[castleofargh]

I invite you to share paper research, personal experiments, and to just link to here when another topic is getting hijacked by some discussion about high sample rate or ultrasounds making an audible difference. That way people can continue discussing here and stop making off topic posts.


Sighted impressions are not accepted as evidence in this section. It is assumed that we can ignore them in this thread and focus on more reliable sources of evidence.
As this thread's OP, I'd like to see this respected.

 

[castleofargh]

Inaudibility is fake news. There are many undergoing researches about ultrasounds and their impact on humans. Your claims only rely on audiometry using air conduction. Science is not settled about an audible limit. Science is not settled about anything in fact not even what is a women or a men. It uses the 20-20khz conventionally because this is what is commonly observed in practice.

We have means to perceive ultrasounds. Some do exist, like fairly solid bone conduction(the paper I read had an apparatus stuck on the jaw in the mouth). Or blasting ultrasounds right on the skin(I seem to remember a need for ultrasound above 100dB SPL, not sure what the exact magnitude was?). We can also by any mean necessary, make our eyes shake in a way we become aware of. And probably other parts of the body can react to high enough dozes of ultrasounds in some ways we might notice while it happens, but those are TBD or at least I didn't not read about them since the embassy guys getting sick and people suspecting ultrasonic attacks(I'd watch a spy movie on this).
And of course, some young kids and a very rare amount of adults, simply can hear higher than 20kHz tones(until they stop being able to).

So it's reasonable to just agree that noticing ultrasounds can happen. It doesn't really matter to audiophiles how exactly we perceive them. It's interesting but not that important for our hobby. What matters is that we do, and to determine under which conditions and if those conditions apply to typical music listening.
So I propose this as the question to answer. The hypothesis being that ultrasounds in music do have a consciously noticed impact on our experience of the music. I say conscious because of all the audiophiles who keep claiming to clearly hear the difference. Unconscious impact, long term impact, those may or may not be significant, I have no idea how to test it and would not care for random "I know what I heard" empty anecdotes on the topic. So I suggest to leave it out of the picture unless someone actually has some fact based information on the topic for a change.
Sighted impressions aren't even up to grade school experiments loosely supervised by a teacher. So please let's not discuss that while pretending that it's anything remotely conclusive. It's not, a sighted impression could be right or wrong. As there is no way to tell without performing an actual listening test, it's worthless. Worst than worthless, it wastes everybody's time in this sub-forum.

Do you agree that if I think I notice something different when my hires file has been stripped of ultrasounds, I can test that proposition and demonstrate it to be true(or not)?
No matter how my body makes me aware of it, if I'm aware of it, then I can put that perception to the test with a blind test. Do we agree on that? If so, we have an hypothesis. We can test it, hermaggerd we're almost starting to do science!

We can consider many tests, answering slightly different questions. For example we could just do a blind test with hires file and 16/44 file of the album. But if we pass that, the actual cause could be many things. It could be that the playback lagged a little on the heavier file. It could be that the source resampled really poorly one of the files. It could be that they come from different masters. It could be that the DAC has a fairly "colored" filter for 44.1kHz files(trebles roll off, or lot of aliasing). And some other reasons(format decoding issues, bit depth difference, buffer issues with the bigger file...). So this wouldn't really test our hypothesis. Ironically that's what almost everybody doing sighted "tests" are using, as if a sighted impression wasn't enough of a problem already.

A better test would be a blind test between an original hires file in .wav(to cross all the t's) and that file converted to 44 or 48kHz, then converted back to the original sample rate. That way everything is identical(file size, format, source and DAC's way of handling it) except for one file that has lost its ultrasonic content.
If we can tell those apart consistently in a blind test then we can confidently say that the conversion caused an audible difference. It doesn't 100% prove that what we're noticing is the ultrasonic content specifically, as it could still be IMD from the ultrasounds coming back in the audible range, or maybe the converter and settings caused something other than just the removal of ultrasonic range(maybe a really crappy band limiting, maybe just a change in gain). But we can try to investigate with other tests or measurements and probably rule out those options. So it's not a dead end. At the very least, passing such a test would confirm that we're hearing a difference when the music has ultrasonic content. That would already be a bog step up in term of demonstrated fact. That in turn could make a good argument about the impact of using hires files when listening to music, at least on our specific playback system with our ears. Which isn't much for the world, but is usually everything that really counts to us Headfiers.


Have you considered trying such tests instead of jumping head first into the marvelously self gratifying adventures of only seeking confirmation on the web and almost always striking gold no matter how bad the idea actually is? I've done perhaps 30 blind tests(pretty conservative guesstimate), and about half of them were attempts at perceiving changes with hires files, because of course I'd like to hear it if there is something worth hearing that improves realism, soundstage and whatever random stuff we read audiophiles claiming to have heard improve with hires. Each test being usually made of 20 trials where I'd try to identify the files for as long as I deemed necessary.
I have yet to pass even one such test. And I haven't met anybody IRL who would accept to try and could pass. Doesn't mean nobody can, but the group claiming it can strangely also happens to be the same group that usually refuses to properly test anything. Saying I'm skeptical is putting it nicely.

On the other hand, I've passed several blind tests when using a redbook file against an hires file, usually I could determine rapidly with some measurements that the cause was one of the reasons I mentioned above. Trying to eliminate that cause also eliminated my ability to pass the test. Back to square one.

And of course when casually listening to music and switching between hires file and the one at 44.1kHz while knowing at all time what it is I'm listening to because I'm seeing the files, I, like most people, have felt all sorts of things. But when I feel like I can tell the difference between 64kbps mp3 and 320 in casual listening, I can then pass a blind test to confirm it. Same with certain levels of background noise, same when trying to tell Celine Dion apart from Barry white by ear. And of course I can! Because I'm actually perceiving differences even without looking at them. With high sample rate files, when I stop looking I also stop being able to tell the difference. But a test between 44.1kHz and a 8kHz conversion and back, is something I can pass. What do you think is the reason for that? Maybe because this time, the frequency range removed is something I could actually notice without looking at the filename? I think that's a pretty fair assumption.




Most people I know who honestly tried .wav against the downsampled then upsampled back version, couldn't pass. It's been done for decades now and failing this is IMO a very strong argument against our initial hypothesis. So until demonstrated otherwise, that's my position on the subject.

 

[Hifiearspeakers]

https://hearinghealthmatters.org/he...ntermodulation-distortion-cuba-sonic-attacks/

“At the same time, intermodulation distortion can produce lower-frequency signals than the original signals. In other words, inaudible ultrasonic waves going through air can produce audible by-⁠products.”

 

[castleofargh]

https://hearinghealthmatters.org/he...ntermodulation-distortion-cuba-sonic-attacks/

“At the same time, intermodulation distortion can produce lower-frequency signals than the original signals. In other words, inaudible ultrasonic waves going through air can produce audible by-⁠products.”

Yup that's what I was referring to when mentioning embassy guys. And I also mentioned IMD later(although without explaining anything ^_^). It's a compelling argument as to why something with ultrasound content could clearly sound different. In fact the first famous and controvertial paper claiming to have demonstrated ultrasound audibility with listeners, got debunked and it was suspected(maybe even confirmed? IDK) that IMD from the playback system had been the reason for people passing that experiment in particular.

In this approach, with the main IMDs being caused by the equipment, it's not going to be the same depending on the gear(and with better gears it won't be audible). Plus it's a distortion, so shouldn't we wish to avoid it as much as possible? IMD isn't famous for being euphonic like some types of harmonic D can be.

 

[bigshot]

We aren't talking about dog whistles or sonic weapons or hearing ultrasonic frequencies underwater or deaf people perceiving through bones or brain waves... we're talking about listening to commercially recorded music. Traditional musical instruments don't produce much of any sound up there, and the sound that is produced is masked by lower frequencies. We can do a listening test between "HD Audio" and regular old CD sound and no one can tell the difference. Mark Waldrop even admitted it's useless on a website dedicated to HD Audio. What more do you want? Moses to come down from the mount with tablets inscribed "Thou shalt not worry about frequencies thou can't hear."?

Folks can go on pretending that "maybe it's important- I don't know for sure" and engaging in "what if" after "what if", but they're just being an ostrich with their head in the sand. This really isn't a question any more. It's been tested and answered and everyone has packed up and gone home by now. It's an absurd waste of time to even argue about it at this point.

For the purposes of listening to recorded music in the home, super audible frequencies are as useless as teats on a bull hog.

 

[Hifiearspeakers]

Yup that's what I was referring to when mentioning embassy guys. And I also mentioned IMD later(although without explaining anything ^_^). It's a compelling argument as to why something with ultrasound content could clearly sound different. In fact the first famous and controvertial paper claiming to have demonstrated ultrasound audibility with listeners, got debunked and it was suspected(maybe even confirmed? IDK) that IMD from the playback system had been the reason for people passing that experiment in particular.

In this approach, with the main IMDs being caused by the equipment, it's not going to be the same depending on the gear(and with better gears it won't be audible). Plus it's a distortion, so shouldn't we wish to avoid it as much as possible? IMD isn't famous for being euphonic like some types of harmonic D can be.

I’d say yes, we absolutely want to avoid that. There are numerous music players, like Neutron, for example, that have an ultrasonic filter built into it.

 

[bigshot]

16/44.1 applies a nice ultrasonic filter for you so your equipment doesn't have to do it.

 

[gregorio]

We have means to perceive ultrasounds. Some do exist, like fairly solid bone conduction(the paper I read had an apparatus stuck on the jaw in the mouth). Or blasting ultrasounds right on the skin(I seem to remember a need for ultrasound above 100dB SPL, not sure what the exact magnitude was?).

We've been doing bone conduction experiments for centuries. Until relatively recently, the last few decades or so, it was done by using a tuning fork placed against the mastoid bone or even between the teeth. Today it is typically done with transducer pads (which convert an analogue audio signal into mechanical vibrations), often mounted on headsets, that are likewise placed against a bone directly adjacent the pinnae (commonly the mastoid, behind the pinnae). Most of the research I'm aware of has nothing to do with ultrasound but for practical applications, such as; hearing aids, communications in noisy/difficult environments (underwater for example) and for corporate or military use where privacy is a priority, as sound presented by bone conducted vibrations cannot be overheard. I believe the first practical application was bone conduction hearing aids in the 1930's.

None of this has anything to do with listening to commercial music or sound recordings though, unless there are audiophiles out there who bolt their speakers directly to their skulls!!

In fact the first famous and controvertial paper claiming to have demonstrated ultrasound audibility with listeners, got debunked and it was suspected(maybe even confirmed? IDK) that IMD from the playback system had been the reason for people passing that experiment in particular.

I presume you are referring to the infamous Oohashi paper? Despite several attempts, the results published by Oohashi could never be repeated, except in one instance, where IMD was found to be the cause. After this and various other debunkings, I believe Oohashi retracted the paper.

G

 

[SoundAndMotion]

I presume you are referring to the infamous Oohashi paper? Despite several attempts, the results published by Oohashi could never be repeated, except in one instance, where IMD was found to be the cause. After this and various other debunkings, I believe Oohashi retracted the paper.

OMG!! The urban legend of "The Debunking of Oohashi" continues...
Please backup ANY!! of this with real papers, not other forum posts that are just part of the urban legend referring to itself.
Please note:
- Oohashi said none of his subjects heard or perceived the ultrasounds. His data was alpha-EEG and PET scans.
- I don't know of anyone attempting to replicate his work.
- Ashihara found IMD in some of his own early work, that he addressed in his later work
- Oohashi ≠ Ashihara. They measured different things (Ashihara with perception and Oohashi with physiology)
- Oohashi hasn't retracted anything
- Oohashi was aware of and avoided IMD products in the audible range by using a special separate super-tweeter

 

[bigshot]

None of this has anything to do with listening to commercial music or sound recordings though, unless there are audiophiles out there who bolt their speakers directly to their skulls!!

Or consult their brain scans when they play an album!

You're right. This might be interesting to some from a purely theoretical standpoint, but it's all irrelevant to listening to recorded music. I'm interested in improving the sound quality of sound I can actually hear.

 

[gregorio]

OMG!! The urban legend of "The Debunking of Oohashi" continues...
Please backup ANY!! of this with real papers, not other forum posts that are just part of the urban legend referring to itself.
Please note:
- Oohashi said none of his subjects heard or perceived the ultrasounds. His data was alpha-EEG and PET scans.
- I don't know of anyone attempting to replicate his work.
- Ashihara found IMD in some of his own early work, that he addressed in his later work
- Oohashi ≠ Ashihara. They measured different things (Ashihara with perception and Oohashi with physiology)
- Oohashi hasn't retracted anything
- Oohashi was aware of and avoided IMD products in the audible range by using a special separate super-tweeter

Unfortunately my memory is a bit hazy, I read Oohashi's papers many years ago and I can't go back over them as they're behind a paywall to which I no longer have access. However, from what I recall, Oohashi's data was not only physiological brain waves and PET scans, he also tested perception and preference. His first paper on the subject was titled "High frequency sound above the audible range affects brain electric activity and sound perception" - So obviously must have included perception. I cannot recall if it was this paper or another where Oohashi claimed that none of his subjects could not perceive ultrasounds on their own, but could when included with full bandwidth content and, he reported an expressed preference. However, this only occurred with speakers and he could not replicate those findings with headphones. I'm paraphrasing here of course and my memory is somewhat shaky but it's these perceptual assertions that have been debunked, not his physiological brainwave results.

Although they don't specifically set out to debunk Oohashi's assertions regarding perception, there are numerous papers whose results contradict them and thereby effectively debunk them. However, I recall a study by NHK which more specifically addressed Oohashi and was therefore especially stringent with their reproduction chain in order to avoid IMD or any other influence of ultrasonic frequencies on the audible band. Fortunately, that study is not behind a paywall: "Perceptual Discrimination between Musical Sounds with and without Very High Frequency Components"

Ashihara (and others) found that IMD in the audible band caused by moderately high levels of ultrasonic content is far more common and more difficult to eliminate than generally supposed. However: I agree that I overstated the case for IMD being the cause of Oohashi's perceptual results. To the best of my recollection, it has NOT been proven that Oohashi "avoided IMD products" and therefore IMD is by far the most likely cause of his results (which together with Ashihara's findings is why the NHK study went to such lengths to avoid it) but IMD has not been "found" to be the cause, as I incorrectly stated. And, as I can't find any hard evidence that he has ever retracted any of his papers/claims, I'm willing to change my stated belief. This may indeed have been nothing but an urban legend.

G

 

[old tech]

I find it hard to understand this fetish with ultrasonic sound with some 'audiophiles', rather than the focus on frequencies that matter to humans. Although 100 years of data have long established the upper limit of human hearing at 20khz for healthy 18 year olds (plus or minus a couple thousand hertz) it is somewhat ironic that the profile of audiophiles are middle and upper age men who would be fortunate to hear anything above 14khz.

The other puzzling aspect of this search for out of scope human frequencies is why the focus on ultrasonics rather than subsonics? At least with the latter there actually can be a perception of these low frequencies as they shake internal organs and room furniture - my guess is that the ultrasonic fetish was started by the vinyl crowd knowing that CD cuts out at 20khz but they can't handle the fact (and never discuss the fact) that CD can get right down to 0 hz and be within 0.5db while doing it, an impossible task for vinyl recording and playback.

And even with a leap of faith and assuming that these ultrasonic frequencies can affect the frequencies we can hear, why is it relevant to playback of a recording? If the ultrasonics are affecting frequencies below 20khz then those affected frequencies will be captured and baked into the recording. Taking this thought bubble further, one can then argue that ultrasonics is bad for playback (assuming your stereo can actually reproduce those frequencies) as it will add to effect that is already baked into the recording. In other words it will cause distortion.

 

[castleofargh]

I find it hard to understand this fetish with ultrasonic sound with some 'audiophiles', rather than the focus on frequencies that matter to humans. Although 100 years of data have long established the upper limit of human hearing at 20khz for healthy 18 year olds (plus or minus a couple thousand hertz) it is somewhat ironic that the profile of audiophiles are middle and upper age men who would be fortunate to hear anything above 14khz.

The other puzzling aspect of this search for out of scope human frequencies is why the focus on ultrasonics rather than subsonics? At least with the latter there actually can be a perception of these low frequencies as they shake internal organs and room furniture - my guess is that the ultrasonic fetish was started by the vinyl crowd knowing that CD cuts out at 20khz but they can't handle the fact (and never discuss the fact) that CD can get right down to 0 hz and be within 0.5db while doing it, an impossible task for vinyl recording and playback.

And even with a leap of faith and assuming that these ultrasonic frequencies can affect the frequencies we can hear, why is it relevant to playback of a recording? If the ultrasonics are affecting frequencies below 20khz then those affected frequencies will be captured and baked into the recording. Taking this thought bubble further, one can then argue that ultrasonics is bad for playback (assuming your stereo can actually reproduce those frequencies) as it will add to effect that is already baked into the recording. In other words it will cause distortion.

Exaggerating the significance of something is a fairly common behavior with all forms of arts. The more subjective the approach, the more likely it is to happen. I'm absolutely guilty of it in other forms
I also believe that availability is a big factor here.
When looking for reasons why the "obviously" higher resolution file feels better, nobody likes to consider possible biases/preconceptions. But everybody gets that we'll have more bits and higher frequency(more samples). We've had decades of nerds trying to explain that bit depth, all other things remaining as they are, is just affecting quantization noise.
On the other hand, with ultrasounds and higher sample rate, you can consider many fancy hypotheses. Frequencies, timing, filters, hearing, other senses(if we don't know which one, it's even better), conscious or unconscious... Ultrasounds are opening the door for load of more or less attractively vague notions we can turn into hifi philosophy. When it's vague, it can't be disproved by nerds. That too makes it attractive on a forum for the guy who barely understand digital sampling, if at all.

Of course the major axiom here is that almost none of those who believe in the audible benefit of ultrasounds, have checked if the idea held against controlled experiment under music listening conditions. We're almost always in the domain of people trying to justify a belief born from sighted impressions. And that in term of science and confidence, is a huge red flag. Maybe even bigger than vague ideas trying to escape from falsifiability.
So we're in this paradox where science has very little to offer as to why ultrasounds would improve music experience, while still an impressive number of audiophiles believe it makes everything better.

None of this has anything to do with listening to commercial music or sound recordings though, unless there are audiophiles out there who bolt their speakers directly to their skulls!!

That's what failing blind tests using highres .wav against the downsampled then upsampled back version of it, under my usual listening conditions, with music I happen to enjoy, is suggesting to me. It is suggesting that none of the hypotheses(not just bone conduction) about ultrasounds improving the listening experience(or degrading it), seems to cause noticeable impact for me under those conditions.

 

[gregorio]

[1] I find it hard to understand this fetish with ultrasonic sound with some 'audiophiles', rather than the focus on frequencies that matter to humans.
[2] The other puzzling aspect of this search for out of scope human frequencies is why the focus on ultrasonics rather than subsonics? At least with the latter there actually can be a perception of these low frequencies as they shake internal organs and room furniture ...
[3] If the ultrasonics are affecting frequencies below 20khz then those affected frequencies will be captured and baked into the recording.
[3a] Taking this thought bubble further, one can then argue that ultrasonics is bad for playback (assuming your stereo can actually reproduce those frequencies) as it will add to effect that is already baked into the recording. In other words it will cause distortion.

1. The reason for the fetish with ultrasound is relatively easy to understand: Marketing! It all started with the introduction of the SACD format, a fundamentally simpler/cheaper technology than CD that Sony nevertheless positioned as several times more expensive and which therefore required some serious marketing to justify. Very soon after the launch of SACD we had the introduction of DVD-A and a format war ensued; on one side several of the most major record labels and on the other Sony, Philips and other record labels. That's a great deal of marketing muscle "duking it out" but BOTH sides unanimously marketing/rebranding CD as an inferior, lower resolution/fidelity format. The only originating source of information for the vast majority of audiophiles is marketing, paid for reviews and other shills, so they really didn't stand a chance against this unified wall of marketing muscle against the CD format. As we're well aware, this has resulted in a number of nonsense "fetishes": Dynamic range, jitter, more analogue sounding, etc. However, one advantage of the ultrasonic "fetish" is that it's very easy to see/verify. Run almost any original DSD, 24/96 or 24/192 commercial music recording through free freq analysis software and anyone can immediately see an obvious difference (content extending beyond 22kHz). The difference with dynamic range is far more difficult or impossible to see, "more analogue sounding" can't really be measured/seen and jitter requires expensive specialist equipment to measure and even then, it's only easy to "see" with test signals.

2. You've partially answered your own question, subsonics with enough energy to feel, shakes room furniture/fittings. There are other practical issues that don't exist with the reproduction of ultrasonic freqs: The units need to be physically large, they're difficult/expensive to manufacture, they require large amounts of amplification power, there's very rarely anything in that freq range except unwanted noise/rumbles/resonances anyway and it's impossible for consumers to stop (or even significantly reduce) these high levels of such low freqs from leaking into other rooms/apartments/adjoining buildings. In fact, even massively expensive anechoic chambers struggle in this regard.

3. True, although we have to be a bit careful with the terminology, because ultrasonics affecting freqs below 20kHz (IE. IMD) are not necessarily captured and baked into the recording but they are captured and baked into the master and therefore the distribution copies (which are typically referred to as "recordings"). Much of the IMD doesn't occur during the performance or recording, it occurs during mixing and mastering. Much of the music recording industry moved to 96kHz sampling rates around the turn of the millennium to accommodate the spurious ultrasonic freqs (that initiate IMD) required by emulators (EQ, compressor, limiter, guitar amp/cab emulators, etc.). Of course, none of this affects the consumer because once the IMD (in the audible band) has be created by the compressor, EQ or whatever, then it's baked into the (44.1kHz) mix/master and the spurious ultrasonic freqs no longer do anything. Unfortunately though, this was easily turned into marketing BS, along the lines of: If the studios/pros need sample rates greater than 44 or 48kHz and it results in an audible difference, then discerning audiophiles need it too! Ironically, within a few years, the studios/pros didn't need greater than 44.1kHz sampling rates either, as the available computing power increased and emulators requiring the use of ultrasonic freqs could simply upsample internally, generate the ultrasonic freqs and audible band IMD and then downsample back to 44.1kHz before outputting it's signal.
3a. I'm not sure I've interpreted what you've said correctly. Audible IMD doesn't just happen, it has to be created by some device with a non-linear response, a vintage compressor or guitar amp/cab for example. So you're not going to "add to the effect already baked into the recording" unless you've got say a vintage compressor or guitar amp/cab in your playback chain. However, if there's enough ultrasonic content in the recording (distribution copy) then your amp or speakers could introduce new/different audible IMD products.

G

 

[SoundAndMotion]

If someone writes: [(1)Intelligent extraterrestrial life cannot exist, (2)because 2+2=5], three issues pop up for me.

1- Is statement (1) true or not? What evidence supports or refutes the idea? How reliable is the evidence? This discussion may or may not be interesting to me.

2- Is supporting statement (2) true or not? Is its truth, or lack thereof, relevant or not?

3- There is a pathological reflex response among many people in forums, that if someone points out the flaw in (2), they must have a certain opinion on (1). ...and maybe should be attacked for it.

@gregorio , do you have an interest in discussing Oohashi and/or research into the relevance (or lack thereof) of >20kHz content to music enjoyment? If so, the Oohashi paper most often cited, both in forums and in other research papers, is this one [link]. The "paper" you cite is a conference paper (not peer-reviewed), and I believe they don't directly measure perception, rather infer perception-relevance from other data, such as "comfortable listening level". Because of issue (3), I'm not interested in blindly discussing this stuff, since most of what I'd say would be misconstrued. On the other hand, I'd love to discuss any paper you'd like (one we've both read).

My comment to you above was of the form of issue (2). Without commenting on Oohashi's work, particularly its relevance or quality, I wanted to point out errors in the "debunking" myth.