The Emperor has no Ears...

[xthread]

Ganked from dilletante, with some embroidery by me.

Humans can hear from around 20hz or so to around 22khz.
Well, some humans can.
We start losing the really high frequency bits when we're about twenty, and it's all downhill from there.

So, in the UK, they had the bright idea 'if we play loud tones that are high enough frequency that teenagers can hear them but adults can't, teens won't congregate.' This appears to work. Listen to an example here.

However, the Street finds it's own uses for technology, and the kids returned fire. They started passing around a high frequency tone as a ringtone, so that they could hear phones going off in class and the teachers couldn't. Hilarity ensues.

I was a bit skeptical when I heard this, so I asked a six year old I happened to have handy over to my desk, and requested 'please listen to this and tell me if you hear anything.'
She reported hearing both tones.

Yow. Just yow.

No cubs over fifteen, Billy!
     Ever heard of a cub with a green flower?

Comments

[shaix.livejournal.com]

Okay, I'm freaked out, now...

[therobbergirl.livejournal.com]

I can hear the first one very clearly and it's quite annoying. But even with headphones and a volume set to 11, I can't hear anything in the second one.

For reference, I'm 38 at the end of this month. My hearing has some damage from blunt trauma as a kid and from Prince as a teenager.

[shannybug.livejournal.com]

I can hear both.

[emberleo.livejournal.com]

Me too - that is, assuming what I'm hearing is what I'm supposed to be hearing.

And I must say - the first one hurts. The second one sounds low enough I'm surprised teachers can't hear it.

--Ember--

[emberleo.livejournal.com]

Ohhh! I hear the second, higher wave above the lower wave in the second recording now - ouch!

--Ember--

[shannybug.livejournal.com]

The first one is painful.

[kimjong-illin.livejournal.com]

Bleah, I suck, I can't hear anything. What an arsehole idea though, playing irritating frequency sounds so teens won't hang out...

[sfo2lhr.livejournal.com]

I'm skeptical, not about loss of high-frequency hearing with age, but about the ringtone story. Hello, vibrate mode? I mean, necessity is sometimes the mother of invention, but really...

[slow-overkill.livejournal.com]

Sometimes the vibrators go "GZZZT... GZZZT" over and over again. x_x Believe me, I've had it happen to me before.

[trinsf.livejournal.com]

So, at least on my children's phones, vibrate makes a noise. If one of my children has a phone in a pocket, or in a backpack, then when the phone vibrates, there a dull buzzing sound from the hard phone vibrating against whatever. In a quiet classroom, their teachers can hear that, and they get in trouble for it, because the phones are supposed to be off.

[jedusor.livejournal.com]

I can hear both. The second one is almost painful, the first one less sharp but still quite clear.

I just made a poll about this on my journal, because I was curious. Ten answers so far- ages are completely mixed on the first sound, but the second one is clearly divided between the younger people and the older people. This is really intriguing.

[trinsf.livejournal.com]

Just did an experiment: both Older and Younger Child hear both tones (though they say the second isn't very loud on my machine). I cannot hear either. Will test ewhac shortly.

By the way, both children said, "Stop it! That's really annoying! STOP playing that noise!" when I asked them to come into my room, without knowing what I was doing. I never heard anything.

[saffroncisco.livejournal.com]

Wow. This is the most fascinating thing the Internet has had to offer in quite some time.

I couldn't hear the first one (mosquito_sound) the first time -- could only hear the crowded room. When I read the comments and was sufficiently convinced that yes, there was something else to be heard, I cranked the speakers up, leaned in close, and tried again, and this time I could hear it, very faintly -- to me, a very soft, very high-pitched warble. I would never have noticed it if my attention weren't completely focused on it.

The second one I could hear quite clearly. Not loud, but quite clear.

I'm 37, and I think of myself as having good hearing.

Now I need to test it on my children and on my slightly-deaf husband. Wheee!

Comment cross-posted to jedusor's LJ poll.

[japlady.livejournal.com]

ok time to get my hearing checked. I knew I was losing it but this is sad.

I can't hear either

[tavella.livejournal.com]

I can hear both (I'm 39), and the second one is *painful*.

Glad to know those teenage years of blasting my walkman apparently didn't screw my hearing!

[woody77.livejournal.com]

18Khz is well into my hearing. Luckily the laptop was set for quiet, and there's a bit of background noise here at the moment.

TV's are what kill me, though. A constant whine at around 15Khz. Drives me bonkers in a quiet house.

Another advantage of living in BFE mountain land is that the ambient noise level is so low that a lot of your hearing comes back.

I think that the problem is less age and more constant noise. Adults live in very noisey environments. Computers, cars, offices, etc. The brain is very good at adaptive filtering of sounds. While I can hear those high pitches with clarity, and can pick up on odd engine sounds with ease, I have a hard time dealing with vocals. I spent most of HS actively trying to filter out voices (teachers) so I could read (in class). Anyway, it adds up over time. And I can say that my hearing has seemed to improve since moving out here to the woods. And it's not like I haven't been mean to my ears recently, either (concerts recently: Tori Amos, NIN, Sisters of Mercy, Slick Idiot, Thrill Kill Kult). And l listen to the stereo loud in the car, with the windows open a lot.

btw, the girl can hear it, too. Although it's VERY directional coming from the powerbook's speakers (beam roughly perpendicular to the screen).

[kengr]

I'm 51 and can hear both.

However, I'm a bit of a special case. I'm astmatic. And for some reason, many asthmatics can hear up to 30kHz or higher.

I verified that I could hear up to 30 kHz with an exhibit they had at OMSI (Oregon Museum of science and Industry) more than 30 years ago, and didn't run across the bit about asthmatics until many years later.

No I dea how much higher I could hear as the exhibit topped out at 30 kHz.

When I was 20, a friend was working on an alarm system that used ultrasonic transducers as part of a motion detector setp. I could faintly here *those* from 10 feet away. And I *think* they ran closer to 40 kHz.

Some older computer monitors drive folks like me nuts because they have a whine at a frequency most folks can't hear (30 or 35 Khz, I think). Newer monitors run that particular section at 60 kHz or higher so it's no longer a problem.

So those kids *could* get a rude shock if they try that with the wrong adult.

[malabar.livejournal.com]

I could hear the teenage one, slightly, but it wasn't annoying. Couldn't hear the kids' one at all.

[solan-t.livejournal.com]

For a moment and only a moment, I could hear the mosquito one when I turned the sound way up. I couldn't hear the other one at all. I am 34 and haven't been doing any of the usual things to destroy hearing. But I have an 8 year old son that may just end up an unwitting lab rat for me.

[tronpublic.livejournal.com]

I can't hear either. I guess I won't need to worry about high frequency phase shift on the output LC filters of my amps.

SACD and DVD-Audio experiment: There have been many arguments about whether the extended frequency response available on these formats is worth your while. Regular CDs can reproduce up to 22.1KHz. SACD and DVD-Audio discs can push close to 100KHz. There are tons of arguments that say that you can hear (or even "feel") the extended frequency range. Those with "golden ears" say that they can tell the difference between the CD and the SACD/DVD-A version of an album. Others say hogwash - that the golden ears are actually hearing the remastering differences and the different electronics that SACDs and DVD-As go through.

Here's what I propose: Set up a double blind test. Scenario "A" is to play a disc (CD, DVD-A, SACD, it doesn't matter) through a stereo system. Scenario "B" is to do exactly the same thing as in "A", but you add another stereo system that's playing a bunch of high frequency crappola. If the test subject can actually hear of feel a difference, he or she should be able to say whether scenario A or B is playing.

[tylik.livejournal.com]

Finally checked this...

The first one, indeed, I can hear just fine.

The second one I can't hear at all, exactly, but it makes me head hurt. I also have a fair bit of background noise...