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Scientists discover mechanism of hearing

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Re: Scientists discover mechanism of hearing

#41

Post by mjan22640 »

9wzYQbTYsAIc wrote: post #26
1letterunixname wrote: post #24

WHAT?! :> I'm at ACL and can't hear a fucking thing. ;) I wonder about the limits of the muscles of the eardrum (TT and stapedius) to prevent hearing damage. For example, I recall awaking one morning being unable to hear because those muscles were isometrically flexing to a degree that prevented the eardrum from move normally. I thought I lost my hearing but then they started to relax over a few minutes. I don't know…

> I can consciously make both eardrums vibrate creating a sound like a rumble I can as well when I consciously try to pop my ear drums.

To me it sounds like cracking joints. I think everybody can do it but maybe not everybody found out that they can.

Re: Scientists discover mechanism of hearing

#42

Post by 1letterunixname »

soulofmischief wrote: post #34
1letterunixname wrote: post #24

WHAT?! :> I'm at ACL and can't hear a fucking thing. ;) I wonder about the limits of the muscles of the eardrum (TT and stapedius) to prevent hearing damage. For example, I recall awaking one morning being unable to hear because those muscles were isometrically flexing to a degree that prevented the eardrum from move normally. I thought I lost my hearing but then they started to relax over a few minutes. I don't know…

What you hear vibrating is not your ear drums themselves, but is a muscle called the tensor tympani. It aids in dampening loud sounds like chewing or screaming. I can also do this.

Yep, the TT. Thanks for precise elucidation. It's layman's terminology because I'm uncertain of the audience composition as HN has become less Ivy League than it once was.

Re: Scientists discover mechanism of hearing

#43

Post by woojoo666 »

monkeycantype wrote: post #35
tasty_freeze wrote: post #29

Earlier quoted context omitted.

The person you are responding to is right and your assertion is incorrect. The person you replied to knows the ear delivers a frequency domain representation. They were disagreeing with the FFT part. The FFT is a specific mathematical construction that carries out a Fourier Transform efficiently through a hierarchy of "butterfly" steps. The ear has no such thing. It is just ~20,000 hair cells, each resonant to a spec…

I'm wading into an area I'm not expert, not to assert but to ask, I remember having an electro-mechanical object explained to me, I think it was a variant of this: https://www.retrothing.com/2008/05/the-harmonium-a.html I can roughly recall the mechanism by which it worked, and was told that this was an analog for how the Fourier transformation worked, and I vaguely remember going through one on paper. The spiral of…

Fourier transform is different from FFT, which is Fast Fourier Transform. FFT is an optimization that involves decomposing a signal into multiple "smaller" signals, recursively performing FFT on those, and then combining the results.

Re: Scientists discover mechanism of hearing

#44

Post by accountofme »

samatman wrote: post #37
accountofme wrote: post #23

Earlier quoted context omitted.

The brain doesn't compute it, the cochlear is an fft! It is a cone shaped structure (that is curled up) that is covered in hairs and neurons. The fatter end is used for low freq and the thinner end is used for hi freq. So the brain takes audio in the frequency domain, not as continuous samples! (I did an Anatomy degree almost 20years ago now, all from memory)

The accurate way of saying this is that the cochlear does Fourier analysis. Folks around here don't handle ambiguity well, and are treating your comment like it's wrong, rather than basically correct except for a harmless conflation of an algorithm for something with the thing itself. Ah well.

thanks for your reply :)

You are right. My apologies for the conflation.

Re: Scientists discover mechanism of hearing

#45

Post by hoseja »

BurningFrog wrote: post #27
formerly_proven wrote: post #13

Hearing is kind of fascinating if you calculate the power supplied to the eardrum in the ~0 dB range, we're talking about attowatts of sound power generating movements in the single-digit nanometer range, which is still picked up and converted to a neuronal response. Meanwhile the whole thing suppresses the far greater pressure fluctuations due to your heartbeat and other movements quite well, and can reasonably cope…

Our hearing is vastly better than our sight. Human hearing can distinguish thousand of individual frequencies, with the highest frequency 1000x the lowest. Human sight can distinguish 3 broad frequency regions, with the highest frequency 2x the lowest. Where vision shines is distinguishing where the signal comes from.

They are orthogonal. Hearing has phase and continuous wideband frequency information but only two channels. Eyesight has millions of channels but discretized narrowband frequency and no phase information.

A many-channel sense with full frequency, phase, polarization, ... information would presumably be very hard to process usefully.

Re: Scientists discover mechanism of hearing

#46

Post by hoseja »

xani_ wrote: post #18
formerly_proven wrote: post #13

Hearing is kind of fascinating if you calculate the power supplied to the eardrum in the ~0 dB range, we're talking about attowatts of sound power generating movements in the single-digit nanometer range, which is still picked up and converted to a neuronal response. Meanwhile the whole thing suppresses the far greater pressure fluctuations due to your heartbeat and other movements quite well, and can reasonably cope…

And it does FFT in realtime too

In hardware actually.

Re: Scientists discover mechanism of hearing

#47

Post by TaupeRanger »

samatman wrote: post #37
accountofme wrote: post #23

Earlier quoted context omitted.

The brain doesn't compute it, the cochlear is an fft! It is a cone shaped structure (that is curled up) that is covered in hairs and neurons. The fatter end is used for low freq and the thinner end is used for hi freq. So the brain takes audio in the frequency domain, not as continuous samples! (I did an Anatomy degree almost 20years ago now, all from memory)

The accurate way of saying this is that the cochlear does Fourier analysis. Folks around here don't handle ambiguity well, and are treating your comment like it's wrong, rather than basically correct except for a harmless conflation of an algorithm for something with the thing itself. Ah well.

No, that's also not accurate. Words mean things. We know that parts of the cochlea respond to different frequencies, but that does remotely imply that the auditory system is doing Fourier analysis, which is a high level mathematical transform with a specific set of formulations. "Fourier Analysis" does not describe every possible method of extracting frequency content from a signal.

Re: Scientists discover mechanism of hearing

#48

Post by samatman »

TaupeRanger wrote: post #47
samatman wrote: post #37

Earlier quoted context omitted.

The accurate way of saying this is that the cochlear does Fourier analysis. Folks around here don't handle ambiguity well, and are treating your comment like it's wrong, rather than basically correct except for a harmless conflation of an algorithm for something with the thing itself. Ah well.

No, that's also not accurate. Words mean things. We know that parts of the cochlea respond to different frequencies, but that does remotely imply that the auditory system is doing Fourier analysis, which is a high level mathematical transform with a specific set of formulations. "Fourier Analysis" does not describe every possible method of extracting frequency content from a signal.

> Fourier analysis of discharge patterns in response to sinusoidal acoustic stimulation provides a consistent and repeatable measure of response phase and amplitude. The Journal of the Acoustical Society of America 58, 867 (1975); https://doi.org/10.1121/1.380735

> sinusoidal frequency domain decomposition of sound waves is a key mechanical phenomenon exploited by our hearing system, leading to in effect a frequency domain transformation of the temporal pattern of compressions and rarefactions that we term sound. https://uncommondescent.com/video/hearing-the-cochlea-the-fr...

That one has a video.

Your case is roughly as incoherent as one which claims that a thrown ball does not perform Newtonian physics. It doesn't have to.

Now that we've disposed of the nonsense that cochlear response is not meaningfully modeled with Fourier analysis, interested parties might have fun with research into all the ways this model is not perfect. I've got a paper loaded in my reader claiming it's actually wavelet analysis, for when I have time and inclination to read it.

Re: Scientists discover mechanism of hearing

#49

Post by djyaz1200 »

BurningFrog wrote: post #27
formerly_proven wrote: post #13

Hearing is kind of fascinating if you calculate the power supplied to the eardrum in the ~0 dB range, we're talking about attowatts of sound power generating movements in the single-digit nanometer range, which is still picked up and converted to a neuronal response. Meanwhile the whole thing suppresses the far greater pressure fluctuations due to your heartbeat and other movements quite well, and can reasonably cope…

Our hearing is vastly better than our sight. Human hearing can distinguish thousand of individual frequencies, with the highest frequency 1000x the lowest. Human sight can distinguish 3 broad frequency regions, with the highest frequency 2x the lowest. Where vision shines is distinguishing where the signal comes from.

Pro DJ here... Agree with the rest of your comment except for... "Where vision shines is distinguishing where the signal comes from."

Suggest closing your eyes and having someone else snap their fingers around you, you'll know immediately where that sound came from. This is accomplished by your mind differentiating the slight time difference between when your left and right ear register the noise as well as the volume difference.

This innate ability can be developed by DJ's to take two songs playing at different speeds and speed or slow them down to match. This is called "beat matching" and before software made this more accessible (aka more automated) it was the key skill necessary for DJ'ing as it allows seamless transitions between songs.

I still find your comment insightful and interesting, I just had to nitpick that one part.

Cheers

Re: Scientists discover mechanism of hearing

#50

Post by musicale »

woojoo666 wrote: post #43
monkeycantype wrote: post #35

Earlier quoted context omitted.

I'm wading into an area I'm not expert, not to assert but to ask, I remember having an electro-mechanical object explained to me, I think it was a variant of this: https://www.retrothing.com/2008/05/the-harmonium-a.html I can roughly recall the mechanism by which it worked, and was told that this was an analog for how the Fourier transformation worked, and I vaguely remember going through one on paper. The spiral of…

Fourier transform is different from FFT, which is Fast Fourier Transform. FFT is an optimization that involves decomposing a signal into multiple "smaller" signals, recursively performing FFT on those, and then combining the results.

s/FF/F/
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