Many of us like to visit the ruins of ancient monuments and temples, trying to picture what went on at these places. But it tends to be a silent movie running in our minds, one that does not tell us what these ancient sacred places sounded like. Fortunately, archaeologists are at last beginning to realise that sound was vital to the religious practices of ancient peoples and so, gradually, the various soundtracks of antiquity are beginning to be investigated.
    Above all others, Freemasons will appreciate that the ancient Egyptians knew many secret arts, and we can safely assume that the secrets of sound were among them. For instance, there is a fallen obelisk in the great temple complex of Karnak in Luxor. If the ear is placed close to the pyramidal point and the block struck with the hand, the whole piece of granite can be heard to resonate. Goethe referred to architecture as "frozen music" and so it seems to have been in ancient Egypt. Did the temples of the Nile have their own notes, their own frequencies?

Vision and Sound

We now know that acoustics were important in other and often much older cultures even than that of ancient Egypt. Take the Palaeolithic painted caves of France and Spain, dating back tens of thousands of years. It has been found that some of the stalactites and stalagmites in them are musical, in that they will issue pure bell-like or gong-like notes when struck. Some archaeologists refer to these musical calcite formations as ‘lithophones’. Most if not all of these relatively rare features had been painted with geometric signs and animal figures in Stone Age times, and they also display ancient percussion marks. It has been found that echoes from the lithophones or human voices tend to be strongest from rock wall surfaces which contain the famous rock paintings. More recent work by the American acoustic researcher, Steven Waller, indicates that some rock art panels produce echoes that act like ‘soundtracks’ to paintings of animals, simulating the rumble of depicted animal herds, for instance, or the roar of a lion or sabre-toothed tiger.
    Association between rock art and acoustics have been noted elsewhere. Bronze Age petroglyphs at the edges of lakes near Helsinki have been found to be carved on rock surfaces that produce distinctly more complex echoes than other surfaces when the initiating sound is delivered from boats on the lakes. Currently, Russian and Finnish researchers are studying ‘palaeoacoustic’ sites on the shores of Lake Onega in Russia. The surface of the lake has been found to amplify the sound these natural stone ‘drums’ make when struck causing it to carry over kilometres. The features are surrounded by concentrations of rock art. Similarly, archaeologists in the United States have identified "ringing rocks" – boulders that emit bell- or gong-like sounds when struck – that are marked with rock carvings.
    This association between rock art and sound is perhaps not surprising – information is beginning to be uncovered by experts indicating that rock art inspired by the ancient and almost universal trance-based religion of shamanism derived from the idea that a spirit world existed behind the rock face, which was conceived of as acting like a ‘membrane’ between that world and this. In trance, shamans felt they could penetrate through cracks and crevices in the rock-face, and also that spirits could pass through from behind it into the human world. It is not hard to appreciate that echoes would have been considered a part of such traffic.
    Archaeologists have now started to use acoustic instrumentation to probe the secrets of ancient monuments. Two teams have been making the early running in the acoustic investigation of Stone Age sites in Britain and Ireland: Aaron Watson and David Keating of Reading University, and Robert Jahn and the present writer, of the Princeton-based International Consciousness Research Laboratories (ICRL) group. The two teams have worked independently of one another.

Making the Old Stones Speak

The Reading team deployed an amplifier and a digital audio-recorder with omni-directional microphone at a range of megalithic sites. The amplifier issued pink noise – that is, sound with a wide frequency spectrum. They observed the behaviour of the sound at recumbent stone circles like Easter Aquorthies, Aberdeenshire, and found the recumbent stone to act like a stage. An officiant singing, uttering or playing music in front of it would project sounds into the centre of the circle, with returning echoes from the perimeter standing stones, which increase in size and thus reflective effectiveness towards the recumbent block. The distribution of stronger sound was contained almost exclusively within the circumference of the stone circle. In a sense, the Reading pair conjured up the ghosts of Stone Age ritualists standing at specific spots.
    Elsewhere in Scotland, the Reading duo performed drumming inside the chambered Neolithic mound of Camster Round, Caithness. Although the drumming could not be heard more than a hundred yards away in the open air outside the cairn, the sound faintly but seemingly magically reappeared inside a companion mound, Camster Long, at least twice as far away.
    In Orkney, at the massive stone block of the Dwarfie Stane, which has chambers and passages that were hewn out of the solid rock in Neolithic times, they encountered another odd phenomenon: when they set up a resonant frequency inside the chamber using their voices, they found that the massive stone block and the air within it appeared to shake vigorously. The vibration was also evident to people standing outside on top of the tomb, so that the sensation of moving stone blocks could be achieved by the use of sound.
    The ICRL team used an omni-directional loudspeaker as a sound source driven by a variable frequency sine-wave oscillator, and a 20-watt amplifier. This was linked to a digital multimeter to verify frequencies, and the amplitude of generated sound waves were plotted using portable sound-level meters. An effectively random selection of megalithic chambered sites in England and Ireland were tested for their natural (primary) resonant frequencies, with only the great chambered passage-mound of Newgrange in Ireland being pre-selected due to the need for special permission.
    The findings surprised the ICRL researchers: all the investigated chambers were found to have a natural resonance frequency in the 95-120 Hertz band, with most at 110-112 Hz – this despite variations in sizes and shapes of the chambers. There was even some evidence of ‘retro-fitting’, as if internal features within the chambers had been placed to ‘tune’ the natural resonance to the required frequency. The great chamber of Newgrange resonates effectively at 110 Hz, and the 19m (62-foot) passage behaves like a wind instrument, with sound waves generated within the chamber filling it, their amplitude decreasing towards the entrance.
    The 110 Hz frequency is in the baritone range – the second lowest level of the male singing voice. The simplest indication to be taken from these findings is that male voices were used in these supposed tombs for the silent dead. This could have been on ritual occasions, or for oracular purposes, in either case most probably at those times of year marked by the entrance of sunbeams into the chambers, for these sites are astronomically aligned – at the 5000-year-old Newgrange, for instance, the beams of the rising winter solstice sun shine through a special roof box above the passage entrance, down the long passage and into the central chamber, making the stones there glow like living gold.

Mind and Body

Both research teams have considered the physiological and mental effects of sound, on the assumption that one of its ritual functions was to generate altered mind states to aid visionary experience. In one acoustic experiment at the Orkney chambered mound of Maes Howe, Keating reported being put into a state in which his body became relaxed but his mind alert, an initial stage of deep trance. Other bodily sensations were felt during on-site experimentation, including the illusion that the sound was being generated inside the participant’s head. The role of infrasound has also been considered. This is sound beneath the threshold of human hearing – a little below 20 kHz. It can’t be heard but it can be felt. Drumming and the sounds of certain other musical instruments can contain infrasonic components, and these would be enhanced inside the cavities of megalithic chambers and passages.
    Meanwhile, the ICRL team appear to be on the brink of scientifically linking the 110 Hz primary resonance band with effects on the brain: current experiments are showing that the specific frequency range around 110 Hz tends to stimulate a certain electrical brain rhythm associated with particular trance-like states.
    Although archaeological acoustic research is still in its infancy, and much more has yet to be learnt, the old knowledge is slowly being unveiled. Soon, perhaps, the old stones will be able to tell us more of their secrets.

Paul Devereux is a prolific author and lecturer specialising in ancient sacred sites and traditional lifeways.