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Speakers for High Frequency Sound

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Anonymous
February 11, 2005 6:40:20 PM

Archived from groups: rec.audio.pro,sci.electronics.design,sci.med (More info?)

Some people can hear an extremely high-pitched sound generated by
television CRTs and television cameras. I have long wondered what
frequency this sound is. So, I am looking around for test equipment to
help me measure it. I plan to use an audio generator (which I can buy
for about $200), but I need to find a set of headphones that can
produce sound at these high frequencies. The low end frequency should
be about 12 kHz, and I would like to be able to go at least to 50 kHz.
I am guessing the sound is somewhere around 40 kHz.

Incidentally, I just got my hearing checked by my ENT (Ear, Nose,
Throat doctor). I measured in the 5-to-10 dB range on both the eardrum
and nerve conduction tests across the entire measured frequency range
(up to 8 kHz for eardrum, 12 kHz for nerve conduction). My doctor said
that they want to see values less than 20 dB, so I am well-within the
safe zone, as far as they are concerned. However, one reason that she
scheduled this test for me is that I complained that I am going deaf in
one of my ears. I have almost completely lost my sensitivity to the
ultra-high pitched sound in that ear. I can hear that sound 100 times
better from my other ear.

People don't realize what a difference it makes to a person's
perception when the range of hearing differs. I can walk into a room
with other people, and they think they are in an empty room. If there
is an operating television in the room, I will be aware of almost
physical contact. Other people can hold a conversation in a normal
voice, but I have to listen over a sound similar to a dentist's drill
or a jet engine. After several minutes of that, I often feel dazed. No
one else even notices anything, except maybe that I am acting a little
more odd than normal.
Anonymous
February 11, 2005 7:17:24 PM

Archived from groups: rec.audio.pro,sci.electronics.design,sci.med (More info?)

> Some people can hear an extremely high-pitched sound generated by
> television CRTs and television cameras. I have long wondered what
> frequency this sound is.

It's the horizontal scanning frequency, 15,734.25 Hz for American color TV.
Trust me. You don't need to measure it.


> So, I am looking around for test equipment to
> help me measure it. I plan to use an audio generator (which I can buy
> for about $200), but I need to find a set of headphones that can
> produce sound at these high frequencies. The low end frequency should
> be about 12 kHz, and I would like to be able to go at least to 50 kHz.
> I am guessing the sound is somewhere around 40 kHz.

If humans can hear it, it can't possibly be at 40kHz, because the best human
hearing extends to only a bit above 20kHz.
Anonymous
February 11, 2005 7:41:36 PM

Archived from groups: rec.audio.pro,sci.electronics.design,sci.med (More info?)

> The high pitched sound is usually from the yoke and flyback
transformer
> (actually an inductor) feeding the television's CRT. For most
televisions in the
> United States that frequency is right at 15,734 Hz because the
vertical scan
> rate for NTSC is 29.97 times per second and it draws 525 lines. 29.97
X 525 =
> 15734.25 horzontal scanning frequency.

That sounds likely, but I have a few questions about that.

1) Is this same sub-unit on a standard television camera?
2) What exactly is converting the electrical energy into sound?
3) If this sound is so square in the middle of normal human hearing (16
kHz is well-within the range of normal human hearing), why have I met
so few people who can hear it?

Question 3 is perplexing, because my sister and I were always the only
people in our classroom or in someone's home who could hear the
television.

One time, when my sister was hospitalized, her nurse tried to turn on
the television set for her, but the set did not appear to turn on. The
nurse was about to leave the room for help with the TV, when my sister
told him that the TV had just turned on. The screen was still black, so
he did not know what to think. Then, the TV slowly produced a picture.
My sister could tell the set was on because she could hear it. No one
else in the room at the time could hear it.

I have worked in a computer call center for several years. At one time,
we had CRT monitors in the room with us. I was the only person who
could hear them. I liked to turn the CRTs off when not in use, because
they hurt my ears. One time, I walked up to two of my associates and
asked them if they would mind if I turned off the CRTs. One of them
already knew I could hear the CRTs, but the other one did not. The one
who did not know was surprised. Naturally, he reached up and turned off
the set, and asked if I could hear the difference. Then, he turned it
on. Then, off. Then, on. The other associate, who understood what I was
experiencing, began to laugh, and called the guy a sadist.

> I hear it loudly enough that I can tell when someone walks around in
an
> adjacent room with a television set on.

Yes, that is what this is like. When I walk down the sidewalk, I can
hear the television inside the homes I pass. I can tell if someone
comes between the television and me, even if they are inside a closed
room.

I was at a hospital recently. As I walked across the lobby, I heard a
television. I looked around. Then, I noticed a television camera inside
a security enclosure box, mostly hidden in the ceiling. It took me a
little longer to find it than it used to, because I had to locate it
with just one ear (as I said, I am mostly deaf in the other ear, now).
Related resources
February 11, 2005 7:43:43 PM

Archived from groups: rec.audio.pro,sci.electronics.design,sci.med (More info?)

pooua@aol.com wrote:
> Some people can hear an extremely high-pitched sound generated by
> television CRTs and television cameras. I have long wondered what
> frequency this sound is. So, I am looking around for test equipment to
> help me measure it. I plan to use an audio generator (which I can buy
> for about $200), but I need to find a set of headphones that can
> produce sound at these high frequencies. The low end frequency should
> be about 12 kHz, and I would like to be able to go at least to 50 kHz.
> I am guessing the sound is somewhere around 40 kHz.
>
> Incidentally, I just got my hearing checked by my ENT (Ear, Nose,
> Throat doctor). I measured in the 5-to-10 dB range on both the eardrum
> and nerve conduction tests across the entire measured frequency range
> (up to 8 kHz for eardrum, 12 kHz for nerve conduction). My doctor said
> that they want to see values less than 20 dB, so I am well-within the
> safe zone, as far as they are concerned. However, one reason that she
> scheduled this test for me is that I complained that I am going deaf in
> one of my ears. I have almost completely lost my sensitivity to the
> ultra-high pitched sound in that ear. I can hear that sound 100 times
> better from my other ear.
>
> People don't realize what a difference it makes to a person's
> perception when the range of hearing differs. I can walk into a room
> with other people, and they think they are in an empty room. If there
> is an operating television in the room, I will be aware of almost
> physical contact. Other people can hold a conversation in a normal
> voice, but I have to listen over a sound similar to a dentist's drill
> or a jet engine. After several minutes of that, I often feel dazed. No
> one else even notices anything, except maybe that I am acting a little
> more odd than normal.
>

Your objective is not clear. If you're gonna measure your own hearing...

How much trouble/expense do you want to expend to measure something you
can't fix?

How useful is a random measurement using unknown/uncalibrated equipment?
I did some experiments 30 years ago trying to measure frequency response
of speakers, rooms, etc. I NEVER got repeatable measurements at high
frequencies...not even close.

One might have the tendency to crank up the level until you can hear
something. That might not be the best thing to do. No need to destroy
what hearing you have left.
YMMV.
mike

--
Return address is VALID.
Wanted, PCMCIA SCSI Card for HP m820 CDRW.
FS 500MHz Tek DSOscilloscope TDS540 Make Offer
http://nm7u.tripod.com/homepage/te.html
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Bunch of stuff For Sale and Wanted at the link below.
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Anonymous
February 11, 2005 7:52:14 PM

Archived from groups: rec.audio.pro,sci.electronics.design,sci.med (More info?)

> It's the horizontal scanning frequency, 15,734.25 Hz for American
> color TV. Trust me. You don't need to measure it.

I need to measure it, to be certain that is what I am hearing.

> If humans can hear it, it can't possibly be at 40kHz, because
> the best human hearing extends to only a bit above 20kHz.

I think you are assuming some things that aren't necessarily so. One
very important assumption you are making that is likely to be wrong is
that no human can hear very much above 20 kHz. There are a number of
ways that assumption could be wrong. In any event, there is no physical
mechanism that would prevent a human from hearing higher frequencies.

Even so, I probably exaggerated the frequency of the sound. I estimate
that the pitch is about double the highest frequency that I heard in
the sound booth at the ENT. The highest frequency they tested was 12
kHz, so I should estimate the sound I hear from a television as 24 kHz.
It's an ear-piercing shriek, in any event.

I can also hear LCD screens, but that's at a lower pitch, I think, and
they are much quieter. I first noticed it when I was in a nature park.
It was very quiet outside, so as I raised my digital camera up to take
a picture, I could distinctly hear the LCD screen.

Now I am taking a college class in a room that has 3 television sets
suspended from the ceiling. One man saw me putting earplugs in my ears,
and asked if I could hear the televisions. It turned out that he is
able to hear some televisions (the one in his college dorm), but he
could not hear the televisions in the classroom. As far as I can tell,
I am the only person in the room who hears those televisions.
Anonymous
February 11, 2005 7:55:33 PM

Archived from groups: rec.audio.pro,sci.electronics.design,sci.med (More info?)

> my hearing is down 30 dB at 8 K(as high as the test at AES went)
> when compared to 3K and I can easily hear it

Did AES test your nerve conduction? I have a suspicion that the sound I
hear is not coming through my eardrums. I am beginning to suspect that
I hear it through my skull, which means nerve conduction.

Your eardrum may not be able to hear so well, but maybe your ear nerves
are still able to pick up sounds normally?
Anonymous
February 11, 2005 8:02:52 PM

Archived from groups: rec.audio.pro,sci.electronics.design,sci.med (More info?)

My objectives are to find out what frequencies I can hear, and to match
one of the calibrated frequencies from the signal generator against the
sound I hear from televisions, so that I can finally know what that
frequency from the television is.

I am certain that just about any commercial audio signal generator is
going to be callibrated well enough to distinguish the frequency I
hear. It isn't that difficult to make a stable signal (particularly in
commercial test equipment, which is what the signal generator is).

As for how much I would spend, well, I can justify some of the expense
because I am an electronics hobbiest. So, I don't mind buying a $200
piece of test equipment as much as I might otherwise. And, I am going
deaf, so I don't have forever to make this test.

But, this is nothing. I would spend over a thousand dollars to test
some of the other things about myself that I want to test. In
particular, I can generate a sensation like electricity throughout my
body, at will. I don't know what that is, but I would like to find out.
As in, I would spend a thousand dollars to find out.
Anonymous
February 11, 2005 8:16:19 PM

Archived from groups: rec.audio.pro,sci.electronics.design,sci.med (More info?)

pooua@aol.com wrote:
> > The high pitched sound is usually from the yoke and flyback
> transformer
> > (actually an inductor) feeding the television's CRT. For most
> televisions in the
> > United States that frequency is right at 15,734 Hz because the
> vertical scan
> > rate for NTSC is 29.97 times per second and it draws 525 lines.
29.97
> X 525 =
> > 15734.25 horzontal scanning frequency.
>
> That sounds likely, but I have a few questions about that.
>
> 1) Is this same sub-unit on a standard television camera?
> 2) What exactly is converting the electrical energy into sound?
> 3) If this sound is so square in the middle of normal human hearing
(16
> kHz is well-within the range of normal human hearing), why have I met
> so few people who can hear it?
>
16 kHz is not square in the middle. When you become an 'old fart' you
will find that out. 16K is your top octave which you will lose as you
age. Sorry, I don't like it either but I actually don't miss hearing
the Horizontal. Been working in commmercial TV for 28 years and haven't
heard the H in more than 10.
GG
Anonymous
February 11, 2005 8:42:28 PM

Archived from groups: rec.audio.pro,sci.electronics.design,sci.med (More info?)

> >I think you are assuming some things that aren't necessarily so. One
> >very important assumption you are making that is likely to be wrong
is
> >that no human can hear very much above 20 kHz. There are a number of
> >ways that assumption could be wrong. In any event, there is no
physical
> >mechanism that would prevent a human from hearing higher
frequencies.

---
> Yes, there is. The mass of the tympanic membrane and the
> sensitivity of the cochlear cilia.

The tympanic membrane (the eardrum) can be bypassed; it is not
absolutely essential in every case for hearing (indeed, there are
hearing aids that do exactly that).

I don't know of a way around the cochlear cilia, short of replacing it
with a functional equivalent (in contrast, the function of the tympanic
membrane is not absolutely essential to hearing). But, what are the
limits of the cochlear cilia? Certainly there are animals that can hear
higher frequencies, and they use the same basic equipment as humans do.


> I've done work trying to determine whether the nonlinearity of the
> auditory system will allow beat notes which occur as a result of
> exposure to the ear of ultrasonic signals which should result in
> heterodynes being generated which can be heard, are heard and, so
far,
> the results have been negative. That is, if the ear is exposed to a
> pair of frequencies, both of which are frequencies higher than can be
> heard, the beat note won't be heard either.

That is interesting in its own way, but I don't believe that is
directly applicable in this case. The sensitive person may not be
hearing a beat note.
---

> >Even so, I probably exaggerated the frequency of the sound. I
estimate
> >that the pitch is about double the highest frequency that I heard in
> >the sound booth at the ENT. The highest frequency they tested was 12
> >kHz, so I should estimate the sound I hear from a television as 24
kHz.
> >It's an ear-piercing shriek, in any event.

---
> Unless you have perfect pitch, your estimates as to the frequency of
> what you heard are close to meaningless.

All the more reason to set up a test and measure it directly. I hate
this guesswork.

---

> >I can also hear LCD screens, but that's at a lower pitch, I think,
and
> >they are much quieter. I first noticed it when I was in a nature
park.
> >It was very quiet outside, so as I raised my digital camera up to
take
> >a picture, I could distinctly hear the LCD screen.

---
> you may have crosstalk between your vision and auditory systems.

I suppose you would need to run a test to find out for certain?
---

> >Now I am taking a college class in a room that has 3 television sets
> >suspended from the ceiling. One man saw me putting earplugs in my
ears,
> >and asked if I could hear the televisions. It turned out that he is
> >able to hear some televisions (the one in his college dorm), but he
> >could not hear the televisions in the classroom. As far as I can
tell,
> >I am the only person in the room who hears those televisions.

---
> It might be instructive to determine whether you can "hear" the
> monitors with your eyes closed.

I absolutely could hear the monitors with my eyes closed. I would be
able to hear them in a pitch-dark room. I have been looking down at my
desk when the instructor has turned them on from his control console,
and I can definitely hear them when he turns them on. The sound of the
televisions is distinct and loud, particular in my good ear. As I say,
I wear earplugs in class to manage the sound.
Anonymous
February 11, 2005 9:16:50 PM

Archived from groups: rec.audio.pro,sci.electronics.design,sci.med (More info?)

They should have tested you with more than just headphones. The
headphones measure eardrum response. The nerve conduction test is done
through the skull. When they tested me for nerve conduction, I wore a
loop with a mass at either end (I did not get a good look at it). One
end was placed ahead of my left ear a few inches, and the other end was
behind my right ear an inch or two.

The difference is important, because eardrum hearing loss may be
reversible or correctible. Nerve hearing loss is not. Also, the
different types of hearing loss use different types of hearing aides.
There are other differences, too, but I don't know what they all are.
My doctor told me that they looked for my nerve conduction to match my
ear conduction pretty closely.
Anonymous
February 11, 2005 9:18:01 PM

Archived from groups: rec.audio.pro,sci.electronics.design,sci.med (More info?)

I am getting "Connection refused" when I attempt to go to that URL.
Anonymous
February 11, 2005 9:19:55 PM

Archived from groups: rec.audio.pro,sci.electronics.design,sci.med (More info?)

<pooua@aol.com> wrote in message
news:1108165220.798267.223400@c13g2000cwb.googlegroups.com...
> Some people can hear an extremely high-pitched sound generated by
> television CRTs and television cameras. I have long wondered what
> frequency this sound is. So, I am looking around for test equipment to
> help me measure it. I plan to use an audio generator (which I can buy
> for about $200), but I need to find a set of headphones that can
> produce sound at these high frequencies. The low end frequency should
> be about 12 kHz, and I would like to be able to go at least to 50 kHz.
> I am guessing the sound is somewhere around 40 kHz.

The high pitched sound is usually from the yoke and flyback transformer
(actually an inductor) feeding the television's CRT. For most televisions in the
United States that frequency is right at 15,734 Hz because the vertical scan
rate for NTSC is 29.97 times per second and it draws 525 lines. 29.97 X 525 =
15734.25 horzontal scanning frequency.

Old black and white televisions were slightly higher: 30 Hz vertical X 525 lines
= 15,750 Hz.

I hear it loudly enough that I can tell when someone walks around in an adjacent
room with a television set on.

John LeBlanc
houston, TX
Anonymous
February 11, 2005 10:16:58 PM

Archived from groups: rec.audio.pro,sci.electronics.design,sci.med (More info?)

On 11 Feb 2005 15:40:20 -0800, the renowned pooua@aol.com wrote:

>Some people can hear an extremely high-pitched sound generated by
>television CRTs and television cameras. I have long wondered what
>frequency this sound is.

No need to measure it. In the US & Canada (and other NTSC countries
such as Taiwan) the high-pitched sound that you can hear is either
15.75kHz (rare these days) or 15.734264kHz. That's when the TV is
locked to a broadcast. If it's on an empty channel, the frequency will
be a bit different.

> So, I am looking around for test equipment to
>help me measure it. I plan to use an audio generator (which I can buy
>for about $200), but I need to find a set of headphones that can
>produce sound at these heigh frequencies. The low end frequency should
>be about 12 kHz, and I would like to be able to go at least to 50 kHz.
>I am guessing the sound is somewhere around 40 kHz.
>
>Incidentally, I just got my hearing checked by my ENT (Ear, Nose,
>Throat doctor). I measured in the 5-to-10 dB range on both the eardrum
>and nerve conduction tests across the entire measured frequency range
>(up to 8 kHz for eardrum, 12 kHz for nerve conduction). My doctor said
>that they want to see values less than 20 dB, so I am well-within the
>safe zone, as far as they are concerned. However, one reason that she
>scheduled this test for me is that I complained that I am going deaf in
>one of my ears. I have almost completely lost my sensitivity to the
>ultra-high pitched sound in that ear. I can hear that sound 100 times
>better from my other ear.
>
>People don't realize what a difference it makes to a person's
>perception when the range of hearing differs. I can walk into a room
>with other people, and they think they are in an empty room. If there
>is an operating television in the room, I will be aware of almost
>physical contact. Other people can hold a conversation in a normal
>voice, but I have to listen over a sound similar to a dentist's drill
>or a jet engine. After several minutes of that, I often feel dazed. No
>one else even notices anything, except maybe that I am acting a little
>more odd than normal.

When I was about 12 years old, I got into a trade show with my Dad
where they had a demo of an ultrasonic welder. It just about took my
head off when they turned it on, but none of the old farts could hear
a thing. I'm now older than he was then. 8-( I can still hear the
racket from a NTSC TV but it's not nearly as loud.


Best regards,
Spehro Pefhany
--
"it's the network..." "The Journey is the reward"
speff@interlog.com Info for manufacturers: http://www.trexon.com
Embedded software/hardware/analog Info for designers: http://www.speff.com
Anonymous
February 11, 2005 10:19:54 PM

Archived from groups: rec.audio.pro,sci.electronics.design,sci.med (More info?)

On 11 Feb 2005 16:52:14 -0800, pooua@aol.com wrote:

>> It's the horizontal scanning frequency, 15,734.25 Hz for American
>> color TV. Trust me. You don't need to measure it.
>
>I need to measure it, to be certain that is what I am hearing.
>
>> If humans can hear it, it can't possibly be at 40kHz, because
>> the best human hearing extends to only a bit above 20kHz.
>
>I think you are assuming some things that aren't necessarily so. One
>very important assumption you are making that is likely to be wrong is
>that no human can hear very much above 20 kHz. There are a number of
>ways that assumption could be wrong. In any event, there is no physical
>mechanism that would prevent a human from hearing higher frequencies.

---
Yes, there is. The mass of the tympanic membrane and the sensitivity
of the cochlear cilia.

I've done work trying to determine whether the nonlinearity of the
auditory system will allow beat notes which occur as a result of
exposure to the ear of ultrasonic signals which should result in
heterodynes being generated which can be heard, are heard and, so far,
the results have been negative. That is, if the ear is exposed to a
pair of frequencies, both of which are frequencies higher than can be
heard, the beat note won't be heard either.
---

>Even so, I probably exaggerated the frequency of the sound. I estimate
>that the pitch is about double the highest frequency that I heard in
>the sound booth at the ENT. The highest frequency they tested was 12
>kHz, so I should estimate the sound I hear from a television as 24 kHz.
>It's an ear-piercing shriek, in any event.

---
Unless you have perfect pitch, your estimates as to the frequency of
what you heard are close to meaningless.
---

>I can also hear LCD screens, but that's at a lower pitch, I think, and
>they are much quieter. I first noticed it when I was in a nature park.
>It was very quiet outside, so as I raised my digital camera up to take
>a picture, I could distinctly hear the LCD screen.

---
you may have crosstalk between your vision and auditory systems.
---

>Now I am taking a college class in a room that has 3 television sets
>suspended from the ceiling. One man saw me putting earplugs in my ears,
>and asked if I could hear the televisions. It turned out that he is
>able to hear some televisions (the one in his college dorm), but he
>could not hear the televisions in the classroom. As far as I can tell,
>I am the only person in the room who hears those televisions.

---
It might be instructive to determine whether you can "hear" the
monitors with your eyes closed.

--
John Fields
Anonymous
February 11, 2005 11:03:10 PM

Archived from groups: rec.audio.pro,sci.electronics.design,sci.med (More info?)

<pooua@aol.com> wrote:
>Some people can hear an extremely high-pitched sound generated by
>television CRTs and television cameras. I have long wondered what
>frequency this sound is. So, I am looking around for test equipment to
>help me measure it. I plan to use an audio generator (which I can buy
>for about $200), but I need to find a set of headphones that can
>produce sound at these high frequencies. The low end frequency should
>be about 12 kHz, and I would like to be able to go at least to 50 kHz.
>I am guessing the sound is somewhere around 40 kHz.

Why not just do a google search for "NTSC video sweep frequency?"
Hint: it's around 17 KHz.

>Incidentally, I just got my hearing checked by my ENT (Ear, Nose,
>Throat doctor). I measured in the 5-to-10 dB range on both the eardrum
>and nerve conduction tests across the entire measured frequency range
>(up to 8 kHz for eardrum, 12 kHz for nerve conduction). My doctor said
>that they want to see values less than 20 dB, so I am well-within the
>safe zone, as far as they are concerned. However, one reason that she
>scheduled this test for me is that I complained that I am going deaf in
>one of my ears. I have almost completely lost my sensitivity to the
>ultra-high pitched sound in that ear. I can hear that sound 100 times
>better from my other ear.

Right, but most places cannot test that high accurately enough. I think
the House Institute in LA can do up to 16 KHz accurately.
--scott
--
"C'est un Nagra. C'est suisse, et tres, tres precis."
Anonymous
February 11, 2005 11:11:40 PM

Archived from groups: rec.audio.pro,sci.electronics.design,sci.med (More info?)

In article <1108168896.929130.108230@f14g2000cwb.googlegroups.com>,
<pooua@aol.com> wrote:
>That sounds likely, but I have a few questions about that.
>
>1) Is this same sub-unit on a standard television camera?

Surely on vidicon tube cameras, which also have a yoke.

>2) What exactly is converting the electrical energy into sound?

Mostly it's the magnetic field from the yoke vibrating things around, but
to some extent it's also microphonic effects in electrolytic capacitors.
Potting the yoke reduces most of it, though.

>3) If this sound is so square in the middle of normal human hearing (16
>kHz is well-within the range of normal human hearing), why have I met
>so few people who can hear it?

Because too many people today have poor hearing from living in a very
loud environment. Try asking some children.
--scott

--
"C'est un Nagra. C'est suisse, et tres, tres precis."
Anonymous
February 12, 2005 12:25:49 AM

Archived from groups: rec.audio.pro,sci.electronics.design,sci.med (More info?)

> > In any event, there is no
> > physical mechanism that would prevent a human from hearing higher
> > frequencies.

> Sure there is. [snip] Basically, you run out of structure at some
point
> in this part of the ear, and the extent and health of this structure
sets
> the highest frequencies that you can perceive.

That would mean there is an upper limit. It does not at all tell us
that no one could hear higher frequencies than 20 kHz.
Anonymous
February 12, 2005 12:27:21 AM

Archived from groups: rec.audio.pro,sci.electronics.design,sci.med (More info?)

> In another post, you mentioned having to focus on a
> particular conversation or a particular flute.

I think you have me confused with someone else. I haven't said anything
in this thread about focusing on a particular sound or conversation or
flute.
Anonymous
February 12, 2005 12:30:39 AM

Archived from groups: rec.audio.pro,sci.electronics.design,sci.med (More info?)

> 8k was as high as the test measured so I am not aware of my
> measured abilities above that

I asked the tech who administered my hearing test last week what the
highest frequency is that the machine could test. I watched as she
touched the buttons on the control panel, and I saw the machine display
the frequency on the monitor. The machine tests a maximum of 8 kHz for
the eardrum, but it tests up to 12 kHz for nerve.
Anonymous
February 12, 2005 12:35:07 AM

Archived from groups: rec.audio.pro,sci.electronics.design,sci.med (More info?)

> How many of you have heard a high-pitched "sound"
> very much like 15 KHz yoke, even though there is no yoke? This is
> sometimes called "ringing in the ears", and is what I was thinking of
when
> I asked those questions about tinnitus.

Yes, I do have ringing in my ears, but it is fairly quiet. That's one
way I can distinguish it from the sound of the TV. The TV set sounds
very loud, so loud that I can hear it 15 feet away through the walls
and closed windows of buildings, or from about 50 feet away in an open
space.
Anonymous
February 12, 2005 12:41:59 AM

Archived from groups: rec.audio.pro,sci.electronics.design,sci.med (More info?)

> Interestingly, your cochlea can hear tremendously high
> frequencies well into "ultrasound" above 20 kHz, so long
> as they are gotten in by bone conduction (putting the
> transducer on your skull). It's the earbones that are the
> block. Perhaps there are some people who have
> particularly good skull connections to their inner ear.

I have a theory that my sinuses might have something to do with it. My
sinus cavities on the front of my face are fairly small, but I know
that I have more sinus cavities farther along the roof of my head. I
also suffer from TMJ, and the pain in one jaw joint is bad enough that
I often can't sleep on that side. So, maybe the internal structure of
my skull explains how I hear this sound, and my sinus and jaw problems.
February 12, 2005 12:44:30 AM

Archived from groups: rec.audio.pro,sci.electronics.design,sci.med (More info?)

<pooua@aol.com> wrote in message
news:1108170172.822645.33210@c13g2000cwb.googlegroups.com...
> My objectives are to find out what frequencies I can hear, and to match
> one of the calibrated frequencies from the signal generator against the
> sound I hear from televisions, so that I can finally know what that
> frequency from the television is.
>
> I am certain that just about any commercial audio signal generator is
> going to be callibrated well enough to distinguish the frequency I
> hear. It isn't that difficult to make a stable signal (particularly in
> commercial test equipment, which is what the signal generator is).
>
> As for how much I would spend, well, I can justify some of the expense
> because I am an electronics hobbiest. So, I don't mind buying a $200
> piece of test equipment as much as I might otherwise. And, I am going
> deaf, so I don't have forever to make this test.

You won't need your hearing to do this test all you need to do is turn on
the tv
and have the proper measurement equipment and a pair of eyes to see the
results
on your equipment.
So there's no hurry.

>
> But, this is nothing. I would spend over a thousand dollars to test
> some of the other things about myself that I want to test. In
> particular, I can generate a sensation like electricity throughout my
> body, at will. I don't know what that is, but I would like to find out.
> As in, I would spend a thousand dollars to find out.
>
Anonymous
February 12, 2005 12:44:36 AM

Archived from groups: rec.audio.pro (More info?)

FWIW, I can hear computer monitors, too, but not as well as
televisions. That's a good thing, because I work in an office with a
hundred computer monitors. The room has to be quiet and I have to pay
attention for me to hear a computer monitor, unless it is going bad.
Anonymous
February 12, 2005 12:56:07 AM

Archived from groups: rec.audio.pro,sci.electronics.design,sci.med (More info?)

> > Some people can hear an extremely high-pitched sound generated by
> > television CRTs and television cameras.

> When they're badly designed / manufactured - yes.

I have never met a functioning CRT that I could not easily hear.

> Incidentally, I just got my hearing checked by my ENT (Ear, Nose,
> Throat doctor). I measured in the 5-to-10 dB range on both the
eardrum
> and nerve conduction tests across the entire measured frequency range
> (up to 8 kHz for eardrum, 12 kHz for nerve conduction). My doctor
said
> that they want to see values less than 20 dB, so I am well-within the
> safe zone, as far as they are concerned. However, one reason that she
> scheduled this test for me is that I complained that I am going deaf
in
> one of my ears. I have almost completely lost my sensitivity to the
> ultra-high pitched sound in that ear. I can hear that sound 100 times
> better from my other ear.

> Well - I had a proper hearing test when I was in my mid 20s and the
nurse
> commented that I had the most perfect hearing she'd ever measured.

> I was on the 0dB line all the way to 8 kHz - the highest frequency
used for
> medical testing it seems.

8 kHz is the max for headphone tests of the eardrum.
12 kHz is the max for nerve conduction (through the skull).

> > Other people can hold a conversation in a normal
> > voice, but I have to listen over a sound similar to a dentist's
drill
> > or a jet engine. After several minutes of that, I often feel dazed.
No
> > one else even notices anything, except maybe that I am acting a
little
> > more odd than normal.

> You mean you have diffiiculty with large background levels of noise ?

> Can't 'reject' it ?

There is a limit to what anyone could reject. As I say, the sound is
similar to the sound of a dentist drill or a jet engine, not just in
pitch, but in volume. This is not a subtle effect.

> Me too. You have high hearing acuity. Your ears are 'wide open' to
stimuli.
> May ppl simply 'filter out' what they're uninterested in.

If I watch TV, I often tune out the sound of the TV. Then, again, the
sound is louder when there no picture displayed. In fact, I can hear
shifts in pitch and volume as a television changes the image it
displays, or if it has trouble locking onto an image.
Anonymous
February 12, 2005 1:18:26 AM

Archived from groups: rec.audio.pro,sci.electronics.design,sci.med (More info?)

<pooua@aol.com> wrote in message
news:1108169534.239460.145530@z14g2000cwz.googlegroups.com
>> It's the horizontal scanning frequency, 15,734.25 Hz for American
>> color TV. Trust me. You don't need to measure it.
>
> I need to measure it, to be certain that is what I am hearing.
>
>> If humans can hear it, it can't possibly be at 40kHz, because
>> the best human hearing extends to only a bit above 20kHz.
>
> I think you are assuming some things that aren't necessarily so. One
> very important assumption you are making that is likely to be wrong is
> that no human can hear very much above 20 kHz.

Yes and no. If the intensity is high enough, it may be possible to discern
pure tones above 20 KHz. OTOH, hearing the removal of sounds is a different
question, and the borderline frequency for most people is around 16 KHz.

> There are a number of ways that assumption could be wrong.

There are a probably an infinite number of ways that any assumption could
be wrong, but that sheds little light on whether the assumption is correct
or not.

> In any event, there is no
> physical mechanism that would prevent a human from hearing higher
> frequencies.

Sure there is. The perception of pitch is based on the activation of hairs
in a coil-shaped structure in the ear. The finest hairs relate to high
frequencies, but they don't go on forever. Basically, you run out of
structure at some point in this part of the ear, and the extent and health
of this structure sets the highest frequencies that you can perceive. It's
not uncommon for this structure to be damaged by listening to excessively
loud sounds.
Anonymous
February 12, 2005 2:53:41 AM

Archived from groups: rec.audio.pro,sci.electronics.design,sci.med (More info?)

> So, anyone up for a controlled experiment?

I'm game, provided the experiment is within reason. I can't quit my job
or spend a day out of town, or anything like that (OK, I might be able
to manage the day out of town).
Anonymous
February 12, 2005 3:18:43 AM

Archived from groups: rec.audio.pro,sci.electronics.design,sci.med (More info?)

William Sommerwerck wrote:
>>Some people can hear an extremely high-pitched sound generated by
>>television CRTs and television cameras. I have long wondered what
>>frequency this sound is.
>
>
> It's the horizontal scanning frequency, 15,734.25 Hz for American color TV.
> Trust me. You don't need to measure it.
>
>
I can easily hear it
and my hearing does not go near 16K
Anonymous
February 12, 2005 3:46:18 AM

Archived from groups: rec.audio.pro,sci.electronics.design,sci.med (More info?)

pooua@aol.com wrote:
>>The high pitched sound is usually from the yoke and flyback
>
> transformer
>
>>(actually an inductor) feeding the television's CRT. For most
>
> televisions in the
>
>>United States that frequency is right at 15,734 Hz because the
>
> vertical scan
>
>>rate for NTSC is 29.97 times per second and it draws 525 lines. 29.97
>
> X 525 =
>
>>15734.25 horzontal scanning frequency.
>
>
> That sounds likely, but I have a few questions about that.
>
> 1) Is this same sub-unit on a standard television camera?
> 2) What exactly is converting the electrical energy into sound?
> 3) If this sound is so square in the middle of normal human hearing (16
> kHz is well-within the range of normal human hearing), why have I met
> so few people who can hear it?

Most people can hear it, at least until they are 25 or so
but most people do not know how to focus their listening and blank it out
kind of like what my son does when I ask him if he did his homework
>
> Question 3 is perplexing, because my sister and I were always the only
> people in our classroom or in someone's home who could hear the
> television.
>
> One time, when my sister was hospitalized, her nurse tried to turn on
> the television set for her, but the set did not appear to turn on. The
> nurse was about to leave the room for help with the TV, when my sister
> told him that the TV had just turned on. The screen was still black, so
> he did not know what to think. Then, the TV slowly produced a picture.
> My sister could tell the set was on because she could hear it. No one
> else in the room at the time could hear it.

There is nothing special about hearing this
my hearing is down 30 dB at 8 K(as high as the test at AES went) when
compared to 3K
and I can easily hear it
george
>
> I have worked in a computer call center for several years. At one time,
> we had CRT monitors in the room with us. I was the only person who
> could hear them. I liked to turn the CRTs off when not in use, because
> they hurt my ears. One time, I walked up to two of my associates and
> asked them if they would mind if I turned off the CRTs. One of them
> already knew I could hear the CRTs, but the other one did not. The one
> who did not know was surprised. Naturally, he reached up and turned off
> the set, and asked if I could hear the difference. Then, he turned it
> on. Then, off. Then, on. The other associate, who understood what I was
> experiencing, began to laugh, and called the guy a sadist.
>
>
>>I hear it loudly enough that I can tell when someone walks around in
>
> an
>
>>adjacent room with a television set on.
>
>
> Yes, that is what this is like. When I walk down the sidewalk, I can
> hear the television inside the homes I pass. I can tell if someone
> comes between the television and me, even if they are inside a closed
> room.
>
> I was at a hospital recently. As I walked across the lobby, I heard a
> television. I looked around. Then, I noticed a television camera inside
> a security enclosure box, mostly hidden in the ceiling. It took me a
> little longer to find it than it used to, because I had to locate it
> with just one ear (as I said, I am mostly deaf in the other ear, now).
>
Anonymous
February 12, 2005 3:46:19 AM

Archived from groups: rec.audio.pro,sci.electronics.design,sci.med (More info?)

On Sat, 12 Feb 2005 00:46:18 GMT, George Gleason
<g.p.gleason@worldnet.att.net> wrote:

>
>There is nothing special about hearing this
>my hearing is down 30 dB at 8 K(as high as the test at AES went) when
>compared to 3K
>and I can easily hear it
>george

Couldn't your hearing be down in the 8k range and still decent in
higher frequencies? It's been quite awhile since I was tested but I
remember that I had a dip in the high-midrange area (right where the
loud guitars and cymbals are!) and then above that I was fine.

Al
Anonymous
February 12, 2005 3:57:53 AM

Archived from groups: rec.audio.pro,sci.electronics.design,sci.med (More info?)

the sound is caused by the magnetostriction of the power transfomer
16khz is not in the middle of the human range; voice is and it is around 3
khz


<pooua@aol.com> wrote in message
news:1108168896.929130.108230@f14g2000cwb.googlegroups.com...
>> The high pitched sound is usually from the yoke and flyback
> transformer
>> (actually an inductor) feeding the television's CRT. For most
> televisions in the
>> United States that frequency is right at 15,734 Hz because the
> vertical scan
>> rate for NTSC is 29.97 times per second and it draws 525 lines. 29.97
> X 525 =
>> 15734.25 horzontal scanning frequency.
>
> That sounds likely, but I have a few questions about that.
>
> 1) Is this same sub-unit on a standard television camera?
> 2) What exactly is converting the electrical energy into sound?
> 3) If this sound is so square in the middle of normal human hearing (16
> kHz is well-within the range of normal human hearing), why have I met
> so few people who can hear it?
>
> Question 3 is perplexing, because my sister and I were always the only
> people in our classroom or in someone's home who could hear the
> television.
>
> One time, when my sister was hospitalized, her nurse tried to turn on
> the television set for her, but the set did not appear to turn on. The
> nurse was about to leave the room for help with the TV, when my sister
> told him that the TV had just turned on. The screen was still black, so
> he did not know what to think. Then, the TV slowly produced a picture.
> My sister could tell the set was on because she could hear it. No one
> else in the room at the time could hear it.
>
> I have worked in a computer call center for several years. At one time,
> we had CRT monitors in the room with us. I was the only person who
> could hear them. I liked to turn the CRTs off when not in use, because
> they hurt my ears. One time, I walked up to two of my associates and
> asked them if they would mind if I turned off the CRTs. One of them
> already knew I could hear the CRTs, but the other one did not. The one
> who did not know was surprised. Naturally, he reached up and turned off
> the set, and asked if I could hear the difference. Then, he turned it
> on. Then, off. Then, on. The other associate, who understood what I was
> experiencing, began to laugh, and called the guy a sadist.
>
>> I hear it loudly enough that I can tell when someone walks around in
> an
>> adjacent room with a television set on.
>
> Yes, that is what this is like. When I walk down the sidewalk, I can
> hear the television inside the homes I pass. I can tell if someone
> comes between the television and me, even if they are inside a closed
> room.
>
> I was at a hospital recently. As I walked across the lobby, I heard a
> television. I looked around. Then, I noticed a television camera inside
> a security enclosure box, mostly hidden in the ceiling. It took me a
> little longer to find it than it used to, because I had to locate it
> with just one ear (as I said, I am mostly deaf in the other ear, now).
>
Anonymous
February 12, 2005 3:59:41 AM

Archived from groups: rec.audio.pro,sci.electronics.design,sci.med (More info?)

This is Spehro Pefhany for forever:
> On 11 Feb 2005 15:40:20 -0800, the renowned pooua@aol.com wrote:
>
> >Some people can hear an extremely high-pitched sound generated by
> >television CRTs and television cameras. I have long wondered what
> >frequency this sound is.
>
> No need to measure it. In the US & Canada (and other NTSC countries
> such as Taiwan) the high-pitched sound that you can hear is either
> 15.75kHz (rare these days) or 15.734264kHz. That's when the TV is
> locked to a broadcast. If it's on an empty channel, the frequency will
> be a bit different.

Do you know what are those frequencies for PAL-M?

Sometimes I notice this high-pitched sound coming from my TV... (the 2
TV's I have at home: a 14" Toshiba and a 20" LG, so it's not a fault on
the TV)

[]s
--
Chaos Master®, posting from Canoas, Rio Grande do Sul, Brazil - 29.55° S
/ 51.11° W / GMT-2h / 15m .

"People told me I can't dress like a fairy.
I say, I'm in a rock band and I can do what the hell I want!"
-- Amy Lee

(My e-mail address isn't read. Please reply to the group!)
Anonymous
February 12, 2005 4:52:26 AM

Archived from groups: rec.audio.pro,sci.electronics.design,sci.med (More info?)

pooua@aol.com wrote:
>>my hearing is down 30 dB at 8 K(as high as the test at AES went)
>>when compared to 3K and I can easily hear it
>
>
> Did AES test your nerve conduction? I have a suspicion that the sound I
> hear is not coming through my eardrums. I am beginning to suspect that
> I hear it through my skull, which means nerve conduction.
>
> Your eardrum may not be able to hear so well, but maybe your ear nerves
> are still able to pick up sounds normally?
>

I have no idea
they gave us headphones and had us press a button when we heard sound
this was end oct 04
but I also feel(subjectivly ) that I can hear things the tests say I
should not be able to
Because I can focus my listening and isolate sounds , like a single
flute out of a flute section from 150 feet away from the orchestra
george
Anonymous
February 12, 2005 4:54:14 AM

Archived from groups: rec.audio.pro,sci.electronics.design,sci.med (More info?)

pooua@aol.com wrote:
>>It's the horizontal scanning frequency, 15,734.25 Hz for American
>>color TV. Trust me. You don't need to measure it.
>
>
> I need to measure it, to be certain that is what I am hearing.
>
>
>>If humans can hear it, it can't possibly be at 40kHz, because
>>the best human hearing extends to only a bit above 20kHz.
>
>
It could easily be measured with Macfoh (www.macfoh.com) and DPA
measurement mics
george
Anonymous
February 12, 2005 7:11:19 AM

Archived from groups: rec.audio.pro (More info?)

On 11 Feb 2005 16:41:36 -0800, pooua@aol.com wrote:

>>I have worked in a computer call center for several years. At one time,
>we had CRT monitors in the room with us. I was the only person who
>could hear them. I liked to turn the CRTs off when not in use, because
>they hurt my ears.

I can't tell where you are from your headers, but, as others have
said, in North America tv's sweep at 15.75-ish KHz. I'm a geezer
but can still hear a really loud deflection yoke.

CRT computer monitors start at twice that and go up from there,
31.5 KHz and up. Cats and dogs can easily hear an octave or so
higher than *that*, so why couldn't an exceptional human?

Chris Hornbeck
Anonymous
February 12, 2005 7:11:20 AM

Archived from groups: rec.audio.pro (More info?)

Chris Hornbeck <chrishornbeckremovethis@att.net> wrote:
>On 11 Feb 2005 16:41:36 -0800, pooua@aol.com wrote:
>
>>>I have worked in a computer call center for several years. At one time,
>>we had CRT monitors in the room with us. I was the only person who
>>could hear them. I liked to turn the CRTs off when not in use, because
>>they hurt my ears.
>
>I can't tell where you are from your headers, but, as others have
>said, in North America tv's sweep at 15.75-ish KHz. I'm a geezer
>but can still hear a really loud deflection yoke.

Until fairly recently (IBM EGA, probably late 1980s), pretty much all the
computer monitors out there in the US ran at NTSC rates and most of them
were video displays in disguise.

>CRT computer monitors start at twice that and go up from there,
>31.5 KHz and up. Cats and dogs can easily hear an octave or so
>higher than *that*, so why couldn't an exceptional human?

Today, computer monitors run at much higher rates than they used to, and
thankfully the sweep whines are now inaudible. Sadly this was not the
case with the Televideo 910 or the (really loud) ADDS Regent.
--scott
--
"C'est un Nagra. C'est suisse, et tres, tres precis."
Anonymous
February 12, 2005 7:12:24 AM

Archived from groups: rec.audio.pro,sci.electronics.design,sci.med (More info?)

On Fri, 11 Feb 2005 17:16:19 -0800, Glenn Gundlach wrote:

>
> pooua@aol.com wrote:
>> > The high pitched sound is usually from the yoke and flyback
>> transformer
>> > (actually an inductor) feeding the television's CRT. For most
>> televisions in the
>> > United States that frequency is right at 15,734 Hz because the
>> vertical scan
>> > rate for NTSC is 29.97 times per second and it draws 525 lines.
> 29.97
>> X 525 =
>> > 15734.25 horzontal scanning frequency.
>>
>> That sounds likely, but I have a few questions about that.
>>
>> 1) Is this same sub-unit on a standard television camera?
>> 2) What exactly is converting the electrical energy into sound?
>> 3) If this sound is so square in the middle of normal human hearing
> (16
>> kHz is well-within the range of normal human hearing), why have I met
>> so few people who can hear it?
>>
> 16 kHz is not square in the middle. When you become an 'old fart' you
> will find that out. 16K is your top octave which you will lose as you
> age. Sorry, I don't like it either but I actually don't miss hearing
> the Horizontal. Been working in commmercial TV for 28 years and haven't
> heard the H in more than 10.
> GG

OK, let's all be honest. How many of you have heard a high-pitched "sound"
very much like 15 KHz yoke, even though there is no yoke? This is
sometimes called "ringing in the ears", and is what I was thinking of when
I asked those questions about tinnitus.

I'm pretty sure I haven't heard 15 KHz horizontal in quite some time, but
right this very moment, I'm hearing the high pitched "eeee" which is
probably attributable to Black Velvet and bud. ;-)

Or maybe three monitors, but they're going at like 70 KHz. I _hope_ I
can't hear that! Could I be hearing magnetorestrictive copuling from four
feet?

Thanks!
Rich

Hah! Magnetorestrictive! That's good enough to leave in! %-}
Anonymous
February 12, 2005 7:16:41 AM

Archived from groups: rec.audio.pro,sci.electronics.design,sci.med (More info?)

On Fri, 11 Feb 2005 17:02:52 -0800, pooua wrote:

> My objectives are to find out what frequencies I can hear, and to match
> one of the calibrated frequencies from the signal generator against the
> sound I hear from televisions, so that I can finally know what that
> frequency from the television is.

The frequency from the television is approximately 15 KHz.

Don't worry about it.

A, there's nothing you can do about it anyway.
Two, so you can hear TVs. So what?

If you're worried about going deaf in the other ear, go to the otitist,
which you seem to have claimed you've already done.

If you're looking for something to _block out_ the 15 KHz, that's a whole
nother discussion. If this is it, I have some other ideas, but you have to
ask, and then I'll post them under one of my wacko personas. ;-)

Good Luck!
Rich
Anonymous
February 12, 2005 7:19:28 AM

Archived from groups: rec.audio.pro,sci.electronics.design,sci.med (More info?)

On Fri, 11 Feb 2005 16:52:14 -0800, pooua wrote:

>> It's the horizontal scanning frequency, 15,734.25 Hz for American
>> color TV. Trust me. You don't need to measure it.
>
> I need to measure it, to be certain that is what I am hearing.

Try just listening to it one time. In another post, you mentioned having
to focus on a particular conversation or a particular flute. Do this to
the sound, and ask what it's trying to tell you. It could be an attempt
to communicate from a higher dimension.

Good Luck!
Rich

for further information, please visit http://www.godchannel.com
Anonymous
February 12, 2005 7:24:29 AM

Archived from groups: rec.audio.pro (More info?)

>CRT computer monitors start at twice that and go up from there,
>31.5 KHz and up.

Sent this before engaging the thought process. Computer monitors
have high frequency power supplies that make noise too. Maybe
that was the issue. Tv's do this at sweep frequency for economy;
computer monitors don't, for the same reason.

Chris Hornbeck
Anonymous
February 12, 2005 7:51:33 AM

Archived from groups: rec.audio.pro,sci.electronics.design,sci.med (More info?)

play_on wrote:
> On Sat, 12 Feb 2005 00:46:18 GMT, George Gleason
> <g.p.gleason@worldnet.att.net> wrote:
>
>
>>There is nothing special about hearing this
>>my hearing is down 30 dB at 8 K(as high as the test at AES went) when
>>compared to 3K
>>and I can easily hear it
>>george
>
>
> Couldn't your hearing be down in the 8k range and still decent in
> higher frequencies? It's been quite awhile since I was tested but I
> remember that I had a dip in the high-midrange area (right where the
> loud guitars and cymbals are!) and then above that I was fine.
>
> Al

8k was as high as the test measured so I am not aware of my measured
abilities above that
George
Anonymous
February 12, 2005 8:13:14 AM

Archived from groups: rec.audio.pro,sci.electronics.design,sci.med (More info?)

pooua@aol.com wrote:

> Some people can hear an extremely high-pitched sound generated by
> television CRTs and television cameras.

When they're badly designed / manufactured - yes.

> I have long wondered what frequency this sound is.

Until recent times mostly around 15 kHz.


> So, I am looking around for test equipment to
> help me measure it. I plan to use an audio generator (which I can buy
> for about $200), but I need to find a set of headphones that can
> produce sound at these high frequencies. The low end frequency should
> be about 12 kHz, and I would like to be able to go at least to 50 kHz.
> I am guessing the sound is somewhere around 40 kHz.

Nope.

No human can hear those frequencies - well proven - forget it.


> Incidentally, I just got my hearing checked by my ENT (Ear, Nose,
> Throat doctor). I measured in the 5-to-10 dB range on both the eardrum
> and nerve conduction tests across the entire measured frequency range
> (up to 8 kHz for eardrum, 12 kHz for nerve conduction). My doctor said
> that they want to see values less than 20 dB, so I am well-within the
> safe zone, as far as they are concerned. However, one reason that she
> scheduled this test for me is that I complained that I am going deaf in
> one of my ears. I have almost completely lost my sensitivity to the
> ultra-high pitched sound in that ear. I can hear that sound 100 times
> better from my other ear.

Well - I had a proper hearing test when I was in my mid 20s and the nurse
commented that I had the most perfect hearing she'd ever measured.

I was on the 0dB line all the way to 8 kHz - the highest frequency used for
medical testing it seems.


> People don't realize what a difference it makes to a person's
> perception when the range of hearing differs. I can walk into a room
> with other people, and they think they are in an empty room. If there
> is an operating television in the room, I will be aware of almost
> physical contact.

You have good hearing acuity.

May not necessarily be a result of perfect hearing but a desire to use your
ears as a useful tool.


> Other people can hold a conversation in a normal
> voice, but I have to listen over a sound similar to a dentist's drill
> or a jet engine. After several minutes of that, I often feel dazed. No
> one else even notices anything, except maybe that I am acting a little
> more odd than normal.

You mean you have diffiiculty with large background levels of noise ? Can't
'reject' it ?

Me too. You have high hearing acuity. Your ears are 'wide open' to stimuli.
May ppl simply 'filter out' what they're uninterested in.


Graham
Anonymous
February 12, 2005 8:17:43 AM

Archived from groups: rec.audio.pro,sci.electronics.design,sci.med (More info?)

William Sommerwerck wrote:

> > Some people can hear an extremely high-pitched sound generated by
> > television CRTs and television cameras. I have long wondered what
> > frequency this sound is.
>
> It's the horizontal scanning frequency, 15,734.25 Hz for American color TV.
> Trust me. You don't need to measure it.
>
> > So, I am looking around for test equipment to
> > help me measure it. I plan to use an audio generator (which I can buy
> > for about $200), but I need to find a set of headphones that can
> > produce sound at these high frequencies. The low end frequency should
> > be about 12 kHz, and I would like to be able to go at least to 50 kHz.
> > I am guessing the sound is somewhere around 40 kHz.
>
> If humans can hear it, it can't possibly be at 40kHz, because the best human
> hearing extends to only a bit above 20kHz.

Using a test generator I was able to *sense* rather than hear 22kHz when I was
in my early 20s.

Now I'm 50 - I seem to top out on 'hearing' at about 16kHz. That makes me quite
lucky it seems.

I do believe you can 'educate' your hearing btw. Be interested to hear - lol -
other ppl's comments.


Graham
Anonymous
February 12, 2005 8:20:45 AM

Archived from groups: rec.audio.pro,sci.electronics.design,sci.med (More info?)

George Gleason wrote:

> William Sommerwerck wrote:
> >>Some people can hear an extremely high-pitched sound generated by
> >>television CRTs and television cameras. I have long wondered what
> >>frequency this sound is.
> >
> >
> > It's the horizontal scanning frequency, 15,734.25 Hz for American color TV.
> > Trust me. You don't need to measure it.
> >
> >
> I can easily hear it
> and my hearing does not go near 16K

Interesting.

Maybe you're hearing some magnetorestriction related noise in the LOPT ?

Maybe you underestimate your hearing ?


Graham
Anonymous
February 12, 2005 8:25:22 AM

Archived from groups: rec.audio.pro,sci.electronics.design,sci.med (More info?)

George Gleason wrote:

> most people do not know how to focus their listening and blank it out
> kind of like what my son does when I ask him if he did his homework

George !

Are you thinking of taking up a new role as a comedian ?

I loved that response. :-)


Graham
Anonymous
February 12, 2005 8:34:51 AM

Archived from groups: rec.audio.pro,sci.electronics.design,sci.med (More info?)

pooua@aol.com wrote:

> > my hearing is down 30 dB at 8 K(as high as the test at AES went)
> > when compared to 3K and I can easily hear it
>
> Did AES test your nerve conduction? I have a suspicion that the sound I
> hear is not coming through my eardrums. I am beginning to suspect that
> I hear it through my skull, which means nerve conduction.
>
> Your eardrum may not be able to hear so well, but maybe your ear nerves
> are still able to pick up sounds normally?

I suspect that the brain compensates actually.

I reckon also that the simple desire to use your ears effectively
influences your result significantly.

E.g. George Martin was a famed record producer but was essentially deaf in
one ear !


Graham
Anonymous
February 12, 2005 8:37:51 AM

Archived from groups: rec.audio.pro,sci.electronics.design,sci.med (More info?)

Rich Grise wrote:

> On Fri, 11 Feb 2005 17:02:52 -0800, pooua wrote:
>
> > My objectives are to find out what frequencies I can hear, and to match
> > one of the calibrated frequencies from the signal generator against the
> > sound I hear from televisions, so that I can finally know what that
> > frequency from the television is.
>
> The frequency from the television is approximately 15 KHz.
>
> Don't worry about it.
>
> A, there's nothing you can do about it anyway.
> Two, so you can hear TVs. So what?
>
> If you're worried about going deaf in the other ear, go to the otitist,
> which you seem to have claimed you've already done.
>
> If you're looking for something to _block out_ the 15 KHz, that's a whole
> nother discussion. If this is it, I have some other ideas, but you have to
> ask, and then I'll post them under one of my wacko personas. ;-)
>
> Good Luck!
> Rich

I love these quirky posts of yours Rich.

Why not simply suggest he buys a decent TV without a noisy LOPT ?


Graham
Anonymous
February 12, 2005 9:26:03 AM

Archived from groups: rec.audio.pro (More info?)

On 11 Feb 2005 21:44:36 -0800, pooua@aol.com wrote:

>FWIW, I can hear computer monitors, too, but not as well as
>televisions. That's a good thing, because I work in an office with a
>hundred computer monitors. The room has to be quiet and I have to pay
>attention for me to hear a computer monitor, unless it is going bad.

"When you get old, God dims your vision, to hide the dust."

You raise several interesting topics. Does one really *want*
to be able to hear these things? Does the "going bad" issue
give any clues? Would a small amount of sound absorbtive
material held just outside the ear canal help you?

Your original question seems to have been lost into the
thread, but you can probably get whatever folks here know
about the topic by googling Len Moskowitz's related (?) quest
a few weeks ago, titled "Supertweeters".

Good fortune,

Chris Hornbeck
Anonymous
February 12, 2005 9:51:34 AM

Archived from groups: rec.audio.pro,sci.electronics.design,sci.med (More info?)

On Fri, 11 Feb 2005 20:06:40 -0800, play_on wrote:

> On Sat, 12 Feb 2005 00:46:18 GMT, George Gleason
> <g.p.gleason@worldnet.att.net> wrote:
>
>>
>>There is nothing special about hearing this
>>my hearing is down 30 dB at 8 K(as high as the test at AES went) when
>>compared to 3K
>>and I can easily hear it
>>george
>
> Couldn't your hearing be down in the 8k range and still decent in
> higher frequencies? It's been quite awhile since I was tested but I
> remember that I had a dip in the high-midrange area (right where the
> loud guitars and cymbals are!) and then above that I was fine.

Hearing is selective.

The last couple of years of my Dad's life, I was staying with him and Mom,
as sort of "the guy who does everything around the house that they're too
old and feeble to do". Mom's job was basically change Dad's diapers. I
helped haul him out of bed and into his chair, or the car, etc.

But when he was sitting in his chair, with Mom in the couch to his left,
and me on the loveseat to his right, and the TV right in front of him,
with the speakers pointed right at him, he had to turn it up uncomfortably
loud, and Mom and I couldn't talk to each other or anything, or he
couldn't hear the TV. But if I went into the kitchen and poured myself
more than a shot of scotch, he could hear the sound of the overpour well
enough to bitch about it.

People decide what they want to hear.

Good Luck!
Rich

for further information, please visit http://www.godchannel.com
Anonymous
February 12, 2005 10:04:52 AM

Archived from groups: rec.audio.pro,sci.electronics.design,sci.med (More info?)

On Fri, 11 Feb 2005 21:35:07 -0800, pooua wrote:

>> How many of you have heard a high-pitched "sound"
>> very much like 15 KHz yoke, even though there is no yoke? This is
>> sometimes called "ringing in the ears", and is what I was thinking of
> when
>> I asked those questions about tinnitus.
>
> Yes, I do have ringing in my ears, but it is fairly quiet. That's one
> way I can distinguish it from the sound of the TV. The TV set sounds
> very loud, so loud that I can hear it 15 feet away through the walls
> and closed windows of buildings, or from about 50 feet away in an open
> space.

This could make for some very interesting experiments. Hear a TV through
walls and closed windows? Or from 50 feet?

I'd really like to see some kind of controlled test there. To me, it
sounds impossible, but I have this dark side, who thinks there's something
more going on. ;-)

So, anyone up for a controlled experiment?

Cheers!
Rich
Anonymous
February 12, 2005 10:05:24 AM

Archived from groups: rec.audio.pro,sci.electronics.design,sci.med (More info?)

"Pooh Bear" <rabbitsfriendsandrelations@hotmail.com> wrote in message
news:420D922D.C6377F65@hotmail.com
> George Gleason wrote:
>
>> William Sommerwerck wrote:

>>>> Some people can hear an extremely high-pitched sound generated by
>>>> television CRTs and television cameras. I have long wondered what
>>>> frequency this sound is.

>>> It's the horizontal scanning frequency, 15,734.25 Hz for American
>>> color TV. Trust me. You don't need to measure it.

Agreed.

>> I can easily hear it
>> and my hearing does not go near 16K

It's a matter of intensity.

> Interesting.

Normal.

> Maybe you're hearing some magnetorestriction related noise in the
> LOPT ?

I think that magnetostriction and related vibration in either the
transformers or the deflection yoke is the usual explanation.

> Maybe you underestimate your hearing ?

The mistake appears to be thinking that the limit of HF hearing is one
number that does not vary with the details and nature of the test.
!