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Guest
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 Posted:
Sat Feb 12, 2005 5:40 am Post subject:
Speakers for High Frequency Sound |
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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.
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Guest
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| Posted:
Sat Feb 12, 2005 6:10 am Post subject:
Re: Speakers for High Frequency Sound |
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| Quote: | 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.
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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. |
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Guest
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| Posted:
Sat Feb 12, 2005 6:10 am Post subject:
Re: Speakers for High Frequency Sound |
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| Quote: | 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.
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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.
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Pooh Bear
Guest
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| Posted:
Sat Feb 12, 2005 6:10 am Post subject:
Re: Speakers for High Frequency Sound |
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Rich Grise wrote:
| Quote: | 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
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I love these quirky posts of yours Rich.
Why not simply suggest he buys a decent TV without a noisy LOPT ?
Graham |
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Pooh Bear
Guest
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| Posted:
Sat Feb 12, 2005 6:10 am Post subject:
Re: Speakers for High Frequency Sound |
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pooua@aol.com wrote:
| Quote: | 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?
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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 |
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Guest
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| Posted:
Sat Feb 12, 2005 6:10 am Post subject:
Re: Speakers for High Frequency Sound |
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| Quote: | 8k was as high as the test measured so I am not aware of my
measured abilities above that
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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. |
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Pooh Bear
Guest
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| Posted:
Sat Feb 12, 2005 6:10 am Post subject:
Re: Speakers for High Frequency Sound |
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George Gleason wrote:
| Quote: | 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
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George !
Are you thinking of taking up a new role as a comedian ?
I loved that response. :-)
Graham |
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Guest
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| Posted:
Sat Feb 12, 2005 6:10 am Post subject:
Re: Speakers for High Frequency Sound |
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| Quote: | 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.
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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. |
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Guest
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| Posted:
Sat Feb 12, 2005 6:10 am Post subject:
Re: Speakers for High Frequency Sound |
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| Quote: | In another post, you mentioned having to focus on a
particular conversation or a particular flute.
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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. |
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Pooh Bear
Guest
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| Posted:
Sat Feb 12, 2005 6:10 am Post subject:
Re: Speakers for High Frequency Sound |
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George Gleason wrote:
| Quote: | 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
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Interesting.
Maybe you're hearing some magnetorestriction related noise in the LOPT ?
Maybe you underestimate your hearing ?
Graham |
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Pooh Bear
Guest
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| Posted:
Sat Feb 12, 2005 6:10 am Post subject:
Re: Speakers for High Frequency Sound |
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William Sommerwerck wrote:
| Quote: | 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.
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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 |
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Pooh Bear
Guest
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| Posted:
Sat Feb 12, 2005 6:10 am Post subject:
Re: Speakers for High Frequency Sound |
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pooua@aol.com wrote:
| Quote: | Some people can hear an extremely high-pitched sound generated by
television CRTs and television cameras.
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When they're badly designed / manufactured - yes.
| Quote: | I have long wondered what frequency this sound is.
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Until recent times mostly around 15 kHz.
| Quote: | 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.
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Nope.
No human can hear those frequencies - well proven - forget it.
| Quote: | 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.
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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.
| Quote: | 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.
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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.
| Quote: | 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.
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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 |
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George Gleason
Guest
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| Posted:
Sat Feb 12, 2005 6:11 am Post subject:
Re: Speakers for High Frequency Sound |
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play_on wrote:
| Quote: | 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
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8k was as high as the test measured so I am not aware of my measured
abilities above that
George |
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Eric K. Weber
Guest
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| Posted:
Sat Feb 12, 2005 6:11 am Post subject:
Re: Speakers for High Frequency Sound |
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Pal M is 15.750 KHZ
Have a look at
http://www.infocellar.com/television/committees.htm
for the other international versions of television for horizontal frequency.
Rgds:
Eric |
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Rich The Philosophizer
Guest
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| Posted:
Sat Feb 12, 2005 6:11 am Post subject:
Re: Speakers for High Frequency Sound |
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On Fri, 11 Feb 2005 16:52:14 -0800, pooua wrote:
| Quote: | 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.
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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 |
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