But that isn’t the question. The question is can we perceive frequencies < 20Hz, and that’s already proven by tuning techniques: you tune out the difference tones until they go to 0Hz. You then asked me a meaningless question about whether I was confusing frequencies with frequency differences, which I’m not, as both are frequencies.
Mark Tillotson said:
All frequencies of electromagnetic wave can be perceived if powerful enough to heat tissue (or cause corona discharge or ionization!).
https://en.wikipedia.org/wiki/Directed-energy_weapon
All frequencies of electromagnetic wave can be perceived if powerful enough to heat tissue (or cause corona discharge or ionization!).
https://en.wikipedia.org/wiki/Directed-energy_weapon
I'd really like to do a THD test at about 12kHz. 12k most can hear, it's 2nd harmonic at 24k almost no one can 'hear'.
Can we hear a difference between a 10% thd 12k and a 0.01% thd 12k sine wave? Given IMD is zero I say we probably can but honestly I don't know.
Now I wonder if the brain's perception process could create percieved intermodulation products. As such we could deffinately sense 20k and beyond through their IMD components in the lower frequency range.
Can we hear a difference between a 10% thd 12k and a 0.01% thd 12k sine wave? Given IMD is zero I say we probably can but honestly I don't know.
Now I wonder if the brain's perception process could create percieved intermodulation products. As such we could deffinately sense 20k and beyond through their IMD components in the lower frequency range.
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You keep saying this, but you don’t tell us what the ‘confusion’ consists of Both are measured in Hz, so both are frequencies, so there aren’t two distinct things to be confused. As to whether we can perceive frequency differences, that is already proven by tuning. I’m at a loss to understand your point.
THD and IMD are due to nonlinearity. If there is x amount of THD, there will be non-zero IMD.
And if there is x amount of THD at 12k, there will be THD at lower frequencies, too. Unless you split bands, add distortion to a certain band, then combine them, which is a very special case.
Allow me to draw to your attention to a novel mechanism for high frequency and ultrasonic hearing:
https://www.tinnitusjournal.com/art...-for-highfrequency-and-ultrasonic-hearing.pdf
The suggestion is that the eye acts as an acoustic lens that passes frequencies beyond the impedance-matching capacity of the eardrum to the inner ear.
Hence airborne ultrasound passes through the eyes which become windows to the inner ear and extend the upper range of human hearing.
Perhaps this novel mechanism is the reason why my hi-fi sounds better when I remove my spectacles! 🤓
https://www.tinnitusjournal.com/art...-for-highfrequency-and-ultrasonic-hearing.pdf
The suggestion is that the eye acts as an acoustic lens that passes frequencies beyond the impedance-matching capacity of the eardrum to the inner ear.
Hence airborne ultrasound passes through the eyes which become windows to the inner ear and extend the upper range of human hearing.
Perhaps this novel mechanism is the reason why my hi-fi sounds better when I remove my spectacles! 🤓
This is an interesting idea, and I like entertaining interesting ideas even if they go against popular wisdom. As far as 'frequency' is a statement of how often something repeats, this seems correct in a broadly technical sense. A pattern of air pressure changes may undergo a full cycle 5 times per second, but we hear it clearly because the cycle contains something more complex than a sine wave. (How does the ear learn to discern sine waves or tonal purity, anyway?)
The lowest octave of a piano consists almost entirely of harmonics and almost no fundamental. However, for us 'musical' types, the perceived frequency may be roughly the gap between individual harmonics. The initial dull thud of the felt hammers is what moves most of the air in a smooth sweeping motion known as bass.
On the other hand, playing 2 notes that are 1 semitone apart may create a fast tremolo or beat frequency. I usually wouldn't count that as 'bass', unless there's also some special effect going on, leading to perception of 'bassiness'. Distortion effects might do that.
Let me rephrase: suppose IMD is zero (which obviously is impossible) could we perceive the supersonic harmonics of a X%THD 12kHz sine wave?
Or is perhaps the only way we can perceive supersonic components through the intermodulation products in the sonic range?
I think it is physically impossible to have zero IMD and x% THD.
Probably you are confused by the fact that THD can be generated by a single frequency signal, but IMD needs two different frequencies.
In this sense I think you will not hear 2nd, 3rd, etc. harmonic of a 12 kHz distorted single frequency signal.
Probably you are confused by the fact that THD can be generated by a single frequency signal, but IMD needs two different frequencies.
In this sense I think you will not hear 2nd, 3rd, etc. harmonic of a 12 kHz distorted single frequency signal.
1) Back in the day, my father tuned pianos. Especially for the higher notes, multiple strings are used for the sake of volume. That also means that each string of these high notes must be in tune with each other, or playing the same frequency. If not, a 'beat' is heard. Strangely, I had a harder time hearing this beat although to my father it was obvious. My hearing in general was superior to his, but I suppose that you could say that my ears were untrained. Being taught music from him changed all of that for me. Before this occurred, many pieces of music were pleasant but I was missing a lot of what was actually going on and why.
2) Incredibly, I am very prone to subsonic vibrations. I have no idea why. I do remember living in AZ in 3 different towns and being able to feel a frequency that I could actually count at 7hz! Sometimes lower. Who the hell knows what that was about. There was once though that I lived in the mountains of Flagstaff and a train was maybe 1/4 mile and yes, I could feel it before I ever heard it. I get that it could happen that way, but this was not the case in the other two towns (Tucson and Bisbee). FWIW, I now live very close to train tracks and feel absolutely nothing. The thing that I surmise is that the actual earth beneath my feet and the makeup of it does play into this scenario. In the present situation, a large deep irrigation canal is between me and the tracks. Hmmm.
3) When I was young, it was sometimes difficult for me to watch TV due to the flyback transformer ringing at maybe 16K. It bothered no one else in my family. In fact for many years, it was difficult for me to be anywhere near noise. Very distracting and even confusing.
Because of these experiences, it was obvious to me that I had superman hearing, but it kept me from society at large. Along with this being evident, my ear brain 'processor' was terrible, and words were difficult for me to understand. In spite of all of this music has had a great effect on my life.
2) Incredibly, I am very prone to subsonic vibrations. I have no idea why. I do remember living in AZ in 3 different towns and being able to feel a frequency that I could actually count at 7hz! Sometimes lower. Who the hell knows what that was about. There was once though that I lived in the mountains of Flagstaff and a train was maybe 1/4 mile and yes, I could feel it before I ever heard it. I get that it could happen that way, but this was not the case in the other two towns (Tucson and Bisbee). FWIW, I now live very close to train tracks and feel absolutely nothing. The thing that I surmise is that the actual earth beneath my feet and the makeup of it does play into this scenario. In the present situation, a large deep irrigation canal is between me and the tracks. Hmmm.
3) When I was young, it was sometimes difficult for me to watch TV due to the flyback transformer ringing at maybe 16K. It bothered no one else in my family. In fact for many years, it was difficult for me to be anywhere near noise. Very distracting and even confusing.
Because of these experiences, it was obvious to me that I had superman hearing, but it kept me from society at large. Along with this being evident, my ear brain 'processor' was terrible, and words were difficult for me to understand. In spite of all of this music has had a great effect on my life.
Id love to test that.
Intermodulation would still occur between the harmonics of the one fundamental right? Albeit at a much lower level. But with a couple % of THD, the IMD components between the harmonics would be audible I imagine.
We can not call 3f - 2f = f as IM product. This adds to the fundamental in phase by a negligable amount. The other IM product would be 3f + 2f = 5f, also out of scope.
Distortion can also relate to modulation of frequencies, in other words modulation distortion. This can occur in the MHz region. Consider a 100 Mhz sinusoid being modulated at 100 Hz and whereupon the input to the 100 MHz includes a high pass of 10MHz. Hence the output can be considered absent of a 100 Hz signal in the spectrum. However if the output is fed into a square law (single sided) non-linearity the output shifts the equivalent of a DC operating point, becoming modulated at 100 Hz, a condition that re-generates a 100 Hz spectrum component. When this is done deliberately this is how AM detection works. If not done deliberately it can be characterized as modulation distortion.
Once while working with an angle grinder doing some metal work, I discovered by chance when having the mouth open at the direction of the angle grinder and metal piece I would experience a loud and very high frequency ultrasonic-like noise as if emanated from inside the head through a steep high pass filter, I played a bit with this odd experience and the difference between having the mouth closed or open was quite profound.
So, if we want to sense the ultimate audiophile experience then we ought to keep the mouth open. :D
So, if we want to sense the ultimate audiophile experience then we ought to keep the mouth open. :D
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Yup, those unique audio experiences that occur right in front of us. I remember once that rolling the back windows down on a VW Rabbit made the worst turbulence that I could ever imagine. At first, I couldn't figure it out.
Re. point 2,
Perhaps - just perhaps you have a rare 'string of genetic code' that relates to how Elephants use INFRASONICS as a major sense ???
Re. point 3,
I had the same sensitivity to the LOUD 16Khz emitted from old tube TV sets.
I will never forget walking down a street where the house-fronts were close to the footpath and noticed an open window with heaps of 16Khz emanating.
Even although I couldn't hear the regular audio > I knew they had a TV set turned on in the front room.
Going back a little, when there was lots of news about concussion >
I recalled that with the 4 times my head has been impacted/struck hard there was an associated PING sound in my head > in the range of 6Khz.
I searched & Googled all I could regarding this PING > and I couldn't find even one reference to this experienced phenomena. It remains a mystery 😕
I recalled that with the 4 times my head has been impacted/struck hard there was an associated PING sound in my head > in the range of 6Khz.
I searched & Googled all I could regarding this PING > and I couldn't find even one reference to this experienced phenomena. It remains a mystery 😕
Nope, not correct. A frequency is how many things happen per second, a frequency difference is not that.
Think people's heights and height differences. A height difference of 3 inches for instance is not a height. Not of a person at least!