Preliminary archaeoacoustic analysis at Tarxien Neolithic Temples, Malta

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Tags: archaeoacoustics , archaeo-acoustics, low-frequency, infrasound, transducers, Malta, Tarxien, Neolithic, SBRG, SB Research Group

A few days before and in conjunction with the Archaeoacoustic Conference  "The Archaeology of Sound" in Malta on 19th -22nd February 2014, a small group of SBRG members performed several archaeoacoustic measurements on some ancient temples in Malta.

In particular measurements were taken at the temples of Tarxien on the island of Malta, and the temple of Ggantija and Xaghra circle on the island of Gozo.

Thanks to Heritage Malta we obtained the authorization for admittance to places normally closed to the public to take acoustic measurements.

The Neolithic temples of Tarxien are in the town of Tarxien on the north side of the island. This is totally surrounded by houses and as a result, it was not very easy to take high-level recordings inside. The analysis of the recordings took a few weeks, but it looks like there is a very low frequency coming from underground in the range between 21Hz and 23Hz, encroaching sometimes infrasound frequencies with a peak of around 18Hz.


 Fig. 1 - Three examples of recordings taken in two different locations within the archaeological complex: the audio track is constant for each recording. There is a  large peak with a maximum of around 21 - 23Hz in almost all surveys, sometimes extending to 18Hz. The hump at the end of the plot in the range of the ultrasounds is an artifact determined by the characteristics of ultra-sensitive microphones, but no ultrasounds were detected inside the temples of Tarxien



Fig. 2 - The trace recorded in the nearby hypogeum of Hal Saflieni, located a short from the temples of Taxien. The very low volume at the start of the line of sound should not deceive: the recording was made at a lower volume. But whatever the volume of the recording, this does not change the result because the peak at 21 - 23Hz, detected in the Temples of Tarxiem, is missing. It is clear that these inaudible seismic noises are probably originating from a nearby geological fault (Malta is in an area with a lot of tectonic plate movements)

As we know and we have verified in previous research on ancient sites in Europe (Bosnia-Herzegovina, Serbia, South England, and also Alatri in Italy), this type of frequency, if at an appropriate volume and not too high, can have a positive effect on brain activity. This effect is particularly evident in people who practice meditation. During the measurements we also attempted to verify the presence of a resonance phenomenon within the comples’s two temples, those in the best condition for this purpose. Various musical instruments were used, from primitive shamanic drum to percussion bells, but without success. Unfortunately, the structure is too destroyed in its higher portions that are deemed to have been covered by a dome roof.


Fig. 3 - The operations of recording inside the temples


These temples were brought to light by the Maltese archaeologist T.Zammit in 1915 after some local farmers had complained in 1913 that when plowing the field above the temples, the plough was ruined by large stone blocks. These temples were further excavated in 1954 by English archaeologist J.D. Evans and four years later by D.Trump who discovered the re-use of them in the times of the Roman Empire as a cellar.

This Neolithic complex was initially built between 3,600 and 3,000 BC as a sacred place, but at the beginning of the Bronze Age (2400-1500 BC) the original temples were reused as storage of funeral urns. This indicates that the original population was replaced by newcomers with different social customs.


Fig. 4 - A look taken from the gates of the temple. At the center of the curator of the archaeological site that has helped us for a better understanding this structure



Fig. 5 - A few more striking image of the prehistoric complex that, as we see, is surrounded by a densely populated town


In addition in the 1950s, where a piece of the megalith was missing, the structure was reconstructed in several places using Portland cement. This ran the risk of restoring something not true to the original, but according to the tastes of the restorer. The type of material used, compared to the original coral limestone megaliths in their uncorrected position, may have been detrimental to the proper sound functioning of the old structure. Also the concrete reconstructions may have damaged the original stone. Unfortunately at the time of the restoration this problem was unknown.

The reconstructed parts of the megaliths appear very light compared to the original under infrared photography, whereas in normal photography, the remanufactured parts appear more visible because they are brighter. The infrared photography also cancels the dark color due to molds and lichens present on the surface of the megaliths and prevent you from grasping the structural element in its entirety.



Fig. 6 - Some infrared photographs which highlight the original stone (in gray) from the reconstructed concrete (in white). In infrared photography the difference between the two different materials is exaggerated by the reflection of sunlight



Fig. 7 - The same architectural element taken using two different techniques. Above: photograph taken with an Olympus E- 5 digital camera with proprietary software which enhances contrast. Below: the same subject taken with a modified Canon infrared camera. There is a clear lack of ability to reflect the sun's rays on cement that looks almost white in color, while the sky is almost completely black


The temple complex consists of four sacred temples. The first of which is located on the eastern side and built between 3,600 to 3,200 BC. Unfortunately despite the five apses being clearly visible, only the foundations remain. The South Temple is the most highly decorated with megalithic constructions that also contain the lower part of a colossal statue of a female figure and the East Temple with its walls of stone slabs and well shaped 'oracle' holes were both built between 3,150 and 2,500 BC. The Central Temple has six apses arranged on one floor and contains evidence of a cover arcs.

Our research group performed measurements on two of the four temples.


 Fig. 8 - What remains of the colossal statue of a woman (Mother Goddess) in the South Temple. This is a copy, the original is in the museum of Archeology, Valetta


With the vibrations from the subsoil, it was observed that some megaliths appear to act as vibration transducers and some concavities or holes in their inner seem to project and focus these vibrations. The mechanism appears to be very interesting and detectable by instruments: an ancient lost technology that can now be rediscovered through the use of today's sophisticated equipment, but once found only by the sensitivity of a person.

The holes found in the megaliths are very deep and are considered to have been used to support the foundations of some sort of barrier or door. But the direction of the holes seems rather directed to a greater sound diffusion of mechanical vibrations as a kind of forerunner to speakers. The mechanism discovered by our associate anthropologist researcher dr. Alesandro Severi, seems to provide an intriguing interpretation of  this archaeological site but requires further in-depth analysis. Certainly we to exercise caution before saying as reported above, so we are already preparing a new inspection on the site to recheck the measurements.


Fig. 9 - A sensitive hand can discern the low-frequency vibration of the air


 Fig. 10 - Graphical extrapolation of the sound from the megaliths


A sincere thank you to the curator of the archaeological site, Joanne Mallia, Prehistoric Sites Department of Heritage Malta, for her kindness and courtesy. Her help enabled us to have access to more parts of the ancient temple.

It will be necessary in the coming months to further survey the archaeological site to study what we found on this occasion.

Paolo Debertolis, Nina Earl - March 26, 2014