Archaeoacoustics

MALTA: 1902 A construction worker unexpectedly broke through the bottom of a household cistern. A dark man-made cavity lay below.

Descending over stone barriers into shadows, he found underground rooms opening up before him -- three stories of sculpted man-sized burrow suggesting some fantasy realm of Mother Earth. Columns and windows defining and tantalizing, spaces cut out of the stone as if it were soft cheese. With all that breathtaking visual weirdness, the odd echo of his footsteps may have gone unnoticed at first. Following the curve, he had to step down another three feet to reach the floor of a dead-end gourd-shaped room hollowed out of solid limestone: the Oracle Chamber.

On the ceiling, painted tendrils and disk patterns of red ocher spin out from the entrance, ending just above the chin-level niche in the side wall. Researcher Paul Devereux.^[2] is among those who think that these could represent acoustical notation. Dark stains on the rim of the niche testify to the resting of many hands in a natural pose as one’s face is aimed toward the painted red lozenges on the wall within. Could these be target spots for achieving the best sound effects? Nearby, at the closed end of the chamber, a distinctive curved channel has been cut at the top of the concave wall. Was this designed to enhance the amplification? Is it possible that the designers of these spaces knew something that modern scientists are just rediscovering? What is this strange giant sculpture? It hasn’t changed much. It is a dark and mysterious place, even today.

Sixty miles south of Sicily, in the middle of the Mediterranean Sea, lies a small cluster of islands known today as Malta. The largest island, with natural deep-water harbors is simply named Malta. To the Romans it was Melita: “honey” in the color of the golden limestone or a specialty product of the local bees. Earlier Phoenician traders called it Maleth, for its safe refuge. We don’t know what it was called six thousand years ago when prehistoric architects came up with the idea to build megalithic temples here. The resulting constructions are the oldest monuments on earth: at least a millennium ahead of Stonehenge and the Pyramids. Our present purpose is to explore the possibility that sound played a large part in the process of their evolution.

The “Temple Period” spanned more than a thousand years of continuous building and elaboration, from about 3700 BC until around 2400 BC when the monuments seem to have been abruptly abandoned without explanation. Where it could be scientifically studied, the stratigraphy generally showed an unpopulated accumulation of dust and debris for several hundred years until a Bronze Age people came to the islands and reused some of the already ancient buildings that they found.

There are more than thirty sites on the islands where it is known that megalithic temples once stood. Today, they are in various states of ruin ranging from a few foundation stones to four amazingly intact complexes. A fifth is a subterranean site: apparently a temple for the dead.

Something was born here on these islands. Some bold and creative prehistoric soul had the first design concept; perhaps inspired by the shape of natural caves or some anthropomorphic desire to pay homage to a deity of the earth. The temples exhibit features that are unprecedented. The earliest use of courtyards, retaining walls, corbelling and the horizontal arch are all found here. Furthermore, there are clear indicators that these processes evolved in situ and were not brought to Malta from somewhere else. It is mind-numbing to consider that these structures have survived through every eruption, flood, earthquake and war in history. As impressive as they are for their age, however, the temples represent more than archaeology.

Although archaeologists have had no explanation for the blossoming of such sophisticated cultural complexity, FAIA architect, Prof. Richard England sees an evolution: “… a gradual growth, from the cave to the tomb. The idea of continuity comes from an underground architecture. Gradually, from these ovular rock-hewn spaces, man moved above ground, and above ground he fashioned an architecture of the living which followed the form of an architecture for the dead.”[3]

With far more sophistication than any ring of standing stones, the monuments are true buildings, with advanced engineering of inner and outer walls, and ring compression systems. They are comprised of walls, still enclosing space as they were thoughtfully pre-designed to do. All clearly of the same school, each is true to the basic form of a central stone-paved corridor interrupted by low thresholds defining paired D-shaped or ovoid rooms to either side. When in use, they were most certainly roofed, although the methodology has been hotly debated. What look like trilithons are actually four-piece arrangements with threshold paving slabs bracing the bases of the uprights.

Stone spacers were slid into horizontal channels like the shelves of a bookcase. Vertical interior wall slabs were pitched with the bottom leaning into the between-wall fill to distribute the weight of the courses above; corbelled rings locked into place with a slight downward tilt. For the outer perimeter walls, megaliths in an alternating face-out and edge-out configuration anchored the considerable mass. The resulting stability is the reason the temples survive today. So far, the Ggantija Temple has been standing up to twenty three feet high for 5,600 years.

Arranging 19-ton megaliths is, of course, not a casual undertaking. With all the time in the world and ample man and ox-power, it was still a serious commitment. Models would have helped work out the details, and in fact vestiges of these preliminary plans do exist. We will never know how much trial and error took place before the first success was achieved, but the motivation must have been tremendous. The temples were expanded and improved on over time as skills and methods were improved. An engineer calculated that, allowing for time taken up in food production, it would have taken 150 men about three years to build one.[4]

Today, nothing of the textiles or furniture remains, but sculpted artifacts show that the temple builders had them. Their hair was styled and their garments were tailored: these were hardly primitive savages.

Recovered artifacts, of which there are quite a variety, reveal stunning self-portraits when carefully lit. There is a quiet dignity about them, with faces tilted upward toward the sky. Some of these Stone Age faces look a lot like people walking the streets of the world today. As a sense of identity emerges, questions arise about who they were and who they may have become.

While gender is an issue of some magnitude where interpretation of the more abstract and cultic figures is concerned, it is interesting to note that in none of them is there any trace of a beard or facial hair. Nor will one see ears. Do the careful hairstyles, the carved hoods and caps imply that perhaps ears were a particularly personal part of the body? It’s a provocative thought that may be indulged for just a moment while the reader considers the possibility of an ancient interest in the manipulation of sound.

Since being cleared of debris, largely by British troops in the mid-1800’s, the temples have been open to the sky. Yet they remain intimate spaces, the scale of which seems to enclose a person in comforting security. Particularly where the corbelling survives, gently closing in the space as the concave wall rises higher, the feel of the original room is easy to imagine. It is not unusual to encounter a group of visitors singing or chanting or toning in the chambers. Why? Because it feels good. There is an odd character to the way the stone plays with the voice. The curved walls invite one to wonder if the sound quality may even have played a role in their design. An absence of ceilings in the exposed temple sites has always made it difficult to know much about acoustic properties in the temples, but the recent installation of protective covers has changed the visitor experience. The soundscape is altered. There are new echoes.

And for those of us who are interested in such things, there is this remarkable underground temple with its ceilings perfectly intact: The Hal-Saflieni Hypogeum, this “haunting place of dreams and secrets”, with eerie sound effects that have been reported for nearly a hundred years.

Since UNESCO-funded renovation, ten people per hour are permitted to pass through computer-timed airlocks and descend via paved and railed walkway into the subterranean complex of rooms. They have watched a short film and learned that the site was manmade by the same people who built the temples, and that the bones of some seven thousand people were once interred in ovoid pits and rooms overlooked by a chiseled masterpiece of space known with some reverence as “The Holy of Holies.” Richard England estimates that 2,000 tons of rock were removed to create these spaces. Like an underground negative mirror of the temples, architectural features were carved out with antler picks, stone hammers and obsidian blades. The original aroma is something we can only imagine today. The atmosphere is cool and humid.

The Hypogeum was reopened by accident in 1902 when builders were putting up the houses in the neighborhood above it. Unfortunately, scientific excavation was not documented when the pottery and figurines were removed from its chambers. Many are now showcased in the National Museum of Archaeology although others have doubtless disappeared into private collections. The human bones are said to have been brought out by wheelbarrow and spread on the fields for fertilizer, but not before it was noted that they had been treated with an application of red ochre directly on the surface. The implication is that after flesh was gone, the bones were interred in the shrine in ancient times, likely with accompanying ritual ceremony.

Standing in the Hypogeum is like being inside a giant bell. At certain pitches, one feels the sound vibrating in bone and tissue as much as hearing it in the ear. It’s actually quite thrilling. As anyone who sings in the shower knows, sound echoing back and amplifying itself from hard surfaces can do unusual things. That effect is hugely magnified in Malta’s limestone chambers.

More modern impressions about the acoustics were recently collected by journalist Billy Cox.[5] "It was unlike any space I've ever been into; it easily surpassed what the Vatican and the Pantheon had to offer," says Tom Hughes, a retired lawyer from Tampa who visited Malta last year. "It was a revelation. It didn't exceed my expectations. It blew my expectations to pieces."

After his own glimpse into the Oracle Chamber, Sarasota arts and architecture critic Richard Storm reiterated National Geographic's first impression. "It was kind of terrifying," Storm says. "Because you sense something coming from somewhere else you can't identify. You are transfixed."

It turns out that these Stone Age builders may have stumbled onto something.

A consortium from Princeton University have pioneered the field of archaeoacoustics, merging archaeology and sound science. Directed by Dr. Robert Jahn, the group set out in 1994 to test acoustic behavior in megalithic sites such as Newgrange and Wayland’s Smithy in the UK. They found that the ancient chambers all sustained a strong resonance at a sound frequency between 95 and 120 Hz. -- well within the range of a bass baritone.[6] It may be the dimensions of the room or the quality of the stone that determines the exact pitch of this echo behavior.

In subsequent testing in Malta sponsored by The Old Temples Study Foundation of Florida, stone rooms dug out for bomb shelters in World War II were found to match the same pattern of resonance, registering at the frequency of 110 or 111 Hz. Other solid stone rooms in Malta have been found to resonate at the same frequency. Maltese composer Ruben Zahra and a research team from Italy have determined that it is also at this level that the Hypogeum’s Oracle Chamber vibrates with its peak resonance.[7] 110 may be a “magic number” where sound is concerned.

Dr. Ian Cook of UCLA and colleagues published findings in 2008 of an experiment in which regional brain activity in a number of healthy volunteers was monitored by EEG through exposure to different resonance frequencies. Their findings indicated that at 110 Hz the patterns of activity over the prefrontal cortex abruptly shifted, resulting in a relative deactivation of the language center and a temporary shifting from left to right-sided dominance related to emotional processing. This shifting did not occur at 90 Hz or 130 Hz.[8]

Whether it was deliberate or not, the people who spent time in such an environment as the Hypogeum under conditions that may have included a low male voice -- in ritual chanting or even simple communication -- were exposing themselves to vibrations that may have impacted their thinking. In addition to stimulating their more creative sides, it appears that an atmosphere of resonant sound in the frequency of 110 or 111 Hz would have been “switching on” an area of the brain that bio-behavioral scientists believe relates to mood, empathy and social behavior.[9]

The physics of the reverberation phenomenon are not so unusual. Sound engineer Daniel Talma explains that: “At certain frequencies you have standing waves that emphasize each other and other waves that de-emphasize each other. The idea that it was used thousands of years ago to create a certain trance -- that’s what fascinates me.”[10]

In the absence of written records, we are never going to know what happened here thousands of years ago. Did some High Priest once stand at this niche and mesmerize the community with the echoing voices of their ancestors or their deity? Were pregnant women coming down into a temple of the dead to introduce their unborn? Were priestesses-in-training being directed in their dreams? These inventive ideas and more have been suggested at one time or another.

Several foreign groups claim to have mapped the acoustics of the Hypogeum, which are said to be extremely complex.[11] Whatever the science or the physics, the people of prehistory probably didn’t understand that part anyway. In the context of environmental psychology, it is the human experience that is now of interest, and there is little doubt that it must have been exceptional in the days when natural was more supernatural.

A multi-disciplinary project has been outlined to undertake a challenging and unprecedented experiment. Once underway, on site in the Hypogeum, they will collect biofeedback data including EEG from living subjects exposed to naturally produced sound in the frequency of 110 Hz, emanating from the Oracle Chamber. The on-site readings will be monitored, coordinated and studied using technical signal analysis tools to determine any physical effect of exposure in actual conditions that were possible in prehistory, and if the replication of such effect might have a modern therapeutic application.

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[1] Griffiths, William Arthur; “Malta and it Recently Discovered Prehistoric Temples”, National Geographic Magazine, Vol. XXXVII, No. 5
[2] Devereux, Paul, "A Ceiling Painting in the Hal-Saf lieni Hypogeum as Acoustically-Related Imagery: A Preliminary Note", Time and Mind:
Volume 2—Issue 2, July 2009, pp. 225–232
[3] England, Richard; on-screen interview; “Legacy of a Lost Civilization”, 2009 documentary
[4] Trump, David H.; on-screen interview; “Legacy of a Lost Civilization”, 2009 documentary
[5] “… an Ancient Mystery”, Sarasota Herald Tribune, 12 March 2010
[6] Jahn, Robert G., et al; "Acoustical Resonances of Assorted Ancient Structures," Technical Report PEAR 95002, Princeton University, March 1995. Devereux, Paul, et al; "Acoustical Properties of Ancient Ceremonial Sites," Journal of Scientific Exploration, 9:438, 1995.
[7] Zahra, Ruben, personal communication, January 2010
[8] Cook, Ian A.; Pajot, Sarah K.; Leuchter, Andrew F., "Ancient Architectural Acoustic Resonance Patterns and Regional Brain Activity," Time and Mind, Volume 1, Number 1, March 2008 , pp. 95-104(10)
[9] (see Left Brain:Right Brain by Dan Eden)
[10] Talma, Daniel; on-screen interview; “Legacy of a Lost Civilization”, 2009 documentary
[11] Devereux, Paul; personal communication, March 2010

"A word spoken in this room is magnified a hundredfold and is audible throughout the entire structure. The effect upon the credulous can be imagined when the oracle spoke and the words came thundering forth through the dark and mysterious place with terrifying impressiveness." ^[1]