[analogsurviver]

That is a valid definition of hearing if you want to define it that loosely, but we *listen* to recorded music, and it's pretty clear that super audible frequencies add nothing to our evaluation of the audio fidelity of recorded music.

The argument isn't can we or can we not perceive (or hear if you want to define the term that loosely) super audible frequencies. At a sufficient volume level, we can feel them and register them in brain waves. The argument is over whether it's at all relevant to home audio. It isn't relevant, because it isn't consciously "listenable" (if you prefer that term). It doesn't occur in music at volume levels sufficient to even register as brain activity. And it's difficult for modern transducers to reproduce at perceivable levels with any sort of fidelity.

It's a purely theoretical argument that is irrelevant to what sort of audio equipment we choose to play our Aerosmith albums on.

I've actually attended a performance of Gamelan Gongs many years ago when my ears were young and fancy free. I remember thinking to myself that it was kind of uncomfortable to listen to at close range. I preferred my Nonesuch Explorer LP that I'm sure had no super audible content at all. I don't know if it was uncomfortable because of the super audible frequencies, or because of the loud percussive nature of the attacks, but I wouldn't go out of my way to experience that again.



I'm afraid it's going to remain plugged up because there's no willingness to stop wallpapering the thread with blather.

There is an old saying that I have found to be very applicable to a lot of things... "The truth rarely lies halfway between two opposing viewpoints." Often there is a side that is flat out wrong. But if they aren't self aware enough to even question themselves and they don't listen to the people around them because their ego won't allow it, you aren't going to get them to stop being wrong.

First, @bigshot , I would like to make it PERFECTLY CLEAR that I have never - or ever will - consented to excluding your posts from commenting upon - similar as I have done for @pinnahertz. You have lost that *right* with your first ever reply to any of my posts - and nobody can change that. Gods - let alone mods - included . Please, do remember that - for good.

You have - frequently, repeatedly, numerous times - stated, citing anecdotal evidence, that any high frequency sound, be it within currently accepted hearing limit of 20 kHz or beyond, causes you discomfort. Ranges from fluorescent lighting trough cymbals to gamelan - and everything else, proven beyond any shadow of a doubt to be capable of producing near and beyond 20kHz, in between.

In contrast, I have stated, again citng anecdotal evidence, the presence of the right amount of ultrasound ( or effects ultrasound produces ) to be pleasurable - and omitting them to be detrimental for my enjoyment of music. Troughout my life and involvement with audio ( say , by now at least 40 years ) , EVERY TIME audio (re)production felt *righr*, *approaching real sound* and whatever adjective describing getting as close as possible to the real thing - involved electronics and transducers ( and in THAT order !!! ) that exceed 20 kHz limit at least twice - but preferably beyond 100 times. I can hear - or perceive, if that is a better term - benefit of such bandwidth in electronics - even if using relatively poor speakers or headsphones.

I have stated, by now many times, my limit to hear steady state sine wave tone. To stay on the safe side - I will proclaim it, on date of 12.12.2018, to be 13 kHz.

Never, not even once, I have preferred anything badwidth limited. And would, categorically, require say loudspeakers to be replaced - if I have to make a demo of my recording. I prefer NOT to do the demo over doing it wrong. PERIOD.

Above describes - perfectly so - our sentiment regarding the CD - or RBCD, to be exact. For you, it is the gift from above - and to me, the scourge from below.
I , with the long and loud grundging, *accepted* CD player in my home only in early/mid 90s, when some of the music I like was really not available on anything else. And because, due to the economics ( remember, my then country, Yugoslavia, at the time dissolved in series of bloody (civil) wars - which were helped in no small measure by your country, the USA ), the CD was the most affordable solution.

Alert for moderators : you may, due to the policies with which I otherwise agree, remove the text just above in parenthesis, slanted and underlined ; you may NOT remove the whole post.

You, bigshot, have usurped this (and attempted in many others ) thread to try to de facto establish a cult following religion - installing RBCD as the ultimate audio format for all times, with yourself as the President/King/Tzar for the lifetime. And been trying, for years, to undermine, ridicule - with all the means at your disposal - any opinion to the contrary.

Remember, one can ALWAYS reduce any HR audio, recorded using microphones/entire recording rig capable of > 20 kHz bandwidth ( analog tape included ) down to RBCD - to satisfy those who deem it is all it takes and will be satisfied with in audio for life .

It DOES NOT work the other way around - upsampling can bring an audible improvement ONLY trough the requirement of using less severe filtering than the brick wall required by RBCD - it can not restore the information, which has been forever lost in the first, bandwidth limited to (just above ) 20 kHz stage.

In my 14 or so years career in recording, there are, unfortunately, recordings of people, who are no longer with us.

And one of my regrets is that I did not have the hardware capabilities ( and knowledge to make the best out of it ) for some of ,by now historical recordings , now at my disposal - not only does a live performance happen only once, sometimes there will be no opportunity for a retake with the particular artist ...

 

[james444]

It may be different with headphones than in a room with speakers. My sub is rated to 12 or 13Hz and it gets low enough that I just feel it and don't hear it. Not sure. I never worried about it because it's all an undifferentiated rumble down there.

With IEMs, we know at least it's definitely "hearing" what's going on, and not some kind of body-related sensation. Only two possible pathways for the 15Hz tone in that case, either via tympanic membrane or conduction through the bony part of the ear canal.

 

[james444]

yup, anything that ends up firing cells in the cochlea in a fairly consistent way is fine for me...

It possibly won't be long until we reach clarification. A new imaging tool based on optical coherence tomography (OCT) enables us to "watch the ear hear":

https://www.sciencedaily.com/releases/2018/10/181017111011.htm

"There are multiple theories of how high-frequency sounds are conducted to the inner ear, and the ability to view the sound-driven motion of large portions of the ossicular chain will help us understand what actually happens," said research team leader Seok-Hyun Yun of the Wellman Center for Photomedicine at Mass General Hospital.

 

[Steve999]

Ermm, I can simply stick in a pair of halfway decent in-ear monitors and fire up a tone generator:
http://www.szynalski.com/tone-generator/

- 20Hz: easily heard / felt at normal listening levels.
- 15Hz: a little quieter, but still easily detectable as slower vibrations / deeper tone.
- 10Hz: here it gets tricky and I have to increase volume to unsafe levels to be certain.

But 15Hz... no problem at all! What am I missing here?

Could just it be harmonic distortion off of the 15 hz tone? Just a layperson’s guess here. If you hear it as a tone rather than just low low low (to paraphrase REM) I’d guess it’s harmonic distortion. 15 hz is pretty much a lot lower than people generally hear as a tone, if I understand correctly. I don’t know how you’d check for distortion v. fundamental tone. Someone else might. Interesting observation. Thanks. I assume the tone generator generates sine waves with no harmonics. I would also guess some source equipment distorts at 15 hz so there’s that too. Just throwing stuff out there as a curious layperson.

 

[gregorio]

Dealing with uncertainty can be both a source of frustration and a fun challenge in science, as well as just about all other areas of life.

This is the root of so many of the evils we run into here:
Firstly and most importantly, there's the massive issue of what is "uncertain" in the first place. Much of what is categorised as "uncertain" by audiophiles is not in fact uncertain and when challenged, the more sophisticated and apparently scientific response is along the lines of: Science is all about theoretical models of reality based on observations, models which are imperfect and evolve over time in response to new observations, new evidence and/or a failure of prediction. However, this is only "apparently" scientific rather than actually being scientific because while this assertion is often true/applicable to many scientific theories, it is also sometimes NOT true/applicable and even when it is, it often has no affect on the practical application of the science. Furthermore, it ignores the fact that we're often not dealing with scientific theories but also with proven scientific theorems and laws.
For example, we might describe Fourier's discoveries and proofs as a "model" of what sound waves are (comprised of), however, it has not followed the path of many theories (such as the theory of evolution for example), it has NOT evolved over time in response to new observations, evidence and/or failures of prediction because in the 200 years or so since Fourier's mathematical proof there have been no failures of prediction and no new observations or evidence to even hint that it might in some way be wrong or incomplete. It's the same story with digital audio/communication theory, certainly the engineering practicalities of applying the theory have evolved but the theory itself has not, there have been no failures of prediction and no evidence which even hints that it might be incorrect in the 70 years since the proof was published, despite the fact that every digital device on the planet puts the theory to the test hundreds of millions to trillions of times per second. A similar but slightly different example demonstrates another part of my statement above, that even when a theory is incomplete and "evolves" it often still doesn't make any practical difference: By about 170 years ago electricity had been fully defined mathematically by Maxwell, Ohm and others but starting around the 1920's, it became clear our understanding (scientific model) of electricity was not entirely complete, it did not include quantum mechanical effects for example. However, this incompleteness only affects what happens in certain extreme conditions (such as at absolute zero for example), outside those specific extreme conditions, Maxwell's, Ohm's and other's mathematical definitions/proofs of electricity still ALWAYS hold true and there's been no evidence in the intervening 150 years to suggest otherwise. And (hopefully) most realise that the recording and reproduction of music doesn't involve anywhere near the extreme conditions required for the basic classical model of electricity to no longer be ENTIRELY applicable.
These 3 "certainties" cover most of the recording and reproduction of music/sound and yet audiophiles (and those who sell to them) still routinely misrepresent them as "uncertainties"! As far as the audiophile community is concerned, a far more pertinent "challenge" than "dealing with uncertainty" would be to gain a far better grasp of what is certain and uncertain in the first place!

Secondly, there are definitely some areas of uncertainty, particularly if we're talking purely about science in say the field of human perception but even here we have to be careful what we mean by "certainty"/"uncertainty". Do we mean we have no idea at all? Do we mean we've got a pretty good idea, for example a "certainty" that a particular perception is a combination of several well defined and accepted theories? Or, do we mean that we actually have an extremely high degree of certainty in how perception works/affects us (and therefore how we can manipulate it) but relatively little science which explains the physical/biochemical processes within the brain which accomplishes this task? For example, centuries of musicology/composition and nearly a century of film sound has given us a very good understanding of how hearing perception works and how it can be manipulated. Again though, many audiophiles are partially or entirely ignorant of all this. This is good example;

What if the reason that, for most people, "home listening can never duplicate the experience of a real concert" is due to those extraneous factors.....
What if, at the actual concert, our brains and auditory cortex were "configured a certain way" - thanks to those bright lights, our expectations, and even a little TCS....
And we're never going to be able to properly replicate the auditory experience unless we replicate all the other factors that account for the configuration that goes with it?....
To me, this is stuff we should be testing....

Most of that isn't a "what if", it's very well known and has been tested exhaustively over the course of more than 6 decades. Why, for example, do you think we record orchestras with multiple mics (and have done since the 1950's), when just two mics can capture all the sound waves that a member of the audience (in the ideal listening position) would hear?

It would be foolish to believe things that we are not convinced are in fact correct.

And it would be even more foolish to not believe the science/facts that ARE correct, and then make-up false assertions entirely based on that foolishness! Yet this is exactly what we see time and again, even from some posters in this sub-forum, let alone the other sub-forums. Ultimately, what you believe and whether you personally are convinced or not is irrelevant, the science/facts do not depend on and are not affected by your belief, understanding or lack thereof.

G

 

[analogsurviver]

Could just it be harmonic distortion off of the 15 hz tone? Just a layperson’s guess here. If you hear it as a tone rather than just low low low (to paraphrase REM) I’d guess it’s harmonic distortion. 15 hz is pretty much a lot lower than people generally hear as a tone, if I understand correctly. I don’t know how you’d check for distortion v. fundamental tone. Someone else might. Interesting observation. Thanks. I assume the tone generator generates sine waves with no harmonics. I would also guess some source equipment distorts at 15 hz so there’s that too. Just throwing stuff out there as a curious layperson.

Oh, come on - and get serious. Any decent portable amp/DAP/whatever used as a source SHOULD be impeccable at 10 Hz and lower - let alone at 15Hz.

In fact, the transducer most likely to be satisfactory for low frequencies < 20 Hz is - IEM. It requires eartips to have PERFECT sealing. Here a good test that can test - in about 10 minutes - the most basic requirements of any headphone/earphonr/IEM : https://www.audiocheck.net/soundtests_headphones.php It does start at 10 Hz ... - for a reason !

 

[Steve999]

One the one hand John Maynard Keynes wrote that the fact that all things are possible is no excuse for talking foolishly. On the other hand Leibniz, Darwin, Tesla, Farraday, the Wright Brothers, etc., were all perceived as talking foolishly in their day. So there’s a tension. Here I think we are more in the economist’s world rather than in the world of groundbreaking scientific discussion, very much so. I have more to learn than I will ever know about science, but spotting those who deal in lies and deception and illogical speculation, in an environment where we need only follow the money to understand much of its origins, is not so much beyond me. So the task is to take things where they will go if we explore the unexpected in the realm of plausible science, but in an environment riddled with and awash in cash from untoward influences. It’s a fine line and requires careful and thoughtful judgment and open-minded discourse, but also a healthy dose of skepticism. There are virtues to warding off disingenuous commercial influences at every pass, but also there are virtues to progressing in informing one another of that which is known but unexpected, or has yet to be known. So we can feel and enjoy ultrasonics through our eyeballs apparently, and even a/b/x testing is subject to problems with auditory memory and expectation bias. But this does not justify the marketing garbage that is the locomotive that drives head-fi. Sound Science is in a tough spot. If we merely spend all of our energies debunking myths that are propogated here under the profit motive, the discussion as to science and sound will be lost in the noise. It’s just something for each poster to keep in mind, the environment we are in, the dual purposes we serve in a moral and educational sense, and the difficulty posed by the engine of head-fi itself. They are the elephant in the ointment and we are the fly in the room. The danger is that those who seek more pleasant scientific or audio discourse and are most knowledgeable will simply choose not to post here, if each poster does not take on more responsibility in ensuring the soundness of their reasoning. Otherwise we will just have scorched earth and nonsense here, chasing one another around in circles.

 

[james444]

Could just it be harmonic distortion off of the 15 hz tone? Just a layperson’s guess here. If you hear it as a tone rather than just low low low (to paraphrase REM) I’d guess it’s harmonic distortion. 15 hz is pretty much a lot lower than people generally hear as a tone, if I understand correctly. I don’t know how you’d check for distortion v. fundamental tone. Someone else might. Interesting observation. Thanks. I assume the tone generator generates sine waves with no harmonics. I would also guess some source equipment distorts at 15 hz so there’s that too. Just throwing stuff out there as a curious layperson.

Nah, I measured THD of my JVC FD01 IEMs at 90dB, it's around 1% @ 20Hz. Presumably, the rest of the chain has far less distortion. And my listening level was maybe 70-80 dB.

IEMs can easily reach deeper frequencies than full-sized headphones and speakers. It's hard to hear something as low as 15Hz as a tone, if you just listen to that single frequency. But if you start at, say, 30Hz and decrease the frequency step by step, you can discern the pitch change quite easily.

 

[Phronesis]

This is the root of so many of the evils we run into here:
Firstly and most importantly, there's the massive issue of what is "uncertain" in the first place. Much of what is categorised as "uncertain" by audiophiles is not in fact uncertain and when challenged, the more sophisticated and apparently scientific response is along the lines of: Science is all about theoretical models of reality based on observations, models which are imperfect and evolve over time in response to new observations, new evidence and/or a failure of prediction. However, this is only "apparently" scientific rather than actually being scientific because while this assertion is often true/applicable to many scientific theories, it is also sometimes NOT true/applicable and even when it is, it often has no affect on the practical application of the science. Furthermore, it ignores the fact that we're often not dealing with scientific theories but also with proven scientific theorems and laws.
For example, we might describe Fourier's discoveries and proofs as a "model" of what sound waves are (comprised of), however, it has not followed the path of many theories (such as the theory of evolution for example), it has NOT evolved over time in response to new observations, evidence and/or failures of prediction because in the 200 years or so since Fourier's mathematical proof there have been no failures of prediction and no new observations or evidence to even hint that it might in some way be wrong or incomplete. It's the same story with digital audio/communication theory, certainly the engineering practicalities of applying the theory have evolved but the theory itself has not, there have been no failures of prediction and no evidence which even hints that it might be incorrect in the 70 years since the proof was published, despite the fact that every digital device on the planet puts the theory to the test hundreds of millions to trillions of times per second. A similar but slightly different example demonstrates another part of my statement above, that even when a theory is incomplete and "evolves" it often still doesn't make any practical difference: By about 170 years ago electricity had been fully defined mathematically by Maxwell, Ohm and others but starting around the 1920's, it became clear our understanding (scientific model) of electricity was not entirely complete, it did not include quantum mechanical effects for example. However, this incompleteness only affects what happens in certain extreme conditions (such as at absolute zero for example), outside those specific extreme conditions, Maxwell's, Ohm's and other's mathematical definitions/proofs of electricity still ALWAYS hold true and there's been no evidence in the intervening 150 years to suggest otherwise. And (hopefully) most realise that the recording and reproduction of music doesn't involve anywhere near the extreme conditions required for the basic classical model of electricity to no longer be ENTIRELY applicable.
These 3 "certainties" cover most of the recording and reproduction of music/sound and yet audiophiles (and those who sell to them) still routinely misrepresent them as "uncertainties"! As far as the audiophile community is concerned, a far more pertinent "challenge" than "dealing with uncertainty" would be to gain a far better grasp of what is certain and uncertain in the first place!

Secondly, there are definitely some areas of uncertainty, particularly if we're talking purely about science in say the field of human perception but even here we have to be careful what we mean by "certainty"/"uncertainty". Do we mean we have no idea at all? Do we mean we've got a pretty good idea, for example a "certainty" that a particular perception is a combination of several well defined and accepted theories? Or, do we mean that we actually have an extremely high degree of certainty in how perception works/affects us (and therefore how we can manipulate it) but relatively little science which explains the physical/biochemical processes within the brain which accomplishes this task? For example, centuries of musicology/composition and nearly a century of film sound has given us a very good understanding of how hearing perception works and how it can be manipulated. Again though, many audiophiles are partially or entirely ignorant of all this. This is good example;

Most of that isn't a "what if", it's very well known and has been tested exhaustively over the course of more than 6 decades. Why, for example, do you think we record orchestras with multiple mics (and have done since the 1950's), when just two mics can capture all the sound waves that a member of the audience (in the ideal listening position) would hear?



And it would be even more foolish to not believe the science/facts that ARE correct, and then make-up false assertions entirely based on that foolishness! Yet this is exactly what we see time and again, even from some posters in this sub-forum, let alone the other sub-forums. Ultimately, what you believe and whether you personally are convinced or not is irrelevant, the science/facts do not depend on and are not affected by your belief, understanding or lack thereof.

G

I think it's generally accepted that science doesn't really "prove" things, but rather draws conclusions from evidence with varying levels of confidence/certainty. The amount of confidence/certainty varies over a range from none to extremely high, and I agree that saying that we have some uncertainty doesn't mean that we have no idea - we may be justifiably very confident about some things.

Also, I think it's worthwhile to make a distinction between science and technology. In technology, we can design things to perform intended functions, and by providing some safety margins, we can pretty much guarantee that they'll function as intended if we use decent models for design, there are no significant manufacturing defects, and there no unanticipated loads; this is certainly the case with electronic devices. In science, since our models can't be proven to be "true" in some absolute and final sense, those models can always evolve and be refined. Even with something like electricity, it was first unified in a model with magnetism, then the electromagnetic and weak forces were unified in a new model, then the electroweak and strong forces were unified in a new model, and now physicists are still struggling to unify the electroweak and strong forces in a model which also includes gravity ("theory of everything"). And of course, when we get into biology, cognition, perception, etc., things are way more complex, and our models aren't nearly as good as we have in many areas of physics.

 

[Steve999]

Nah, I measured THD of my JVC FD01 IEMs at 90dB, it's around 1% @ 20Hz. Presumably, the rest of the chain has far less distortion. And my listening level was maybe 70-80 dB.

IEMs can easily reach deeper frequencies than full-sized headphones and speakers. It's hard to hear something as low as 15Hz as a tone, if you just listen to that single frequency. But if you start at, say, 30Hz and decrease the frequency step by step, you can discern the pitch change quite easily.

It’s a worthwhile discussion to have. I would need to look into it, but I may not have the resources. Based on my experience as a layperson and my lay perceptions I doubt what you say, but I accept it is not without plausible support. If you could show me something peer-reviewed that indicates that humans hear pitch at 15 hz I would be interested. My belief is that you cannot. I think you could do well to do further research or search out other possibilities.

 

[gregorio]

The amount of confidence/certainty varies over a range from none to extremely high, and I agree that saying that we have some uncertainty doesn't mean that we have no idea - we may be justifiably very confident about some things.
Also, I think it's worthwhile to make a distinction between science and technology. In technology, we can design things to perform intended functions, and by providing some safety margins, we can pretty much guarantee that they'll function as intended if we use decent models for design, there are no significant manufacturing defects, and there no unanticipated loads; this is certainly the case with electronic devices. In science, since our models can't be proven to be "true" in some absolute and final sense, those models can always evolve and be refined. Even with something like electricity, it was first unified in a model with magnetism, then the electromagnetic and weak forces were unified in a new model, then the electroweak and strong forces were unified in a new model, and now physicists are still struggling to unify the electroweak and strong forces in a model which also includes gravity ("theory of everything"). And of course, when we get into biology, cognition, perception, etc., things are way more complex, and our models aren't nearly as good as we have in many areas of physics.

But isn't this largely semantics? Sure, in an absolute sense we can't be absolutely certain of anything, we can't be absolutely certain that pigs can't fly, that unicorns don't exist or that the Earth isn't flat. But if we've got a mathematically proven theorem that's demonstrated trillions of times per second, by billions of devices for many years, with no evidence or even hint that in some way it be incorrect/incomplete and has therefore never evolved or been refined, how much more certain of anything can we ever be? And yes, as I stated, the model of electricity has been refined and likely will be more refined in the future but none of that affects Ohm's Law (for example) as it pertains to home stereo systems. Now if one day we're all listening to Michael Jackson's Thriller while sitting on a singularity inside a black hole, then I'll not be nearly so entirely certain that Ohm's Law is applicable but until then ...

G

 

[Steve999]

It’s a worthwhile discussion to have. I would need to look into it, but I may not have the resources. Based on my experience as a layperson and my lay perceptions I doubt what you say, but I accept it is not without plausible support. If you could show me something peer-reviewed that indicates that humans hear pitch at 15 hz I would be interested. My belief is that you cannot. I think you could do well to do further research or search out other possibilities.

So I double-checked myself. Apparently, some humans can hear down to 12 hz under ideal laboratory conditions.

https://en.m.wikipedia.org/wiki/Hearing_range

This is a long way from proving that you or any human can hear pitch at 15 hz over IEMs, but it’s a start.

 

[Phronesis]

But isn't this largely semantics? Sure, in an absolute sense we can't be absolutely certain of anything, we can't be absolutely certain that pigs can't fly, that unicorns don't exist or that the Earth isn't flat. But if we've got a mathematically proven theorem that's demonstrated trillions of times per second, by billions of devices for many years, with no evidence or even hint that in some way it be incorrect/incomplete and has therefore never evolved or been refined, how much more certain of anything can we ever be? And yes, as I stated, the model of electricity has been refined and likely will be more refined in the future but none of that affects Ohm's Law (for example) as it pertains to home stereo systems. Now if one day we're all listening to Michael Jackson's Thriller while sitting on a singularity inside a black hole, then I'll not be nearly so entirely certain that Ohm's Law is applicable but until then ...

G

I agree, in much of electronics, for all practical purposes, our models are very accurate and reliable and need not evolve further, even if they can't be proven "true" in an absolute sense.

In my own area of engineering, our models are usually not as good as models based on circuit theory, but the assumptions based on Newtonian mechanics are effectively treated as being certain and we lose no sleep over that.

With audio, it's when we bring listeners and perception into the models, as with any type of listening test, that things get messy and the effects of even very tiny differences in gear wind up introducing a sliver of uncertainty and open the door to debates.

 

[KeithEmo]

OK, just to be perfectly clear, I DO NOT specifically assert that ultrasonic frequencies are audible, or that they have a perceptible effect on what we hear, or our enjoyment of music. ALL I assert is that the opposite has not been conclusively proven. I DO NOT KNOW IF ULTRASONIC FREQUENCIES HAVE SOME EFFECT ON OUR PERCEPTION OF MUSIC OR NOT.

When I went to high school, everyone "knew" that all matter was composed of little indivisible things called protons, neutrons, and electrons, there were no such things as dragons and unicorns, dinosaurs were cold blooded reptiles, and a cool prehistoric fish called a coelacanth had been extinct for about 30 million years. However, today, we are quite certain that two of those things we used to be quite certain of are in fact wrong, and a third one is in serious doubt. I'm pretty sure there are no unicorns or dragons, and nobody has proven to have found one yet, but that's one out of four.

HOWEVER, someone suggested that "I could never be satisfied with the results of any test proving that ultrasonic frequencies are inaudible." In fact, they may be right, because it is virtually impossible to prove a negative, unless you start by testing every human on Earth... and, even if you do, new ones keep being born to muddy the issue.

HOWEVER, I can describe pretty simply how we could perform a test that would be reasonably free of obvious flaws, and it wouldn't even necessarily be terribly expensive to do so.

Anyone who is actually interested in science should continue to read on.....

First off, in any proper experiment, you need to start by describing EXACTLY what you're testing for. How about: "Determining whether the presence of ultrasonic harmonics, or other audio information, at levels similar to the audible content, makes a perceptible difference in how we perceive audio recordings of music or other frequently recorded sounds".

Second, we need to find or produce some samples of what we're trying to test. We can't test whether people can hear it unless we first confirm that we have it to begin with. This DOES NOT mean "finding some high quality recordings" or "using some samples everybody thinks are high resolution". It means using test samples that we have CONFIRMED contain high frequencies. (At this point I'm going to add another detail... let's test for the presence of frequencies up to a reasonable 30 kHz... if they turn out to be audible, then we can consider looking higher.)

So, let's start by choosing some sound sources that we believe contain harmonics that go that high. I suggest we try cymbals, gamelan music, and the sound of breaking glass. (I'm not going to bother to specify that we need someone to bang on the cymbals and gongs - and break the glass.) Now we dig out our measurement microphone, or bat-hunter microphone, or whatever you like, and measure our sources to make sure there really is something there at between 20 kHz and 30 kHz. We don't care if it sounds nice... we're simply confirming that we actually have a legitimate source of ultrasonic content.

Now we record some sounds or music. And, yet again, we whip out our spectrum analyzer and confirm that the ultrasonic content that was there to begin with (which we confirmed in step 1), made it onto the recording. If we already have recordings THAT WE CAN CONFIRM MEET THIS REQUIREMENT then we can use them. Likewise, we can skip confirming that the ultrasonic components are present in our live sources IF AND ONLY IF WE CONFIRM THAT THEY ARE PRESENT IN THE RECORDING.

Now we choose our playback equipment, which may include some headphones, some speakers, or both. And, yet again, we play our samples through the equipment we plan to use and confirm that the ultrasonic content in those recordings is making it to the spot where our test subjects' ears will be when we run the test. (We can use the same microphones we used to record it with - if we recorded it ourselves.)

NOW, we can use our best available filters to take our KNOWN GOOD SAMPLES, and create versions of them that are identical except for being band-limited to 20 kHz.

And, finally, we can select our test subjects, making sure to select a wide cross section of people of all ages, sexes, ethnicities, and all the other demographics. (We may find out that Native Americans, or people from Eastern Germany, can hear things that white Europeans can't.)

Assuming we recorded our own samples, an interesting extra step would be to allow our test subjects to hear the sources live "so they know what to listen for". (It might be interesting to have two groups, one which does this, and one which does not, to test the effects of "learning" on the results.)

And, being SCIENTISTS, we carefully document ALL OF THE STEPS WE TOOK. We list the details of every piece of equipment we used. And, if we made our own test recordings, we provide both details of exactly how they were recorded, and provide copies of them to anyone who wishes to confirm our results. (And, if we found suitable commercial recordings, we provide enough information that someone could buy a copy of the exact same recording to use to confirm our results.)

Note that, while somewhat tedious, none of this is especially EXPENSIVE to do. It's all within the budget of a typical college or audio club. You will also note that any of the really expensive gear, like precision measurement microphones, or high quality recording gear, can almost certainly be rented or leased. (And, when you lease test equipment, it almost always comes with traceable calibration certificates and all that sort of thing.)

I can't speak for today, but, when I went to college, you wouldn't earn a passing grade in a lab course if you missed more than a few of these details. I also left out a few steps, like the analysis of the flaws you yourself are aware of with your test protocol. (For example, we are always going to be limited to testing a limited sample of different sound sources, so we cannot claim to have tested all possible sound sources.)

If you follow those guidelines, and don't skip any steps, then you will have results that any reasonable scientist will at least consider credible.

PLEASE go back and read the actual descriptions of as many "credible tests" as you can find.... and, if you can find any that met the BARE MINIMUM I outlined above, do please post them for the rest of us. Of course, even without proper testing, there is no harm in asserting an opinion, or mentioning that there is no scientific data to support someone else's opinion..... but that doesn't technically rise anywhere near the level of "proof".

The consensus of all the research I have come across in this area is that there is no support for any of it. For example, the article in the link just below provides a summary of the evidence and the flaws in the proponents' arguments. It is worth listenting to the discussion as it is quite interesting and covers it more thoroughly than the texts. The EU and others may be still conducting studies in this area and this is mainly political to appease certain interest groups and anti-wind farm agitists.

https://skeptoid.com/episodes/4388

and in response to feedback from that episode.

https://skeptoid.com/episodes/4459

I wish you would provide some references as the only study I know of which you seem to referring to is the 1998 Tandy study of how infrasound can effect vision (which btw is not considered to be of peer review quality). When he measured the infrasound in the laboratory, the showing was 18.98 hertz--the exact frequency at which a human eyeball starts resonating. The sound waves made his eyeballs resonate and produced an optical illusion: He saw a figure that didn't exist.

What any of this has to do with ultrasonics and music is beyond me.

 

[KeithEmo]

Absolute is absolute and typical is typical.

If you want to make claims about "what a typical human can hear", or "what would probably matter to most of us", then typical values make perfect sense. However, if you want to make absolute statements, or generalities - which are a form of absolute statement, then you must use the extremes when you do so.

You also do in fact need to specify all the details....

For example, can a human being lift over a ton?

That sounds like a simple question...
I'm absolutely certain that I couldn't lift more than a few hundred pounds.
However, I do know several people who can lift several hundred pounds.
I have no idea what the average is - and that might be interesting.
And the limit for what most of us consider "a normal sort of lifting weights" is just under 600 pounds.

However, according to the Guiness Book of World Records....
The heaviest weight lift documented by a human is OVER THREE TONS.
(6270 pounds, lifted in a "back lift", by a fellow named Paul Anderson in 1985.)

If you want to make generalizations, then you simply need to make sure everyone knows that's what you're doing. That's why we have words like "most" and "usually" and "typically". Most of us understand that we can;t lift nearly as much weight as Paul.... and I've never heard of a car company offering "lift handles" on their latest model "just in case you're strong enough to lift it by hand". Perhaps someone needs to look into why audiophiles are so eager to believe that each and every one of them is exceptional... and so easy to convince that they're that outlier.

And, yes, perhaps a good start would be to play some test tones, ON YOUR EQUIPMENT, USING YOUR SPEAKERS, AT A LEVEL YOU FIND COMFORTABLE, to see what actually is likely to make a difference TO YOU.

When abusing figures to justify audiophoolishness, it's very common to take the absolute worst or best case figures and pretend that they are typical. That makes it possible to move the goalposts and say things like, "Normal human hearing goes up to 20kHz, but there are examples of people who can hear higher than that. Surely we should allow for the exceptions to the rule." Once you've moved the goalpost that far, the next step is to go back to normalizing the exceptions and starting the process all over again. This is what people routinely do with data rates. "16/44.1 is fine for normal people, but *I* can hear up to 24/96!" And once you've swallowed that, they start whittling away at that saying, "24/96 is fine, but no one has proven SCIENTIFICALLY that there isn't someone in the world who can hear 48/192." All of that is rhetoric and what ifs.

The truth is that plain old CD quality sound is all you would ever need for the purposes of playing commercially recorded music in your home.