Can we hear sound above 20kHz!

[Jasonovich]

The well held view, our ears cannot hear beyond 20kHz. I may be poking the bear but this has met some scrutiny as per Callan's YT video. This at best will encourage debate, though they'll be a fair serving of Meh, nothing to see, move on.

I do believe psychoacoustics come into play, I feel the brain perceives a sensory presence even though the ears are unable to decipher the sound at 20kHz, I do think it adds something to the enjoyment of the music but that's just my own humble opinion. What are your thoughts on this?

View: https://youtu.be/q_HfTgN1kB4?si=o2Bcf2x9Agf-KpDS

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journals.physiology.org

 

[podknocker]

Many people when born have been shown to respond to 25kHz and the range of hearing does diminish from mid to late teens. I play the audio test tones on Spotify and I can hear 13kHz easily and just hear 14kHz, if turned up a bit. Its the hairs and structures inside the inner which react to certain frequencies. If they are not there, due to age, or damaged through very loud music for example, then there is nothing there to send the relevant and corresponding electrical signals to the brain. Sound, like vision and colour, is a perception and is constructed inside the brain. Sounds don't actually exist, only vibrations in the air. You need a device, like an ear and then a brain to 'understand' the signal. I studied human physiology many years ago and there are some great text books out there. In this study, addition of very high frequencies did show a change in brain activity, but it's really adding harmonics to the audible sounds. I found this video to be very interesting, especially the part about Shepard tones.

View: https://www.youtube.com/watch?v=Sn07AMCfaAI

 

[Gray]

I've repeatedly read the theory that, if a system can reproduce ultrasonic frequencies, then it's better at the ones we can hear.

Probably the same reviewers that report better bass when they're testing super tweeters! 🤨

 

[Cricketbat70]

The well held view, our ears cannot hear beyond 20kH

I'd love to know how sensitive my sons ears are. My wife has a rechargeable candle lighter that has two electrodes about a centimetre apart that creat a little arc between them that ignites the candle wick. I can hear the electric arc humming, my son has to leave the room as it hurts his ears when it's used. My son ended up shouting at his mum once, she was lighting a load of candles and he asked her nicely a few times not to use the device and she completely ignored him thought he was making a fuss over nothing (my wife wears hearing aids and obviously can't hear this little device)

 

[Jasonovich]

Many people when born have been shown to respond to 25kHz and the range of hearing does diminish from mid to late teens. I play the audio test tones on Spotify and I can hear 13kHz easily and just hear 14kHz, if turned up a bit. Its the hairs and structures inside the inner which react to certain frequencies. If they are not there, due to age, or damaged through very loud music for example, then there is nothing there to send the relevant and corresponding electrical signals to the brain. Sound, like vision and colour, is a perception and is constructed inside the brain. Sounds don't actually exist, only vibrations in the air. You need a device, like an ear and then a brain to 'understand' the signal. I studied human physiology many years ago and there are some great text books out there. In this study, addition of very high frequencies did show a change in brain activity, but it's really adding harmonics to the audible sounds. I found this video to be very interesting, especially the part about Shepard tones.

View: https://www.youtube.com/watch?v=Sn07AMCfaAI

I went for sample A!

 

[Revolutions]

Isn’t this common knowledge?

It’s long been accepted that humans can unconsciously perceive higher frequencies. We just can’t hear them. That’s why acoustic instruments sound so much better in real-life than on record.

 

[Vincent Kars]

That’s why acoustic instruments sound so much better in real-life than on record.

Really?
A lot of acoustic instruments don't exceed the 10 kHz: https://alexiy.nl/eq_chart/
Not to mention 20 kHz

 

[Revolutions]

Really?
A lot of acoustic instruments don't exceed the 10 kHz: https://alexiy.nl/eq_chart/
Not to mention 20 kHz

Lots of instruments will go to 20 & way above: violins, trumpet, piano & guitar are some common ones. Cymbals have been recorded above 100 kHz.

 

[Friesiansam]

I've repeatedly read the theory that, if a system can reproduce ultrasonic frequencies, then it's better at the ones we can hear.

Probably the same reviewers that report better bass when they're testing super tweeters! 🤨

If you can think of an idea, no matter how ridiculous, there will likely be someone on the interwebs, who claims to have a theory that can prove it.

 

[podknocker]

Ever since humans started making music, we've designed instruments to make sounds within the range of human hearing. Some instruments, such as cymbals, do produce sounds outside the range of human hearing, but this is an unintended consequence and is merely a byproduct of the design. Metallic materials are inherently capable of producing the higher octaves, but humans never made cymbals to produce sounds we can't hear. Apart from cymbals and artificial sounds produced by synths, nearly all musical instruments have been designed to make sounds similar to those produced by the human voice and natural sounds we have evolved to hear for hunting, or things to run away from. You need to hear the roar of a lion and you also need to hear a mosquito, to avoid being bitten etc. The chart above is accurate and most instruments make sounds most humans can hear, even in later years. Humans have never made instruments to not hear them. The piano, string, woodwind and brass instruments were designed to be heard. That's the point. They may produce harmonics outside the range of human hearing, but this was never intended. The suggestion that instruments sound better in real life, rather then a recording doesn't stand up. CDs can hold information all the way to 20kHz and later formats can cope with even higher frequencies. A real life cymbal will produce harmonics you can't hear, in the same way as a recording of a cymbal on CD. The limitation is the quality of other components, such as loudspeakers and most tweeters make sounds a cat, bat or dog could hear.

 

[manicm]

Ever since humans started making music, we've designed instruments to make sounds within the range of human hearing. Some instruments, such as cymbals, do produce sounds outside the range of human hearing, but this is an unintended consequence and is merely a byproduct of the design. Metallic materials are inherently capable of producing the higher octaves, but humans never made cymbals to produce sounds we can't hear. Apart from cymbals and artificial sounds produced by synths, nearly all musical instruments have been designed to make sounds similar to those produced by the human voice and natural sounds we have evolved to hear for hunting, or things to run away from. The chart above is accurate and most instruments make sounds most humans can hear, even in later years. Humans have never made instruments to not hear them. The piano, string, woodwind and brass instruments were designed to be heard. That's the point. They may produce harmonics outside the range of human hearing, but this was never intended. The suggestion that instruments sound better in real life, rather then a recording doesn't stand up. CDs can hold information all the way to 20kHz and later formats can cope with even higher frequencies. A real life cymbal will produce harmonics you can't hear, in the same way as a recording of a cymbal on CD. The limitation is the quality of other components, such as loudspeakers and most tweeters make sounds a cat, bat or dog could hear.

It's funny, everyone wants bit-perfect, but playing around with parametric eq negates that.

Then hires audio requires amp, source and speakers to handle frequencies above 30 or 35khz. Not all do this, and not all consumers check this before shouting hires.

 

[podknocker]

CD was invented to cope with the sounds humans can hear and cover the dynamic range of human hearing. Higher than CD resolution is pointless, but higher resolution formats can move the noise and distortion into ranges outside human hearing. The best HIFI is making sounds we can't hear, but this will affect the sounds we can hear. I would argue the distortion produced by a tweeter at 20 to 50kHz will have a negligable affect on what you hear. An oscilloscope would probably show this, but I think many people think human hearing is better than it really is. We've evolved to hear things we need to hear. Nature never intended humans to hear the distortion from loudspeakers fed by an electronic device producing sounds at 50kHz.

 

[Revolutions]

Nature never intended humans to hear the distortion from loudspeakers fed by an electronic device producing sounds at 50kHz.

hate to break it to you, but nature doesn’t have an agenda. I’m fairly sure it wouldn’t have chosen to create a slow moving animal that needs loads of calories to function, isn’t very strong & can’t see in the dark.

Evolution is a system of best-fit, not optimisation. We have many, many physiological & psychological quirks that serve no clear purpose for survival & reproduction.

 

[nopiano]

I’ve not watched the videos above, but I do recall a few years ago a study reporting that humans can ‘perceive’ ultrasonics. Rather than through the ears, however, we apparently ‘hear’ through our eyes! Yes, really.

As a spectacle wearer, I tried with and without specs, but didn’t conclude anything much. However, I’m now lucky to hear above 9kHz, so double that and beyond is of no concern!

 

[podknocker]

hate to break it to you, but nature doesn’t have an agenda. I’m fairly sure it wouldn’t have chosen to create a slow moving animal that needs loads of calories to function, isn’t very strong & can’t see in the dark.

Evolution is a system of best-fit, not optimisation. We have many, many physiological & psychological quirks that serve no clear purpose for survival & reproduction.

Hate to break it to you, but nature does have an egenda. It's to push and test every possible organism, to survive and adapt to any possible environment and stress imposed upon it. Your statement doesn't really mean anything as optimisation is required to achieve best fit. My point that humans have never needed to hear 50kHz sounds is still correct. 'Needs loads of calories' doesn't mean anything. Humans will consume and burn calories as required. We are primates and hunter gatherers. We've not evolved to see well in the dark, as our prey are active during the day and we've never been nocturnal primates. 'Not very strong' also means nothing. We are as strong as we need to be to hunt and perform natural, nomadic, hunter gatherer activities. We are currently evolving into sedentary animals, consuming far more energy than we would normally need to survive. Obesity is slowly killing our species, since the availability of endless calories and sedentary jobs and leisure time has been the biggest part of our waking hours. Up to the industrial revolution, we were optimised to be outside in the daytime, searching for food and new habitats. We've always expended energy to find food. The modern human diet is not what the human gut expects and being sat down all day, eating crap will gradually destroy all our genes and at some point, we'll be unable to carry out natural human activity, if we ever need to do it again. Another 100 generations and we will probably be unable to move, with tubes at both ends, glued to chairs, with many people typing nonsense on forums like this one.

 

[Revolutions]

Hate to break it to you, but nature does have an egenda. It's to push and test every possible organism, to survive and adapt to any possible environment and stress imposed upon it. Your statement doesn't really mean anything as optimisation is required to achieve best fit. My point that humans have never needed to hear 50kHz sounds is still correct. 'Needs loads of calories' doesn't mean anything. Humans will consume and burn calories as required. We are primates and hunter gatherers. We've not evolved to see well in the dark, as our prey are active during the day and we've never been nocturnal primates. 'Not very strong' also means nothing. We are as strong as we need to be to hunt and perform natural, nomadic, hunter gatherer activities. We are currently evolving into sedentary animals, consuming far more energy than we would normally need to survive. Obesity is slowly killing our species, since availability of endless calories and sedentary jobs and leisure time has been the biggest part of our waking hours.

ok I wasn’t exactly clear. By optimisation, I meant “the most effective version possible”. And best-fit as “whichever genes managed to survive”.

Example: our brains are incredible machines, but too calorie hungry & slow to actually analyse the billions of sensory data inputs it receives every second without shortcuts. That’s where biases/heuristics come from, & why things like optical illusions are so effective.

Our massive advantage over animals we hunted, and the ones that hunted us, is consciousness. And as far as anyone can tell, that’s an accidental outcome of the way our brains work. Without our ability to imagine & communicate to work in groups (& learn to use tools), we’re slower, weaker & generally less able to defend oursevles than pretty much any animal. Out advantage is a random accident of physiology. You’d be crazy to design something like that & not change things if there was an agenda or a direction.

We didn’t evolve to see in daylight because our prey are active during those hours. We’ll never know that. The only thing we know is that, for some reason, any people who were excellent at seeing in the dark died without reproducing. (Over millions of years)

I never said humans need to hear beyond 50 kHz. I merely said we have a tonne of evolutionary junk that isn’t actually useful - ie our bodies being able to perceive sounds we can’t hear.

 

[podknocker]

There is an abundance of scientific literature out there to prove we've adapted to move and hunt in the daytime., you just need to have the inclination and interest to look for it. We are primates and have always hunted in the daytime. We evolved to see red to identify ripe fruit from unripe fruit, for example. You can't see red in the dark. The human brain has adapted to use complex language and tools. This has given us an advantage when stalking other animals. We are at the top of the food chain on this planet, as we could choose to kill and eat any other species out there. We are unique in this regard.

 

[Revolutions]

There is an abundance of scientific literature out there to prove we've adapted to move and hunt in the daytime., you just need to have the inclination and interest to look for it. We are primates and have always hunted in the daytime. We evolved to see red to identify ripe fruit from unripe fruit, for example. You can't see red in the dark.

If you think this through, how would you evolve to see red in order to identify ripe fruit?

 

[Rodolfo]

I've never actually known what I can hear below 20khz, and I'm only somewhat curious intellectually, not clinically (up to) where I can hear. I am very thankful that well into my 8th decade I seem to be able to hear joyfully, and with mostly the same equipment, power and volume levels, and locations as ever, including live ones. I also am not bothered by a number of sounds or levels or locations that some of my peers and others are. That is plenty and enough.

Above 20K? Below? Who knows...

 

[podknocker]

Example: our brains are incredible machines, but too calorie hungry & slow to actually analyse the billions of sensory data inputs it receives every second without shortcuts. That’s where biases/heuristics come from, & why things like optical illusions are so effective.

Our brains are designed to perform the way they need to. Brains DO analyse the billions of sensory data inputs they receive every second and cope really well. You seem to imply there is a flaw in the most complicated organ to exist in nature. We've survived and populated the planet because we are capable of incredible brainpower. The suggestion that our brains are too slow and calorie hungry is nonsense. Your brain uses the calories it needs and it's as quick as it needs to be, to allow it to cope with the world around us. The human brain has adapted to a very different world, over the last 100 years or so. The way current generations have responded to our society, in order to cope with the demands of a world far different to the one our grandparents would have experienced, will change how the human brain is wired and it will allow us to think and behave in ways we can't imagine now. The technology around us has forced our brains to react and adapt to a much different world to the one we had 50000 years ago. Human intelligence is significantly higher than many centuries ago and I think we should appreciate it. Our ancestors would struggle if they were suddenly placed in a huge city, highly populated and surrounded with all this interweb shite. Science is showing our reliance on technology and social media, including this forum, is changing how the human brain works. One downside is that if humans ever need to return to a non technological world, our innate and instinctive skills may have disappeared, replaced by brain functions developed for a world far different to the one our ancestors dealt with. Who knows what the future will bring and we may find our current skills are useless, if we need to return to our previous hunter gatherer way of life.

 

[podknocker]

If you think this through, how would you evolve to see red in order to identify ripe fruit?

Any ancestral primate with a slight mutation to the genes responsible for colour vision, would choose slightly riper fruit than its peers. This would give it access to more sugars and nutrients, as riper fruit has more cells broken down by enzymes, allowing the release of more energy and nutrients. Its offspring would have this advantage and the ability to see riper fruit would be passed down through the generations. This fitter generation would have an advantage and after millions of years, you have primates, such as humans with the ability to eat ripe bananas, rather than green ones with very little nutritional value. Dogs don't see reds and have not needed red to see ripe fruit, being carnivores. Dogs and cats also make their own vitamin C because they don't eat fruit. Humans don't have an active gene to encode for vitamin C production, as we've always eaten fruit and don't require it. Maybe if we stopped eating fruit and we survived scurvy, a dormant gene might switch on and we could make our own vitamin C again. Our current reliance on fruit has probably turned this gene off forever and it's irreversible. I had a friend who's mum never ate fruit or veg and suffered macular degeneration, so keep eating your colourful, natural foods. There'a loads out there explaining this stuff if you really want to learn it. This is a great way to start, if you have a genuine interest in evolution:

https://www.amazon.co.uk/Selfish-Gene-Anniversary-Landmark-Science-dp-0198788606/dp/0198788606/ref=dp_ob_image_bk

 

[Revolutions]

@podknocker I think I’m still not being clear. Needless to say I’ve read the selfish gene, and many other books & papers on evolution, psychology & neuroscience. My job requires me to have a solid grounding in psychology & sociology.

The difficulty with your post above is that you’re giving humans knowledge of what fruit is healthy before they know it is healthy. I’m fairly certain that Dawkins highlights in his book that genes do not have foresight. It’s a good case of correlation not equaling causation: because we survived we must be the best version. And it’s an example of survivorship bias (a version of that heuristic, concerning bomber plane armour during WWII, was famously discussed by Malcom Gladwell in one of his books).

The reality for evolution is complex…

Scenario 1
- humans move to new place with red fruit & blue fruit
- some can see the colour difference, some can’t
- some who can see the difference will be naturally attracted to one colour or the other, creating a small group who both see the red fruit & desire the red fruit
- people who eat the blue fruit tend to die
- slowly the group realise blue fruit is bad
- some people still can’t see blue fruit: without being assisted by those that can see the difference, they have a 50/50 chance of choosing the wrong fruit & slowly die out, likely producing less children
- within the population who can see red vs blue, some of them prefer blues. They also slowly die out & likely produce less children
- as the children of people who can see red vs blue & prefer red over blue grow up, they have a strong preference & the culture quickly adapts, whilst our genes also start to switch & trigger the desire for red

Just in that massively oversimplified option there are endless variables that we will never know the answers to. And, importantly, there is the interplay between nature & nurture that we currently have no way of unpicking which leads to what (eg, do your children love reading because your love of reading was passed on via the genes, or is it because your love of reading means you often sit with a book they copied your behaviour? That's far beyond our ability to currently measure at present.)

Our brains are designed to perform the way they need to. Brains DO analyse the billions of sensory data inputs they receive every second and cope really well. You seem to imply there is a flaw in the most complicated organ to exist in nature. We've survived and populated the planet because we are capable of incredible brainpower. The suggestion that our brains are too slow and calorie hungry is nonsense. Your brain uses the calories it needs and it's as quick as it needs to be, to allow it to cope with the world around us. The human brain has adapted to a very different world, over the last 100 years or so. The way current generations have responded to our society, in order to cope with the demands of a world far different to the one our grandparents would have experienced, will change how the human brain is wired and it will allow us to think and behave in ways we can't imagine now. The technology around us has forced our brains to react and adapt to a much different world to the one we had 50000 years ago. Human intelligence is significantly higher than many centuries ago and I think we should appreciate it. Our ancestors would struggle if they were suddenly placed in a huge city, highly populated and surrounded with all this interweb shite. Science is showing our reliance on technology and social media, including this forum, is changing how the human brain works. One downside is that if humans ever need to return to a non technological world, our innate and instinctive skills may have disappeared, replaced by brain functions developed for a world far different to the one our ancestors dealt with. Who knows what the future will bring and we may find our current skills are useless, if we need to return to our previous hunter gatherer way of life.

As for this: yes, I’m absolutely implying that our brains are flawed, for exactly the reasons I tried to explain. Our brains weren’t designed, they evolved. They are incredible, wondrous things that do analyse billions of inputs every second, yes. But they also discard even more data. We use patterns to try and predict what will happen, which lets us ignore lots of data. If our brain took time to process the data, we would become a thinking machine that isn’t able to act fast enough & we would get eaten. That’s a v helpful feature for escaping predators, but using pattern-making shortcuts creates a massive flaw allowing for heuristics & biases to appear which often lead to poor decision making (therapists, magicians & marketers deliberately exploit those weaknesses in different ways).

TL/DR: the brain is beautifully capable & flawed all at the same time.

Evolution is complex, messy & far from optimised. It’s a game of whatever is ‘good enough’ survives. There’s a lot of things that aren’t true in what you’ve written here. For example, that intelligence has improved. The simple answer to that is we have no way of knowing because intelligence has only been measured the late 19th Century. So the statement must be false by that alone. If you’re talking about brain size & density, I would very much expect a baby from 3000 years ago to have exactly the same capability as a child born today.

Humans are capable of incredible cultural evolution because we record information for the next generation to learn & build on. That is remarkable. And does lead to changes in the brain regions. That is a product of elasticity in the brain, similar to learning new things or our bodies adapting after losing sight or hearing. But it doesn’t change the brain we are born with at any kind of pace. The evolution I thought we were discussing is the classical physiological type, which happens slowly over millions of years. The impact of which, also creates a massive problem: our brains are expecting office life but our bodies are still wired for living in the open. Far from helpful, creating cognitive dissonance & stress that will reduce your lifespan in the long run.

Ah crap, this post got unnecessarily long. Probably not helpful to anyone. Happy to discuss more - probably best done via private messages as I think we’ve well & truly taken Jason’s post off-topic. That was definitely my fault- shouldn’t have responded to your initial post with a smart-arse retort, sorry Pod 😔

 

[podknocker]

@podknocker I think I’m still not being clear. Needless to say I’ve read the selfish gene, and many other books & papers on evolution, psychology & neuroscience. My job requires me to have a solid grounding in psychology & sociology.

The difficulty with your post above is that you’re giving humans knowledge of what fruit is healthy before they know it is healthy. I’m fairly certain that Dawkins highlights in his book that genes do not have foresight. It’s a good case of correlation not equaling causation: because we survived we must be the best version. And it’s an example of survivorship bias (a version of that heuristic, concerning bomber plane armour during WWII, was famously discussed by Malcom Gladwell in one of his books).

The reality for evolution is complex…

Scenario 1
- humans move to new place with red fruit & blue fruit
- some can see the colour difference, some can’t
- some who can see the difference will be naturally attracted to one colour or the other, creating a small group who both see the red fruit & desire the red fruit
- people who eat the blue fruit tend to die
- slowly the group realise blue fruit is bad
- some people still can’t see blue fruit: without being assisted by those that can see the difference, they have a 50/50 chance of choosing the wrong fruit & slowly die out, likely producing less children
- within the population who can see red vs blue, some of them prefer blues. They also slowly die out & likely produce less children
- as the children of people who can see red vs blue & prefer red over blue grow up, they have a strong preference & the culture quickly adapts, whilst our genes also start to switch & trigger the desire for red

Just in that massively oversimplified option there are endless variables that we will never know the answers to. And, importantly, there is the interplay between nature & nurture that we currently have no way of unpicking which leads to what (eg, do your children love reading because your love of reading was passed on via the genes, or is it because your love of reading means you often sit with a book they copied your behaviour? That's far beyond our ability to currently measure at present.)


As for this: yes, I’m absolutely implying that our brains are flawed, for exactly the reasons I tried to explain. Our brains weren’t designed, they evolved. They are incredible, wondrous things that do analyse billions of inputs every second, yes. But they also discard even more data. We use patterns to try and predict what will happen, which lets us ignore lots of data. If our brain took time to process the data, we would become a thinking machine that isn’t able to act fast enough & we would get eaten. That’s a v helpful feature for escaping predators, but using pattern-making shortcuts creates a massive flaw allowing for heuristics & biases to appear which often lead to poor decision making (therapists, magicians & marketers deliberately exploit those weaknesses in different ways).

TL/DR: the brain is beautifully capable & flawed all at the same time.

Evolution is complex, messy & far from optimised. It’s a game of whatever is ‘good enough’ survives. There’s a lot of things that aren’t true in what you’ve written here. For example, that intelligence has improved. The simple answer to that is we have no way of knowing because intelligence has only been measured the late 19th Century. So the statement must be false by that alone. If you’re talking about brain size & density, I would very much expect a baby from 3000 years ago to have exactly the same capability as a child born today.

Humans are capable of incredible cultural evolution because we record information for the next generation to learn & build on. That is remarkable. And does lead to changes in the brain regions. That is a product of elasticity in the brain, similar to learning new things or our bodies adapting after losing sight or hearing. But it doesn’t change the brain we are born with at any kind of pace. The evolution I thought we were discussing is the classical physiological type, which happens slowly over millions of years. The impact of which, also creates a massive problem: our brains are expecting office life but our bodies are still wired for living in the open. Far from helpful, creating cognitive dissonance & stress that will reduce your lifespan in the long run.

Ah crap, this post got unnecessarily long. Probably not helpful to anyone. Happy to discuss more - probably best done via private messages as I think we’ve well & truly taken Jason’s post off-topic. That was definitely my fault- shouldn’t have responded to your initial post with a smart-arse retort, sorry Pod 😔

You don't need to apologise and it's impossible for me to be offended!

 

[Dom]

Its possible that early humans knew that music would play a large part in our lives, so we evolved our hearing range for that.

 

[abacus]

Humans cannot hear above roughly 20Khz, that is proven fact, however, that higher frequencies can be perceived (Not heard) by humans is quite possible.

Bill