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Published on Mar 7, 2012
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. 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). Filming and editing by Paolo Debertolis. January 2012