Interesting video from Dave Rat:
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Interesting. Maybe the occiput works as an amplifier/resonator, which is detected by the part of the brain that interprets sound?
aliasing? ( i guess its not just a mirror on the left)
he should show a fft analyzer to visualize the full spectrum
to see if its recognized by the ears or the skull, let the contestant wear some earplugs.
but this discussion about the importance of frequencies beyond 20k for high end listening is very esoteric. in normal music, signals above 20k just contains some cymbal crashes from drums etc. just take a 96khz recording, high pass it at 20k and tune it down 1 octave (play it at half speed). you will hear just some sizzeling. you miss nothing, when you āonlyā record up to 20khz. higher frequencies though can be used to shape ditheringnoise and get better dynamics when going down in word length.
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No. Thereās no reason to believe humans can do that.
Research into things like this should be properly double-blinded to prevent knowledge from the experimenter somehow influencing the perception of the subject.
Also, getting the setup for such an experiment right is hard. For example because most equipment is not designed to handle playback of high-frequency signals beyond human hearing correctly.
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Yeah, Iād want to see the spectrum of that mic. Just because it looks a bit like like 40kHz sine doesnāt mean there arenāt tones in the audible range. The main carrier could be very loud and so we wouldnāt see the lower frequency tones in the waveform.
why hear above 20 kHz ?
in other words ā why be like bats ?
weāve already got coronavirus from them, and it does not go well.
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you would never hear 30KHz but a tiny amount of distorsion on the playback chain could lead to cross modulation and produce frequencies in the audible rangeā¦
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From the comments on the video it seems that bone conductance is a theory, Iād have thought that the frequency would be too high to cause vibration of bone though?
Can anyone else hear strobe lights fire? I can hear them from a distance, sometimes as much as several blocks away. Iām referring to non-LED strobes.
Similar idea to using binaural beats to make 7hz perceptible.
Hmm, frequency following could be at play here, but I wonder what mechanism in the skull/brain would be perceiving 40khz?
I lost the ability to hear above 18kHz at least quite a while ago, but if you point something like that at my ear I definitely think I (and others) could feel it if the amplitude is high enough. Itās almost like some kind of nausea when Iāve tried similar with a signal generator in the past.
The same way you can feel 0.001Hz at high amplitude, or āwindā as it is more commonly known. 
On the flipside to that though, at ānormalā audio volumes, or within an audio mix I donāt think you can hear it at all.
I donāt worry about it and still use the 44.1 kHz sample rate.
But recording with 32 bit float is way more interesting. Really next level 
in the youtube comments the tester answered, that the signal could also be feeled with plugs in the ears of the contestant. so its not the ears, that can sense above 20k, its something else. strange ā¦
Similar. I think the very purpose of this type of speaker he has is to modulate the carrier frequency of 40kHz in order to make super-directional sound in the audible frequency range. He just says he is not actually modulating with anything, so itās just the 40kHz carrier. Iām suspicious of that. Not that he is lying, but that thereās something going on he doesnāt know about.
Itās so unscientific that having a conversation about it is pretty pointless.
if you apply non linear distorsion to a complex signal containing frequency above 20kHz, due to intermodulation distorsion you can tottally get frequency content under 20kHz, and consequently you would hear it.
what i am saying regarding this experiment is that if the original >20khz sine wave reach the ear of the tester in its immacculate sine wave form, he would never ear it. but there are so many ways to distort, produce harmonical content, add noise ā¦ and then intermodulation in this signal chain (from the source to the internal ear of the listener) that i believe that thz only thing that can be audible is result of distorsion, <20khz
imho of course 
what is that? i never heard about it
Canāt skin act as a receptor as well?
We feel a slight wind, maybe small hair can catch some inaudible vibrations of air pressureā¦
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definitely! We can also reprogram our senses. I once saw a documentation about a blind guy who built himself an interface to āseeā with his skin and he said he uses it just like any other sense. I think this whole biohacking science is super interesting. Looking forward to injecting some shroom DNA and get super powers 
2 tones slightly out of tune with one another can be used to create phase cancellation if played simultaneously. Youāll hear the ābeatsā of the phase cancellation.
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