• Voice1:08

Team Member:
Prof. Iegor Reznikoff

The Ħal Saflieni Hypogeumis an underground prehistoric burial site. Discovered in 1902 during construction works.  The complex is  made up of interconnecting rock-cut chambers set on three distinct levels. Earliest remains at the site date back to about 4000BC, and the complex was used over a span of many centuries, up to c. 2500 BC.
The uppermost level consists of a large hollow with burial chambers on its sides. This hollow was probably originally exposed to the sky and excavations in the early 1990s indicate that there might also have been a monumental structure marking the entrance. A doorway leads to the Middle Level, which contains some of the best known features of the Hypogeum such as the intricate red ochre wall paintings and the beautifully carved features in imitation of architectural elements common in contemporaneous Megalithic Temples.  The deepest of the three levels is known as the Lower Level, which is accessed down seven steps in the chamber popularly known as the ‘Holy of Holies’.
Ħal Saflieni Hypogeum is a unique site inscribed on the World Heritage List as “a site that bears a unique testimony to a cultural tradition which has disappeared”.
Paintings in red ochre, which decorate some of the walls within the site, are the oldest and only prehistoric paintings recorded on the Maltese Islands. Beautifully carved featured in imitation of architectural elements common in the above-ground temples, include an example of what a roof of these structures would have looked like.

While it is important to note that we can never know for certain what transpired within the Hypogeum 5,000 years ago, science can help expand the possibilities.

Our Investigative Team was richly multi-disciplinary.  Archaeology, Architecture and Acoustic Engineering helped define the when, what and the mechanics of how.  Backgrounds in Art and Music helped examine abstract expression.  Psychology and Anthropology addressed a human element that has not changed in long millennia.

Malta's Ħal Saflieni Hypogeum site is multi-chambered and acoustically complex.  Although legends and myths about its sound behavior have persisted since its rediscovery in 1902, the February 2014 exercise is the first scientific examination of its resonant properties to produce results.  A full report is being prepared for publication.

This preliminary report has been prepared by:
Dr. Paolo Debertolis, Department of Medical Sciences,
University of Trieste, Italy
Linda C. Eneix, The OTS Foundation, USA and Malta

The Ħal Saflieni Hypogeum Research Project
Malta, February 2014


Team Member: Nina Earl


  • Shamanic drum0:47

  • Friction drum0:34

Strong stimulation of resonance by harmonics of the drum at 114Hz   It is important to achieve a high volume pressure for good response The response is like a male voice saying “oooh”    If the drum is sounded with a soft hand instead of by a hard hit there is no resonance by the environment


Sound behavior in the Hal Saflieni Hypogeum is extremely complex, as is the physical effect of resonance on brain activity.  Pilot laboratory testing underscores the need for more neurophysiological study.

FRICTION DRUM - Some resonance but not strong


Katya Stroud, Heritage Malta

The acoustic properties of the (Hypogeum) site were not immediately apparent to its excavators, but when it was noticed, it became one of the highlights of any visit to the hypogeum. This acoustic phenomenon, together with the hypogeum’s mysterious nature and its suggestive ambience, slowly resulted in the site becoming associated with a number of fantastic stories, urban myths and legends.  Amongst these are stories of serpent priests, genetic mutation, humanoid beings, and screams of children lost in caves underneath the site. Despite their dubious origins and unfounded nature, these stories are still making appearances in local and foreign media.

It is now up to science to help us zoom back onto the real questions about the nature of the Ħal Saflieni Hypogeum, particularly its acoustic design and effects. Very brief and preliminary studies have been carried out on the acoustic nature of this part of the site. Unfortunately none have provided conclusive results. We may now have the opportunity to apply the latest scientific techniques, so as to start realistically evaluating this amazing phenomenon at the Ħal Saflieni hypogeum.



Team Member:
Prof. Torill Cristina Lindstrom


Baseline Sound of

Ħal Saflieni Hypogeum

  • Shouting0:15
Voice can stimulate the resonance of the structure at two frequencies (114Hz and 68-70Hz) 
Under the supervision of Heritage Malta, we placed microphones in the Oracle Chamber of Malta's Hal-Saflieni Hypogeum, a UNESCO World Heritage Site.  We used two digital recorders (Tascam DR-680 and Tascam DR-100) with power battery set at 192kHz of sampling rate for DR-680 (range 10Hz-96KHz) Ultrasensitive microphones Sennheiser MKH 3020 (frequency response of 10Hz to 50,000Hz) with shielded cables (Mogami Gold Edition XLR) and gold-plated connectors.  We tested the response of the chamber by different voices and by simple musical instruments which could have been present in the time the hypogeum was in use (4,000-2,500 BC) 

With volume and good speakers, you can discover some of  the Hypogeum's resonant nuances in these recordings.


  • Conch shell and horn0:59

Warming up in the Hypogeum,
Prof. Iegor Reznikoff


  • Hal_Salfieni_Reznikoff26:35

 VIDEO:  SBRG Research Group, Bosnian Pyramids:

Investigator Dr. Paolo Debertolis, SBRG Research Group,
Maria-Elena Zammit, Heritage Malta,
Linda Eneix, The OTS Foundation

Thanks to all team members, particularly to
Anna Borg Cardona and Kerem Akalin
for this segment of the investigation

We have no direct evidence of any of the instruments we used ever being used in the Hypogeum or elsewhere in Malta. - but all are just 'possible'.

- Anna Borg Cardona 

We discovered that the response in the Oracle Chamber is both 114Hz and 68-70Hz, so at these frequencies it is possible to activate the resonance of the structure.  If you speak at this low 70 Hz frequency (Oracle's voice) you can push the voice in all the hypogeum.  But in this way only a male voice can stimulate this phenomenon.  The shamanic drum can stimulate the resonance by its harmonics at the right rhythm.  The friction drum can also do it but without a good tuning up at 114Hz, the effect is less. It is possible to stimulate the phenomenon of resonance not only with a low male voice (praying or singing,) but also with a percussion instrument.  The use of the phenomenon for ritual purposes was not limited to a male with a low voice, but could equally have been exploited by a female with a drum.

The Ħal Saflieni Hypogeum Research Project



CLIP: Anthropologist Richard Rudgley ponders the architectural intentions of the Hypogeum's builders.  Courtesy of  Granada Television




  • RudgleyHypo0:42