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hypersonic effect discussion

Discussion in 'Sound Science' started by kiteki, Jul 6, 2011.
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  1. Anaxilus


    Quote:
    So you aren't debating whether humans can perceive infrasonics just whether headphone drivers can reproduce them?
     
    Plus I thought I was clear in my post the degree to which I uphold those values and wish to participate.  Largely because people have reading problems on threads like these.
    ______________
     
    Didn't recall seeing it posted so just in case.  
     
    http://en.wikipedia.org/wiki/Infrasound
     
     
  2. Head Injury
    Quote:

    No, but I am debating your claim that Sony is a big proponent of supersonic playback.
     
    Or infrasound for that matter, but I was under the impression we were talking about what the thread is about.
     
  3. Anaxilus


    Quote:

    That's what I thought but you asked for graphs of various drivers.  What does that have to do w/ the audibility of hypersonic, ultrasonic or infrasonic frequencies? [​IMG]
     
     
  4. Head Injury
    Quote:

    Nothing. I never said it did. You claimed that Sony was a proponent of such frequencies, and used misleading and incomparable frequency ranges to support your point. I'm asking for graphs to determine whether or not Sony actually does utilize these frequencies any more than other manufacturers, because the numbers you quoted are basically meaningless.
     
  5. Anaxilus


    Quote:

    Maybe this is easier for you to take in.
     
    I ******* hate this forum.
     
     
  6. kiteki
     
    Some people look in shop windows and don't know the human hearing limit of 21kHz or so, just like TV's with 1:10000000000 contrast ratio, that must look good. :)
     
    I think the dumb thing about SACD is the labels which take old recordings and 'convert' it to SACD, what's the point in that?  That won't have any benefit at all for 2-channel, if they want to upmix to 5.1 channels, they should release it on DVD-A, like the Björk Surround collection which she remastered herself.
     
    No point buying an SACD player (or DSD device) to listen to a 4-channel upmix, like Bluebeard pointed out, the benefit (whether audible or not) is in the recording technique itself, which differs from PCM.
     
    Now, some label didn't like the fact you can't master DSD, so they came up with DXD, so if I understand it correctly, DSD recordings is the only interesting part, .DSF format, as long as that was the recording technique.
     
     
  7. Mischa23v
    Dear ben,

    Firstly, I would like to apologize for what I said in beginning of my previous post. I was a little moody and tired and acted very immaturely when I wrote it. I’m deeply sorry and I assure you that I did not mean it. You brought up a lot of interesting points that really got me thinking.
     
    Thank you for sharing those sites, I’ll be sure to read them thoroughly. I do agree with some of your highlights, but not everything.
     
    Here we go:

    1. “A million things? Well, I am in fact rather confident that there's a million mathematical proofs and philosophical deductive arguments. But everything else - yes, faith, emotions, etc. - we can measure to some degree” - unfortunately as a MD, psychiatrist I can assure you with absolute certainty that we cannot measure love in anyway or degree. However, it’s not really relevant. Please feel free to link me any research that proves otherwise. We're talking about love though not affection or attraction or anything else.
     
    2. I’m sorry but I couldn’t follow your point when you meantioned formal listening.
     
    3. Is that so? Could you explain how the upper frequency hearing limit in humans decreases with age as a function of damage to the cilia hair cells in the cochlea then?
     
    “There are many causes of presbycusis. Most commonly it arises from changes in the inner ear of a person as he or she ages, but presbycusis can also result from changes in the middle ear or from complex changes along the nerve pathways leading to the brain. Presbycusis most often occurs in both ears, affecting them equally. Because the process of loss is gradual, people who have presbycusis may not realize that their hearing is diminishing.” I’m not following what your trying to imply here
    Our ears are extraordinary organs that are purely mechanical. Thus, allowing us to scientifically determine their limits. The brain determines the pitch of the sound based on the position of the cells sending electrical impulses. Louder sounds release more energy at the resonant point along the membrane and so move a greater number of hair cells in that area. The brain knows a sound is louder because more hair cells are activated in that area. However, look at all research that has been done. By determining which hairs move at which frequency you can determine the real limits of human hearing. In all medical research I found, the real range in a very healthy child’s ear should be from 8hz to 33khz. So where did the 20hz to 20khz come from?

    “If humans could hear to 0 Hz, though, for example, we would be bombarded by useless low frequency noises all around us. From an evolutionary standpoint, 20Hz-20kHz, seems to cover most of the useful noises to survive, communicate, and procreate.”

    “Because predators that chased humans (big cats, wild dogs and other humans) only communicated in that frequency. Also it is the dynamic range in which we (Humans) generally communicate, so we had no need for other frequencies. After generations of natural selection we ended up just hearing in this range.”

    “Hair cells in the inner ear are of various lengths, to resonate at various frequencies. For whatever reason, it is no longer an adaptive advantage to hear ultrasonic noise, so evolution dropped that range of sound from the human genome. Evidently the range of 20 to 20,000 Hz is adequate for our needs.”
    4. And how is that attribute manifested and passed on? Physically through our genes?
    Babies are afraid of loud noises and falling why is that true? They were born with those fears. genes are memory blocks that hold way more information than just appearance. People are afraid of black animals because in past at night they were much harder to see and were more likely to bump into them and get attacked by them. Of course most would say it’s because it’s bad magic or what not. Why do you learn to talk when you’re so young? Language is way more complex than people tend to believe. From finite number of letters you can make an infinite number of sentences, and no matter how you arrange them you can still understand them. Each language follows an exact mathematical equation. You’re born with ability to understand language in any form it comes in.
    The traits that you find attractive in women for example are traits that are handed down to you by your ancestors. Traits handed down through thousands of years of experiments which allowed them to produce the healthiest babies. Those traits are what you perceive as being attractive. Anyway this isn’t really important either.
     
    5. Not true, it's a physical limit within our cochlea. Not true at all, all research I have seen indicate that it’s a mental limit.

    There is this really awesome invention for blind people. It’s chip implemented in blind people’s tongues that feeds them sensory information through tongue. It’s really cool cause they can actually see with it. Not as we see but still they can see stuff. The most intriguing part of research to me was that even if you send information that a normal person shouldn’t be able to see like stuff coming at them from behind or stuff that a normal person cannot see. Even if you send those signals they’re still unable to see them. So even though the brain is receiving something that it normally shouldn’t, it chooses not to process new information.

    “Training helps listeners, yes, but no amount of training has been shown to make humans magically hear (not see) the difference between 44.1 kHz and 96 kHz sampling rates.”

    Hopefully you will enjoy reading this as much as I did:
     
    Many scientifically minded types will offer the results of such A/B (and often A/B/C tests where one choice is secretly offered twice) as proof that there's no audible difference in one thing or another, such as 24 vs 16 bit, 44.1 vs 96k, x amount of tenths of a db of level difference and so on. To them, the "science" is inarguable. I say, if they want to take it as such, then they should go ahead and knock themselves out.
     
    It is interesting nonetheless. I myself have actually "failed" some of these tests, in spite of "passing" them repeatedly when they're somewhat less formally set up, and in my regular day-in day-out work as a recording engineer [*see note at end of post]. There is no question in my mind that 24 bit sounds different and better than 16 bit, and that 96KHz rates are slightly better sounding on less than exotic converters than 44.1.
     
    But the scientists drone on about their "proof", and given that I have experienced some of the same "comparison confusion" in formal testing that they offer up as such, it's led me to ponder what the deal is here. As I said before, I know I can hear the difference, have done so innumerable times, and will not ever accept the notion that it is in my imagination. Please take that as a stipulation, at least on my side of the discussion, because it is, and will remain, non-negotiable. Thanks.
    So...what gives then...why do even decades-trained golden-eared types like me get tripped up sometimes on these tests when the rest of the time it's pretty much a no-brainer? I have a theory, and I suppose that's all it is, but anyway, here goes:
     
    The problem is inherent in the nature of the tests due to their necessarily temporally-shifted presentation (listen to "A", *then* B" and/or "C"), and the utterly fluid, innate temporal instability of the material itself (music). For a listener to decide which of A/B or A/B/C is the same or different, they must mentally "catalog" a series of brief impressions of the precise nature of "A" in *every single detail* for a given amount of time before listening to "B", doing the same, and then mentally weighing their *memories* of the two extremely complex data sets against each other. So the listener not only must memorize all details of "A" at any given moment in time, but also an entire ever-shifting *stream* of "A". Then compare that to a similarly ever-shifting stream of "B". Pretty challenging stuff...
     
    As I shamelessly bragged earlier, and here I go again, I have some seriously trained hearing, and can do the above pretty well. Even so, I find myself trying to store an overwhelming number of data points - the reverb had that sense of depth and breadth at one moment, the cymbal had this amount of top end at another moment, the vocal's midrange had that degree of warmth at yet another - and so on, and on and on. After a few turns around the A/B/C listening merry-go-round I...sometimes...fall off.
    If I may be forgiven for my now-uncontrollably escalating arrogance, your typical "experienced listener" can't shine my shoes in this classroom. Why? Retention of the critically relevant information is virtually impossible without serious training and experience given the test circumstances: time offset and the inherently elusive nature of the material. It's hard even for highly trained experts like...you know...
     
    The problem is similar to a conventional memory test: verbally give a test subject a list of words and numbers to repeat, and the average person will fail almost every time on a list that only takes about 10 seconds or so to recite.
     
    So, "scientific music listening comparisons" with this type of critically limiting factor are, in my humble opinion, only useful in a very rough, general way, and thus are not really "scientific" at all, in the strictest sense. Bear in mind that it would be a very simple matter to assemble a group of normally-abled listeners who could provide statistical "proof" that an MP3 compressed version of a music track sounded "the same" as the uncompressed original. Ask a few teenagers about it.
    The problem is that since there's no really good way to do this test, thus making the above the "most scientific" one we can manage, it's given the same kind of credibility that other, much more inherenently valid tests do in fact deserve.
    Visual ones, for example. If we set aside deliberate optical illusion "trick questions" such as comparing same-sized circles either inside a larger, contrasting colored circle or against a white background (they will appear different), a visual comparison is a good counterpoint:
    A test subject is shown two drawings of a tree side by side and asked to report on any differences. In case one, the drawings are on the same page. The test subject can easily spot differences in height, color, contrast, detail and so on by looking at both drawings simultaneously. Even if two separate drawings are shown with a short time lapse between the viewings, we're still looking at a static image. The viewer can focus *indefinitely* on any part of the images to compare them (unless a temporal limitation is deliberately introduced). This will produce results that are hard to dispute. Not so with strictly temporally based material.
     
    Remember the infamous "New Coke" taste test that "proved" it tasted better than "Old Coke"? It's not entirely equivalent to sound, but it was similarly scientifically flawed, with similarly dubious results.
     
    One last point - here's a revealing little test to try on a few different people: play them a fairly simple recording involving, for the sake of discussion, piano, cello, flute and trumpet, and then ask "what instruments are in this recording"? I have personally heard people answer "I can never identify any of the instruments in a recording". Critical listening's not so easy for some of us...
     
    Bottom line:
     
    Music is fluid, invisible, and inherently unstable. Conventional scientific testing methods are not adequate where establishing supposed proof of the difference or lack thereof between such subtle distinctions as 16 and 24 bit or 44.1 and 96 KHz are concerned.
    End of rant. Sorry for the long one!
     
    [*Note: actually, I should have mentioned that the only formal listening test I "failed" was a .1db level difference A/B/C test. I've also passed it repeatedly under different circumstances. Conventional scientific wisdom has it that the smallest audible difference is .2 or .3db]
     
    Kay try this,
     
    Have someone show you a picture of tree and another picture with same tree but some of branches have moved cause of wind. If they show it to you side by side you will easily spot differences ( at least I did). But if they show you first one, then show you second one after hiding first one? Would you really be able to spot difference (because honestly I couldn’t, I didn’t know where to start looking)? Just because test made it really hard for you to spot difference doesn’t mean that you are unable to. I know for a fact that I can tell the difference between 44.1 and 96k recording with good equipment.
     
    Best wishes,
    msicha
     
  8. kiteki
     
    Mischa are you capable of discerning the difference in for example Linn Records downloads, 16/44 versus 24/192?
     
     
     
  9. Mischa23v
    I remmeber reading something about a futuristic form of capital punishment might be the Lethal Sound Chamber (instead of lethal gas). strap the condemned into a sound-proof chamber and expose the poor S.O.B. to 400 dB ultrasonic SPL. that'll do more than damage his hearing.
     
    Originally Posted by kiteki 
    I'd venture the only conclusive data is we can't 'hear' that extension, the issue arises when we can 'feel' or 'see' frequencies lol.
    I mean, you can make a window break at a specific frequency, so who knows if you can't make a brain break? Just theory of course.
     
     
  10. Mischa23v
    Let me put it this way, I can tell difference between 16bit and 24bit way easier than telling difference between 44.1 and 96/ 192. (Using capable equipment)
     
    Quote:
    Originally Posted by kiteki
    Mischa are you capable of discerning the difference in for example Linn Records downloads, 16/44 versus 24/192?
     
     
  11. kiteki
     
    Then why not perform a blind test between 16/44.1 and 24/44.1.
     
  12. Mischa23v
    Think of a way to test people without having to rely on how good their short term memory is. I've tried cutting a song to parts with some being at 44.1/16 and others being at 44.1/24.and listening to all of them. Out of 8 parts I was able to guess 2 parts with absolute certainty. However, My Fiancé who happens to be a sound engineer was able to correctly guess at a much higher success rate. If I remember correctly he only made a mistake with 2 of parts.
     
     
  13. Head Injury
    Quote:

    Well, for one, 2 of 8 and 6 of 8 aren't very statistically significant. For two, didn't you know which parts were which if you placed them manually?
     
  14. BlackbeardBen
     
    Quote:

     
    Okay, here goes a (relatively) short reply:
     
     
     
     
    1.  Regarding the emotion/feeling of love, I do not mean to say we can entirely quantify it or our brain (yet - maybe we will long in the future) like we can a computer circuit, software, and output.  What I mean is that it is not entirely unmeasurable:
     
    http://www.scientificamerican.com/article.cfm?id=graphic-science-passionate-love-in-the-brain
    http://www.insidestory.iop.org/mri.html
     
    It would not be unreasonable to think that it may be possible to measure one's love for different people/animals/whatever by the strength of the activity in these regions of the brain.  Perhaps even type of love is distinguishable even now - lovers versus family, for example.
     
     
     
     
    2.  I mean formal listening where one undergoes actual, calibrated and measured training to identify different aspects of sound.  Like I said, Harman offers the software to do some of this absolutely free of charge.  They use it for training testers for their own internal audio testing (blind and sighted):
    http://seanolive.blogspot.com/2010/12/how-to-listen-course-on-how-to.html
     
     
     
     
    3.  Regarding the upper frequency limit of human hearing, I'll I'm trying to get at is that it is a physical limitation in our ear and its nervous receptors, not a case where our brain does not consider extraneous information (which it of course does with all of our senses including hearing).
     
    Sources?  I spent way too much time looking this up as it seems that no one else really cares whether it's our brain or our ears that limits our hearing range, except those scientists that are studying the exact mechanisms of our ear.  However:
    http://www.tufts.edu/~rwhite07/PRESENTATIONS_REPORTS/PNAS_INPRINT.pdf
    http://www.neuroreille.com/promenade/english/ear/inear/inear.htm
    http://www.pnas.org/content/99/5/3318.full
    http://physrev.physiology.org/content/88/1/173.full#B._Cochlear_Bandwidths_and_Models
     
    And a bit on the cochlear amplifier:
    https://iris.ucl.ac.uk/research/browse/show-publication?pub_id=206298&source_id=3
     
     
     
     
    4.  I don't think we have any disagreement here.
     
     
     
     
    5.  I'm sorry, but that post you copied from dvxuser.com (It'd be prudent to link to the original post or at least cite it) unfortunately does not refute the validity of blind testing in audio.  Yes, blind testing is not perfect - it does take time to switch between samples - but if you do blind testing properly, you absolutely minimize the problems it has.  How do you do this?  With testing audio files, it's absolutely trivial: Use Foobar2000's ABX Comparator.  It allows instantaneous switching between time-aligned files, and allows you to set where you start the sample.  What does this mean?  That you can repeatedly listen to a single detail time and time again with no lag between the different samples.  Why is that important?  When there are subtle differences between two samples, testing has shown that the easiest way to identify between them is to listen to short samples so as to minimize the loss of auditory memory.  However, if you think that the stress of such testing causes you to hear no difference, you can spend days listening to each sample before you make a decision.
     
    The claims against blind testing, while based on a tiny grain of truth (that you can never prove the null hypothesis that there is no difference between the two samples - except mathematically as in the case with FLAC vs. WAV) - are blown out of proportion and fabricated as a red herring against the far greater, fatal flaws of sighted listening tests:
     
    Sighted listening tests are fatally flawed by biases that are entirely eliminated by double blind testing.  Expectation bias in sighted listening will influence you to hear what you expect to hear - even subconsciously.  Cost, perceived quality, and other reviews will influence what you hear, even if there is no audible difference in the sound alone.  These effects can be huge, and are measurable (by comparison with blind testing):
    http://seanolive.blogspot.com/2009/04/dishonesty-of-sighted-audio-product.html
     
    Now, you may ask about potential bias against hearing a difference, by those who don't think that they will.  That's a legitimate concern - but there is a workaround.  Testers can actually "trick" the testees by either telling that one thing is being changed in the blind test (that you would expect to hear a difference from), or by not revealing at all what is being tested.  You can't do this yourself at all, of course; not without some serious programming anyway.  But it is possible to work around this potential bias.
     
    Another thing you have to consider is the sum of all the evidence - that is, many tests.  I don't spend my time doing statistical analysis of testing, but there are those that do and can explain this in much better detail.  The gist is that a few passing tests out of many fails can either be out of pure chance (i.e. a false positive) or out of an actual percieved difference (an actual "golden ear" type situation).  When large scale tests or compilations of other tests have this happen (and tests with many participants but relatively few trials per participant invariably have these happen), you have to do further testing on those individual case subjects to determine which of these possibilities is the case.  Without doing so, you can only take the data as a whole.  For example, if you do your tests with the normal level of significance of 0.05 - that is there is a 5% chance that the results are caused by guessing - 1 out of every 20 studies where you are guessing is going to be a false positive.  That's pretty high, isn't it?  Hence, if you do many short tests, you will get a false positive here and there.  This is why reproducability is vital.
     
    So my point is that while blind testing is not perfect, it's the only way to remove your personal concious and subconcious biases from the testing, and thus the only valid way to make comparisons when we are dealing with minutae differences.
     
    Also, I don't mean to imply that it is impossible that there are audible differences between properly dithered 16/44.1 and higher resolution music at normal volumes.  But dither makes a big difference as you can see with the link to #10 here: http://www.head-fi.org/t/513481/are-blind-tests-bogus-examples-of-blind-tests-with-positive-results  Incidentally, that thread (the one by Prog Rock Man) shows how blind testing actually works when there are in fact audible differences.  That gearslutz thread is very promising regarding actual audible differences, actually - but with good dither, it's clear that if there are in fact audible differences they're absolutely tiny.  That's why I don't worry myself about taking up the extra space - if the differences between Redbook and high-res audio are that near-impossible to detect but under certain circumstances they are in fact barely audible in blind testing, I'm not going to worry about it.  There's far bigger differences to be made, and far more important things to spend time on.
     
    Oh, and here's another (large, this time) study for you: http://www.bostonaudiosociety.org/explanation.htm
     
    That said, just for a factor of safety regarding possible audibility of dither noise and allowance for filters at high frequencies, I would go so far as to say that 20 bit, 48 kHz audio is likely the sweet spot.
     
  15. kiteki
    I'm taking the liberty to revive this thread to discuss the Pras & Gustavino paper which you can read here - http://mil.mcgill.ca/wp-content/papercite-data/pdf/pras_sampling_2010.pdf
     
    "Findings from the listening tests suggest that expert
    listeners can detect differences between musical
    excerpts presented at 88.2 kHz and 44.1 kHz.
    Moreover, the qualitative analysis of verbal
    descriptors indicates that these differences were
    perceived in terms of spatial reproduction, high
    frequency content, timbre and precision. However,
    the ability to perceive these differences depends on
    the format comparison and musical excerpt. Listeners
    could significantly discriminate between files
    recorded at different sample rates only for the
    orchestral excerpt, the only recording of a complex
    scene with different musical instruments playing in a
    medium concert hall. This finding provides support
    for theories that high-resolution formats..."
     
    (cont.)
     
     

     
    I'm also interested in discussion on how to ABX subliminal stimuli, such as subliminal advertising, do you think this is even theoretically possible, or is an fMRI required?
     

     
    Lastly, I noted there is a 0.75 second interval in the ABX switching in the 24/44 vs 24/88 test.
     
    I think it's possible such slightly longer intervals could help the acuity of the listener, since I think time-aligned, volume-matched 0.1 second switching could introduce an illusion of unity.
     
    An example I can think of is when trying perfume, if you switch rapidly between two different (however similar) perfumes, it's difficult to identify the differences - however, if you take a short pause such as 6 seconds, or smell coffee beans inbetween the two perfumes, you can more accurately identify the uniqueness.
     
    This could have to do with pattern identification, since the human mind likes to quickly process long sequences of information ー it's not designed to juxtapose instantly vaporising high velocity scintillation in raw data!
     
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