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Warning to the readers

Experiments on sound and resonance phenomenon continue in Ravne’s tunnels


TAG: pyramids Bosnia, the Bosnian pyramids, archaeoacoustics, Civilization of Visoko, pyramids, archeology, artifact, tunnels Ravne, SBRG, SB Research Group

Among  measurements made in this week of January 2012 on electromagnetic phenomena and  emission of sounds and ultrasounds in Ravne’s tunnels, the most fascinating and suggestive experiment was undoubtedly the phenomenon of "resonance" still present in those sections of the tunnels in which  excavations or safety measures haven’t heavily modified the original structure.

The experiment was performed to find out the level of voice frequency producing a sound response in the whole structure.
For this reason, together with our team, we have collaborated  with professional harmonic singers who tried to create resonance within the tunnels.

Undoubtedly while listening to ancient Aramaic singing in an environment of this kind, more than being concerned with a scientific perspective, we have been struck by the suggestion of such an extraordinary moment.
The tunnel, in fact, free from visitors or tourists because of the above mentioned illumination problems, provided an unexpected originality.

The main character of this initiative was our sound engineer, Heikki Savolainen, who masterfully recorded voices, sounds and noises.
The voices of the singers were tracked by using professional equipment with sample rates up to 96,000 hz.


Singer Denise Myriam Cannas while  performing different frequencies of voice


The method of the recordings was mainly based on the air-recording of the voices of the singers by means of stereo microphones Sennheiser . At the same time, the response of the tunnels' resonance was assayed with highly sensitive microphones Hydrophones, placed in the water on the bottom of the tunnels and connected to another recorder (Marantz and Zoom recorders).



In the break between recordings we immediately checked the results on our computer

The sound mirror, provided by the large surface of water, enabled us to evaluate the spectrum response of sound at a very long distance from the source emission.

The first preliminary results were obtained by superimposing the different   recording tracks in the computer; this enabled us to discover that the resonance frequency of the original tunnel is very low, around 74 hz. But equally interesting was the spread of the voice of female singer Denise Myriam Cannas that put a strain on her voice for about two hours.



The experiment took a total of about 3 hours, but the careful observation of the sound tracks will require at least a couple of months of analysis in a professional studio.

Paolo Debertolis - January 20th, 2012

1) Original recording of the song, that was sung in ancient tunnels, by the microphones in the air to test the frequency response performed by singer Denise Myriam Cannas: here.

2) Original recording of part of harmonic singing sung in Ravne’s tunnels. The harmonic singing shook the tunnels for several seconds after the end of the sound. It is a reaction of approximately 20 seconds  which can be listened with high fidelity headphones and NOT with computer speakers. If you use the headphones with a high level of bass sounds, you can catch the response of this vibration very deeply. This vibration of resonance was recorded by Hydrophones placed in water.

Find the track here.

The final record was obtained by superimposing the tracks of microphones placed in the air (Sennheiser), which collected vibrations of the voice of the singer, with those collected in water (Hydrophones) which recordedthe tunnel's sound response .

A brief video summary of the preliminary research, here.



We resumed research in the tunnels of Ravne

TAG: pyramids Bosnia, Bosnian pyramids, Visoko Civilization, pyramids, archeology, artifact, Ravne tunnel, SBRG, SB Research Group

After a long, forced break in SBRG research, our research group has finally resumed work at the site of Visoko. In this period working outside was impossible owing to the heavy snowfalls of the past few days.
And, as during last winter, Ravne’s tunnels remain the only place in which research could be continued as we were protected from snow and cold continental climate.

The current situation looked very dramatic in this site. The opening of a new, not original tunnel, in the wall, located in the area in which the structure below the floor was found in July 2011 by GRP, has caused a change in the movement of the flows of air in this part of the tunnels and therefore it caused a stagnation of moisture never seen before.

Last year at this time the tunnels were always dry and well ventilated. Today, instead, an incredible amount of stagnated fog was in the first portion of the tunnel for almost one hundred meters. The phenomenon was particularly evident with the flash of the camera in the images below.

The environment was saturated with water and, despite the drain pipe that runs beneath the floor in the first 100 meters of the tunnel, mud was everywhere on the floor, covered by by a series of muddy puddles that splash anyone who ventures inside.
I believe I have never seen anything like this before in Ravne’s tunnels.


Fig. 1 - A thick fog ominously came out from the main entrance of the tunnel and accompanies the visitor for about a hundred meters in the path of the tunnel; later the tunnels return dry


As if this were not enough, one night a few days ago, some thieves arrived in the tunnel and stole all the existing electrical wiring of the lighting equipment with the majority of the most powerful lights. The theft to recover copper is a well known plague around here and it’s the third time that this happens in Ravne. But this time the damage was really too much for an associated desire to destroy for vandalism. The cables were cut and the lights which had not been stolen were broken.

This time the work was methodical and must have required several hours to be done, taking into account approximately a mile of cable placed on the entire length of the tunnels in their various loops.


Fig. 2 - Electrical boxes are isolated and switches have the cables cut. The thieves didn’t even waste time in detaching the sockets from multiple plugs, but they directly cut the threads with a wire cutter. The lights that were not stolen had been left in their place but the light bulb had been broken.


Therefore there was no light in the tunnels which had sadly gone back into darkness. This situation forced the closing of the tunnels to the visiting tourists.

The Foundation of the Bosnian Pyramid of the Sun will recover these severe damages next month, thanks to a generous donation of a Bosnian sponsor who is determined to resolve what happened. On this occasion, finally, the Foundation will install an alarm system connected to the local police station, thus preventing the recurrence of such episodes.

So, at the end of February visits to this tourist site will be resumed, thus providing oxygen to the exhausted finances of the Foundation which takes care of excavations here, thanks to admission tickets.

With referenceto the area of the structure discovered in July 2011, situated under the floor of the tunnels, conditions were even worse. A small river lazily flowed on it and the mud was king.


Fig. 3 - A small river lazily flows above the area of the structure, discovered  in July 2011 with GPR

Works to clean up the area with concrete casting above and below the structure and a new drainage tube have totally failed. Indeed, they have certainly worsened the existing situation.

Any serious work to bring to light the interesting structure is now impossible and if Foundation wants to do this, it must make another careful and calibrated study.

Works that differ from simply emptying the earth from the tunnels, cause a series of cascading consequences, producing several unpredictable problems.

Ravne’s tunnels are perfect in their simplicity and they respond very badly to any action that changes their delicate balance. As evidence of this, the end part of tunnels, which was also the least emptied, now appears dry, ventilated and there isn’t any loss of material. Props are not even necessary, thanks to the pointed shape of vaults. Where the tunnels widen, the builders laid stone walls, which still retain their supporting function . But if someone tries to change their shape, by raising the ceiling or by extending its walls, collapses begin to appear, despite the modern props.
It is incredible that the unchanged portions are also those that hold up better to the wear of time, thus confirming the architectural skills of the builders.


Fig. 4 - In the portions where the tunnel is saturated with water, props are rotting and a forest of mould and mushrooms rise even on stones

Unable to go on with further excavations and having to continue research, we decided to continue the analysis of the tunnels' electromagnetic forces already discussed in previous articles. We also continued our research on ultrasound inside the tunnel and on the phenomenon of "resonance".
In the disaster we have just described, however, we had the opportunity to work in a place free of visiting tourists and without electric fields produced by the presence of power cables for lighting. The environment was perfectly quiet and dark, perfect for our measurements.

So lighting was made only by lamps on our helmets or by portable LED torches. This created very cozy environments and also allowed us to take evocative photographs that recall the conditions of the tunnels at the time of their construction.


Fig. 5 - Unlit tunnels create even more mysterious  but extremely fascinating environments


In the next few days we will illustrate the methods, instrumentation, and results of this week's research because the Foundation of the Pyramid of the Sun provided us with an exclusive and continued opening of the tunnel. In the second half of the week other collaborators will come and will assist us in the surveys.

Paolo Debertolis - January 18, 2012




Report of November 2011 on the situation inside Ravne labyrinth


TAG: pyramids Bosnia, Bosnian pyramids, Visoko Civilization, pyramids, archeology, artifact, Ravne labyrinth, SBRG, SB Research Group

In November 2011 our research team decided to do an inspection in Visoko to evaluate the possibility of begining excavations, to bring the structure discovered last July under the floor in Ravne’s  tunnels by GPR to light.

The situation that occurred was disastrous. The work we did to remove water from the area surrounding the structure completely failed its purpose.

A stream seems to go peacefully throughout the surrounding area and above the structure with a deepth of four inches.


Fig.1 - The appearance of the gallery, above the underground chamber, is disheartening. A four inch deep stream  continues to flow, despite the efforts made by workers of the Foundation for cleaning up (Ajdin Ahmetspahic photos)


This situation is partly due to the change of air flow in the tunnel, following the opening of original sections of tunnel. 


Fig. 2 - Some sections of the tunnels continue to be closed because of the danger of collapse (Ajdin Ahmetspahic photos)


The change in air flow has caused condensation to run from the walls and vaults like small rivulets of water, this was caused by the high humidity in the tunnels.

All that water contributes to the conglomerate to loosen encouraging small and significant increases of tunnel collapses. In the past years, under direction of  controversial work, such collapses have eliminated the original morphology of the tunnel and extending shape. Unfortunately the change of catenary shape, which was able to release the pressure of the overlying strata, now leads to the formation of points of least resistance, from which come off blocks of conglomerate smashing the boards placed above the props. In sections where the original catenary shape remained, there is not any problem with static.

During an inspection of the archaeological site, we have seen a collapse that has taken part of the electrical system, leaving most of  tunnel in the dark. Thanks to the lamps placed above our helmets, we were able to find the exit, while the workers evacuated the collapsed area from debris to restore the electrical continuity.


Fig. 3 - The collapse that we witnessed which left us in the dark. A block of conglomerate that broke off from the ceiling broke through the boards placed over the props, but other blocks were stopped by guards (Ajdin Ahmetspahic photos)


Fig. 4 - The workers of the Foundation later removed precarious blocks and inserted security guards (Ajdin Ahmetspahic photos)



Fig. 5 - All of us were very puzzled by this situation. On the left, Dr. S. Acconci, in the center our new collaborator Dr. M. Merlo, right prof. P. Debertolis (Ajdin Ahmetspahic photos)


At the end of the site inspection we had a meeting with dr.sci. Semir Osmanagic, the chief of  Bosnian Foundation of the Pyramid of the Sun. In it, dr.sci. Osmanagic clarified the direction for the future of the Foundation under three priorities, as well as reported on the Foundation's website (here), and stating the global financial crisis has reduced sponsorship.


Fig. 6 - At the end of the site inspection we had a frank exchange of views with the scientific director of the Foundation, dr.sci. Semir Osmanagic, who outlined the Foundation’s future intentions(Ajdin Ahmetspahic photos)


The priorities, set by dr.sci. Semir Osmanagic, are:

1) The first thing to do is to secure the tunnels to prevent further collapses, other priorities including research will take a back seat. The archaeologist Acconci had reported this problem for some time, but it was not taken into consideration.

2) The Foundations second priority is to bring to light the structure, but according to when they will consider it’s appropriate to do so, not according to our availability.

3) The third priority is to dig in the direction of the Pyramid of the Sun, but without removing the water from the tunnels. It will take several years to reach this goal. It is unclear how long they want to operate in an ambient environment saturated with water vapor, with 20-30 cm of water on the floor without changing the shape of the structure.

This program decided unilaterally by Foundation, needs a rethink in terms of our collaboration between our research group and the Foundation of the Bosnian Pyramid of the Sun, both in time and scope.

From this moment on, it is very unlikely our research group will continue to collaborate with the Foundation of the Bosnian Pyramid of the Sun to identify other artifacts that may be present in the tunnels or on the surface.

However, we will continue to collaborate with the Foundation in regard to the research and study of electromagnetic and vibratory phenomena
(ultrasounds) throughout the entire Bosnian pyramid complex.

Paolo Debertolis – Friday, November 11, 2011



Maintenance work continues in Ravne, but when excavations will resume in the tunnels seems most uncertain


TAG: pyramids Bosnia, Bosnian pyramids, Visoko Civilization, pyramids, archeology, artifact, Ravne tunnels

The two workers of the Foundation still on-site, Edo and Salko, continue their work of shoring and reinforcement of props in the tunnels.
But it seems that changes are necessary for future conservation. Under direction from a professional archaeologist these changes would only be a little different from the methods implemented up to now.


Fig. 1 - The maintenance work is carried out only by two workers (Ajdin Ahmetspahic photos)

In any case hard times loom for the Bosnian Pyramid of the Sun Foundation, which takes care of the excavations in Ravne tunnels. The global financial crisis has led to a dramatic reduction in donations from private sponsors which have allowed it to continue digging, even in winter.


Fig. 2 - Tunnel passages that do not have secure access are closed to public (Ajdin Ahmetspahic photos)

There is now the possibility that there are no funds to pay the team of workers who, last winter, allowed non interruption of the research inside Ravne tunnels and led to significant successes, such as the discovery of new section unsealed tunnel (here) or the discovery of artifacts (here).


Fig. 3 - Moment to fatigue for Salko who remains one of the best workers (Ajdin Ahmetspahic photos)

Probably the excavations will resume only in January with the arrival of a dedicated budget for all of 2012 by the Bosnian Government.

Ravne tunnels will remain open all winter for sightseeing.


Fig. 4 - Outside, the problem of water drainage remains a serious problem in Ravne tunnels (Ajdin Ahmetspahic photos)

Meanwhile, researchers of SBRG will maintain their presence in this archaeological site pursuing other lines of research. Unfortunately we had to suspend excavations, which had just begun, to unearth the underground structure discovered in July of this year, because, without support of the Foundation workers, it’s impossible to construct the access ramp down to the structure.

Paolo Debertolis & Richard Hoyle - October 28, 2011




While we are waiting to resume the excavations, Foundation's workers continue maintenance work in Ravne’s Labyrinth

TAG: pyramids Bosnia, Bosnian pyramids, Visoko Civilization, pyramids, archeology, artifact, Ravne tunnels

Maintenance work continues in tunnels of Ravne by replacement of decayed or insufficient supports. The work is being carried by two workers of  Foundation of the Pyramid of the Sun under direction of leading archaeologist, Sara Acconci.

In November, to resume the excavation work, we will wait for the return of a greater number of workers of the Foundation and volunteers who have decided at their own expense to continue the work.
What is becoming more clear to our research group is that the builders of the tunnels had the same problems of partial collapses like present time.

For this reason they remedied it with long sections of dry stone walls on the side of the tunnels where it was necessary to expand the size.


Fig. 1 - Where there is a dry stone wall there isn’t any collapse. In upper images the section recently opened and that closes the third alveolus path in the tunnel Ravne (images by Ajdin Ahmetspahic)

As it can be observed from the images, where workers have shored up tunnels many times, tunnels sometimes modified by the workers for various reasons, sometimes if there is a failure of a support beam you can have a collapse of  the vault with material falling. Where there is a dry stone wall on the side of the tunnel, there isn’t any collapse of the structure even though it is not shored up.


Fig. 2 - Where the path of the tunnel was enlarged by the workers of the Foundation for various reasons, eliminating the catenary profile, despite the props, the material tends to fall from the side of the walls impeding the passage (image by Ajdin Ahmetspahic)


Fig. 3 - In the enlarged and propped tunnels, if props are rotten or not sufficient in number you can observe a collapse. At the present moment the workers are strengthening all areas that are at risk and replacing damaged props (images by Ajdin Ahmetspahic)

This method of using dry stone walls on the sides of tunnels has often been used in prehistoric and early historic periods and it indicates the high level of awareness and knowledge that the builders of Ravne’s Labyrinth had.

Paolo Debertolis - October 14, 2011




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