Making noise over the [Kokomo] hum

[Rossen]

Yes OOO, the Schumann resonance has been considered as possible cause. But this hypothesis has too many shortcomings.
1. Schumann resonance as phenomenon isn't since yesterday. It exists milions years. It isn't clearly why in the past it hasn't produced a hum, but now it does.
2. In Internet there are people claiming during the last years the Schumann resonance has changed its spectrum. It isn't true. Around the world there are many laboratories observing Schumann frequencies night and day. As far as I know nobody has observed something extraordinary in this area.
3. Schumann resonance is very weak effect. But in this frequency range there are many artificial sources. They must produce stronger effect than Schumann resonance. For example in Germany and other europian countries, where the hum is present, there is strong 16.7 Hz background. It is from railroad what use this frequency of the supply. This is close to second Schumann frequency and must produces similar effect.
In fact, Schumann resonance hypothesis is from the class of ELF/ULF explanations of the hum. In same class is the submarine explanation. But every hypothesis in this class suffers from one serious defect - 50/60 Hz problem. 50/60 Hz background is the most strong LF background in all countries. May be only in places as the Antarctic or Central Tibet this background doesn't exist. Especially its magnetic component. And the question is: Why don't the hearers hear 50/60 Hz near the power lines in their homes for example? Or why don't they hear the background from the monitors of the computers? Etc.
Some people are inclined to consider a modified Schumann resonance hypothesis. They think that the effect is opposite. Because of the very loud LF electromagnetic background in industrial countries, some people suffer from a deficit of Schumann frequencies. This hypothesis considers Schumann resonance as some kind of universal synchronizer for living organisms. I don't know what is the basis for such consideration. But if even it is right then we have another problem. Many hearers live in rural regions where the LF electromagnetic background isn't so loud as in cities. In such regions Schumann resonance can be observed comparatively easily by good ELF antenna.
So that, the situation with Schumann resonance is complex.

 

[OOO]

What still irritates me is that some people hear it and some people don't. 68 Hz is well inside the human hearing range and in addition this range isn't very sensitive to hearing damage (hearing sensitivity tends to degrade above 1 kHz due to acoustic stress). So I assume that statistical dispersion in human hearing sensitivity isn't that large (although it naturally exists) in that range.

On the other hand I believe that if the hum was of artificial origin there must be considerable dispersion in its intensity, i.e. some very very loud "hum places" and some very quiet (I think we all share this experience concerning artificial noise). So if there are people who hear the hum almost everywhere and people who don't hear it anywhere, the dispersion in intensity must be smaller than the dispersion in hearing sensitivity. This seems unlikely to me.

 

[OOO]

By the way: recently (about one or two weeks ago) I heard some fluttering noise in my left ear (few seconds, very low pitch <10Hz). It was obvious to me that this was due to some periodic muscle spasm in my ear (don't know if there are muscles at all, but that's what it sounded like) and it is likely to be the result of stress. So what about the hum being the result of stress induced muscle tremor (in this case at a higher frequency than mine) inside the ear or probably the skalp ? There is considerable variation in the sensitivity to stress.

Aditionally I remember once having read about some doctors measuring sounds coming (!) from the ear itself for the purpose of some diagnosis. Don't know if this is really true, maybe I misunderstood something. But if it is, them hum could probably be measured inside the ear or by electromyography.

Edit: I have found something about it: http://en.wikipedia.org/wiki/Otoacoustic_emission

 

[Far Star]

OOO, otoacoustic sound has been investigated in some hearers. From what I understand
hearers are usually aware that the sound source is generated outside their bodies. It would take more reading than I have time for to cover those that have been tested for such. I'm not aware of any long time hearers reporting that otoacoustic emissions are the sole source for what they hear, once it has been investigated. That's not to say it isn't a factor for some people.

If you hear the fluttering sound again see if it goes away when you close your eyes or look upward. If it's the same type of phenomena I've experienced the sound may stop at certain positions.

 

[OOO]

OOO, otoacoustic sound has been investigated in some hearers.

Too bad. It seemed to be such a good idea...

 

[B. Elliott]

I stumbled across this letter on Nature when researching geothermal convections and the ocean tides contribution to resonance. Apparently I was way off with the convection idea, but either way...

The Earth's 'hum' is driven by ocean waves over the continental shelve

Recent observations on Earth, however, suggest that the predominant excitation source lies under the oceans8, 9, 10. Here I show that turbulence is a very weak source, and instead it is interacting ocean waves over the shallow continental shelves that drive the hum of the Earth. Ocean waves couple into seismic waves through the quadratic nonlinearity of the surface boundary condition, which couples pairs of slowly propagating ocean waves of similar frequency to a high phase velocity component at approximately double the frequency.

http://www.nature.com/nature/journal/v445/n7129/full/nature05536.html

 

[Ivan Seeking]

I stumbled across this letter on Nature when researching geothermal convections and the ocean tides contribution to resonance. Apparently I was way off with the convection idea, but either way...

The Earth's 'hum' is driven by ocean waves over the continental shelve

http://www.nature.com/nature/journal/v445/n7129/full/nature05536.html

However, the first sentence states:

Observations show that the seismic normal modes of the Earth at frequencies near 10 mHz are excited at a nearly constant level in the absence of large earthquakes1. This background level of excitation has been called the 'hum' of the Earth. [continued]

The so called Taos Hum is claimed to be around 80 Hz, so we are off by a factor of about 100,000.

For humans, the normal range of audible frequencies is about 20 Hz to 20,000 Hz.

 

[B. Elliott]

However, the first sentence states:

The so called Taos Hum is claimed to be around 80 Hz, so we are off by a factor of about 100,000.

For humans, the normal range of audible frequencies is about 20 Hz to 20,000 Hz.

Whoa, that is way out of range, isn't it?

I did some quick Googling using 80Hz as key word when this page popped up. Although it's still a bit off from the 80Hz frequency, it is only 30Hz off from the Kokomo and still well within the range of human hearing.

What does the author mean by 'riding' the lower frequency signals? I'm a bit confused by this.


Unknown ELF-Signals and Ground Currents

By reducing the filter intensity for testing purposes, the 50 Hz signal can also be made visible on screen. The shape of the 50 Hz signal proves that the above mentioned signals can not be a modulation of the 50 Hz signal: The 50 Hz signal is “riding” on the lower frequency signals. This shows, that it is not a modulation but a superposition, which only can be possible if there are different, independent sources.

http://www.vlf.it/kurt/elf.html

 

[Ivan Seeking]

I did some quick Googling using 80Hz as key word when this page popped up. Although it's still a bit off from the 80Hz frequency, it is only 30Hz off from the Kokomo and still well within the range of human hearing.

I was using 80 Hz as an average. Since it has never been measured we don't know exactly what if any frequency is involved. People describe it as a sound that would be in the 50 to 100 Hz range, but we don't even know if this claimed phenomenon is real. The reports may be due to something like tinnitus.

What does the author mean by 'riding' the lower frequency signals? I'm a bit confused by this.


Unknown ELF-Signals and Ground Currents

http://www.vlf.it/kurt/elf.html

[/quote]

This is something else entirely - the Schumann Resonance, which is an electromagnetic resonance in the ionosphere resulting from electrical activity, such as lightning. Ultimately what he is trying to determine is if the 50 Hz signal results from the Schumann resonance, or if it is an artifact of 50Hz AC used in Europe for electrical power. He apparently concludes that it is not caused by the 50 Hz power grid, but that is not a published paper and not a legitimate reference here.