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The phenomenon of resonance in the Labyrinth of Ravne. Preliminary results


TAG: pyramids Bosnia, the Bosnian pyramids, Civilization Visoko, pyramids, archeology, archaeo-acoustic, resonance, tunnel Ravne, SBRG, SB Research Group




The phenomenon of resonance is something known about for thousands of years. It is often only partially understood, confused with episodes of mystical philosophy. We find traces of it in ancient writes and in the oral tradition, but also in ancient artifacts and prehistoric architecture (1).

  Although today it appears to be a well recognized phenomenon by physics and is used in many technologies. Not yet mastered to its full extent, resonance can be found in astronomy or in that world of energies that are determined at the atomic level. Resonance phenomenon is an area that appears where little or no exploration has taken place in terms of mechanical, chemical, electromagnetic, biological and acoustic fields (1). However science now appears to be increasingly interested in it to understand certain natural phenomena that have otherwise been inexplicable.

 Without going too deeply into complex physical mechanisms, we can say that resonance is the phenomenon in which an object absorbs energy, transforms it and makes it again in another form, but the best. At antipodes of resonance phenomenon we find the entropic energy lost by mechanisms in a chaotic and random system.

Resonance can be found at any level of the cosmos where we find any form of energy. From the movement of the spiral of our galaxy to the oscillations of the electrons of a semiconductor: a phenomenon we can find anywhere and everywhere where we find resonance vibrations.

 Of all attempts to describe the phenomenon of resonance in a simple way, the most comprehensive one cited by J. Mortenson will be described below.

 Let's imagine a simple ball that floats in a sea of energy, surrounded by heterogeneous waves, which are not the same size as our ball (Figure 1).


 Figure 1 (from J. Mortenson, 2010)


 If the waves are much longer than the diameter of the ball, the ball will roll over up and down like a boat on an ocean.

 But what happens if the waves are of length smaller than the diameter of the ball?

 The ball will no longer move forward or backward, or up and down, but the waves, on the contrary, will exceed or will be reflected from its surface. Principles are clear enough and exemplified by classical thermodynamics.

 Now, however, we can imagine that the wave height and the diameter of the ball are the same amplitude (Figure 2). If the wave crosses the surface of the ball, when it reaches the opposite side of the ball it is reflected back, instead of overshooting this side.

 Then the wave returns back and collides with the first side initially crossed and is reflected back again. At this point the wave continues to go up and down inside the ball to infinity.

 At this point we can also say that the wave energy remains trapped in the ball. If another homogeneous wave enters the ball, the energy of that wave will again be completely absorbed. Then the homogeneous waves and the ball will be in resonance and no portion of the energy will be wasted or lost outside of the ball.



Figure 2 (from J. Mortenson, 2010)


 Therefore, when the wavelength of energy is equal to the size of an object that absorbs it which then changes into another form, we have the process of transformation of energy called “resonance”. Resonance is in simple terms, the process of transformation of energy that happens when you grant power to objects.

 Since we live in a continuum of space and time, energies and objects may be coupled in terms of both time and synchronicity and in terms of space, wavelength or size. When energies and objects are coupled in terms of time, it is said they have frequencies matching or "resonance frequencies".

 Since everything in our universe is in constant motion and there are many wavelengths and frequencies possible in and around us, all may be subject to resonance processes. And that last sentence explains the power of the concept of resonance.

 When an object is exposed to a resonant energy, the energy is concentrated in the object and becomes available for the execution of useful work and maintain an order far away from equilibrium of a static system probabilistic.

 Other nearby objects that do not resonate with the same frequency (not tuned to that frequency), will not accumulate and transform the resonant energy and will remain in equilibrium with their condition and their dynamics. This makes the transformation of energy by resonant process very precise, objective and verifiable, compared to the random processes of transformation by entropic energy.

 When considering the concept of resonance, we begin to understand how this phenomenon can influence and control the field of fundamental interactions between energy and matter, this concept concerns the physics, chemistry or biology fields.

 In this article we will examine the acoustic resonance and the particular phenomena of resonance in some ancient structures caused by the emission of sound waves at various frequencies.


The resonance in Neolithic Age

 There are several studies that have showed that this phenomenon was already known in the Neolithic Age. Some megalithic civilizations had many resonant features, these were understood to be used mainly for ritual or mystical reasons.

 Among the pioneers of research in this area were the group PEAR (Princeton Engineering Anomalies Research) of University of Princeton directed by prof. Robert G. Jahn. They conducted various experiments in 1994 at six Neolithic sites through the use of electronic sound generators to measure their acoustical properties (2).

 The six sites were: Wayland's Smithy, Chun Quoit, and Cairn Euny, in Great Britain.; Newgrange, Cairns L and I, Carbane West Ireland. All these sites are dated to before 3,500 BC (2).




 Table 1 (from R.G. Jahn et al, 1995)


The rooms were all bounded by crudely carved stones, but they also had very different configurations, both in size and shape. Newgrange was cruciform for example, others were square or hive or like the petals of a flower.

 The acoustic measurements in the six Neolithic sites showed all structures featured a strong resonance of between 95 and 120 Hz (with a wavelength of about 3 m). Despite considerable differences in chamber shape and exterior wall sizes, the resonant acoustic models were very similar with nodes and antinodes interspersed perfectly conforming to the central source of sound. In some cases, the design of the stone inside and outside resembled those of the acoustic models (2).

 Since these resonant frequencies are within the range of an adult male voice, the conclusion was that through the use of song and prayer, the chambers resonance efficiency was principally used for ceremonial purposes.



Map and resonance at Wayland's Smithy (by RG Jahn, 1995)



 The accuracy of construction however, was not down to mathematics as in a modern building. Wayland's Smithy (Great Britain) for example, has a cross-shaped configuration with two chambers east and west with a central corridor, the resonance frequency was not the same in the two side chambers. The west chamber which was cuboid in shape, had a resonance frequency of around 102 Hz. The east chamber which was more rectangular, had a resonant frequency of 117 Hz. To produce this unique stereo effect, the source of the sound had to be positioned at the center of the corridor in the middle of two chambers (3).

  All six structures examined by PEAR presented a resonance of around 110Hz. In some cases it appeared that some of megalithic stones had been erected and positioned intentionally to improve the acoustic properties of the chamber. This indicates a strong understanding of acoustic properties and resonance phenomenon in ancient times (3).


 It should be considered that the search by Jahn and collaborators was not the only such research in this field. Research on British Neolithic burial mounds by Keating and Watson of Reading University, also widely cited by Corliss in his catalog of archeological anomalies (5), is worthy of note.

It is important also to cite archaeological sites of ancient Greece such as theaters, Neolithic tombs and the famous Hypogeum in Malta. Alongside painted musical stalactites in caves inhabited in the Paleolithic period and the curious stones ''noise'' in Southern California used by the ancients Native American rituals (5).

 Armed with this background and previous experience we opted to study the Ravne tunnels (Visoko, Bosnia-Herzegovina). These were considered by some to be very old mines perhaps of the Neolithic period, but without valuing it as a very special temple, where ceremonies could have taken place.


The Ravne tunnels

 This is a series of tunnels dug into conglomerate in ancient times located close to Visoko (Bosnia-Herzegovina). We will discuss how much of the structure has been extensively altered at various times.

 It is certain that in the 1960s during the period of ex-Yugoslavia, the tunnels were modified as originally designed by miners in search of a water source for farmers. On that occasion an Eternit perforated pipe was placed just below the floor for a hundred meters and was capable of collecting all the water coming through the walls that collected at the bottom of the tunnels.

 The tunnels were also propped up in a large part and it is conceivable that the original Gothic arch shape was enlarged and modified in several locations.

 Similarly, in recent years large buttresses topped by wooden planks were used to make the structure more safe for visitors by preventing falling debris. This again has changed their original appearance.

 At approximately 250 meters from the tunnel entrance, we found other sections that had been mysteriously closed with earth up to the ceiling, as well as a large part of the side tunnels that lead from the open path. The motivation of this seal is not known and also our research group (SBRG) made several assumptions, never really supported by concrete evidence.

 Since 2007 the Foundation of the Bosnian Pyramid of the Sun, which has the government grants to carry out the archaeological excavations, proceeded to remove this seal to unearth large tracts of previously inaccessible tunnel.

 At the end of 2010, the work of volunteers and Foundation workers, reached an unexpected result. Prior to the de-sealing of the last sections of the tunnel a completely original tract was discovered, it was partly flooded and extended hundreds of meters.

  This new section of the tunnel has allowed us to rediscover the original shape of this structure which had been lost in other sections. The structure is quite simple, sometimes there is a large channel with minimum water flow in the base with walkable sidewalks. In other areas there are large stone walls along the side that do not appear to have been placed there to support the structure.




 Map updated in July 2011 of the Ravne tunnel (compiled by arch. L.Krsasovec Lucas). Blue in the new section means discovery is not possible over the dotted line as the water reaches the ceiling.


  We wanted to find those sounds found in prehistoric and protohistoric ancient temples, using the partly flooded original structure of the tunnel. The purpose of this research was to determine whether the morphology of the tunnel was only a random excavation typical of a mine and therefore free from special acoustic phenomena such as MRI or, their design was for another purpose such for ceremonies as found in Great Britain and Ireland.



 The entrance to the new section of tunnel was discovered in December 2010 (SBRG)



Materials and methods

Being a preliminary study we choose to not slavishly examine every part of the new
of tunnel with electronic sound generators. Instead we wanted to recreate the conditions present in ancient times where one male or female voice was singing or praying.

After nearly twenty years, our recording equipment and microphones were far more dynamic and high-end compared to the equipment used by PEAR group of Princerton. We used a dynamic high-end microphone extended in the ultrasound field with a sampling rate until 96.000Hz (Marantz PMD661 and Zoom H4N equipment).

To accurately incorporate the possible response to resonance by tunnels were introduced ultrasensitive omnidirectional microphones used by sea biologists (Aquarian H2a-XLR Hydrophone, frequency response from 10Hz to100.000Hz) into water which lies on the bottom of the tunnels of the new section.


 One of the used digital recorders (Marantz PMD661) and omnidirectional microphones can be used under water (Hydrophones Aquarian H2a-XLR) (SBRG)


This type of microphone has a wide bandwidth normally used by sea biologists to hear the song of the whales up to several kilometers away. In this case since the sound is transmitted very quickly in water, with the body of water acting as a reflector capable of capturing the resonance vibration of the tunnel up to many meters away.




 The maneuvers for the positioning of the microphones and recorders in the stretch of the original tunnel-free lighting (SBRG)


 At the same time, to verify the correlation between the vibrations of the voice of the singers and the response of the tunnel we wanted to record the voices of singers. We used microphones with a wide dynamic range, but also with a flat response at different frequencies (Sennheiser MKH 800 Twin capacitor, response Frequency 10Hz - 50.000Hz).




 We recorded the correct positioning of the singer after each performance, using the computer to test this.



 We used PRO TOOLS ver. 9.05 and Praat version 5.3.02 software for Mac to overlap and mix the various tracks recorded using two different methods.

 We analyzed the correlation between the sound source and response of the tunnel through sound spectrum graphics.

 The singers performed a repertoire of ancient chant and overtone singing. The latter was able to excite the surrounding structures with fixed unmodulated frequencies, typical of various mystical songs.


Preliminary results and conclusions

 Sound examination was immediately possible to verify a response sound resonance at very low frequencies, which lasted up to 20 seconds after the end of harmonic singing.

 The sound response of the tunnel was approximately 74 Hz, showing the shape of a wave similar to a Gaussian curve easily excited by the singers.

 The experience lasted several hours and was always repeated at the right vocal strain, confirming the repeatability of the phenomenon on equal terms.

 Although only preliminary, the examination carried out shows it would appear difficult to achieve a similar sound in a structure whose path is just random as is typical of a mine.

 The duration of the phenomenon does not appear typical of an echo or a reverberation. Rather it is more typical of a resonance phenomenon evidently sought through a link between the structure and the human voice.

 Further research is necessary using sound generators (electronic oscillators) that are able to resonate with the exact structure. An operation that we hope to undertake in the coming months.

Paolo Debertolis, Heikki Altero Savolainen, Carmine Barisano - February 17, 2012




(1)   J. Mortenson: “The Fall and Rise of Resonance Science”; Proceedings of Materials Science & Technology, pp. 2864 – 2875, 2010

(2)   Jahn R.G., et al.: "Acoustical Resonances of Assorted Ancient Structures," Technical Report PEAR no.95002, Princeton University, March 1995.

(3)   Jahn R.G., Devereux P., Ibison M.: "Acoustical Resonances of Assorted Ancient Structures,"  J. Acoust. Soc. Am. Vol.99 no.2, February 1996; 649-658

(4)   Devereux Paul, et al; "Acoustical Properties of Ancient Ceremonial Sites," Journal of Scientific Exploration, 9:438, 1995

(5)   William R. Corliss. Glen Arm: “Ancient Structure. Remarkable Pyramids, Forts, Towers, Stone Chambers, Cities, Complexes. A Catalog of Archeological Anomalies” ,The Sourcebook Project, 2001, Hardback, Maryland




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

B) Original recording of part of Harmonic singing made in Ravne tunnels. Harmonic singing shakes the Ravne tunnel for approximately 20 seconds after the termination of the sound. This can only be listened to using a high fidelity headset and not computer speakers. If the headphones are used with a large amount of bass you can catch the vibration response very deeply. This sound file was taken by microphones (Hydrophones) placed in water, which are able to capture the sound from a very long distance.

Find the track here.

The sound file was obtained by superimposing the traces of microphones placed in the air which collect the vibrations of the voice of the singer, with those placed in water recording the resonance response of the tunnel.

C) Path of the microphones in water only. In it, the resonance effect without the voice of the singer,

D) A brief video summary of the preliminary research,



Translated by Nina Earl





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