hearing There’s an “Inverse Piano” in Your Head

[mevdinc]

A fascinating article on how our ears process sound.
 

Apparently there's a builtin amplifier in our ears which does active processing of sound.
I saw this posted on Twitter by Bill Armstrong @Bil_Arm).

Here's the link.
https://www.scientificamerican.com/article/theres-an-inverse-piano-in-your-head/

[Audiophile Neuroscience]

It has been said that the outer ear (pinna) and middle ear (little bones hammer, anvil and stirrup) can amplify sounds by about 20dB. It appears the inner ear (cochlea) hair cell oscillations may amplify another 20 - 50dB (if my maths is close to correct).

 

The even more exciting research alluded to in the article is potential drug therapy or localised gene therapy to restore the hair cell transducers in the inner ear. These can be lost  with aging/noise etc, leading to presbycusis, a type of  sensorineural hearing loss)

[Audiophile Neuroscience]

I like Hudspeth's view of science " “Yes, science is the disinterested investigation into the nature of things. But it is more like art than not. It’s something that one does for the beauty of it, and in the hope of understanding what has heretofore been hidden."  Imagination to discover things rather than just using science to affirm the known, or worse, to assert the impossible.

[AnotherSpin]

33 minutes ago, Audiophile Neuroscience said:

I like Hudspeth's view of science " “Yes, science is the disinterested investigation into the nature of things. But it is more like art than not. It’s something that one does for the beauty of it, and in the hope of understanding what has heretofore been hidden."  Imagination to discover things rather than just using science to affirm the known, or worse, to assert the impossible.

 

Science is an offhand way to claim the knowledge of a nature of things

[Audiophile Neuroscience]

20 minutes ago, AnotherSpin said:

 

Science is an offhand way to claim the knowledge of a nature of things

 

Only if your name begins with Ralph....

[AnotherSpin]

42 minutes ago, Audiophile Neuroscience said:

 

Only if your name begins with Ralph....

 

Who's Ralph?

[sphinxsix]

I think this article has been written by @Ralf11 ,, it starts with his avatar/profile photo

Well done, Ralph!

BTW why a guinea pig's cochlea.?

[look&listen]

1 hour ago, sphinxsix said:

I think this article has been written by

 

8 hours ago, Audiophile Neuroscience said:

I like Hudspeth's view of science " “Yes, science is the disinterested investigation into the nature of things. But it is more like art than not. It’s something that one does for the beauty of it, and in the hope of understanding what has heretofore been hidden."  Imagination to discover things rather than just using science to affirm the known, or worse, to assert the impossible".

Me also, but that is NOT Ralf11 !!

[sphinxsix]

2 hours ago, look&listen said:

Me also, but that is NOT Ralf11 !!

I want to hear it from Ralf himself

 

[Ralf11]

there is an art to doing science, yes

 

a buddy has a quote from Henri Poincare on his Emails that is most xlnt - I'll try to dig it up

 

guinea pigs are easy to maintain in a lab 

 

I used to have a nice s.e.m. of damaged hair cell clusters - maybe have time to dig for that too...

 

AN's summary above seems about right; need to read that article to see if it's anything new

 

an inverse piano would be a harpischord, right?

[Ralf11]

just starting a book on Film Criticism and the guy starts off with a survey of art criticism (he begins with Aristotle) - apparently everything is art now (as the producer to work link has been surpassed by the work to consumer link - Denise Levertov summed it all up in a poem)

[Ralf11]

damn - that was a short article

 

Rocky U. has a lot of stuff going on re sensory systems both there and nearby - Monell Chemical Senses center is not too far away

 

all the sensory stuff is a bit of a sideline for me - if I was still coupled into the "electric-cooled pony harness"* of academia I'd be trying to deploy grad. students in that direction tho...

 

Vision is a more interesting sensory modality tho; not to mention what is the real benefit of cognition? 

 

 

*sensu Zappa, 1971

[NOMBEDES]

11 hours ago, Audiophile Neuroscience said:

It has been said that the outer ear (pinna) and middle ear (little bones hammer, anvil and stirrup) can amplify sounds by about 20dB. It appears the inner ear (cochlea) hair cell oscillations may amplify another 20 - 50dB (if my maths is close to correct).

 

The even more exciting research alluded to in the article is potential drug therapy or localised gene therapy to restore the hair cell transducers in the inner ear. These can be lost  with aging/noise etc, leading to presbycusis, a type of  sensorineural hearing loss)

 

I bought a small amount of OTIC at $5.50.   It has not hit $5.50 since the day I bought it. (how sad) That said, this is what is known as a flyer.  If they develop a drug that can help with Tinnitus or restore age related hearing problems......big if.....why I might make a few bucks.

[Ralf11]

to AN's amplification comment ...

 

the ear is so sensitive that it is very near the noise floor set by air molecules bouncing off the ear drum

 

so... further evolution in that specific direction is not possible; at different frequencies or with some real fancy processing (RFP).. sure

[Audiophile Neuroscience]

3 hours ago, Ralf11 said:

to AN's amplification comment ...

 

the ear is so sensitive that it is very near the noise floor set by air molecules bouncing off the ear drum

 

so... further evolution in that specific direction is not possible; at different frequencies or with some real fancy processing (RFP).. sure

 

ralph are you talking about S/N ratio or signal amplification.

 

The article says ( in relation to the cochlea hair cells I presume) "In the case of our ears , the sound that goes into the ear is actually mechanically amplified by the ear, and the amplification is between 100- and 1,000-fold. It’s quite profound. And the active process also sharpens the tuning of hearing, so that we can distinguish frequencies that are only about 0.1 percent apart. By comparison, two keys on a piano are 6 percent apart."

[Kal Rubinson]

15 hours ago, Audiophile Neuroscience said:

It has been said that the outer ear (pinna) and middle ear (little bones hammer, anvil and stirrup) can amplify sounds by about 20dB.

The pinna is directionally selective and the auditory meatus is a tuned pipe.  The middle ear operates as an impedance transformer.  Amplification is probably not the right term for their operations. 

 

15 hours ago, Audiophile Neuroscience said:

It appears the inner ear (cochlea) hair cell oscillations may amplify another 20 - 50dB (if my maths is close to correct).

That is another story.

[Ralf11]

I think the "amplification" usually discussed is the mechanical ... ah... boost by the 3 little bones (hammer/anvil/stirrup) or... <Latin>

 

Art Benade's book discusses tuned pipes in horrifying detail (but not any ears - all on instruments)

[Kal Rubinson]

1 hour ago, Ralf11 said:

I think the "amplification" usually discussed is the mechanical ... ah... boost by the 3 little bones (hammer/anvil/stirrup) or... <Latin>

Think of the bony levers and the difference in the area of the tympanic membrane vs. that of the oval window as acting as a transformer.  An electrical transformer exchanges voltage and current while the middle ear exchanges pressure and force.

http://audilab.bmed.mcgill.ca/AudiLab/private/ghosh/chap3_r2.htm

[Audiophile Neuroscience]

3 hours ago, Kal Rubinson said:

The pinna is directionally selective and the auditory meatus is a tuned pipe.  The middle ear operates as an impedance transformer.  Amplification is probably not the right term for their operations. 

 

Apart from HRTF "The pinna collects more sound energy than the ear canal would receive without it and thus contributes some area amplification. The structures of the outer and middle ear .....can be considered both a pre-amplifier and limiter for the human hearing process. ....The outer and middle eears contribute something like a facor of 100 or about 20dB of amplification"

http://hyperphysics.phy-astr.gsu.edu/hbase/sound/earsens.html#c1

 

 

 

The first 2 hits on google on ear amplification....

 

 

When the eardrum vibrates, the sound waves travel via the hammer and anvil to the stirrup and then on to the oval window. When the sound waves are transmitted from the eardrum to the oval window, the middle ear is functioning as an acoustic transformer amplifying the sound waves before they move on into the inner ear.

The middle ear – parts and functions of the middle ear | Anatomy

https://www.hear-it.org/The-middle-ear-1

 

 

Which part of the human ear amplifies sound?

The Outer Ear. The auricle (pinna) is the visible portion of the outer ear. It collects sound waves and channels them into the ear canal (external auditory meatus), where the sound is amplified.

How the Ear Works | Johns Hopkins Medicine Health Library

https://www.hopkinsmedicine.org/.../specialty.../hearing/hearing.../how-the-ear-works.ht...

[Ralf11]

ossicles shown here:

 

http://www.jugosparabajardepeso.info/organdiagram/17398-17399

 

 

[Audiophile Neuroscience]

 

[Ralf11]

it's like an FFT - inside your head ~!

[Kal Rubinson]

10 hours ago, Audiophile Neuroscience said:

Apart from HRTF "The pinna collects more sound energy than the ear canal would receive without it and thus contributes some area amplification.

........................................

The first 2 hits on google on ear amplification....

........................................

When the eardrum vibrates, the sound waves travel via the hammer and anvil to the stirrup and then on to the oval window. When the sound waves are transmitted from the eardrum to the oval window, the middle ear is functioning as an acoustic transformer amplifying the sound waves before they move on into the inner ear.

........................................................

Which part of the human ear amplifies sound?

The Outer Ear. The auricle (pinna) is the visible portion of the outer ear. It collects sound waves and channels them into the ear canal (external auditory meatus), where the sound is amplified.

Yadda, yadda.  The use of the term "amplification" in these instances is convenient but less than accurate.    Most of these phenomena involve (1) processes that are physically more efficient (pinna),  more efficient at certain frequencies (external meatus), less lossy at certain frequencies and/or transform one form of energy with another (middle ear).  AFAIK, all the energy conveyed through the outer and middle ear comes from the external world and there is no increase in energy (which would have to come from some other source) in any of those processes.  I guess most find it is easier to say "amplify" than to explain impedance transformation.  

 

Just being didactic.

[Audiophile Neuroscience]

17 hours ago, Kal Rubinson said:

Yadda, yadda.  The use of the term "amplification" in these instances is convenient but less than accurate.    Most of these phenomena involve (1) processes that are physically more efficient (pinna),  more efficient at certain frequencies (external meatus), less lossy at certain frequencies and/or transform one form of energy with another (middle ear).  AFAIK, all the energy conveyed through the outer and middle ear comes from the external world and there is no increase in energy (which would have to come from some other source) in any of those processes.  I guess most find it is easier to say "amplify" than to explain impedance transformation.  

 

Just being didactic.

 

Its ok to be didactic if you are correct.

 

I think we need a little more evidence than "yadda, yadda", "AFAIK" and "I guess".

In the three references I provided the physicists, hopkinsmedicine and hearit.org, you assume they didn't actually mean amplification. I assume they did unless there is contrary evidence.

 

I am not suggesting that amplification in the outer or middle ear breaks the first law of thermodynamics.Without going into the possible mechanics of how it is achieved - if indeed there is an increase in measurable dB, then amplification has occurred, not just reduced losses or impedance transformation.

 

 

 

 

[Kal Rubinson]

5 hours ago, Audiophile Neuroscience said:

I am not suggesting that amplification in the outer or middle ear breaks the first law of thermodynamics.Without going into the possible mechanics of how it is achieved - if indeed there is an increase in measurable dB, then amplification has occurred, not just reduced losses or impedance transformation.

Would you think of a transformer as an audio amplifier even though it can increase the voltage by a measurable number of dB but with the commensurate dB loss in current?   So, to quote one of your references: "the middle ear is functioning as an acoustic transformer amplifying the sound waves before they move on into the inner ear."  I added the underline to indicate that the writers do understand the issue but choose to use the more readily understood term "amplifying" creating documents like this for the general public.  

 

In the example of the middle ear transfer function, pressure is "amplified" (by about 28dB) but at the expense of force in order to maximize the transfer of energy (or minimize the loss) as it is passed from the air in the external meatus to the liquid endolympth in the cochlea.  The transfer of energy from a low density to a relatively higher density medium would otherwise be very lossy (think of how the noises of the beach are muted when you submerge in the surf). 

 

Again, I refer you to a text that is written more rigorously for scientists where you will see that the use of the term "amplify" is used much more conservatively:  http://audilab.bmed.mcgill.ca/AudiLab/private/ghosh/chap3_r2.htm