Ultrasound audibility

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

?

Is Serious losing his mind?

  1. It sure seems like it

    10 vote(s)
    23.3%
  2. No, more research needs to be done on the limits of human perception

    27 vote(s)
    62.8%
  3. Maybe

    12 vote(s)
    27.9%
Multiple votes are allowed.
  1. Ardacer

    Ardacer Friend

    Pyrate Contributor
    Joined:
    Oct 15, 2017
    Likes Received:
    986
    Trophy Points:
    93
    Location:
    Croatia
    Candidate for the most useless superpower
     
  2. Thad E Ginathom

    Thad E Ginathom Friend

    Pyrate
    Joined:
    Sep 27, 2015
    Likes Received:
    14,130
    Trophy Points:
    113
    Location:
    India
    Just wait until some joker breaks into your house and obliterates all the labels on your LPs!

    .
     
  3. frenchbat

    frenchbat Almost "Made"

    Joined:
    Sep 26, 2015
    Likes Received:
    1,369
    Trophy Points:
    93
  4. ultrabike

    ultrabike Measurbator - Admin

    Staff Member Pyrate MZR
    Joined:
    Sep 25, 2015
    Likes Received:
    8,960
    Trophy Points:
    113
    Location:
    Irvine CA
    Oh sweet Jeezus
     
  5. purr1n

    purr1n Desire for betterer is endless.

    Staff Member Pyrate BWC
    Joined:
    Sep 24, 2015
    Likes Received:
    89,771
    Trophy Points:
    113
    Location:
    Padre Island CC TX
    This is actually not difficult to do. It's just a matter of practice and having a sufficient amount of assburgers. The clean groove rings give the song lengths away for typical pop records. For classical which often has form with repeated sections of motifs, this can be seen in the groove patterns.
     
    Last edited: Jul 26, 2019
  6. Hrodulf

    Hrodulf Prohibited from acting as an MOT until year 2050

    Pyrate
    Joined:
    Sep 28, 2015
    Likes Received:
    4,276
    Trophy Points:
    113
  7. Thad E Ginathom

    Thad E Ginathom Friend

    Pyrate
    Joined:
    Sep 27, 2015
    Likes Received:
    14,130
    Trophy Points:
    113
    Location:
    India
    Fairly easy to tell the loud and quiet passages too. But not so easy to name the passage, in front of the TV camera, repeatedly.

    I'm assuming it was a fair test, because, hey, the world was a better place fifty years ago! (And was but a naive teenager) ;) :D
     
  8. bilboda

    bilboda Florida boomer

    Pyrate Banned
    Joined:
    Nov 20, 2016
    Likes Received:
    834
    Trophy Points:
    93
    Location:
    Miama
    That mixed with infrasonics would likely have produced those results...infrasonic sounds have been show to produce sickness and uneasiness before,
     
  9. Serious

    Serious Inquisitive Frequency Response Plot

    Pyrate BWC MZR
    Joined:
    Sep 28, 2015
    Likes Received:
    2,594
    Trophy Points:
    113
    Location:
    near Munich, Germany
    Quick experiment for everyone to try: I recorded a sound with known high amounts of ultrasound (banging keys together) with a microphone with a decent response in the ultrasonic range (WM-61A) and then used filters to get rid of the ultrasonics. I started with minimum phase filters, but to my ears the result was absolutely horrendous, so I used RePhase's Linear Phase Brickwall filters and the JRiver MC disk writer to save the output. Attached are four files:
    • The original file. Seems to contain lots of ultrasound into the 40kHz range where it rolls off quite abruptly, most likely due to the microphone used.
    • Three different stages of lowpass filtering: 21kHz, 42kHz and 63kHz brickwall filtering.
    I just used the foobar2000 ABX comparator plugin in test mode for comparing the files. After initially hearing 0 difference because I had set the output to DirectSound (which was set to 44.1kHz) and fixing my error, I started to hear some differences.
    The nature of those differences however was opposite to what I was expecting. The lower the highpass filter was, the more of an assault to my senses the sounds were. At 63kHz I'm not too sure if I can tell the difference. However for some reason it does seem to sound somewhat higher-pitched with the ultrasound past 63kHz, which doesn't really make any sense.

    I was going to attach the files here, but even at only 11 seconds it seems the files are too large in .flac with the strongest compression. So Dropbox it is: https://www.dropbox.com/sh/qzhrkixsdeuf3jl/AABn6WPnNimCi-3l9YltcYcna?dl=0
     
  10. Pogo

    Pogo Friend

    Pyrate
    Joined:
    Jun 14, 2018
    Likes Received:
    494
    Trophy Points:
    93
    Location:
    SoFla
    I'm blowing my dog whistle up into the eastern sky, hoping for some ionospheric skip.
    Lemme know if you feel a sudden urge to scratch.
     
  11. jfunk

    jfunk New

    Joined:
    May 28, 2020
    Likes Received:
    26
    Trophy Points:
    3
    Location:
    cheltenmham
    I don't know if this is of interest but I did a bit of research into the perception of frequencies outside the the 20-20khz range in Uni
    I found a paper (Fukushima, 2014) where they used an electroencephalogram (EEG) to measure responses from the centro-parieto-occipital regions of the brain it was shown that we have noticeable responses to frequencies over 48khz

    I could not figure out how to add images properly but here are a couple that show the results

    https://www.customcans.co.uk/images/alphaeeg1.jpg

    [​IMG]

    https://www.customcans.co.uk/images/alphaeeg2.jpg

    [​IMG]
     
  12. Armaegis

    Armaegis Friend

    Pyrate BWC
    Joined:
    Sep 27, 2015
    Likes Received:
    7,462
    Trophy Points:
    113
    Location:
    Winnipeg
    I'd be curious to see how they differentiated between direct aural stimulation vs ultrasonic stimulation of the grey matter itself. I'd also like to see them replicate with a deliberate intermodular tone within the hearing range, and compare that vs a standard tone.

    I'm not doubting the results per se, but I need way more context and baselines.
     
  13. jfunk

    jfunk New

    Joined:
    May 28, 2020
    Likes Received:
    26
    Trophy Points:
    3
    Location:
    cheltenmham
  14. purr1n

    purr1n Desire for betterer is endless.

    Staff Member Pyrate BWC
    Joined:
    Sep 24, 2015
    Likes Received:
    89,771
    Trophy Points:
    113
    Location:
    Padre Island CC TX
    I don't understand a few things about the study:

    upload_2020-5-31_8-9-30.png
    [​IMG]
    • Why does LFC + HFC (16-48kHz) show less brain activity than LFC (20-16kHz)?
    • Why didn't these dudes do a LFC + HFC (16-48) + LFC (> 48kHz)? That is why did they NOT examine the effects of the full spectrum?
    The study seems rather convoluted.

    P.S. What if in the last case, the LFC + HFC (>48kHz). with the bite out of the audio band, showed the most brain activity because the programmable filter introduced phase shifts in the audio range or impulse response ringing? I mean, we got a notch filter there which is two filters, a LP and a HP.
     
    Last edited: May 31, 2020
  15. jazglers

    jazglers New

    Contributor
    Joined:
    Jun 22, 2019
    Likes Received:
    18
    Trophy Points:
    13
    Location:
    Los Angeles
    For me, its . . . kinda different than what you experienced. In order of hurts my ears the most to the least: original, 63kHz, 42kHz, 21kHz . . . .. but I just don't tend to like sounds sometimes.

    I can get what you're saying about the lower pass filter. To me it can seem harsh because the 'sounds' kinda pop in and out, almost bell like or maybe xylophone like. With the original I can hear the ultrasound, I guess, and the evolution of the sound seems more fluid or ethereal or soft. Kinda sounds abit like that asmr breathing stuff.
     
  16. Serious

    Serious Inquisitive Frequency Response Plot

    Pyrate BWC MZR
    Joined:
    Sep 28, 2015
    Likes Received:
    2,594
    Trophy Points:
    113
    Location:
    near Munich, Germany
    @jazglers that sounds like what I had initially expected, so I Just tried it again on three different rigs: My Voxativ OBs, my HD800 and three way speakers with a traditional 1" ceramic dome tweeter. Those have a very well damped 28kHz-ish tweeter resonance that barely sticks up above the rest of the range. Past 30kHz they roll off.
    The difference was easiest to hear on my Voxativ OBs, then the 3-way speaker and then my HD800. It was actually somewhat difficult on the HD800. Still, I felt my impressions were consistent on all three systems. I thought the original file sounded most natural. Maybe we are talking about different things. I'd agree the original can sound the "sharpest", but the sharpness seems to decay much more quickly. Hard to explain for me. Overall it's less annoying to listen to for me. Not that this is particularly pleasant to listen to.
    I have to make a more proper file for testing that's less crappy than the above. I left the noise at the end in on purpose and didn't rerecord it despite the noise already starting before I started the recording, because I felt it fit.

    Some people seem to claim you can start to feel uneasy from ultrasonic sine waves. Personally I doubt it. I can leave my CRT on no problem, despite its flyback transformer vibrating at between 80kHz and 140kHz depending on the resolution and refresh rate. Usually I run it at between 120 and 140kHz. The question is how loud that is. I might be able to measure it in a couple weeks.
    CRT TVs make me sick after just a couple minutes with their 15.6kHz whine.
     
    Last edited: Jun 6, 2020
  17. jazglers

    jazglers New

    Contributor
    Joined:
    Jun 22, 2019
    Likes Received:
    18
    Trophy Points:
    13
    Location:
    Los Angeles
    I do agree that the original file sounds the most natural . . . natural as in closest to what I'd actually here jangling my own keys. By comparison, the 21kHz file sounds artificially cut-off. It's just my ears kinda hurt when listening to high pitched noises for whatever reason, so I personally try not to listen to them too much. . . at least in this case where its not musically compelling. If it were a cymbal crash I'd actually want to listen to that. Stuff like that. But then again, I'm listening pretty loudly. . . and generally, when listening to music I do like those high trebles when done well, especially live, so . . . its conditional.

    The possible sharpness of the original file . .. yeah those sounds decay super quick, I agree. Yeah, I agree its the sharpest or rather finest treble. . .as opposed to the more coarse sounding treble of the filtered files. . . anyway, this was on my hd650, modded like how i had described and was immediately evident to me as I played each clip, one after the next.
     
  18. Serious

    Serious Inquisitive Frequency Response Plot

    Pyrate BWC MZR
    Joined:
    Sep 28, 2015
    Likes Received:
    2,594
    Trophy Points:
    113
    Location:
    near Munich, Germany
    I finally got some microphones with specified response up to 80kHz. I bought some of the Knowles MEMS mics (among others) and used them to get a feel for the ultrasonic response of mine and my dad's main speakers. I also spent some time looking at an FFT for different sounds. It seems many small electret mics (despite their size) roll off quite severely past 20kHz. Mic grille design might play more of a role here than the actual diaphragm.

    I attached the FR I measured for both speakers. Don't take the audioband response as gospel, they are generally nearfield measurements and not indicative of the FR measured normally. Read the comments on the measurements - they are very preliminary results and should just be viewed as a general indication and not as an accurate representation of reality. I simply took the specified response of the microphone model and used that as a calibration, not a measured FR for this particular microphone. I also only compensated for the A/D and D/A response, not the FR of the speaker amps. The OB speakers were measured on my desktop PC build and somehow have a 70kHz spike that I couldn't get rid of (turned off CRT and Plasma TV). The laptop measurement of the Reference 3K does not have this issue. Generally it seems both speakers extend past the usual 20kHz bandwidth quite easily, with the 3 way speaker with ceramic drivers showing generally better extension at the high end, but also a noticeable ultrasonic peak of the tweeter. Still, I find the roughly -20dB at 100kHz I got from the Voxativs a pretty stunning result aswell.
    The way drivers roll off is definitely not a digital-like brickwall limit, rather a generally slow rolloff, that will often be a bit ragged in nature due to breakup.

    It also seems that many sounds that are wideband in nature also have no issues extending past 20kHz. Sibilants, compressor nozzle hiss, the ticking of a clock, etc. There are many sounds which show good ultrasonic extension. Compressor nozzle hiss seemed to extend especially well.

    I have to say I was pleased with the performance of this MEMS mic considering its size. These are microphones like they are probably used in phones and the noise performance is pretty good considering their tiny size. Others are specified with even better SNR. I can't wait to try those. I'm also looking forward to measuring other sounds in the 20-100kHz range. I could see my CRT flyback transformer quite clearly on the FFT when I put it in a low resolution for less than 100kHz vertical scanning frequency. Normally it's past 100kHz, though.
     

    Attached Files:

  19. Raimei Templar

    Raimei Templar Friend

    Pyrate
    Joined:
    Dec 8, 2019
    Likes Received:
    776
    Trophy Points:
    93
    Location:
    Osaka
    Dont think this study has been linked yet but https://asa.scitation.org/doi/10.1121/1.5063819 found that some people did suffer adverse effects from frequencies that they can no longer actually hear. The study in questions used frequencies ranging from 13.5khzto 20khz on people who could not longer actually hear them based on their hearing tests. Very interesting results, basically people exposed to the high frequencies experienced feelings of irritation and had difficultly concentrating on a task. Not "true" ultrasonics as that is within the human hearing range but those people had lost that hearing.

    The study came to being after people found that the goddamn mosquito sonic weapon used in Europe was causing them irritation I believe. Those things should be banned, I cant believe people are ok with destroying kids hearing like that. I have seen reports of it as much as 108db in volume! A teenager will just leave before there is any serious damage but what about a parent taking a baby around, baby will be having their ears murdered and parents might just feel mild irritation not realizing what is happening. Infuriates me as a parent.

    Study also brings up a very interesting point which is that part of the reason there arent more studies of ultrasonic sounds is that in many cases to truly find out if there were any adverse effects you would need to expose the subjects to very high volumes 100bs/spl or more which is unethical for any researcher who actually believes it will do harm to do. I think people handwave away the effects of ultra and infasonic partially because they arent accounting for what might happen if they are exposed to very high volumes rather the relatively low noise from CRTs and such.
     
  20. evonimos

    evonimos New

    Joined:
    Jul 8, 2020
    Likes Received:
    13
    Trophy Points:
    3
    Location:
    Athens
    I know i hear zero above 15kHz.
    However, i can't rule out rare super-abilities in other people.

    Myself even might be able to do it, after being treated with a secret brew of Kykeon...
     

Share This Page