|
|
| Author |
Message |
Matthew Fields
science forum Guru Wannabe
Joined: 26 Oct 2005
Posts: 200
|
 Posted: Thu Oct 27, 2005 7:09 pm Post subject:
Re: how your ears work
|
|
|
In article <1130436682.884685.159130@g49g2000cwa.googlegroups.com>,
<StpNrrs@aol.com> wrote:
| Quote: | What the original "how your ears work" (
http://ultrapiano.com/manufacturers/EarPage.jpg ) is getting at is that
the ear and brain do not perform spectral analysis of sound at all! The
hair cells are not tuned to specific frequencies, but simply transmit a
nerve impulse onto the aural nerve when they have been squashed by
pressure in the cochlea. Because of the large number of hair-cells
individually sending nerve impulses, patterns of impulses occur on the
aural nerve. These patterns of pressure variations are recognised by
the inner brain while they are on the aural nerve. From this simple
information we recognise human speech and can distinguish between words
and understand its emotional content.
|
Okay, but the frequencies of simple sine waves do have high corrolation
with specific columns of brain tissue being excited. How exactly this
corrolation arrises is good for some research, but it isn't done in any
simple straightforward way by the cochlea.
--
Matthew H. Fields http://www.umich.edu/~fields
Music: Splendor in Sound
To be great, do better and better. Don't wait for talent: no such thing.
Brights have a naturalistic world-view. http://www.the-brights.net/ |
|
| Back to top |
|
 |
J Ketutsalo
science forum beginner
Joined: 26 Oct 2005
Posts: 6
|
| Posted: Thu Oct 27, 2005 7:39 pm Post subject:
Re: how your ears work
|
|
|
StpNrrs@aol.com wrote:
Ok. I had to take a look at the text. It does not say that the ear and
the brain do not perform spectral analysis. It says that the information
in the auditory nerve is not a mere spectral analysis of sound, which is
very much true. However, the neural impulses travelling through the
auditory nerve *include* information about the spectral content of
sound, and that information is used by the brain. No doubt about that. |
|
| Back to top |
|
|
Matthew Fields
science forum Guru Wannabe
Joined: 26 Oct 2005
Posts: 200
|
| Posted: Thu Oct 27, 2005 8:18 pm Post subject:
Re: how your ears work
|
|
|
In article <djradt$gui$1@nyytiset.pp.htv.fi>,
J Ketutsalo <ei.kiitos@spammia.fi> wrote:
| Quote: | StpNrrs@aol.com wrote:
What the original "how your ears work" (
http://ultrapiano.com/manufacturers/EarPage.jpg ) is getting at is that
the ear and brain do not perform spectral analysis of sound at all!
Ok. I had to take a look at the text. It does not say that the ear and
the brain do not perform spectral analysis. It says that the information
in the auditory nerve is not a mere spectral analysis of sound, which is
very much true. However, the neural impulses travelling through the
auditory nerve *include* information about the spectral content of
sound, and that information is used by the brain. No doubt about that.
|
Or at least some sort of information from which spectral information
can be estimated.
--
Matthew H. Fields http://www.umich.edu/~fields
Music: Splendor in Sound
To be great, do better and better. Don't wait for talent: no such thing.
Brights have a naturalistic world-view. http://www.the-brights.net/ |
|
| Back to top |
|
|
stickyfox@gmail.com
science forum beginner
Joined: 23 Oct 2005
Posts: 10
|
| Posted: Thu Oct 27, 2005 8:22 pm Post subject:
Re: how your ears work
|
|
|
J Ketutsalo wrote:
| Quote: | stickyfox@gmail.com wrote:
Transients are where it's at, frequency-wise. Have you ever looked at a
spectrogram of a sound audible to humans, and wondered why the majority
of the graph is dedicated to pitches above 1 kHz?
Yes, I have. And the reason is that such a spectrogram is easy to
compute, even if it doesn't correspond to human perception.
|
So where are all the difficult-to-compute, but much more useful
spectrograms at the correct frequencies?
| Quote: |
Practically all of
the information that identifies a sound is near the top of our audible
spectrum, and it's the "kinks" in signals that carry this
high-frequency content.
No, it isn't. You can identify almost all sound through a telephone, and
the telephone bandwidth stops at a bit over 3 kHz. In fact, if you throw
away 3-20 kHz, you certainly lose some information but if you throw away
0-3 kHz, you lose most of the information. For example, you won't be
able to understand speech.
|
Have you ever mistaken someone's voice on a telephone call?
| Quote: | If you chop up a sound into 1/25-sec pieces, and throw half of them
away, you won't lose any information at all, unless the original sound
has a fundamental frequency of less than 25 Hz.
Imagine a signal with an impulse that is, say, 1/1000 seconds long. It
will be very clearly audible. If you throw it away, you lose all the
information in the signal.
|
One single impulse would be a harmonic of a fundamental frequency of
zero, much less than 25 Hz. As I said, you will lose anything below
your chopping frequency. And a component having zero Hz frequency isn't
going to be carrying much information. There used to be a "pop," now
there isn't. But this doesn't have anything to do with the
identification of sounds by the brain.
Boo-yah. |
|
| Back to top |
|
|
Matthew Fields
science forum Guru Wannabe
Joined: 26 Oct 2005
Posts: 200
|
| Posted: Thu Oct 27, 2005 8:30 pm Post subject:
Re: how your ears work
|
|
|
In article <1130444530.372752.62360@g47g2000cwa.googlegroups.com>,
stickyfox@gmail.com <stickyfox@gmail.com> wrote:
| Quote: |
J Ketutsalo wrote:
stickyfox@gmail.com wrote:
Transients are where it's at, frequency-wise. Have you ever looked at a
spectrogram of a sound audible to humans, and wondered why the majority
of the graph is dedicated to pitches above 1 kHz?
Yes, I have. And the reason is that such a spectrogram is easy to
compute, even if it doesn't correspond to human perception.
So where are all the difficult-to-compute, but much more useful
spectrograms at the correct frequencies?
Practically all of
the information that identifies a sound is near the top of our audible
spectrum, and it's the "kinks" in signals that carry this
high-frequency content.
No, it isn't. You can identify almost all sound through a telephone, and
the telephone bandwidth stops at a bit over 3 kHz. In fact, if you throw
away 3-20 kHz, you certainly lose some information but if you throw away
0-3 kHz, you lose most of the information. For example, you won't be
able to understand speech.
Have you ever mistaken someone's voice on a telephone call?
If you chop up a sound into 1/25-sec pieces, and throw half of them
away, you won't lose any information at all, unless the original sound
has a fundamental frequency of less than 25 Hz.
Imagine a signal with an impulse that is, say, 1/1000 seconds long. It
will be very clearly audible. If you throw it away, you lose all the
information in the signal.
One single impulse would be a harmonic of a fundamental frequency of
zero, much less than 25 Hz. As I said, you will lose anything below
your chopping frequency. And a component having zero Hz frequency isn't
going to be carrying much information. There used to be a "pop," now
there isn't. But this doesn't have anything to do with the
identification of sounds by the brain.
Boo-yah.
|
If you throw away single-sample impulses, you're throwing away the
transients of some percussion instruments.
I really suggest YOU try the reversal on high xylophone music--
yourself--and see if you can convince yourself that it works reliably
and doesn't sound audibly wrong. If it doesn't, THEN try your
method of throwing away half the data--say, alternating 50ths of a second--
and apply it to variety of things. See what its limitations are,
and document them. Publish in IEEE or an electronic music journal.
I have music to write, and won't do your homework for you. :)
--
Matthew H. Fields http://www.umich.edu/~fields
Music: Splendor in Sound
To be great, do better and better. Don't wait for talent: no such thing.
Brights have a naturalistic world-view. http://www.the-brights.net/ |
|
| Back to top |
|
|
stickyfox@gmail.com
science forum beginner
Joined: 23 Oct 2005
Posts: 10
|
| Posted: Thu Oct 27, 2005 8:37 pm Post subject:
Re: how your ears work
|
|
|
Matthew Fields wrote:
| Quote: | I really suggest YOU try the reversal on high xylophone music--
yourself--and see if you can convince yourself that it works reliably
|
I probably won't, because I think the idea is bollocks, and much
lossier and less efficient than numerous methods that are already in
use. But maybe the person who suggested it would be interested in
trying it.
I also don't think it would be any less forgiving to "high xylophone
music" than it would to, say, "Girls" by the Beastie Boys. |
|
| Back to top |
|
|
J Ketutsalo
science forum beginner
Joined: 26 Oct 2005
Posts: 6
|
| Posted: Thu Oct 27, 2005 8:59 pm Post subject:
Re: how your ears work
|
|
|
| Quote: | stickyfox@gmail.com wrote:
If you chop up a sound into 1/25-sec pieces, and throw half of them
away, you won't lose any information at all, unless the original sound
has a fundamental frequency of less than 25 Hz.
Matthew Fields wrote:
I really suggest YOU try the reversal on high xylophone music--
yourself--and see if you can convince yourself that it works reliably
|
stickyfox@gmail.com wrote:
| Quote: | I probably won't, because I think the idea is bollocks, and much
lossier and less efficient than numerous methods that are already in
use. But maybe the person who suggested it would be interested in
trying it.
|
End of discussion. |
|
| Back to top |
|
|
Bob Cain
science forum Guru
Joined: 07 Jun 2005
Posts: 360
|
| Posted: Thu Oct 27, 2005 8:59 pm Post subject:
Re: how your ears work
|
|
|
Matthew Fields wrote:
| Quote: | In article <djradt$gui$1@nyytiset.pp.htv.fi>,
J Ketutsalo <ei.kiitos@spammia.fi> wrote:
StpNrrs@aol.com wrote:
What the original "how your ears work" (
http://ultrapiano.com/manufacturers/EarPage.jpg ) is getting at is that
the ear and brain do not perform spectral analysis of sound at all!
Ok. I had to take a look at the text. It does not say that the ear and
the brain do not perform spectral analysis. It says that the information
in the auditory nerve is not a mere spectral analysis of sound, which is
very much true. However, the neural impulses travelling through the
auditory nerve *include* information about the spectral content of
sound, and that information is used by the brain. No doubt about that.
Or at least some sort of information from which spectral information
can be estimated.
|
Does this not imply that the ear/brain could match sounds based
partially on their containing Fourier components higher in frequency
than what they can detect as pure sinusoids (the way hearing bandwidth
and sensitivity are commonly measured)?
Bob
--
"Things should be described as simply as possible, but no simpler."
A. Einstein |
|
| Back to top |
|
|
maestro@ultrapiano.com
science forum Guru Wannabe
Joined: 23 Oct 2005
Posts: 145
|
| Posted: Thu Oct 27, 2005 10:58 pm Post subject:
Re: how your ears work
|
|
|
Matthew Fields wrote:
| Quote: | In article <djradt$gui$1@nyytiset.pp.htv.fi>,
J Ketutsalo <ei.kiitos@spammia.fi> wrote:
StpNrrs@aol.com wrote:
What the original "how your ears work" (
http://ultrapiano.com/manufacturers/EarPage.jpg ) is getting at is that
the ear and brain do not perform spectral analysis of sound at all!
Ok. I had to take a look at the text. It does not say that the ear and
the brain do not perform spectral analysis. It says that the information
in the auditory nerve is not a mere spectral analysis of sound, which is
very much true. However, the neural impulses travelling through the
auditory nerve *include* information about the spectral content of
sound, and that information is used by the brain. No doubt about that.
Or at least some sort of information from which spectral information
can be estimated.
|
Yes, of course the information that spectral analysis gives, is
contained in the electrical impulses that the ear sends along the aural
nerve into the brain. The information contained by the numbers in a
..wav or .mp3 file is also contained in the same electrical impulses,
but it is pointless to mention that as anything to do with what the
brain does with the pressure variation information that it receives -
spectral content is similarly irrelevant.
It is also true that experiments have been performed with sinewave
inputs to the ear, which cause indentifiable hair-cells to fire.
However, these experiments do not claim to prove that specific
hair-cells encode specific frequencies, but unfortunately they do not
disprove it either. The hair-cells are all fairly similar, although
the ones at the centre of the spiral cochlea are somewhat shorter and
stubbier than the ones at the other end of the spiral. The only
difference between them biologically is that the shorter haircells take
more pressure before they fire their synapse, and also take longer to
recover before they can fire again, than the longer ones. Because of
that, each individual hair-cell must be responsive to all audible
frequencies at any amplitude, but some are more responsive than others.
The ear/brain is actually tuned 'by nature' to hear and understand
human speech, and is particularly good at identifying the tiny nuances
which give the emotional content and indicate the speaker's state of
mind. The ups and downs in pitch and the changes in loudness during
normal speech are all part of what the brain recognises when it hears a
voice, but does anyone suggest that the ear is encoding these important
parts of spoken sound at the hair-cell level? Of course not, the
hair-like structures have not evolved to detect 'ups' or 'downs' in the
voice of a potential mate - so why should anyone take seriously the
idea that the ear performs a spectral analysis of human speech - what
evolutionary advantage would it give?
If someone had only ever heard their parents talking, and had never
heard sinewaves before, if you played a sinewave (440Hz from a
tuning-fork A, for example) they would at first say that the tuning
fork sounded like their mother or father, until they had learned that
the new sound was a different thing. The ability to identify sinewaves
is a learnt ability, and is not evolved by nature.
I think that most theorists are confusing themselves with the idea of
building an 'artifical ear' that can hear by itself, which could be
perhaps plugged into the brain to cure deafness. Human ears don't hear
- they channel air pressure variations into the cochlea. The
hair-cells transduce these pressure variations into electrical impulses
which travel along the aural nerve. The aural nerve acts as a delay
line, containing about a 25th of a second's worth of information at any
one time. The brain matches features and patterns in the information
on the aural nerve against remembered information patterns (from
previously heard sounds) to produce the sensation of hearing. |
|
| Back to top |
|
|
Matthew Fields
science forum Guru Wannabe
Joined: 26 Oct 2005
Posts: 200
|
| Posted: Fri Oct 28, 2005 12:02 am Post subject:
Re: how your ears work
|
|
|
In article <djrf3p0hu4@enews1.newsguy.com>,
Bob Cain <arcane@arcanemethods.com> wrote:
| Quote: |
Matthew Fields wrote:
In article <djradt$gui$1@nyytiset.pp.htv.fi>,
J Ketutsalo <ei.kiitos@spammia.fi> wrote:
StpNrrs@aol.com wrote:
What the original "how your ears work" (
http://ultrapiano.com/manufacturers/EarPage.jpg ) is getting at is that
the ear and brain do not perform spectral analysis of sound at all!
Ok. I had to take a look at the text. It does not say that the ear and
the brain do not perform spectral analysis. It says that the information
in the auditory nerve is not a mere spectral analysis of sound, which is
very much true. However, the neural impulses travelling through the
auditory nerve *include* information about the spectral content of
sound, and that information is used by the brain. No doubt about that.
Or at least some sort of information from which spectral information
can be estimated.
Does this not imply that the ear/brain could match sounds based
partially on their containing Fourier components higher in frequency
than what they can detect as pure sinusoids (the way hearing bandwidth
and sensitivity are commonly measured)?
|
No. If you'd like to explain how you got there, let us know.
--
Matthew H. Fields http://www.umich.edu/~fields
Music: Splendor in Sound
To be great, do better and better. Don't wait for talent: no such thing.
Brights have a naturalistic world-view. http://www.the-brights.net/ |
|
| Back to top |
|
|
Bob Cain
science forum Guru
Joined: 07 Jun 2005
Posts: 360
|
| Posted: Fri Oct 28, 2005 12:22 am Post subject:
Re: how your ears work
|
|
|
Matthew Fields wrote:
| Quote: | In article <djrf3p0hu4@enews1.newsguy.com>,
Bob Cain <arcane@arcanemethods.com> wrote:
Does this not imply that the ear/brain could match sounds based
partially on their containing Fourier components higher in frequency
than what they can detect as pure sinusoids (the way hearing bandwidth
and sensitivity are commonly measured)?
No. If you'd like to explain how you got there, let us know.
|
Were there no intrinisc decomposition by frequency at the ear, just an
associative mechanism that matches learned patterns of cochlear
excitation with semantics, then one might not hear a high frequency
sinusoid whose presence as a Fourier component might be necessary to
make a match with something learned.
Bob
--
"Things should be described as simply as possible, but no simpler."
A. Einstein |
|
| Back to top |
|
|
Matthew Fields
science forum Guru Wannabe
Joined: 26 Oct 2005
Posts: 200
|
| Posted: Fri Oct 28, 2005 1:09 am Post subject:
Re: how your ears work
|
|
|
In article <djrqvo0sr6@enews1.newsguy.com>,
Bob Cain <arcane@arcanemethods.com> wrote:
| Quote: |
Matthew Fields wrote:
In article <djrf3p0hu4@enews1.newsguy.com>,
Bob Cain <arcane@arcanemethods.com> wrote:
Does this not imply that the ear/brain could match sounds based
partially on their containing Fourier components higher in frequency
than what they can detect as pure sinusoids (the way hearing bandwidth
and sensitivity are commonly measured)?
No. If you'd like to explain how you got there, let us know.
Were there no intrinisc decomposition by frequency at the ear, just an
associative mechanism that matches learned patterns of cochlear
excitation with semantics,
|
Very odd sort of bifurcation.
The decomposition is in the brain, not the ear.
The associative pattern-matching is in a different section of the brain.
| Quote: | then one might not hear a high frequency
sinusoid whose presence as a Fourier component might be necessary to
make a match with something learned.
|
Logic derived from a bifurcation is only as good as the evidence
showing that no other cases deserve consideration. In this case,
a third case has long since been established.
--
Matthew H. Fields http://www.umich.edu/~fields
Music: Splendor in Sound
To be great, do better and better. Don't wait for talent: no such thing.
Brights have a naturalistic world-view. http://www.the-brights.net/ |
|
| Back to top |
|
|
Bob Cain
science forum Guru
Joined: 07 Jun 2005
Posts: 360
|
| Posted: Fri Oct 28, 2005 6:48 am Post subject:
Re: how your ears work
|
|
|
Matthew Fields wrote:
| Quote: | In article <djrqvo0sr6@enews1.newsguy.com>,
Bob Cain <arcane@arcanemethods.com> wrote:
Matthew Fields wrote:
In article <djrf3p0hu4@enews1.newsguy.com>,
Bob Cain <arcane@arcanemethods.com> wrote:
Does this not imply that the ear/brain could match sounds based
partially on their containing Fourier components higher in frequency
than what they can detect as pure sinusoids (the way hearing bandwidth
and sensitivity are commonly measured)?
No. If you'd like to explain how you got there, let us know.
Were there no intrinisc decomposition by frequency at the ear, just an
associative mechanism that matches learned patterns of cochlear
excitation with semantics,
Very odd sort of bifurcation.
The decomposition is in the brain, not the ear.
|
So you think that decomposition by frequency is done by a neural
structure predicated by the genes? I.e., it is standard equipment and
not built by experience?
| Quote: | The associative pattern-matching is in a different section of the brain.
then one might not hear a high frequency
sinusoid whose presence as a Fourier component might be necessary to
make a match with something learned.
Logic derived from a bifurcation is only as good as the evidence
showing that no other cases deserve consideration. In this case,
a third case has long since been established.
|
I have no idea what you are talking about.
Bob
--
"Things should be described as simply as possible, but no simpler."
A. Einstein |
|
| Back to top |
|
|
J Ketutsalo
science forum beginner
Joined: 26 Oct 2005
Posts: 6
|
| Posted: Fri Oct 28, 2005 8:21 am Post subject:
Re: how your ears work
|
|
|
StpNrrs@aol.com wrote:
| Quote: |
I think that most theorists are confusing themselves with the idea of
building an 'artifical ear' that can hear by itself, which could be
perhaps plugged into the brain to cure deafness.
|
I don't know any theorist who would claim things are that simple.
| Quote: | Human ears don't hear
- they channel air pressure variations into the cochlea. The
hair-cells transduce these pressure variations into electrical impulses
which travel along the aural nerve.
|
This reminded me of cochlear implants which exist and work. The implants
transduce the sound arriving to the ears to electrical pulses that
stimulate the auditory nerve. A deaf child receiving such an implant
will learn to hear (although not as well as with normal hearing) and
speak. However, an adult might not learn to understand speech unless
deafened after learning the ability naturally.
| Quote: | The aural nerve acts as a delay
line, containing about a 25th of a second's worth of information at any
one time.
|
The auditory nerve does not preserve any information. True, it takes a
finite time for the sound to travel through the nerve, but the brain
cannot sample what is in the middle. 25th of a second sounds like a time
when the information is well beyond the auditory nerve but has not
reached the cortex, yet. At these intermediate stages some past
information is available.
| Quote: | The brain matches features and patterns in the information
on the aural nerve against remembered information patterns (from
previously heard sounds) to produce the sensation of hearing.
|
On this I can agree. |
|
| Back to top |
|
|
Matthew Fields
science forum Guru Wannabe
Joined: 26 Oct 2005
Posts: 200
|
| Posted: Fri Oct 28, 2005 2:12 pm Post subject:
Re: how your ears work
|
|
|
In article <djshj7013ls@enews2.newsguy.com>,
Bob Cain <arcane@arcanemethods.com> wrote:
| Quote: |
Matthew Fields wrote:
In article <djrqvo0sr6@enews1.newsguy.com>,
Bob Cain <arcane@arcanemethods.com> wrote:
Matthew Fields wrote:
In article <djrf3p0hu4@enews1.newsguy.com>,
Bob Cain <arcane@arcanemethods.com> wrote:
Does this not imply that the ear/brain could match sounds based
partially on their containing Fourier components higher in frequency
than what they can detect as pure sinusoids (the way hearing bandwidth
and sensitivity are commonly measured)?
No. If you'd like to explain how you got there, let us know.
Were there no intrinisc decomposition by frequency at the ear, just an
associative mechanism that matches learned patterns of cochlear
excitation with semantics,
Very odd sort of bifurcation.
The decomposition is in the brain, not the ear.
So you think that decomposition by frequency is done by a neural
structure predicated by the genes? I.e., it is standard equipment and
not built by experience?
|
Yes. But it's not done in the cochlea, and there's no requirement for
it to be anywhere as straightforward a thing as a Fourrier transform.
| Quote: | The associative pattern-matching is in a different section of the brain.
then one might not hear a high frequency
sinusoid whose presence as a Fourier component might be necessary to
make a match with something learned.
Logic derived from a bifurcation is only as good as the evidence
showing that no other cases deserve consideration. In this case,
a third case has long since been established.
I have no idea what you are talking about.
|
The third case is that a frequency-corrolated neurology has been
established to exist hardwired, but it's not in the cochlea.
--
Matthew H. Fields http://www.umich.edu/~fields
Music: Splendor in Sound
To be great, do better and better. Don't wait for talent: no such thing.
Brights have a naturalistic world-view. http://www.the-brights.net/ |
|
| Back to top |
|
|
Google
|
|
| Back to top |
|
|
|
|
The time now is Sat Jan 10, 2009 12:06 am | All times are GMT
|
|
Bankruptcy | Guitar Lessons | Loans | Online Loans | Fantasy Football News
|
|
Copyright © 2004-2005 DeniX Solutions SRL
|
|
Other DeniX Solutions sites:
Electronics forum |
Medicine forum |
Unix/Linux blog |
Unix/Linux documentation |
Unix/Linux forums
|
Powered by phpBB © 2001, 2005 phpBB Group
|
|
FAQ
Search
Memberlist
Usergroups
Register
Profile
Log in to check your private messages
Log in
Forum index
»
Science and Technology
»
Physics
»
Acoustics
