Infrasound Research

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Gartloney Rat
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Infrasound Research

Unread post by Gartloney Rat » Thu Sep 06, 2012 9:59 am

This is an aspect of the Yowie phenomenon that gets mentioned repeatedly when discussing encounters and it is one that I am particularly interested in. I have been looking at the research done on the use of infrasound elswhere in the animal kingdom.

Assuming that the Yowie has the capabilty to produce low frequency sounds, it seems possible (based on how other creatues employ it) that they would be frequently emitting very low frequency vocalisations. These could be to advertise territorial claims, while hunting to freeze their intended prey or simply to communicate with others of the same species.

Since reports of audible vocalisations do not seem to be too common and assuming that Yowies are not mute I wonder if there may be a dialogue going on that is outside the range of normal human hearing? It would be interesting to monitor background level infrasound in an active area.

Are any members actively investigating this concept at present? I recall a thread on the subject a couple of years ago where this was discussed in some detail, I wonder was there any conclusion from this research? If you are involved in this what equipment do you use, particularly what microphones and where did you get them?

andrew

Re: Infrasound Research

Unread post by andrew » Thu Sep 06, 2012 2:15 pm

Gartloney Rat wrote:Are any members actively investigating this concept at present? I recall a thread on the subject a couple of years ago where this was discussed in some detail, I wonder was there any conclusion from this research? If you are involved in this what equipment do you use, particularly what microphones and where did you get them?
You can use any good electret microphone (Panasonic make them) but you will need low pass filters to remove the frequencies above 20Hz and then amplify what is left and record the signal on good digital (normal) audio recorders with a cable feed into the mic socket. These are not a regular items bought off the shelf anywhere but look up volcano monitoring infrasound systems and you will find detailed circuits. You should be able to detect sounds down to 1Hz this way but you will software to analysis the recordings because you cannot hear them - obviously. This will also pickup the sound of them walking as is easy to show. They will also pick up a lot of man made and natural infra sound - wind, running water, road, noise, planes etc etc. Obvously they need to be located well away from homes and roads and rivers. Technically advanced work and you will need to know what you are doing to design and construct the front end system.

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Re: Infrasound Research

Unread post by Gartloney Rat » Sat Sep 08, 2012 11:02 am

Thanks for the reply Andrew, I agree that this is a technically advanced field and probably fairly expensive to achieve. I am still looking into the feasability at present. However there are quite a few resources describing research into elephants, tigers etc that provide useful information. I think this research would have to be done in an area away from man made infrasound sources and preferably away from waterfalls etc so in a flat area. I am theorising that man made sources would have a readily identifiable signature probably with a repeating pattern. So you'd be looking for anomalies that stand out from the background. I have some of the gear that I would need or at least know where to get it. I will continue with my research.

andrew

Re: Infrasound Research

Unread post by andrew » Sat Sep 08, 2012 12:29 pm

Gartloney Rat wrote:Thanks for the reply Andrew, I agree that this is a technically advanced field and probably fairly expensive to achieve. I am still looking into the feasability at present. However there are quite a few resources describing research into elephants, tigers etc that provide useful information. I think this research would have to be done in an area away from man made infrasound sources and preferably away from waterfalls etc so in a flat area. I am theorising that man made sources would have a readily identifiable signature probably with a repeating pattern. So you'd be looking for anomalies that stand out from the background. I have some of the gear that I would need or at least know where to get it. I will continue with my research.
The system I mentioned is not expensive to make but you will need the expertise to select the best low noise, low power op amps that will do the job and you will have to redesign the component values to produce the correct frequency cutoff for the low pass filters and amplifiers. I estimate the cost is less than $30 and have already bought the multiple microphones I need for mine. The best ones are the panasonic WM60's. Like I said this is technically challenging work if you do not have the background and I have looked for commercial gear but found none. If it were, the vulcanologists around the world would not be making their own. Their circuits are pretty close to what you will need.

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Re: Infrasound Research

Unread post by forestguy » Sat Sep 08, 2012 1:20 pm

GRat - though you might be interested in some of these links I pulled together earlier in the year. I tried to keep it all to publicly available content, rather than straight peer-reviewed content which would cost to access:

Infrasound in the animal kingdom:

Elephants
http://www.jstor.org/discover/10.2307/4 ... 6200552773

Cassowaries
http://www.pngibr.org/publications/pdf/ ... ck-Auk.pdf

Okapi
http://scienceblogs.com/tetrapodzoology ... eek-day-3/

Rhinos
http://discovermagazine.com/1992/apr/therhinossilentc38

Alligators
http://scholarlyrepository.miami.edu/oa ... tions/570/

Giraffes
http://www.pbs.org/wnet/nature/episodes ... nels/2256/

Whales
http://www.livescience.com/8450-blue-wh ... nsane.html

^This article also touches on some of the issues that people are talking about when attributing infrasound to hairy hominids.

Cheers,
FG
"What is reported is different to what is remembered which is different to what was seen which is different to what was present."

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Re: Infrasound Research

Unread post by Gartloney Rat » Mon Sep 10, 2012 10:32 am

Thanks Andrew and FG for your informative replies. I note that the WM60s have been discontinued and replaced by the WM61. Both these capsules have a beautiful flat frequency response right across the range but their advertised response bottoms out at 20hz. Presumably they have some reduced capability below this, any idea what it may be? Also I have noted a few mikes that have an advertised response down to aound 6hz (at a price!). These are variously designed for wildlife , ENG and industrial purposes. Do you see any advantage, apart from cost, to self constructing rather than buying off the shelf?

Have you got to the stage of deploying your equipment yet? Did you get any interesting results?

Thanks FG for the references I will be looking at them over the next few days. It seems like the more I look the more links to research that I discover! I am also planning on visiting the local uni libraries, there are some periodical articles I'd like to read. Lucky I'm retired, gives me time to check this stuff out!

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Re: Infrasound Research

Unread post by forestguy » Mon Sep 10, 2012 11:01 am

Gartloney Rat wrote:I am also planning on visiting the local uni libraries, there are some periodical articles I'd like to read. Lucky I'm retired, gives me time to check this stuff out!
And there's so much online in the library catalouges - it's almost worthwhile signing up to do a course (just tick along doing 1 subject a semester externally) just to be able to access all the journal subscriptions etc.
"What is reported is different to what is remembered which is different to what was seen which is different to what was present."

andrew

Re: Infrasound Research

Unread post by andrew » Mon Sep 10, 2012 1:08 pm

Gartloney Rat wrote:Thanks Andrew and FG for your informative replies. I note that the WM60s have been discontinued and replaced by the WM61. Both these capsules have a beautiful flat frequency response right across the range but their advertised response bottoms out at 20hz. Presumably they have some reduced capability below this, any idea what it may be? Also I have noted a few mikes that have an advertised response down to aound 6hz (at a price!). These are variously designed for wildlife , ENG and industrial purposes. Do you see any advantage, apart from cost, to self constructing rather than buying off the shelf?

Have you got to the stage of deploying your equipment yet? Did you get any interesting results?
As I indicated I have found none off the shelf that do what I need. Regardless of the model of electret, most do have that flat response to 20Hz but do go lower in practice. The sensitivity is the most important feature as is low electronic noise. You might notice some of those circuits I allude to use up to four mics in parallel to reduce the inherent electrical noise. From memory the vulcanologists use these down to 0.1Hz. I have not finished mine as I am waiting for some special op amps from overseas. Also self construct design means you can incorporate a variable low pass roll off in the design. Presumptive yowie foot step recordings seem to peak around 100Hz but I would like to record up to 1000Hz as well if I want. Not deployed yet per the above comments. First they have to be tested with the audio recorder etc anyway.

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Re: Infrasound Research

Unread post by mlj1mlj1 » Wed Sep 19, 2012 4:18 pm

A couple of key points. Some at SIR now beleive the Sasquatches can hear your equipment, such as stealth cams and electronics emitting sound all the time or when they are triggered, which would make them easy to foil all the time. I personally beleive infrasound is incorrect and an electrical explaination is more plausible based on my field experiences. Look to the symptoms of electro shock therapy and you will find the same symptoms. Generally sound doesn't fry equipment either. You often feel it in your chest and your heart is a musclle that functions on electricity if I recall. Plus, its a proven fact elephants, which are a substansially larger mammal emit infrasound and no one in Africa is complaining of these symptoms when they are around. The puzzle pieces just don't fit infrasound as an explaination. Ask our fried DVR. MIKE J-SIR

andrew

Re: Infrasound Research

Unread post by andrew » Wed Sep 19, 2012 5:53 pm

mlj1mlj1 wrote:A couple of key points. Some at SIR now beleive the Sasquatches can hear your equipment, such as stealth cams and electronics emitting sound all the time or when they are triggered, which would make them easy to foil all the time. I personally beleive infrasound is incorrect and an electrical explaination is more plausible based on my field experiences. Look to the symptoms of electro shock therapy and you will find the same symptoms. Generally sound doesn't fry equipment either. You often feel it in your chest and your heart is a musclle that functions on electricity if I recall. Plus, its a proven fact elephants, which are a substansially larger mammal emit infrasound and no one in Africa is complaining of these symptoms when they are around. The puzzle pieces just don't fit infrasound as an explaination. Ask our fried DVR. MIKE J-SIR
I have no idea what you are trying to say.

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Neil Frost
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Re: Infrasound Research

Unread post by Neil Frost » Wed Sep 19, 2012 8:18 pm

G’day Andrew,

As you would know, I really have very little understanding of this phenomena, despite constant attempts to do so. Infrasound: I know that it is used by many other species for various communicative reasons but, regarding these hominoids, I have always believed that the triggered responses in witnesses have been mainly due to other stimuli. If ultrasound is responsible, then, once again, aren’t we discussing the possibility of a hominoid other than a hominid? Can you do this? I don’t think so!

There are many possible and alternative explanations. A major contributing factor, I think, is their ability to induce fear, partly brought about through their learnt interaction with Aborigines across millennia and more significantly, through the greatly exaggerated and naive (ignorant) responses of non-indigenous Australians, during this current time period. This is learnt behaviour used to initiate a fear response and is not an innate ability! The triggers are, most likely, numerous and subtle but, clearly, finely tuned.

So, what are the triggers? I don’t think that they are necessarily surprising! From experience, they can be as simple as breaking a branch and not allowing it to fall to the ground. From a basic and inherent understanding, or intelligence of of how things sound as they fall, the missing sound sequence alerts the witness to a potential problem. There are many more examples. The communication in this case is basic and universally understood, as with the sound of a twig snapping in isolation! Ultrasound is not required to obtain a response in these circumstances!

Then, there is the following digital recording shortly after an encounter. Clearly, it is bipedal and is communicating with another. What it is, I don’t know and neither does anyone that I am aware of. Options welcome!
Animal X1.mp3
Neil
You do not have the required permissions to view the files attached to this post.
a = 32 mm; b = 50.4 mm; c > 66.67 mm and < 68.11 mm IPD. From film neg degree separation 0.25˚ to 0.3˚ @ 13500 mm = IPD > 58.9 mm and < 70.7 mm. Mean IPD from average of both methods = 66.1 mm. Max pupil dilation ≈ 30 mm. Eye height ≈ 1850 mm.

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Re: Infrasound Research

Unread post by Gartloney Rat » Wed Sep 19, 2012 9:38 pm

Hi Neil, I kind of like the idea that the "nameless dread" might be generated within the mind of the person having the encounter. But are there not reports where a person feels fear and their hair stands on end for no obvious reason before the actual sighting or any sound is heard? Maybe it works the same way as when you can feel that someone is watching you and some people are more sensitive to this than others.

Also how about the extreme fear sometimes displayed by dogs and horses? They presumably are unable to recognise the triggers which would cause fear in humans and unless they have had a prior encounter would have no preconceptions about Yowies. Unless instinct tells them Yowie smell = very bad.

Anyway thats my thoughts based purely on reading other peoples reports, whereas I believe you have had many encounters so are far more qualified to express an opinion on the subject.

Interesting recording i've never heard anything like it outside of a sci fi movie. Was it recorded in Oz?

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Neil Frost
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Re: Infrasound Research

Unread post by Neil Frost » Wed Sep 19, 2012 10:07 pm

G’day Gartloney Rat,

Today I was speaking to a witness. As he spoke of his encounter, the memory of it was sufficient to trigger an involuntary response based simply upon his memory of events that he was unable to totally identify. Similarly, without having had these experiences, I was reacting also with goosebumps, probably from past experiences that I vaguely identified with.

As for dog and horses, they probably have better senses than us and are not as reliant upon the same set of cognitive triggers as us, maybe - as you say.

As for the recording, it was made after a shared experience, a few hundred metres from home. Most people agree that it sounds quite unusual.

Neil
a = 32 mm; b = 50.4 mm; c > 66.67 mm and < 68.11 mm IPD. From film neg degree separation 0.25˚ to 0.3˚ @ 13500 mm = IPD > 58.9 mm and < 70.7 mm. Mean IPD from average of both methods = 66.1 mm. Max pupil dilation ≈ 30 mm. Eye height ≈ 1850 mm.

andrew

Re: Infrasound Research

Unread post by andrew » Thu Sep 20, 2012 6:43 am

Hi Neil (and GR)

I just could not follow the thread of what Mike -SJR was trying to say. As for infrasound, it does seem to pervade our world in many subtle ways. I understand the infrasound communications by many large animals, as Forestguy pointed out well in another thread, and I am 100% sure that yowie walking and foot thumping has a high level of infrasound, as a spectral analysis of walking recordings shows. Because infrasound travels so far, their thumping would be a reliable long range communication medium, as you have experienced. The other intriguing facet of this is that our various brain patterns - alpha through delta etc - all occur at infrasonic frequencies. Whether that causes us to be subconsciously responsive to infrasound is moot as far as I can determine from the many research papers available, but it is plausible.
We do know that very high level infrasound does effect the human body but what is not clear from research, by the likes of NASA, is whether low volume infrasound causes the human mind to be effected. The results are at best conflicting but I suspect there may be a causal effect. It may be that the "dread response" is a mental reaction to such infrasonic sounds at specific frequencies but it is difficult to know or prove. Your points about a finely tuned use of sounds as a deliberate interaction tactic is yet another area that is fascinating. That includes the use of growling, as seems to be experienced in some encounters over time.

It makes total sense to me that yet another large animal would use "vocal" infrasound to communicate over long distances. I have not looked at the spectrum of your animal X sound yet but it would not surprise me if it has infrasound components. I am waiting for the hawk moths to reappear at home to see if I can compare their wing beat sound purely as an exercise. Their sound is very similar to what you recorded but, as we both know, that may be purely serendipitous.

My real interest in infrasound is with detecting them walking as a means to determine any pattern with their presence in remote areas and also as a way to perhaps trigger cameras.

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Re: Infrasound Research

Unread post by mlj1mlj1 » Thu Sep 20, 2012 9:16 am

In the US, infrasound is felt by some in other organizations to be the cause of an unknown, but very real physical distress that they can cause you while in the field and they are around close by. I think this distress is real, but not sound related, but electrical. It is real phenomenon here you must be aware of. Some of the symptoms are seizures, head aches, paralyzation, etc. I have heard 8 individuals do a macabre vocalization in a canyon in unison for 2 minutes at one time. The sound was very low, but audible and quite intimidating. It felt like a drum and reverberated through you. I think some are confusing that with Infrasound, which is inaudible if I recall. I hope that clarifies what I am trying to convey.

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Re: Infrasound Research

Unread post by mlj1mlj1 » Thu Sep 20, 2012 9:21 am

Here they wood knock to locate each other without saying a word, also, making the need for infrasound unnecessary. I have three separate individuals around me wood knock in response to mine from three separate sides. They were letting each other know where the other was is my thought. Most humans don't even pay attention to one knock, so it is very effective long range communication tool under most folks radar.

andrew

Re: Infrasound Research

Unread post by andrew » Thu Sep 20, 2012 11:47 am

mlj1mlj1 wrote:Here they wood knock to locate each other without saying a word, also, making the need for infrasound unnecessary. I have three separate individuals around me wood knock in response to mine from three separate sides. They were letting each other know where the other was is my thought. Most humans don't even pay attention to one knock, so it is very effective long range communication tool under most folks radar.
Thanks for clarifying Mike. It is an absolute fact that impulse sounds, like knocks, have infrasonic frequencies (very long wavelengths) as well as audible components and the former travel a long way and will curve around and over land features. Communication method? I would think very likely. You probably need the shorter wavelength, higher audible frequency components to better establish direction of the source though. This is just applied Physics in action.

I doubt we will ever know how they use sound until one is available for study and I hope that does not happen.

As far as the electrical side is concerned, I do not see how anyone can prove that, so I will just have to leave it as a floating assumption. We have so much to learn but I am sure we will get a handle on the weird stuff eventually. I personally would not be leaping to turn assumptions into facts too quickly in the meantime.

Your account of that noise in the canyon is awesome. I don't suppose you had a recorder on at the time? I would be interested in hearing some good tracks of captured sounds.

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Re: Infrasound Research

Unread post by mlj1mlj1 » Fri Sep 21, 2012 7:07 am

It will all come to light some day. What I am trying to say is this is much more complicated than we all are imagining. More so than I thought. We have quite of bit of evidence of the electrical aspect that will be brought to light soon. The trail camera dilemma is a portrayal of that phenomenon in action. In the Yosemite valley, the Mewouk Indians tell a tale that everywhere the Sasquatch goes he is followed by a lantern or light. There simple portrayal is true to a certain degree. The how or why is yet to be discovered. I have seen it for myself.

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Re: Infrasound Research

Unread post by mlj1mlj1 » Fri Sep 21, 2012 7:08 am

No good recorder at that time, but I have 5 now. :)

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