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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. bigshot
    If this is his show, he needs a theme song.
  2. analogsurviver
    You have - obvious from above - always worked witH mixes. Which go trough MANy electronic components and who knows how many manipulations ( baNdwidth limitting, compression, de-essers, plugins, etc,etc - which, each and all, have resolution / bandwidth limitations) - and are, according to my definition , already - FUBAR.

    You would have to use something clean and pure to begin with - noth something that went trough the normal studio workflow. And you would have to use equipment that does support bandwidth at least to 40 kHz. It has been possible for more than 40 years - so no excuses are possible on this count.
    Last edited: Dec 21, 2018
  3. Steve999
    I am just outside a concert hall and in an hour will be listening to a live choir with brass, strings and percussion. If someone could please tell me what to listen out for for the unattenauted effects of 40 kHz I would be most grateful. :robot:
    Last edited: Dec 21, 2018
  4. Phronesis
    Just get close to the instruments. The elation you feel from basking in the ultrasonics will be obvious. :)

    Merry Christmas to all who celebrate it for real or just for fun!
  5. old tech
    The reaction on that thread is hardly surprising. It is a SACD forum and anything that challenges their beliefs, no matter how well supported, would invoke a strong negative reaction.

    It is no different to carrying a pig inside the Sistine chapel.
  6. old tech
  7. KeithEmo
    I'm not going to make any specific assertions about reasons here.....
    However... here is a general suggestion:

    If there are cymbals, listen to the cymbals when they crash, and try and fix in your head the part of their character that makes them "sound like metal hitting metal".
    And, if there are any spots where the cymbals are hit with wire brushes, try and fix the sound of "little scratchy wires hitting a big metal plate".
    Think about the "tss tss" sound escaping steam makes... and how this is UNLIKE that sound.
    And, if there are trumpets, listen to the sort of sharp ripping sound they make when they get loud.
    And, when you go home, see if the recordings you have seem able to deliver a convincing imitation of the way they sound.
    Those are the things that I've generally found most recordings to fail to reproduce with convincing realism.

    And, if you don't think any of your recordings manages to sound exactly the same as the real thing, try and figure out why.

    analogsurviver likes this.
  8. Phronesis
    As we discussed before, I suspect that the difference is due to acoustics, rather than presence vs absence of ultrasonics. A difference in how 10-20 kHz is presented to our ears in the two settings seems enough to account for the perceived difference.
    gargani and old tech like this.
  9. Killcomic
    I've never been to a concert where things sounded different to a recording. In fact, the sounds tend to be less immersive as instruments are mono, and the sound seems to come from one direction as opposed to funky stereo effects.
    So I guess recordings do sound different to concerts, but it's not the quality of the instrument sound. It's the positioning because it would sound flat otherwise.
  10. KeithEmo
    I suspect you could be right.

    I should also note that I am not a fan of classical music.
    And, when you see a rock or pop band "live", you're often just listening to a public address system anyway.
    (And it is often not nearly as good as a high quality home system.)

    And, yes, the acoustics of a home are not likely to be a good match for the acoustics of a concert hall.
    (But I would expect a good recording, played through headphones, to be able to deliver the sound of the hall somewhat better.)

    And, finally, I have had the opportunity to listen to rock bands play, from within a few feet....
    And, at that range, I find the cymbals to be unpleasantly loud, and unpleasantly harsh....
    (So, in terms of being enjoyable, I'm not convinced that I would want them to reproduced accurately.)

  11. KeithEmo
    I can't tell....
    Most of their other products seem to be at least somewhat reasonable....
    And they are a well established and "reputable" brand....
    But then I see a "carbon ring" which is supposed to help neck pain, can be worn as a bracelet, and is also claimed to improve room acoustics.
    (These seem to me to be the audiophile equivalent of "homeopathic remedies" - which notably seem to be considered to be "legitimate medical products" in the UK.)

    Bear in mind that there are companies who sell "special fuses" which are supposed to make your audio equipment sound better...
    And I've even seen page-long discussions about which way they're supposed to face when you install them :)/

    If you want to check out some really outlandish claims, check out "Machina Dynamica" or Google "Peter Belt".

  12. Killcomic
    Last edited: Dec 22, 2018
    old tech likes this.
  13. castleofargh Contributor
    *castleofargh puts on his devils advocate costume*

    we all agree here that this is 1337% snake oil product?
    I know why I believe that. but given how you're always on the cautious side of things saying that we need to know for sure before drawing conclusions, I wonder why you're not defending this the same way you've been defending various hypotheses pulled out of a hat and not supported by any clear evidence? on such a product, shouldn't you weight in with a strong "maybe, maybe not, we cannot say"? where do you draw the line? if you allow me to reuse an argument from a few pages back, maybe in the future we'll discover some tech that will let us measure the very real benefits of that wooden piece of crap, and optimize its use. meanwhile we might want to keep it around for the day when it might become more relevant.
    and maybe water has a memory and sugar pills are more than that when made with the moronic dilution process? it's not like we have definitive evidence that those can never cure anybody from anything. we have only consistently failed to demonstrate an effect.

    *takes off costume*
    this IMO is the real danger of demanding highly conclusive science before rejecting an idea, instead of requiring highly conclusive science to support that idea before we do the same. all this is in some ways very similar to the audible benefits of hires? many people will come saying that they clearly perceive an effect and will share a great many anecdotes about it. while experiments on those same people will typically fail to support their claims. from where I stand, all similar situations should lead to rejecting the ideas, at the very least until supporting evidence is brought out.
    Last edited: Dec 22, 2018
    bfreedma, old tech and gregorio like this.
  14. KeithEmo
    I THINK we all agree that this one is snake oil (or perhaps tree sap)?
    Although it is by no means the most far fetched product currently for sale.

    The answer to your question is simple.... although not as concise as one might like.

    The reason is that there is no reasonable scientific basis for any mechanism by which holistic dilutions might even possibly work.
    We actually know a lot about chemistry... and especially the chemistry of water.
    And, as it turns out, we know that there is no theoretical mechanism present by which their claimed "trace memory" could occur.
    (Not only have the failed to show that it DOES occur; they have failed to provide an explanation of how it MIGHT occur.)

    Likewise, as far as I know, there is no known mechanism by which a small wooden block could or would cause a significant alteration in room acoustics.
    The effect of adding a piece of wood to a room can be quite accurately calculated, it would turn out to be minor, and there are no major unknowns in the equation.)
    (If they had presented a plausible theory, consistent with at least some known science, about how the wood block MIGHT affect room acoustics, then testing the claim would be justified.)

    If we actually knew exactly how human hearing and perception worked in detail we could make similarly accurate assessments there.
    However, in fact, while we know a lot about some aspects of it, we still don't know much about others, so we are unable to make accurate predictions.

    We have some very detailed and presumably accurate information about how humans consciously percieve continuous sine wave signals within a certain frequency range at various SPL levels.
    (When we play frequency sweeps for people, at different levels, we know when they hold up their hands indicating that they heard something.)
    We can also make some pretty reasonable inferences about how we humans consciously percieve frequencies outside that range.
    (When we play frequencies outside that range, at reasonable levels, people DON'T hold up their hands indicating they hear something.)
    Note how, when I actually phrase what we know accurately and in detail, it seems somewhat limited.

    Here's an interesting sample of what you come up with when you analyze things like this somewhat carefully.
    The generally accepted frequency range of human hearing... for continuous sine waves... is 20 Hz to 20 kHz.
    And, by the basic math, a 44k sample rate is perfectly adequate to reproduce any frequency below 20 kHz.
    This would seem to suggest that 44k is a perfectly adequate sample rate to record audio for humans.

    Now, note that the time interval associated with a single sample at 44k is about 25 microseconds.
    Now, let's look at what might happen to a transient signal (any signal that starts suddenly).
    Many DAC filters add multiple cycles of ringing to the beginning or end of transients.
    So, WOULD a single extra cycle of ringing added to one channel be audible?
    Well, if you do the math, adding one cycle of ringing to the start of the signal will cause it to begin 25 microseconds sooner.
    And we know, from several well documented tests, that humans can detect a phase shift between their left and right ears of as little as 10 microseconds.
    So, according to those tests results, a single cycle of ringing added to one channel would produce an error that was more than DOUBLE THE MINIMUM LEVEL OF HUMAN AUDIBILITY.
    Therefore, there is a perfectly reasonable mechanism by which it MIGHT HAPPEN.

    I personally suspect that this effect would probably be beyond the ability of our brains to detect or notice.
    And, it should rerely if ever be the case that ringing would be added anything other than symmetrically.
    HOWEVER, in fact, a single cycle of ringing at 44k is NOT "obviously beyond our physical ability to detect" after all.
    That means that it would probably be a good idea to run a few tests and find out ifi it's audible or not (rather than make an ASSUMPTION that could be wrong).
    (That way we'll know whether we have to worry about a single cycle error or not.)

    And, just a bit of perspective, for those who think "we've known all about human hearing for a hundred years"....
    We didn't figure out that a bacteria causes stomach ulcers until 1982.
    (And a lot of people were convinced we knew a lot about medicine before then.)

  15. gregorio
    1. "And, just to be clear, it's really nice that you're convinced that" misquoting me is a valid argument!!
    2. The tests were done and the students could not hear above 18kHz. Can you please explain how reproducing freqs that NONE of the test subjects could hear, could have affect the results.
    3. Did it occur to you that the systems used represent extremely (or beyond) competent systems compared to what even ardent of audiophiles own. Or, are you saying that some cheaper, consumer or audiophile systems are superior to a SACD mastering facility?
    4. At least you're consistent, you're misquoting yourself as well as me!
    5. And you would definitely not have got a passing grade in my university and I should know, as I was responsible for awarding the grades!!
    1. Which is yet another self-contradiction! How can you be waiting for proof "either way" when you've already stated several times that science cannot prove a negative? Are you going to wait for "legitimate scientific proof" until you accept the theory of evolution, climate change or numerous other examples? Are you going to wait for "legitimate scientific proof" that Santa, flying pigs or unicorns don't exist?
    2. You keep saying that but you never do. Round and round and round we go!!

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