The Sound Book: The Science of the Sonic Wonders of the World (8 page)

The oldest known wind instruments are flutes made from bird bones and ivory, found in a cave in Geissenklösterle, Germany, about 36,000 years old, from the Upper Paleolithic era.
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The best preserved is made from a hollow vulture's wing bone. It is about 20 centimeters (8 inches) long with a V-shaped notch at one end and five fingering holes.

How can archaeologists be confident that the bones were musical instruments? Holes could be made accidentally; unbelievably, swallowing and regurgitation by hyenas can create round holes in bones.
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But the Geissenklösterle bones have signs of deliberate and careful working, implying that the holes were precisely and purposefully placed. A replica was made and played. Treating the vulture's wing bone like a flute and blowing over the edge at one end produces a note. Pretending the bone is like a small trumpet and blowing a raspberry down the tube is also effective.
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Besides flutes, there is evidence of 30,000-year-old percussion and scraping instruments, along with the prehistoric use of ringing rocks and cave acoustics. A xylophone made from stone might seem an implausible musical instrument, more likely to produce a disappointing clunk than a resonating bong, but certain stones can generate notes. Examples are found around the world: from the tall slender rows of musical pillars in the Vittala Temple in Hampi, India, which ring like bells, to the large rock gongs in the Serengeti, Africa, made from boulders and covered in percussive marks, which make metallic clangs.

Nicole Boivin, from the University of Oxford, has studied the rocky outcrops at Kupgal Hill, southern India. These formations contain boulders of dolerite that create loud ringing tones when hit with granite stones. But did ancient people ever play the rocks? The best evidence is the Neolithic rock art alongside the percussion marks, showing that the site was used for many thousands of years.
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In a cave at Fieux à Miers in the south of France, there is a large, 2-meter-high (about 7-foot) stalagmite that rings like a gong. Fractures from when it was struck have been dated to 20,000 years ago.
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Dating percussion marks on rock gongs can be difficult, but in this case the new layers of calcite over the damage give an inkling of the age. What's more, this cave was only recently unsealed, and other prehistoric artifacts found inside indicate when it was occupied.

When I was younger I used to go caving, and I was strictly warned to be very careful of delicate stalactites and stalagmites. Earlier, in the mid-twentieth century, attitudes were more relaxed, allowing an act of “vandalism” to produce the most fantastical stone instrument. Luray Caverns in Virginia contains the Great Stalacpipe Organ, which entertains visitors and occasionally accompanies brides marching down the subterranean isle.

Andrew Campbell, the tinsmith from the town of Luray, discovered the cave back in the late nineteenth century. A report by the Smithsonian Institution in 1880 commented, “There is probably no other cave in the world more completely and profusely decorated with stalactite and stalagmite ornamentation.”
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When I visited, a year after my trip to Wayland's Smithy, I was amazed by the number of formations. They seemed to cover every surface. The curators have lit the cave with bright lights, giving visitors the impression that they're walking around a film set.

The organ is toward the end of the tour. In the middle of the cathedral cavern, among a forest of cave formations, sits an item that superficially resembles a regular church organ. But when a key is pressed, instead of compressed air blowing through an organ pipe, a small rubber plunger taps a stalactite, which rings and makes a note. The current instrument uses stalactites covering 1.4 hectares (3.5 acres) of the cavern. “It is the largest natural musical instrument in the world,” the tour guide proudly announced in a staccato Virginia twang so rapid that every other sentence was unintelligible.

With each key connected to a different cave formation, the organ can play thirty-seven different notes. A magazine article from 1957 reports, “Visitors stand enthralled as melody and chords play all round them. No twinkly tunes these, but full-throated music rolling through the cavern.”
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Apparently I heard a rendition of “A Mighty Fortress Is Our God,” a sixteenth-century hymn by Martin Luther, but I struggled to pick out any semblance of a tune. It was my own fault; I stood very close to the stalactite that plays the musical note B-flat to get a good view of how it worked. But this meant that the volume balance between the different notes was awry. The cave formations playing the notes are strung out over such a large area that many were too distant and quiet. From where I stood, the music appeared to have only five notes, and it was more like a piece of avant-garde experimental music than a hymn.

In the middle of the cavern the balance between notes is better, and the reverberance of the cave adds an ethereal quality to the music. A combination of the natural ring of the stalactites and reverberance in the cavern means that notes start and end vaguely. By standing close to one stalactite, I could examine the quality of one note in detail. It reminded me of a metallic gong or church bell.

The Great Stalacpipe Organ was the brainchild of Leland W. Sprinkle, an electronic engineer whose day job was at the Pentagon. While visiting the cavern, Sprinkle heard a tour guide hit a cave formation with a rubber hammer, and he was inspired to make the instrument.
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He then spent three years armed with a small hammer and a tuning fork, searching for good cave formations. When he tapped a stalactite, it would ring with the cave formation's natural resonant frequency. So his task was to find stalactites that produced a beautiful ringing tone and also had a natural resonant frequency close to a note in a musical scale. As Sprinkle discovered, the most visually impressive formations often failed to produce a sound that lived up to their appearance. Only two formations were naturally in tune, so others had to be altered. Sprinkle used an angle grinder to shorten these stalactites, thereby raising the natural frequencies of the cave formations, and eventually he produced a scale of notes that were in tune.

Sprinkle certainly did not spend a long time worrying about appearance. The Stalacpipe Organ looks as if a cowboy electrician botched the cave's wiring. The mechanisms are crudely bolted onto neighboring cave formations and walls, and wires hang loosely and without organization around the space.

Leland Sprinkle is not the only person to become obsessed with making the perfect rock instrument. In the nineteenth century, Joseph Richardson took thirteen years to construct a large stone xylophone out of hornfels slate from the English Lake District. According to the
Journal of Civilization
, Richardson was “a plain unassuming man, with no refinements of education, but possessed of musical talent.”
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The vast instrument currently resides in the Keswick Museum and Art Gallery in Cumbria, where visitors are actively encouraged to play it.

The stones of this “rock harmonicon” span two rows over 4 meters (13 feet) long, with steel bars and bells on two upper levels (Figure 2.2). The bass notes are poorly tuned, and the tone varies across the instrument. Some stones ring beautifully, like a wooden xylophone, while others sound like a beer bottle being struck with a stick. A better percussionist might be able to coax a more musical sound than I did. One historical account recalls, “The tones produced are equal in quality, and sometimes superior in mellowness and fulness, to those of a fine piano-forte, under the hand of a skilful player.”
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One of the key skills of a good percussionist is the ability to make the mallets rebound quickly, so that they do not inhibit the vibration of the instrument. According to the museum's curator, the whole instrument plays sharp; that is, the frequencies of the notes run higher than the standard scale. To tune the instrument, Joseph Richardson chipped away at each slate bar, gradually raising the frequency of the note. If he removed too much stone, the slate played sharp and there was nothing that he could easily do to flatten the note.

Figure 2.2 Richardson's rock harmonicon.

According to the
Journal of Civilization
, the Richardson rock harmonicon was so large that it needed three of Joseph Richardson's sons to play it, “one playing the melody, the next executing a clever working inner part, and the third the fundamental bass. Its power extends to a compass of five octaves and a half . . . extending, in fact, as high as the warble of the lark, down to the deep bass of a funeral bell.”
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I managed a plodding rendition of “God Save the Queen”—quite appropriate, since Queen Victoria had requested command performances at Buckingham Palace by what a handbill advertising a public concert described as the “Original Monstre Rock Band.”
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According to the
Times
, the first performance was “one of the most extraordinary and novel performances of the Metropolis.”
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The Richardson family toured Britain and the continent playing music by Handel, Mozart, Donizetti, and Rossini.
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John Ruskin, the great Victorian writer and critic, used to own a lithophone made from just eight rocks, and in 2010 a new instrument was constructed for Ruskin's old home in the English Lake District. Star percussionist Evelyn Glennie gave a celebratory performance on the new lithophone, which has forty-eight keys arranged in a sweeping arc around the player. The instrument contains green slate, blue granite, hornfels, and limestone from various local valleys and mountains. Writing in the
Guardian
newspaper, Martin Wainwright described the different sounds: “The clinker gives a short, martial note; the green slate a pure, clear, soft sound.”
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The team of geographers and musicians that constructed this new instrument also investigated what makes a rock ring. The size, shape, and material determine the frequency of the sound. But what intrigues me most is why some stones go bong while others merely clunk. When a percussionist strikes a stone that rings, the energy is held in the rock for some seconds, with the stone's vibration being gradually transformed into sound waves in the air that you hear. The rocks that go clunk lose their energy too rapidly within the stone. Good wineglasses ring when gently tapped. But rest a finger on the edge of the glass, and the sound disappears almost immediately. The friction between the glass and the finger dampens the vibrations and prevents the ringing. For rocks, the damping comes from the internal structure of the stone rather than your finger.

In 2010, I interviewed violin manufacturer George Stoppani for a BBC radio program about how to choose the right wood for the best-sounding violin. He went around his dusty workshop tapping pieces of wood to allow me to hear the different sound qualities. Only wood with the right grain density and microscopic structure produces a clear tone, which rings on for a few seconds—evidence that it can be used to make a world-class violin. It is similar with rock.
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Within the stone, vibrations are being passed from molecule to molecule. If there are any cracks or hairline fractures, then it is more difficult for the vibration to travel within the rock and the stone will ring less well. In the age of steam, wheel tappers working on the railways exploited the same principle, checking mechanical defects invisible to the naked eye by tapping the wheels of the trains with a small hammer. Lack of a satisfying ring indicated cracks, which could lead to a catastrophic failure of the wheel. But there is more to this than just cracks. Hit a piece of sandstone and it will not ring, whereas a piece of slate, like those I played at the Keswick museum, can impersonate a gong. Both stones originated from layers of sediments, but slate has been transformed by hundreds of millions of years of pressure into a denser material with a more ordered molecular structure. Vibrations can pass more easily between the neatly arranged molecules in slate than between the loosely packed grains of sand in sandstone.

M
y wife likes to have long phone calls while wandering around the house. As she walks between rooms, her voice changes in fascinating ways, both for her family in the house and for people at the other end of the phone line. Her voice is stronger and harsher in the kitchen because of the hard, reflective tiles and flooring, and clearer and warmer in the living room with soft furnishings, which deaden the sound. The microphone in the handset is picking up a mixture of the sound that travels straight from her mouth and the reflections bouncing off the walls, floor, ceiling, and objects in the room. She cannot sneak into the bathroom during a phone call with me because the bright reverberation is a dead giveaway. Size also matters: larger rooms tend to create a livelier, booming sound.

Now imagine you are prehistoric person wandering around a dimly lit cave system. Your voice will alter as you move from cavern to cavern, through narrow entrances and down tortuous tunnels. The sound quality varies because of the changing patterns of reflections from the rocks. In large caverns a booming reverberance might be heard, in extreme cases mimicking the sound of a church. But in smaller caverns and tight squeezes, the key acoustic effect is
coloration
.