What the medical profession has to say about inaudible frequencies

[sal]

Interesting read. Take it for what it's worth. Didn't dig too deep into related articles

https://pubmed.ncbi.nlm.nih.gov/10848570/

https://pubmed.ncbi.nlm.nih.gov/28203213/

 

[pozz]

Oohashi et al have been debunked. They did not control for intermodulation.

There are multiple references to this article across ASR if you're interested.

 

[sal]

Certainly. I’m not promoting a viewpoint here. Though it is interesting to see how they perform these studies

 

[pozz]

This is less for you @sal than for others looking in.

Starting from lecture 14, this series of lectures is by an ENT specialist and researcher: https://ocw.mit.edu/courses/brain-a...-04-sensory-systems-fall-2013/lecture-videos/ If you get far enough into them you'll note that his method of presentation is to correlate psychophysical research based on subjective responses to what is known of anatomy and brain function. The major issue with claiming ultrasonics are audible is that they have no sensory pathway. This is on top of the difficulty in getting the signal chain to reproduce them correctly.

 

[sal]

I'll try to make it through those videos It did get me thinking though. How gas can a neuron fire? Even if the ear could transmit those frequencies, could the brain process it anyway.

https://aiimpacts.org/rate-of-neuron-firing/

Turns out a neuron can fire every 0.16 seconds on average, that likely varies from person to person. And the sheer amount of neurons in the brain suggests that the brain could process a lot more audio data than we can hear. Was also curious as to the frequency response/sampling rate (or equivalent measurements) of the nerves between your ears and the brain. Quickly got lost in some medical jargon that I don't understand

Again, this is going to vary from person to person and degrade with age (as with everything else). Wondering if there are any easily digestible studies around this

 

[sal]

This is less for you @sal than for others looking in.

Starting from lecture 14, this series of lectures is by an ENT specialist and researcher: https://ocw.mit.edu/courses/brain-a...-04-sensory-systems-fall-2013/lecture-videos/ If you get far enough into them you'll note that his method of presentation is to correlate psychophysical research based on subjective responses to what is known of anatomy and brain function. The major issue with claiming ultrasonics are audible is that they have no sensory pathway. This is on top of the difficulty in getting the signal chain to reproduce them correctly.

What is also interesting, as that we still don't know what the type 2 audio nerves are for.

 

[pozz]

I'll try to make it through those videos It did get me thinking though. How gas can a neuron fire? Even if the ear could transmit those frequencies, could the brain process it anyway.

https://aiimpacts.org/rate-of-neuron-firing/

Turns out a neuron can fire every 0.16 seconds on average, that likely varies from person to person. And the sheer amount of neurons in the brain suggests that the brain could process a lot more audio data than we can hear. Was also curious as to the frequency response/sampling rate (or equivalent measurements) of the nerves between your ears and the brain. Quickly got lost in some medical jargon that I don't understand

Again, this is going to vary from person to person and degrade with age (as with everything else). Wondering if there are any easily digestible studies around this

This is pretty complicated. There is actual firing and then there are preparatory states, saturation, feedforward, feedback, and so many other structural aspects of the brain I glancingly understand. These firing rates over time are also not intuitive (like if you look at phase locking), since they don't match the physical waveform.

 

[Kal Rubinson]

Turns out a neuron can fire every 0.16 seconds on average, that likely varies from person to person.

It varies from neuron to neuron depending on its receptors, membrane channels and resting potential.

Was also curious as to the frequency response/sampling rate (or equivalent measurements) of the nerves between your ears and the brain.

Pretty much the same range.

This is pretty complicated. There is actual firing and then there are preparatory states, saturation, feedforward, feedback, and so many other structural aspects of the brain I glancingly understand. These firing rates over time are also not intuitive (like if you look at phase locking), since they don't match the physical waveform.

There are many signal coding mechanisms.

 

[Wes]

lossy ones too

 

[Kal Rubinson]

lossy ones too

Without doubt.

 

[CMOT]

It varies from neuron to neuron depending on its receptors, membrane channels and resting potential.

Pretty much the same range.

There are many signal coding mechanisms.

Raw firing rate isn't always (or often) the relevant parameter when talking about the auditory system and timing. There is a thing called delay lines:

https://en.wikipedia.org/wiki/Coincidence_detection_in_neurobiology

This is how "Bats can separately perceive the delays of two concurrent electronically generated echoes arriving as little as 2 μs apart"
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC22885/

Humans definitely have something similar for computing the difference in arrival time between the two ears. And delay lines might be in play for other components of auditory processing as well.

 

[CMOT]

Oohashi et al have been debunked. They did not control for intermodulation.

There are multiple references to this article across ASR if you're interested.

Hah! hadn't seen this yet, but had an audition expert look at the paper - they pointed out that there are definitely some signal differences (probably due to the filtering) below 26 khz. (we verified using an overlay of the two signal plots). Plus it is not that rare to have some individuals who can hear signals above 20khz, so there could have been effects from that as well...

 

[Kal Rubinson]

Raw firing rate isn't always (or often) the relevant parameter when talking about the auditory system and timing. There is a thing called delay lines:

https://en.wikipedia.org/wiki/Coincidence_detection_in_neurobiology

This is how "Bats can separately perceive the delays of two concurrent electronically generated echoes arriving as little as 2 μs apart"
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC22885/

Humans definitely have something similar for computing the difference in arrival time between the two ears. And delay lines might be in play for other components of auditory processing as well.

Indeed. We have such mechanisms at many loci from the Superior Olive (both parts) up to the primary sensory cortex. My previous smiley was intended to emphasize the multiplicity of coding mechanisms.

 

[CMOT]

Yes. Plus bats are really cool....

 

[Jim Matthews]

https://aiimpacts.org/rate-of-neuron-firing/

Turns out a neuron can fire every 0.16 seconds on average, that likely varies from person to person. And the sheer amount of neurons in the brain suggests that the brain could process a lot more audio data than we can hear.

I think this is far more Important regarding our generational "taste" as we age than most care to admit. I have always suspected that I can't process any music that charts out above 100 bpm.

I just can't keep up when "the changes" happen faster than I can register the previous chord. My favorite composers do surprising things a split second before I catch on.

Perhaps this is why electronica leaves me cold and Jimmy McGriff is an endless delight. Apparently, I'm 50 years behind The Times.

 

[Kal Rubinson]

Yes. Plus bats are really cool....

Not so much in the past year or so.............

 

[sal]

I think this is far more Important regarding our generational "taste" as we age than most care to admit. I have always suspected that I can't process any music that charts out above 100 bpm.

I just can't keep up when "the changes" happen faster than I can register the previous chord. My favorite composers do surprising things a split second before I catch on.

Perhaps this is why electronica leaves me cold and Jimmy McGriff is an endless delight. Apparently, I'm 50 years behind The Times.

yes. I an relate to this.

on a somewhat related note. I do see a lot data on frequency and volume sensitivity, but don’t hear too much about transience, or ability to hear detail. Obviously music is not expressed in a sine wave, though any instance of the waveform can be expressed as frequency. in my head this equates to a sample rate. Not sure if that is the correct analogy. I other words, what’s the smallest detectable instance of a wave form

 

[sal]

Not so much in the past year or so.............

Meh, I don’t buy that explanation for a minute

 

[CMOT]

Not so much in the past year or so.............

The interesting thing is why bats carry so many viruses that might be bad for humans. Bats have an incredibly high metabolism because of flying so they apparently can fend off/live with all sorts of viruses that are bad for the rest of us. So they are virus “reservoirs”. And they are the most numerous mammal in the planet. Just don’t eat them.