Is what mentioned in this paper real?

[JRS]

RE ultrasonic hearing - the ability of humans to hear or directly "detect" ultrasonic frequencies: @pozz is absolutely correct, The only source for this is the discredited and never-replicated Oohashi "hypersonic effect" study. It's nonsense - and if you come across an audiophile or hi-fi vendor claim that humans can hear ultrasonics and that claim references any source, that source is either Oohashi or another source which in turn relies on Oohashi and nothing else.

Interesting. A p value of 0.001 can't be blown off, and so there was definitely neurological cause that preferentially attacked white matter. Certainly hysteria can't be invoked, leaving one with 2 or 3 to choose from. Given the locations of the reports it is hard not to believe there is a political correlation. Beyond that who knows. Certainly, the US is not above suspicion given it's history, but that's a bit too far down the rabbit hole to go. The only other plausible mechanism is a neurotoxin and there are no shortage of chemicals that preferentially cause hearing damage, but that's more at the transduction end of things, and not involving swaths of inter-hemispherical white matter (cabling connecting brain regions). It's a puzzle.

 

[pozz]

I would have thought that the cochlear can vibrate at ultrasonic frequencies as much as it likes, but if there are no hairs active at those frequencies nothing gets to the auditory nerve for normal hearing of those frequencies to take place. You'd need to establish some other route to stimulation of nerves for it to work.

On top of that the nerves themselves have to be ready to react to that particular signal. That's the tonotopic organization of the brain, seen in all aspects of auditory processing.

William Yost, another researcher, studied ultrasonic perception in animals. His theory was that their very wide range of hearing >20kHz is actually a tradeoff for lacking processing power (can't remember the exact term he used). They hear higher, but at the cost of much wider critical bands, which provides greater range of energy for activation. So far less efficient than the human brain in that sense.

 

[Galliardist]

Odd you shpuld mention that: just today I was listening to a podcast talking about the beyond audibility of many hi-res specs, and the only material that could be reliably perceived as sounding different when fc was raised from 20 to 30kHz was weird music using gamelan triangles. Apparently they generate some bad-assed harmonics.

Which podcast? (not that I'll have time to listen for a while)? I'm a bit wary of this, would like to see whether the information comes from the same source I remember looking at. If it's above 20kHz, though, I'd venture that it is not being "heard" in the sense of going through the ear into the auditory nerve in the expected way for sound.

 

[kyle_neuron]

It seems the idea is plausible.

(PDF) Theory and design of an ultrasound loudspeaker

PDF | The design of directive loudspeakers is a challenge fortraditional techniques because it implies big speakers dueto the sound wavelength. In this... | Find, read and cite all the research you need on ResearchGate

www.researchgate.net

(PDF) On Cuba, diplomats, ultrasound, and intermodulation distortion

PDF | This paper analyzes how ultrasounds could have unintentionally led to the AP news recordings of metallic sounds heard by diplomats in Cuba.... | Find, read and cite all the research you need on ResearchGate

www.researchgate.net

The “Cuba” thing is disproven, yet still interesting in principle. The topic has been investigated by Steve Goodman (author of the Sonic Warfare book and part of the AUDINT experimental sound collective) and despite the apparent plausibility of the 'attack', the actual effect would need to work through many layers of dense wall material.

There are parents for ultrasonic advertising systems, but none implemented physically yet that I'm aware of.

I think the bigger concern is being told to buy a TV as you walk past a shop window, rather than having mind control beamed into your brain from 50 miles away...

 

[JRS]

Which podcast? (not that I'll have time to listen for a while)? I'm a bit wary of this, would like to see whether the information comes from the same source I remember looking at. If it's above 20kHz, though, I'd venture that it is not being "heard" in the sense of going through the ear into the auditory nerve in the expected way for sound.

I'd have to look for the secondary source--who I am referencing is Mark Waldrep, a dyed-in-the-wool skeptic when in comes to high resolution sources and recordings. He consistently derides MQA and in his book repeatedly asserts that the Redbook standard is beyond human perception with two exceptions: the usefulness of having 24 bits available when recording ultrawide dynamic range content and you want to keep everything in the comfortably safe zone, and 2) that there is material--i.e. the triangles which have been reliably perceived, that would be cut off by the brick wall filter (iirc he refers to them as weird ultrasonic harmonics).

Now what is interesting is that the sounds were not perceived as such, but instead added something intangible to the music which was notable when absent. He isn't suggesting that as a result we should change any recording standards or rewrite any acoustic textbooks--just that this appeared to be the only legitimate example in audio where ultrasonic perception has been demonstrated. This guy is on our side, so I see no reason to doubt the veracity of the report. The only other reason for extending bandwidth is in his opinion to allow for a gentler HF rolloff that could be done say at 24k--and even then he sees no compelling need for 99..9% of music, the exception being with symphonic music on occasion and when a lot of HF percussive sources like cymbals are present.
Source: Music_and_Audio_A_User_Guide_To_Better_Sound. Waldrep, Mark