Researches of archaeoacoustics in hypogeum of Cividale (Italy) by SBRG

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TAG: archaeo-acoustics, archaeoacoustics, hypogeum, Cividale, resonance, ultrasounds, SBRG, SB Research Group

Our research group has recently started a study of the acoustic phenomena present in Cividale hypogeum, which according to some historians can be attributed to the Celtic culture.

The Hypogeum of Cividale is located near the Natisone river, it has a single window on this river near the entrance. The rest of the rooms are carved in the conglomerate and appear to be free of other outside passages, the entire structure is without ventilation. We know that in Roman times this was used as a prison.


Fig. 1 – The fascinating hypogeum of  Cividale (Udine)



This underground structure is similar to other  much older structures, for example the hypogeum of Malta, which has absolutely peculiar acoustic phenomena.

At this time in our investigation we are evaluating the presence of resonance phenomena, by use of the human voice and electronic devices capable of emitting tones at different frequencies.


Fig. 2 - The operators at work during the night


For the initial tests which were carried out during the night (to minimize the interference from human activity on the surface above), we used a Tascam DR-680 digital recorder and Sennheiser MKH 3020 microphones equipped with shielded cables Mogami Gold Edition XLR and gold-plated connectors.


Fig. 3 - The exceptional microphones Sennheiser 3020 (frequency response 10-70.000Hz) in different positions in the fourth room of  hypogeum


In the first room we examined, we confirmed the presence of a resonance of around 101-102 Hz.
Who in ancient times applied these baritone tones at this frequency at a particular point of this room during singing or praying to stimulate the structure to resonate with a direct effect on the human body during the ritual?


 Fig. 4 -The experiment was carried out below the watchful and disturbing empty eyes of these carved faces in the underground conglomerate


 Fig.5 - The group of researchers who participated at the experiment


Our purpose is to backdate the structure in more ancient times than the Celtic presence in Friuli.

Paolo Debertolis – January 10, 2013


A sincere thank you from the SBRG research group to the owners of Cividale del Friuli hypogeum for their helpfulness and kindness in yielding even at night their ancient monument for our experiments. Heartfelt thanks also to Mr. Federico, who patiently gave us the keys of the hypogeum to our researches at all hours of the day.