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  • #51
    Originally posted by Weasel View Post
    You are completely wrong. Interference does not change frequency.

    Mind you, I trust you that you hear a difference here, but it's not because it's "higher quality". In fact, it's the opposite. It's probably because of aliasing. In short, the signal is worse at 96khz than 44khz or whatever.

    So the difference you hear is because the 96khz is degraded and has aliasing from higher frequencies.

    Sorry to burst your bubble. Just physics and math. No amount of snake oil will change that.
    I never said it was changing the frequency. It can change the waves that you hear by giving constructive interference (the waves gives an additive effect) or destructive (where the waves give a subtractive effect).

    When I say that I can hear a difference I am referring to the formats, not trying to say I am hearing some 40Khz wave.

    The biggest issue I have is people always try and talk about some 20Khz wave in isolation, there are harmonics from waves, there are multiple waves and they are not perfect sine waves. Can you hear everything, no, but it can effect the things you can hear.

    I will give some examples so you know what I am talking about. The Nyquist frequency, working at twice the frequency of the wave won't tell you much. You could have a harmonic of the frequency you think you have, don't know the shape of the wave. Get a job looking at frequencies and need to see the slew rate and shape of the wave form and you tell your boss all you need is a Nyquist sampling rate on your Oscope. You will get fired when you can't give accurate results. 10X or more is the sampling rate you need to get a good view of the wave.

    Look at reticle layout and swing curves for photolithography, there is a good example of constructive and destructive waves. Read up on isolated features and dense features and how they are drawn differently.

    The problem with so many of these articles they are the equivalent of freshman physics, assume no friction, assume no air resistance, etc. The real world is you have a lot of frequencies happening at the same time and they are not all perfect sine waves.

    I will also note there is a lot of snake oil in audio, special cables is a great example where we are awash in it. The very best thing is to listen and decide for yourself and see what sounds good for you.

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    • #52
      Originally posted by Weasel View Post
      That's aliasing. You don't hear above 20khz, it just gets converted (resonated) to 1khz.
      Its not to 1khz is a 1khz block moved to another section in the hearable range.

      Please note the in ear conversion is about 95 percent efficiency. So 150db at between 21khz-22khz I get hit with about 143db in the range I can hear..


      Originally posted by Weasel View Post
      I don't know if you're serious or not, but those numbers are too insane.

      A freaking jet engine is around 140db from up close. 146db is double that, and every +6 is double.
      https://www.militaryworldsrl.com/en/...ound-dogs-945/
      Yes from 20khz to 25khz you have 150db dog and rat deterrent items as well.

      Originally posted by Weasel View Post
      200db is like... 1000 times louder than a jet engine. You sure about that?
      Do note I said some Ultra sonic cleaners. Most stop between 140-150db. But if 140-150db ultra sonic cleaner that is damaged and is now resonating the bastard can get up to 200db and quite nasty and why the instructions say not to put you hands in while running because at 200db they can be flesh damaging when combined with water..

      Most people would not think that the ultra sonic cleaner you see at most glasses shops is in fact louder than a jet engine.

      Main reason for the 150db true dog whistle is for cattle dogs and the like.you are looking at dog though binoculars somewhere 2 to 5km away and you blow whistle for the dog to come back. That is not going to work if it not kind of powerful.

      Anyone who says they can hear above 20khz by any means who does not have problems because of it are for sure lieing the insanely loud stuff around you every day of the week above 20khz is surprising to most people.

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      • #53
        Originally posted by oiaohm View Post
        Its not to 1khz is a 1khz block moved to another section in the hearable range.

        Please note the in ear conversion is about 95 percent efficiency. So 150db at between 21khz-22khz I get hit with about 143db in the range I can hear..



        https://www.militaryworldsrl.com/en/...ound-dogs-945/
        Yes from 20khz to 25khz you have 150db dog and rat deterrent items as well.
        Those rat deterrents are a pain. I found out how they worked when during a family vacation and the others in the family didn't get why I refused to go near the house... After I set out to find what the loud noise was (not pleasant, high frequencies are hard to pinpoint when they are at your pain threshold) and finding the darn thing my father burst out laughing that I had been classified as a rat.

        In my case, no surgery, just have a couple of bands in the high frequencies (no idea where, but know it is a fair bit above where most people hear) where I hear stuff. Only other people I've met with similar issues are non-neurotypical (quite common among people with asperger syndrome for instance - and is one of the many reasons they hate going shopping (low quality flourescent light sources emit a high-pitched whine, and so does badly tuned "detectors" for alarms. (For others: imagine being in a place littered with car-alarms that has been set off and you're in the ballpark of the experience)))

        Originally posted by oiaohm View Post
        Anyone who says they can hear above 20khz by any means who does not have problems because of it are for sure lieing the insanely loud stuff around you every day of the week above 20khz is surprising to most people.
        You don't need to go that high, above 18kHz it starts to get noisy and above that it gets worse the higher up you get. I rarely leave home (unless when at the countryside) or head into cities without some means of controlling the sound hitting me (usually in the form of good closed around-ear headphones or well-fitting in-ear earphones (also has the advantage of allowing me to listen to music at lower than ambient sound as well - when I have music playing (not always the case)).

        To tie back a bit to the start - what is "good enough" also depends an awful lot of how the sound interacts. (My favorite thing to do with people that don't get why I insist on lossless and excessive gear is to just subject them to a brief 2h pass of taiko-drums followed by a 4h pass of opera. With good gear (or live) that is enjoyable but with stuff that cuts close to where hearing is the experience is tiring (music and sound is a lot more than simply hearing - a quirk often lost in discussion (this also is why piano and organs (the wind-instruments) sounds bad when recorded, a big part of the experience are not via the sense of hearing))

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        • #54
          Originally posted by vsteel View Post
          I never said it was changing the frequency. It can change the waves that you hear by giving constructive interference (the waves gives an additive effect) or destructive (where the waves give a subtractive effect).

          When I say that I can hear a difference I am referring to the formats, not trying to say I am hearing some 40Khz wave.

          The biggest issue I have is people always try and talk about some 20Khz wave in isolation, there are harmonics from waves, there are multiple waves and they are not perfect sine waves. Can you hear everything, no, but it can effect the things you can hear.
          The point is that you can embed the constructive interference into the 20khz range. There's simply no reason to have anything above.

          Let's use an analogy. You are the Predator and see infrared with some special goggles. Cool eh? But we all know that everyone who watches the movie can see the "infrared", how is that possible? Because it's embedded into the normal visible range, which the goggles (or interference) would do anyway. There's simply no reason to actually emit the infrared and have people use the goggles or w/e.

          And btw I'm super skeptical about interference because, again, it cannot change frequency. But eh, whatever. Point is the same.

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          • #55
            Originally posted by oiaohm View Post
            Its not to 1khz is a 1khz block moved to another section in the hearable range.
            Lol dude that's exactly the same thing.

            Originally posted by oiaohm View Post
            Please note the in ear conversion is about 95 percent efficiency. So 150db at between 21khz-22khz I get hit with about 143db in the range I can hear..
            It doesn't matter. A jet engine is 140db loud, it's not "perceived by the ear" as 140db, and it's still going to crush your ears.

            Originally posted by oiaohm View Post
            https://www.militaryworldsrl.com/en/...ound-dogs-945/
            Yes from 20khz to 25khz you have 150db dog and rat deterrent items as well.
            Yikes, that's scary. And yet, there's a huge difference between 150db and 200db. I guess a dog would simply be dead if he had to hear 200db from up close.

            Originally posted by oiaohm View Post
            Anyone who says they can hear above 20khz by any means who does not have problems because of it are for sure lieing the insanely loud stuff around you every day of the week above 20khz is surprising to most people.
            Yeah, I'll take your word for it but I find it hard to believe (not only you, just seems so bad for the poor dogs). I'm surprised it doesn't shatter windows, lol.

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            • #56
              Originally posted by Weasel View Post
              And btw I'm super skeptical about interference because, again, it cannot change frequency. But eh, whatever. Point is the same.
              It is not about changing frequency, it is how the frequencies you can't hear can distort and change the ones you can because of their interactions.

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              • #57
                Originally posted by Weasel View Post
                It doesn't matter. A jet engine is 140db loud, it's not "perceived by the ear" as 140db, and it's still going to crush your ears.
                It does if you don't avoid it the result is 6 to 8 days of ear pain. This is why if sound system put out a high freq would cause people like me to panic it a bad thing to be hearing.

                Originally posted by Weasel View Post
                Yikes, that's scary. And yet, there's a huge difference between 150db and 200db. I guess a dog would simply be dead if he had to hear 200db from up close.
                Not so answer the next bit will explain why.

                Originally posted by Weasel View Post
                Yeah, I'll take your word for it but I find it hard to believe (not only you, just seems so bad for the poor dogs). I'm surprised it doesn't shatter windows, lol.
                Reason why 150 db at 20khz+ does not shatter glass is the frequency. Not enough duration of force is applied to the glass to in fact break glass. Higher the audio frequency the higher the db you need to do damage.

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                • #58
                  Originally posted by oiaohm View Post
                  Reason why 150 db at 20khz+ does not shatter glass is the frequency. Not enough duration of force is applied to the glass to in fact break glass. Higher the audio frequency the higher the db you need to do damage.
                  You've mostly got it.

                  It is hard to make a low frequency sound that is loud. It's not uncommon to have subwoofers that operate in the thousands of watts.

                  As you move into the 500Hz range it becomes MUCH easier, requiring less energy to move the air, but your ears are also increasingly sensitive (tuned) to those frequencies. This continues up to ~5kHz. The sensitivity of your ears stay at that gain until ~8kHz, but because there is less energy in the waves, it is less painful. The sensitivity of your ears and the energy within the wave decreases at the same time, resulting in less damage.

                  Is it possible for a 25kHz wave to damage your ears at 150db? You'd have to be near it. Remember that the amplitude of the sound is inversely proportional to the square of the radius from you to the source.


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                  • #59
                    Originally posted by vsteel View Post
                    It is not about changing frequency, it is how the frequencies you can't hear can distort and change the ones you can because of their interactions.
                    Well even if so (though it's probably rare, and they have to be very close in frequency but not quite, to create "beats"), you can always embed the change (you know, downsampling mathematical formulas, no need for anything fancy) into the audible spectrum, so anything above 20khz is useless (except for your dog).

                    e.g. you mix/record/edit at 24-bit 192khz and then downsample so all of it is within audible spectrum at the end to 16-bit 44khz or whatever. This way there's no waste of useless information and everyone can hear the "interference" without needing expensive equipment. I'm sure this is what every studio does, though.
                    Last edited by Weasel; 06 February 2019, 11:50 AM.

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                    • #60
                      Originally posted by profoundWHALE View Post
                      You've mostly got it.

                      It is hard to make a low frequency sound that is loud. It's not uncommon to have subwoofers that operate in the thousands of watts.

                      As you move into the 500Hz range it becomes MUCH easier, requiring less energy to move the air, but your ears are also increasingly sensitive (tuned) to those frequencies. This continues up to ~5kHz. The sensitivity of your ears stay at that gain until ~8kHz, but because there is less energy in the waves, it is less painful. The sensitivity of your ears and the energy within the wave decreases at the same time, resulting in less damage.

                      Is it possible for a 25kHz wave to damage your ears at 150db? You'd have to be near it. Remember that the amplitude of the sound is inversely proportional to the square of the radius from you to the source.
                      Interesting. I admit I know more about theoretical DSP stuff so more about digital waves than what type of energy you need to reproduce analog waves (as that's what I know to do and coded). I do know, though, that for light, higher frequency waves have more energy, so this seems like it's the inverse, based on what you said.

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