there are no other soft/hardware combinations vulnerable to the same error when working in PCM mode.

    DSD is INHERENTLY free from inter-channel phase difference happening - and if this was its only advantage over PCM, it would still be the decisive one.

    And, YES, that is AUDIBLE. I will specify the exact "chain of events leading to disaster" that anyone of you can put together on your computer and test with your own ears using HEADPHONES.

    And that should be more than proof enough human beings ARE sensitive for inter-channel difference of below 20 micro seconds .

    Let alone FAR greater timing error any multi miking introduces per default ...
     
    Last edited: Dec 24, 2018
  7. analogsurviver
    In the spirit of time, the ultimate - for me, but not me alone - Christmas audiophile album :


    This upload has all the tracklisting and credits in the comments. Unfortunately, ALL the various versions of the same upload now available on YT made from the original pressing https://www.discogs.com/Oscars-Motettkör-Torsten-Nilsson-Marianne-Mellnäs-Alf-Linder-Cantate-Domino/master/384453 have the last five or so minutes cut off - I expect that is because of the last song on the album, White Christmas by Irving Berlin - and likely copyright ingingement problems.

    For the CD lovers, Silent Night from later CD release :


    And, in "glorious" 240p audio of YT ( YT is steadily reducing the quality of less played videos...), the White Christmas by Irving Berlin


    Cantate Domino is available as LP, CD, SACD and HR downloads ( both DSD and PCM ) - and is a testimony to the fact that excellent recordings have been possible , as proven in this case, at least from 1976 on.

    Merry Christmas to everyone - regardless of the format in which you prefer to play your music.
     
    Last edited: Dec 24, 2018
    raypin likes this.
  8. sonitus mirus
    Thank you for the correction. I was mistaken about the 15kHz cutout on all videos.
     
  9. bigshot
    The specs on YouTube uploads have changed over time, and they vary according to the resolution of the video. It depends on when it was uploaded and how high a resolution the video was.
     
    sonitus mirus likes this.
  10. gregorio
    1. No one, NOT me and NOT the authors, have claimed it applies to "all SACDs" or "all stereo systems" and incidentally you've missed a variable: "All listeners". It is clearly impossible to test all SACDs, all stereo systems and all listeners, I've ALREADY posted the quote from Meyer and Moran explicitly stating this and I even bolded it so you wouldn't (inadvertently) miss it. The ONLY person stating that this study "claims to apply it to all CDs, SACDs and all stereo systems" is YOU. Therefore, YOU are effectively arguing with YOURSELF!!

    2. No, that is NOT the error, there is no error, the test results DO "support a general claim that adding a CD loop would be inaudible in other circumstances". However that is all they do, the results of the test ONLY provide supporting evidence for the claim, NOT proof.

    3. Oh the irony! YOU didn't read what I wrote, you didn't read (or misinterpreted, mis-assumed and misrepresented) what YOU quoted and you apparently didn't even read what YOU, yourself wrote. You quoted Mayer and Moran but then misrepresented what they actually stated and then spent pages arguing that (your misrepresentation) of their claim was erroneous. And, YOU stated that their test results represented "reasonably compelling evidence" but since then you've effectively been arguing that it's not valid evidence at all, because they didn't document every detail (regardless of relevance)??

    4. The recording process (whether CD, SACD or anything else) ALWAYS contains an inter-channel phase difference! As two microphones (mic capsules) cannot occupy the same position in time and space, there will always be an inter-channel phase difference and it will ALWAYS be substantially more than 10 micro-secs (sometimes as much as several milli-secs). What doesn't introduce any inter-channel phase differences is the digitisation (and reconstruction) process, regardless of whether it's CD or SACD.
    4a. It's not impossible, pretty much nothing is absolutely impossible but it's exceedingly unlikely. I'm not aware of any DAC chips which suffer from this error and as the analogue signal (electricity) is travelling at about a third the speed of light, cables and other equipment in the chain would have to be very seriously different in length to introduce 10 micro-secs of inter-channel delay. However, such a delay from a listener's perspective would always exist, unless they were positioned precisely between the speakers to an accuracy of greater than 3.43mm and they never move from that position.
    4b. But what you "merely pointed out" was incorrect. 10 micro-secs of inter-channel delay is ONLY audible under specific conditions, conditions which did NOT exist in any of their sample SACDs (or any other commercial music SACDs). Again, your premise if false, all tests have a limited scope. They did not bolt the test subjects' heads in precisely the correct position (and neither do audiophiles or anyone else when listening to music), they did not measure or document humidity, temperature or air pressure, they did not measure or document the magnetic field strength of the Earth or gravitational waves or solar activity at their test locations, nor other variables which could "possibly" affect the signal. Not even the most rigorous of scientific tests can eliminate everything that "might possibly" affect the test, hence why they must always have a limited scope.

    DSD is inherently free from inter-channel phase differences occurring, exactly the same as CD. Please present your "solid evidence" to the contrary!

    15kHz was the standard upper limit for analogue video and analogue TV broadcast for many decades and even carried through well into the '90's when much/most of the chain was digital. It's only really with fully digital systems and HDTV where the 15kHz cut-off was dropped. This is maybe where your confusion originated?

    G
     
    Last edited: Dec 25, 2018
  11. Phronesis
    Since the crowd around here is a skeptical bunch that doesn't assume that price necessarily correlates with sound quality, I'm wondering, have you guys given the Sony MDR-Z1R a listen? It's their TOTL $2300 headphone. I tried it over the past few days and find that it sounds like crap, the tonal balance is just a mess. I'm wondering if some people like it because they expect to like it, are influenced by some favorable reviews, and haven't bothered to compare it with other headphones with some controls. A lot of people on head-fi who say they like it say they didn't like it at first, but the sound got much better after many hours of 'burn in' and/or upgrading to an expensive cable. I boxed it up today and will be returning it tomorrow, a week before it's due to back to the shop.
     
  12. sonitus mirus
    I've always seemed to enjoy what Sony considers to be their "house" sound. Though, I would not spend this kind of money on headphones, as headphones are merely something used for specific, rare situations in my experience. I'll take speakers every time, the more the merrier. Was there any type of music that sounded best with the Z1Rs? That 70mm driver is enormous.

    Speaking of too much money, I was browsing MSB's latest DACs and noticed this odd statement:

    MSB Grammar.PNG

    http://www.msbtechnology.com/DACS/select-features/

    I can easily underestimate the importance of clean power, at least with regards to the absurd levels they seem to take it. I believe they meant to say that the importance of a clean power supply cannot be overestimated.

    Just making fun of the fabulously wealthy to get my jabs in where I can. :)
     
    WoodyLuvr likes this.
  13. Phronesis
    Delete
     
    Last edited: Dec 31, 2018
  14. Killcomic
    Just once I’d like hear someone say: “I burnt in my headphones for 48 hours and now they sound utterly rubbish”.

    If there us an actual change in sound, why is it always an improvement?
     
    gargani and WoodyLuvr like this.
  15. dprimary
    I burnt my old near fields in for about 23,000 hours and they sounded rubbish when I was done.
     
    gargani, Killcomic and WoodyLuvr like this.
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