"Music is perpetual, and only the hearing is intermittent." -ThoreauA couple of weeks ago, my wife and I went to the circus together. Someday, I vowed, I'll be strong, flexible, and stable enough to do the amazing hand-balancing tricks we saw.
And all the while, the six-year-old girl behind us screamed her piercing, high-pitched scream, cheering the performers on.
(This is totally appropriate behavior, IMO, and no children reading this should be discouraged from screaming at the circus.)
Now, one of us has better hearing than the other. And while one of us found the high pitched screaming to be a minor annoyance, the other was simply in agony. What's going on here?
It's going to take a little bit of biology and a little bit of physics to figure it out. First off: how does your ear work?
The sound waves -- which are pressure waves -- enter your ear and press up against the tympanic membrane, better known as your eardrum.
The vibrating eardrum causes the three little bones in there -- the hammer, anvil, and stirrup, known collectively as the auditory bones -- to vibrate as well. The last one, the stirrup, pushes against the cochlea, and this is where your hearing takes place. How? To get the simple answer, we need to know what the cochlea looks like on the inside?
Your cochlea is a spiral-shaped structure, like a snail's shell, that's filled with fluid and lined with tiny hairs known as cilia. The most sensitive cilia are the ones closest to the outside: only a tiny vibration is needed to set them in motion. These are also the most easily destroyed. So when you do things to damage your hearing like go to rock concerts without earplugs, listen to your headphones or stereos too loudly, fire a gun without protective gear, or have your "friend" scream in your ear, these sensitive cilia get destroyed.
The bad news? Once they're destroyed, they pretty much never grow back. So while a newborn baby can hear up to about 20,000 Hz, very few adults can. At age 31, my hearing stops somewhere around 13,000 Hz. There are a few sites out there to test your hearing, so I've stolen some sound files to allow you to find where your hearing, approximately, cuts out.
I can hear the 12,000 Hz tone but not the 14,000 Hz one. However, as many of you will notice, the closer the tone gets to your hearing threshold, especially if it's loud, the more painful it gets to listen to!In other words, people with better hearing are also more sensitive to these ultra-high-frequency sounds, and are more likely to find them painful!
So now, onto the physics. When you have something like a tuning fork (above), it emits sounds at just one frequency. In other words, if the fork is tuned to emit at 440 Hz, you hear a sound at 440 Hz and nothing else.
But what if you didn't have a tuning fork. What if you had something like an open pipe, a string, or vocal cords? (Thanks, Nathan @5.)
If you just play the string (or hit the pipe, or make a note with your voice, etc.), you don't just play at the frequency you're trying to hit. You also get all of the overtones. If you sing an "A" at 440 Hz, you also make a sound at 880 Hz, and another one at 1320 Hz, and another one at 1760 Hz, and so on.
What does this mean for the screaming girl? If she screams at 5,000 Hz, then someone like me can hear the 5,000 Hz fundamental and the 10,000 Hz overtone, but that's it. However, someone with better hearing than I have can also hear the 15,000 Hz overtone, and possibly even the 20,000 Hz one!
(A fun test of this is to see is how many of you can hear an old CRT television when it's not turned on to a channel. I can't, but if you can hear 15.6 kHz or higher, you probably can!)
So if you can hear these high-pitched sounds, you've got the bittersweet blessing of having excellent hearing, but also of being sensitive to painful sounds that people like me will never hear. At least now, when you're the only one in a room who can (or can't) hear something, you'll know why!
Physical Science
Life Science
Comments
Age 59 - I can only hear the 8 & 10 khz :(
Posted by: NewEnglandBob | May 10, 2010 9:27 PM
I find it fascinating that I have gone to a lot of clubs and rock concerts, and yet before my parents got rid of their old CRTa few months ago I could always tell when they'd accidentally turned off the cable box and left the set itself on. I could hear it whining halfway across the house!
Posted by: John Armstrong | May 10, 2010 9:29 PM
It turns out, children use 19KHz ringtones to signal each other in the class. During the exam.
But they don't know that my phone runs spectrum analyzer application.
Mwahahahahaha!
Posted by: Alex Besogonov | May 10, 2010 9:40 PM
Age 21, and I can hear the 18 kHz, but not the 19 kHz.
I've heard those televisions before, and it can sometimes drive me crazy -- there was one in a hotel so piercing I couldn't stand to be in the same room.
Posted by: Lissamphibia | May 10, 2010 10:49 PM
"Vocal cords", please!
Posted by: Nathan Myers | May 10, 2010 11:18 PM
If you've actually got a way to strike a tuning fork and not get any overtones, I desperately need to know what it is, before we start the sound unit.
Posted by: magista | May 10, 2010 11:30 PM
Well, this cat snoozing nearby seems to be irritated more to the higher freqs than the lower freqs 20,19,18 caused her to flinch and give me a dirty look and at 17 she got up and left, I guess you call that "freqed out"...actually she does not care for them at all.
As for me I too hate the sounds of old tv tubes warming and capacitors charging.
Posted by: Sphere Coupler | May 11, 2010 1:03 AM
This is awesome!! May be I've to stop listening to music too much :-)
Posted by: Pramod K Vinakoti | May 11, 2010 2:18 AM
I'm 21 here. 14k was almost painful, but 15k was much quieter. I couldn't hear 17k or 18k, but my hearing returned at 19k. Is this normal or do I have to get my computer (or ear) checked out?
Posted by: Jesardia | May 11, 2010 2:45 AM
Hmmm. Something odd going on. I'm 50 and can hear all of them.
8K is loud and piercing. 12K piercing but a little less loud. 12K to 16K each step seems higher but weaker. 17K to 20 K the sound gets more muffled and it seems to go down in pitch. But I can clearly and distinctly hear each tone. All of them. Something has to be wrong with the audio playback.
I went to rock concerts and used earphones. I shot guns a bit and worked in a machine shop. I can't say that I've been shy about damamging my hearing. But I can still hear the 20K tone.
Bugger all ... I'm a freak.
Curiouser and curiouser.
Posted by: Art | May 11, 2010 3:09 AM
Magista,
Some tuning forks do resonate, but it isn't at a frequency one, two, three times (etc.) as large as the fundamental. They resonate at something like 6.25 times that frequency. What's more, is that those overtones are both low in amplitude and dissipate quickly.
In other words, if you take your tuning fork, strike it, and wait about 2 seconds and then record it, it will record as a single frequency.
And Sphere Coupler,
That is hilarious. Thanks for sharing!
Posted by: Ethan Siegel | May 11, 2010 3:56 AM
Am 68. Hear till 13'000, but my wife . . . say I don't hear her.
Posted by: controline | May 11, 2010 5:07 AM
Why does sound separate by frequency so nicely inside the cochlea? It must have something to do with the gradual narrowing of the tube as it spirals in. What's the physics behind frequency separation in the ear? - thanks.
Posted by: David | May 11, 2010 6:05 AM
There has to be some resonant or unintentional lower harmonics in the samples or in this way of determinating the hearing!
For my ears 14k is the highest pitch. The higher samples I hear way lower than 14k. In fact 18k is the only sample I didn't hear and I heard even the 20k sample! From 15k on the tone I heard was some lower harmonics not the shimmering high pitch itself.
I don't know if it's my hearing, physics or the samples, but 14k was last sample where I heard the real higher shimmering tone.
Conclusion: my hearing cuts obviously at about 14 - 15k but I heard the 20k SAMPLE. 18k was only sample I didnt hear at all.
Posted by: Kari | May 11, 2010 6:12 AM
31 and I still notice 16kHz, but only cause it hurts my ears; don't really hear the tone.
Posted by: rijkswaanvijand | May 11, 2010 7:31 AM
32, never gone to rock concerts or the like, never fired a gun. And I can only hear the 14k one at best.
Bugger.
Guess I'll try the cat next.
Posted by: Sili | May 11, 2010 8:50 AM
39 and can hear them all - despite two toddlers having taken it in turns to try deafening me for about 4 years now :*/
Posted by: Peter | May 11, 2010 9:02 AM
31, well, I can hear 18,000 hz with my left ear, but only 17,000 with my right. I've been to my fair share of heavy metal and rock concerts, but I also tend to develop an anxiety-like problem when the decibel level gets too loud so maybe it's a protective mechanism...though it didn't protect me from playing bass loud or being near the largest amp I could find. I know they say it's highly improbable, but my sister could hear at near 22,000 hz when she was very young. Still, it's not like one person's cochlea is really that much longer than the others. Which makes me wonder, if one person is born with the ability to hear at a higher threshold than another, does similar sonic damage effect (taking into account the other variables such as body size, environment, gender, etc.) the same frequency cells? Basically, if the damage where to occur in the 16,000 to 20,000 range, should it matter that one can hear at 18,000 while another hears at 20,000 before the cumulative damage?
Posted by: Helioprogenus | May 11, 2010 10:40 AM
I used to work with someone who had totally trashed his hearing from working with very high amplitude ultrasonics. How high? ~180 dB. So high that if you put a cotton ball at the focal point it would catch on fire.
These were 44 kHz whistles. He always said that it wasn't true that you couldn't hear 44 kHz, you could if it was loud enough.
Posted by: daedalus4u
| May 11, 2010 11:52 AM
43 yrs old. i can hear the 15 KHz but nothing over it. guess the ear plugs at concerts didn't help much!
Posted by: rob | May 11, 2010 2:28 PM
I have the same experience as Art (#10) and Kari (#14): I can hear all tones, but the 15 kHz one sounds the highest to me. In the other ones there's definitely a sound, but it sounds lower in pitch and more muffled.
I'm 33 and I used to be very sensitive to high pitched sounds: old televisions on stand-by could drive me crazy, while other people wouldn't notice them. I seemed to have lost that frequency.
Posted by: Martijn | May 11, 2010 2:37 PM
i grew up listening to punk and metal and going to concerts a couple of times a week in college. i'm 26 and still listen to loud music on a daily basis. not surprisingly, my hearing seems to be atrocious. the last frequency i can hear is 12,000 hz and it sounds really quiet and piercing to me. considering that i'm about to go blast some Neil Young, i'd say it looks like i'll have some quiet golden years to look forward to.
Posted by: ryan | May 11, 2010 4:29 PM
A few years ago there was this ringtone popular with the kiddies because old fogies like me weren't supposed to hear it - except in my case it was painfully loud even when the kiddies could barely hear it. I'd definitely need a cockpit headset at the circus.
I don't know if those sound files or my headset are any good; the higher frequencies have serious harmonic distortion and mix down to lower frequencies. I'll need to borrow an oscilloscope from somewhere. I can still hear the ~15KHz whine of TV tube flyback transformers quite clearly though - so many people don't believe that I can hear their tube TVs running. Last time I did a test (8 years ago) I could still hear above 20KHz; I can't remember how many decibels though.
Posted by: MadScientist | May 11, 2010 10:35 PM
Very interesting to learn why I am constantly in agony at such high frequency noises. But the mystery question remains: the girl herself is very young so her hearing should still be intact - then why don't her screams hurt herself??
(Assuming that if it did so she most likely wouldn't do it repeatedly...)
Posted by: Diana | May 12, 2010 2:04 PM
Sad -- only 42 and can't hear the 14kHz. I'll have to try this on my 12-year-old sometime.
Posted by: Squiddhartha | May 12, 2010 2:26 PM
I can hear the 8, the 10, and the 12. Nothing at all after that. I am 59. Due to ear infections as a child, I have had what the doctor called a "high frequency hearing loss" since age 6. It seems to be getting worse - I notice I'm saying "huh?" a lot, and I need the TV sound turned up to the point where it's uncomfortable for the others in the room. A wireless headset fixes that. I'm very worried because I am an opera singer and I don't want to get to the place where I can't hear the music. It's ok so far, though. Thanks for a very interesting site!
Posted by: Jenni | May 12, 2010 4:51 PM
Those that are having problems with the high frequencies sounding lower you most likely are past the the signal response of your listening device or the limits of the sound card in your computer. The system is just doing the best it can.
Posted by: the backpacker | May 12, 2010 5:47 PM
Say, what? Can you explain this for me, so I can use it in may classroom?
You have a market of about 400,000 teachers built in, I figure. Will this help us get the phones turned off when appropriate?
Posted by: timpanogos.wordpress.com
| May 12, 2010 5:49 PM
42, and 16K. And yes, I can still hear the shriek of an untuned TV screen.
As an aside - I turned up the speakers when I couldn't hear the 17K tone, and when the 16K played it made me jump. Kinda sorta hurt.
Posted by: Warren | May 12, 2010 7:16 PM
Age 41, only half a dozen or so lifetime rock concerts (but a lot of symphony concerts). I can hear the 12K very loudly. I hear the 14K clearly, but fainter (computer volume control is steady). The 12K and 14K sound monotonic to me; the lower frequencies have a multitone warble.
Above 14K I don't hear the tone, but I do hear the tiny click at the start and end of the playback.
Posted by: --E | May 13, 2010 10:41 AM
I'm 25 and can hear them all perfectly clearly. That can't be right...
Posted by: Wendy | May 13, 2010 2:07 PM
I've been a professional DJ for almost 20 years, playing in clubs/dance parties on average 3 nights a week consistently, for that time period and I can hear all up to 16,000! I can't believe it :-)
Posted by: Alex | May 13, 2010 3:59 PM
I'm 50, and my hearing cuts out around 12 khz.
On the brighter side, this means I can resample all my MP3s at 22050 Hz, and fit twice as many on my MP3 player.
Posted by: anon | May 13, 2010 9:42 PM
#13, the cochlea is able to separate sounds by their frequency because of the shape of the basilar membrane (the membrane upon which the hair cells sit (which have the cilia that Ethan was referring to projecting from the top of them). At the base of the cochlea, where high frequencies are "registered", the basilar membrane is very thick and narrow. As you progress towards the apex of the cochlea, where the lowest frequencies are registered, the basilar membrane becomes flatter and wider (think of a door stop that gets progressively wider at the end).
The physics of sound waves is such that high-frequency sounds have less energy and attenuate faster than low frequency sounds. So together, the physics of sound wave propogation and the shape of the basilar membrane allow for the separation of frequencies in the cochlea.
Posted by: Michelle | May 13, 2010 10:03 PM
I'm in my 40s and can hear 20,000 Hz. All of them.
Been to lots of very loud dance parties and gigs, had ringing ears for days after some of them, still have some tinnitus that I only notice when I go to bed, and can't easily hear people speak in noisy spaces when friends can hear them.
What's with my ears? :)
Posted by: Eerie | May 13, 2010 10:18 PM
Oh, sigh. Only a couple years ago I was still hearing 13,000. Now I can't hear 12,000. I use moments like these to remind myself that I'm organic and temporary and need to get used to it, but I'm still hoping they find a way to regrow cilia in the next few years. Rogaine for ears?
Posted by: RamblinDude | May 13, 2010 10:22 PM
Eerie, there's a term for that, aptly named "the cocktail party effect" wikipedia has a brief explanation for it.
Posted by: Michelle | May 13, 2010 10:28 PM
Thanks, Michelle. I had heard of that before and the links are interesting. I might see if I can train my brain to be better at it. Nice to know that it is less likely I'm losing my hearing. :)
Posted by: Eerie | May 13, 2010 10:40 PM
My brother used to have a '72 Dodge Dart Swinger. He fiddled with the engine till it was probably illegal, and then he took us out riding in it. The first (and only) time I went, we were traveling along happily until we hit about 50 mph. I thought my head was going to explode. It probably had more to do with rpm than mph, but at any rate, I had to cover my ears and clench my teeth together because I felt like my entire body was going to rattle apart. Nobody else in the car felt this way. When we got back home I was shaking and had to go lay down. My ears took a while to recover.
Posted by: Leanne | May 13, 2010 11:03 PM
I made it to 15. When I hit the 16, my residents said, "what the hell is that annoying sound"
Me:"What sound?"
Posted by: PalMD | May 14, 2010 2:52 PM
At 38 my hearing is like yours, can hear 12K but not 14K. My 7 year old was begging me to stop, and he heard up to 20K. Now I know why he is sound defensive.
Posted by: Beccy | May 15, 2010 1:45 AM
I'm 68 and have tinnitus caused by industry years ago, can hear 10k well, 12k a little. I usher weekly for a world class orchestra and numerous other unamplified gigs. I always bring earplugs for the amped stuff, and leave if it's pounding. I'm constantly amazed by the reviewers in the audio magazines who claim to hear all kinds of nuances and overtones. They're always male, and many are as old as I am. I think they must be the most amazing males on the planet, great liars, or writing what their prodigal grandkids tell them.
We have some friends whose hearing was damaged in the service. Both are known for their loud voices. One finally went to the VA and got hearing aids. He's a different person with them in. The other on is too vain to believe that he's shouting.
Posted by: mr.ed | May 15, 2010 6:19 AM
Cat seems to be mostly unimpressed.
Posted by: Sili | May 15, 2010 9:49 AM
for everyone who says they can actually hear the 20k sound: you're actually hearing your speakers working, and not the actual sound. if it's not shrill and hurts your ear, it's definitely the wrong sound. sorry to burst the bubble of the people who think they have magic ears.
Posted by: cheng | May 17, 2010 2:07 AM
i can hear up until 19k and that's it. however, i can't hear that or 18k if they're in succession. i can hear 18k alright, then 19k only if i listen to it individually. the 20k sound i can't hear at all.
btw, i'm 31.
Posted by: crissy | May 17, 2010 1:20 PM
i'm unable to hear 8k dB since about 25 years old due to gradual worsening of sensory-neural loss for as long as i can remember. i don't know life without tinnitus, 4k+. the hurting loudness near the cut-off frequency is actually due to recruitment of extra nerves to compensate for the signals lost in the ear. because of the loss of some kinds of noise, it is often possible to hear noises others don't, like the instrument noise at high frequencies, or even other sounds. nature made quite sure we will remain able to hear something even when we loose as lot. btw, the whole neural system and the brain also assist with frequency differentiation, not only the cochlea.
Posted by: Antoinette | May 17, 2010 3:37 PM
I put the volume up to full...I'm 13, and I can hear to the 20,000 mark...barely...but the most clear was the 18,000 mark.
Posted by: Sonny | June 10, 2010 8:13 PM
There's some weird stuff going on, 14kHz was barely audible but I can hear 18kHz pretty well.
Bad lowpass filter on audio output? Abnormally broken hearing? Bad MP3 encoding?
Anyway, this kind of test should probably be done with a device that has nyquist limit way above 22kHz.
Posted by: jarno | August 21, 2010 7:55 PM
Ah, now I'm writing two comments in a row, but:
For those who think "I can hear 20kHz" folks are definitely bullshitting themselves, I have an anecdote: once upon a time I could hear the whine not only from television and 200 line CGA modes (15.75kHz, _very_ annoying), but also from 350 line EGA mode (21.8kHz, not that annoying but audible).
I can't figure a source for aliasing or undertones in that "audio system".
Posted by: jarno | August 21, 2010 8:42 PM
I have a High freq. hearing loss, and I can't hear any of those expect the 10k which is quiet surprising because my Hz start to drop at the beginning of 2k hz (away from normal hearing) but at 6-8k hz, I Have a severe loss, but most Audiograms don't go above 8k hz because from what I was told, is that after 8k hz, there isn't any normal speech that could possible make a 10k hz sound (without the lower one,like 5k hz)But I'm glad you posted this blog, I always love to learn more about my disability and this gives me a better understanding how it works!
Posted by: Adam Mothana | September 2, 2010 5:08 AM
Well I guess it really is selective hearing cause I can pick up everyone of those tones but when the wife asks me to take out garbage or wash dishes I swear I did not hear her. lol
Posted by: Matthew Morrell | October 4, 2010 11:12 PM
Thru the speakers, 12,000 cps was it. Thru headphones, out to 17,000 cps. I've done shooting without protection and the right ear is not so great. I'm 61, and in music -- very conscious of ear damage now. From 16,000 up, these tones seem to produce a pedal tone, which is much lower than the main frequency.
Posted by: Alan Fontana | October 28, 2010 7:23 PM
I was told that of the 5 rows of cilia in the cochlea, only two deal with audible frequencies, the other 3 are thought to deal with time. Sound arrivals between a person's two ears can be detected at differences down to 5-6 microseconds. This means each ear can judge a sound arrival to the hearest 1-2 microseconds. So music sampled digitally at 24,000 times/sec.
can really be heard by the inner ear as a series of discrete steps, unlike an analog signal. It would seem the cochlea is better than the Compact Disc standard.
Posted by: Al Fontana | October 28, 2010 7:40 PM
Tinnitus when gradually installing may be the consequence of a bad posture that may be due to bad condyle position caused by lacking or diminishing teeth length ...
I spent years understanding the process maybe this link could be helpful :
http://www.guerirdesacouphenes.com/howtogetridoftinnitus/index.php?option=com_content&view=article&id=77&Itemid=90
Posted by: gda2010 | February 25, 2011 10:43 AM
39 yo - lots of loud Walkman abuse in the 80's
lots of Rave PA abuse in the 90's
lots of Rock concerts right through
Always had loud but decent home and car stereo's
Can hear everything up to 15 and then slightly painful resonances 18+
Everything between inaudible.
Although I will retry this in front of some studio monitors instead of laptop speakers which certainly have limited response.
Will repost shortly.
Posted by: Chris | May 17, 2011 9:49 AM
Would you go instantly deaf if you shot your friend at a rock concert?
Posted by: Chris | May 17, 2011 9:52 AM
Service member. 23 years Old. Can't hear above 13. Been in explosions where it left my ears bleeding. Hope it don't get worse
Posted by: Mike | June 27, 2011 6:53 PM
Service member. 23 years Old. Can't hear above 13. Been in explosions where it left my ears bleeding. Hope it don't get worse
Posted by: Mike | June 27, 2011 6:53 PM
At 78 years I could detect 8K Hz ,but no higher! Of course one needs high quality headphones,or speakers, not the usual computer add-ons.My GP says hearing normal for my age- I worry about what it will be like when I'm old!
Posted by: Dave | November 10, 2011 4:59 AM
I'm 14 years old and I could hear all of them except for number 19. 20 was low but i could still hear it.
I listen to music through earphones alot, but never very loud. Lately though, my hears hurt when listening to earphones. Is there something wrong with my ears?
Posted by: Julia | December 20, 2011 9:26 PM