Ultrasound audibility

Discussion in 'Audio Science' started by Serious, Jul 7, 2019.

?

Is Serious losing his mind?

  1. It sure seems like it

    8 vote(s)
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  2. No, more research needs to be done on the limits of human perception

    18 vote(s)
    62.1%
  3. Maybe

    8 vote(s)
    27.6%
Multiple votes are allowed.
  1. Serious

    Serious Inquisitive Frequency Response Plot

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    Alright, you know how the saying goes - measure twice, cut once. Well, this is similar. With the UMIK connected to my noisy PC I couldn't make out the intermodulation distortion in the FFT, but with my laptop I can. They're still very low in level - the loudest tone is at -9db and another one at 6kHz at -10db, which should be well below the threshold of hearing, so I'm not entirely convinced that that's what I was hearing, but it might be more likely than hearing 30kHz at 80db. Note that to get the noise this low I put the mic as close to the driver as I could (less than 10cm from the voice coil). I measured the FR at that position and at my testing position 5m away from the driver and lowered the level accordingly (18db). If anything the tones are even lower in level than this, but the FR is close enough in the range of interest. The tones are about 80-85db lower in level than the 30kHz tone should be. I might add some -70dbfs white noise to try to mask the IMD and see if I can still hear something. Or I could try to cancel out each of the three tones.

    Here's the FFT: 1M Length and a couple averages, so a few minutes per each measurement.
    [​IMG]
     
  2. Serious

    Serious Inquisitive Frequency Response Plot

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    Well, I think I'm actually losing my shit. I made a google drive folder with the files with -70dbfs white noise added to them to mask the IMD, but I think I can still hear a difference between the 30kHz file and the one with just the noise. It gets very hard after a couple tries though and I need to wait for a couple minutes so I can concentrate on it again. The -70dbfs vs no noise was even harder - I only had the output set to around 80db corresponding to 0dbfps, too. Maybe slightly less around 78db.
    https://drive.google.com/drive/folders/1k8ONZbCi0vWSvLoZ5t9w9rKUPcta_QvY

    Feel free to give it a try. I should probably give a psychiatrist a try. At this point it could be placebo too, but I used the ABX comparator tool in foobar.

    FWIW I don't really give a shit if my music contains information past 15kHz. I'd much rather have a low noise recording than one that goes to 60kHz.
     
    Last edited: Jul 8, 2019
  3. skem

    skem Friend

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    1) The ear canal is also nonlinear and can, therefore, also generate subharmonics, transducers and other IMD aside.

    2) There is evidence ultrasound is directly audible in humans. No psychiatrist needed. See:
    https://www.ncbi.nlm.nih.gov/m/pubmed/23384569/

    3) The above does not imply the inclusion of ultrasonic information would make music sound better or more real, in my subjective opinion. (NB, Serious didn’t claim this, he says the opposite—I am just agreeing).
     
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  4. jazglers

    jazglers Rando

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    Comparing the 30k Hz and the just white noise file, I think I can "hear" a difference, though it's mostly in the form of a spine-tingly sensation with the 30k Hz one. Like the difference between a silent room and one with some electrical devices humming. I tend to get audio headaches easily, so maybe this is a bit easier for me.
     
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  5. Hrodulf

    Hrodulf Prohibited from acting as an MOT until year 2050

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    Is there a way how one can reliably play back such information? Ribbons and AMT's can go beyond 20kHz, without breakup problems, but I can't imagine the polar response at these frequencies.
     
  6. Thad E Ginathom

    Thad E Ginathom Friend

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    Personal experience: I hear it. Can't deny a person's experience, but can question the interpretation. @Serious seems to be pretty balanced in his enquiry into this.

    Engineers and scientists: I hear you guys too, and give a lot of weight to what you have to say. And if you guys want to redefine ultrasonics, maybe you have a case. But hasn't the range of human hearing been understood and defined for quite a long time? Isn't it only the emergence of band-limited digital recording that caused audiophiles to start feeling that they were missing something, and making claims about stuff being not understood? Of course, science moves on; instrumentation and measuring moves on --- and accepted stuff can be shown up as simply wrong.

    From the practical point of view, and fondly recalling the days when I could actually hear frequencies that, for instance, differentiate the sounds of p, b, d, t, etc, in human speech, It seems to me that time spent playing with some software showed just how low the frequencies with useful musical information are. "sss ss sssss sss sssssssssssss" starts well within that 20-20k range. Or... perhaps there are some ears to which it makes a difference.
     
  7. bilboda

    bilboda Friend

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    Normal hearing tests will get the response yes or no to can your hear this? The subject will determine if they can identify the sound usually having some advice on what to listen for, a tone. And that will be that.

    It doesn't mean the hearing stops there.
    Detection can go on and on with no way to describe what you can't identify. So, there's no such thing as defined human hearing. Just rule of thumb. Not talking of bat hearing, just the limits of testing and measuring.
     
  8. atomicbob

    atomicbob dScope Yoda

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    My A.D.A.M. S3A are specified 32 Hz to 35 KHz ± 3 dB SPL.
     
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  9. Thad E Ginathom

    Thad E Ginathom Friend

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    Normal hearing tests, yes. But is that the pinnacle of experimental practice on this? Maybe I have too much faith in science!
     
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  10. Ardacer

    Ardacer needs to read more, post less

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    Subharmonics from ear canal + imd as measured, agreed, most likely. Cool stuff. huh ;)

    Did you know it's possible to see a single photon? Also, we can percieve near infrared in total darkness too, as somewhat of a green-ish hue, and it's quite possible to see your own visual noise if you focus.
     
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  11. Thad E Ginathom

    Thad E Ginathom Friend

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    I thought you said visual nose.

    Well, yeah... That too. Our brains are great at filtering things.

    Hmmm...
     
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  12. Ardacer

    Ardacer needs to read more, post less

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    Hahahahah :D
    Visual nose, amazing. :D
    I guess you could say, some people have a nose for noise


    That reminds me. Some people have seriously poor signal to noise ratio, visual. Actually a syndrome, called visual snow.
     
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  13. Thad E Ginathom

    Thad E Ginathom Friend

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    The last time I was reading (don't know why!) about our nose not appearing in our vision, the writer called it brainoshopping.

    Yes, brains are really good at filtering their sensory input. Actually, I seem to remember some lecture on youtube about the amount of data that is filtered out in the various stages of processing ear input.
     
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  14. sfoclt

    sfoclt Friend

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    I found this elsewhere and may be of interest:

    Seeing High Frequencies

    It has always puzzled me that adding a super-tweeter always seems to add "air" to a soundstage even for people with hearing that doesn't get past 12Khz. I once posed this to Dick Sequerra and his response was that you can't assume that the ears are the only inlet to the brain for sonic information. He went on to say that the ocular cavities are a major entry point for high frequency info. I thought about this for a while and then filed it away to some deep dark corner of my brain to digest at a later date.

    Recently I came across this article that puts forth a plausible explanation into this and seems to tie in with other reports of listener fatigue from systems where the "highs don't sound right"

    [​IMG]


    I have also always noted the recommendation for eye protection when using ultrasonic cleaners and always thought is was just a "belt and suspenders" safety thing for possible splashes. This opens up a whole new concern given the popularity of ultrasonic cleaners for vinyl.

    https://hifiheroin.blogspot.com/2019/07/seeing-high-frequencies.html


    Eyes as Fenestrations to the Ears: A Novel Mechanism for High-Frequency and Ultrasonic Hearing

    https://pdfs.semanticscholar.org/2702/810e3bfde17fc044cd7775b49e9c9a77ee8f.pdf
     
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  15. fp627

    fp627 Friend

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    I'm thinking about this from a slightly different perspective as these are all things I've wondered about. This is all anecdotal, late lunch not long enough for me to go pull up articles.

    - What % of the population w/o hearing loss actually falls into 20-20khz? With 7 billion+ people, I'm sure some people are able to hear up to 30khz+. I also wonder if various genetics/ethnicity/other inborn factors play a role (in b4 not PC).

    - How different do we hear the same things? Two anecdotes - 1) last audiologist I saw said there are a few certain hearing response curves that she has noticed correlates to audiophiles). 2) Even in a small place like SBAF some of us have very different preferences.

    - IIRC those with the best sense of smell amongst people have almost 2x as many smell receptors in their nose as those with the worst. I'm sure I could look it up, but perhaps this is the same for hair in our ears (hairs in our cochlea are the main part of our hearing)?

    - About 12ish years ago as a college freshman I used to be able to hear pure tones, albeit not very consistently, up to about 25 or 26khz. By the time I was a college senior, I could only hear up to about 24khz consistently. However, there were tone generators in this one lab and sometimes people would leave them on at around 25 or 26khz - I would be slightly on edge and feel like my ears were annoyed (or that there was a weird energy in the air) until the generators were turned off. IMO my hearing isn't even "that good".

    - What about psychoacoustics and its relation to 20khz+ hearing? IIRC the same audiologist told me that normal for being able to hear a conversation/speech in noise environments varies a lot too, typically +5db to -5db (i.e. the speech needs to be 5dB louder than background noise for some people to hear more than 50% of the speech vs some people can still hear 50%+ of the speech down to -5dB quieter than background noise). However, this is due to how your brain processes sound and is supposed to be independent of hearing loss, individual hearing response curves, etc. Are some more sensitive to "high frequency" b/c their brains process sound different.

    - Last one is somewhat obvious one but not mentioned above yet: 5Hz or 50khz, still sound energy. It still makes it's way to and into our bodies. We have bones in our face (and other mechanisms elsewhere) that are a small part of our hearing - I'm sure some of this sound energy still tickles the certain bones of some people enough that they "know" there are other sounds. On the opposite end, I can't hear 10Hz bass rumble, but I do feel it in my chest.
     
  16. Thad E Ginathom

    Thad E Ginathom Friend

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    Amounts to... With so many people, some must be capable of the supernatural. Might be true.
     
  17. fp627

    fp627 Friend

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    Have only seen 1 or 2 episodes, it may be edit or sensationalized for tv, etc. but that's what this show is about:
    https://en.wikipedia.org/wiki/Stan_Lee's_Superhumans
     
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  18. Ardacer

    Ardacer needs to read more, post less

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    Well, it's not beyond reason to assume it might be the case, why not. There is that one girl with extra cones that sees everything differently, that's true and wildly more weird than that
     
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  19. Thad E Ginathom

    Thad E Ginathom Friend

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    Why not indeed! The world is full of weirdos and weird things, and long may it be so! But that stuff is not what gets included when it comes to, say, the specification of speakers.
     
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  20. bilboda

    bilboda Friend

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    ]We are all weird in different ways that can't be measured yet. Maybe a speaker design should include filtering out ultrasound frequencies , if it sounds good, that is. A Gandalf filter.
    [​IMG]
     
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