Archaeoacoustics in Tuscany at Abbadia San Salvatore

  • Print


TAG:  electromagnetic waves, ultrasounds, archaeoacoustics, Mount Amiata, SBRG, SB Research Group, Paolo Debertolis, Niccolò Bisconti

The hypothesis of our research group is that in some archaeological sites considered sacred for thousands of years, there are measurable natural phenomena that make the place somewhat more mystical than others.

Following this line of research, we started to test various sacred sites in Tuscany to assess this hypothesis. We found interesting archaeo acoustic effects, in some of them. Among them was the Cistercian abbey of San Salvatore in Abbadia San Salvatore in the province of Siena.

The first evidence of the existence of this monastic center in this location dates back to a document from 762 AD, but the existence of this place can be traced back to the sixth century BC during the process of urbanization of Northern Etruria by the Etruscans.

The excavations carried out in the area of the abbey in the '90s however, also gave rise to the discovery of arrowheads and flint, indicating the presence of a population since the Upper Paleolithic period.

The abbey also has a large sixteenth-century cloister with a huge tank of water, the depth of which is considerable and that according to oral tradition, sits on a natural source of water. It also collects rain from the surface above and filters it with an ingenious system of cleansing by carbon tanks located on the sides.


Fig.1 - The well at the centre of the cloister of the abbey of San Salvatore offers the only access to the huge tank below


The depth is greater than ten meters from the edge of the pit at the center of the cloister. Such a tank of water is precious in archaeo-acoustics because it works like a huge dish that collects the sound from the underground, thereby behaving like a perfect transducer.



Fig. 2 - The well was closed for about 15 years and the rusted padlock had to be sawn off


Thanks to the availability of the monks still present in the abbey, the parish priest Father Amedeo and Don Roberto (who recently celebrated 60 years of priesthood), we proceeded to reopen the well at the center of the cloister which had been closed for over 15 years and introduced microphones in deep water.




Fig. 3 - In the pit were placed two microphones Hydrophones that despite being equipped with a cable of 12 meters, are not resting on the bottom of the tank


 Fig. 4 - Immediately we have observed a strong ultrasonic signal coming from underground



Fig. 5 - Above: the recorder used, a Tascam (Teac group) DR-680 rated at 192 kHz sampling, 24-bit. Below: the high noise level of the signal is clearly visible on the screen of the VU-meter



Fig. 6 – We also placed another digital recorder in the cloister to verify the presence of spurious sounds from the environment that could affect the main recordings 


 Fig. 7 - Overview of the cloister with the equipment in place

The results appear extremely interesting: in all recordings made over two hours is present a very intense mechanical ultrasonic vibration, oscillating between 26kHz and 30kHz with a mean peak around 28.000Hz. with the look of a Gaussian curve.


Graph 1 – There is a peak of ultrasounds around 28.219Hz with an almost total silence on the other frequencies


 We took ten recordings with a long pause between one and the other, but the result was the same in all records over a period of three hours.

The recording system was built by a digital recorder Tascam DR-680 prepared for a sampling to 192kHz which can collect ultrasounds up to 96.000Hz without distortion and by microphones Aquarian Hydrophones H2a XLR (with a frequency response from 10Hz to 100.000Hz ). 


 Fig. 8 - We performed an immediate graphic control on recordings so that optimal adjustments of recording volume and execution times could be undertaken


Transposing the ultrasonic signal in the audible band was similar to a modulated whistle, that you can listen to here.

To check whether the signal was present in a larger area of the abbey we placed the microphones in a mining pond located less than 500 meters as the crow flies, but we did not detect any unusual signal.



Fig. 9 - The lake mining of “Gore” placed at few hundred meters away as the crow flies from the abbey. Its audio analysis did not record anything special



Fig. 10 - We  also examined other bodies of water nearby, but we did not find any ultrasonic frequency as that found in the Abbey of San Salvatore



The microphones placed in the surrounding area did not give any result for the presence of ultrasounds as in the tank of the Abbey of San Salvatore.


Fig. 11 - The complete group of researchers SBRG who performed the experiment. From left to right: mr. Andrea Venturini, photographer, prof.agg. Paolo Debertolis, physical anthropologist, mr. Giorgio Tondi, sound engineer, mr. Antonio Pacini, technical, dr. Niccolò Bisconti, archaeologist



It is expected in the future we will re-run the measurements at different times of the day as we did in our research of archaeo-acoustics in Bosnia.

Paolo Debertolis – November 8, 2012



Sincere thanks from all the research group SBRG to Giorgio and Verena Pacini, owners of the restaurant and bed & breakfast "Fonte Magria" who provided food and lodging for researchers and large rooms for the instrumentation. The restaurant "Fonte Magria" will therefore be our point of reference for next researches in Tuscany (also for good cooking!).