The Sound Book: The Science of the Sonic Wonders of the World (2 page)

This particular group was re-creating a soundwalk that Murray Schafer and colleagues had first carried out in the 1970s. We followed a set of prescribed exercises—from trying to count the number of propeller aircraft heard flying over the formal gardens in Regent's Park (pointless nowadays, though you can still count jets), to trying to suppress a loud noise by consciously ignoring it. I chose the loudest sound around, a pneumatic drill that was hammering away on Euston Road.

Ignoring a pneumatic drill proved very hard to do; indeed, at first it seemed impossible. Trying to disregard the pounding noise immediately made it more obvious because of the way our hearing works. Seals might be able to close their outer ears when diving, but humans have no way of physically shutting out sound. We have no “earlids,” and there is no auditory equivalent of closing our eyes or averting our gaze. Our hearing is constantly picking up sounds. We cannot physically stop the eardrum, the tiny bones in the middle ear, or the tiny hair cells in the inner ear from vibrating. Inevitably, the inner ear generates electrical signals, which travel up the auditory nerve into the brain. Fingernails scraping down a blackboard or the climax to a Beethoven symphony, good sounds or bad—the ear sends the audio upward. The brain then has to work out which sounds are important and must be paid attention to, and which ones can be safely ignored. Something noisy and abrupt, like the roar of a tiger or the squealing of car brakes, catches our attention immediately so that we can fight or take flight. When we hear something less threatening, we have to think and decide which sound we want to attend to.

Auditory attention was first researched after the Second World War, as the military tried to understand why fighter pilots sometimes ignored crucially important audible messages.
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A typical experiment had people listening on headphones and saying aloud the words they heard through one of their earphones. Simultaneously, researchers played a distracting message in the other ear. After this test, subjects could recall very little about the distracting message. Scientists would make changes to the distracting speech—switching talkers or language, and even playing the sound backward—yet most people failed to spot the changes.
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Although many of us believe we listen to multiple sounds simultaneously, and even believe that women are better than men at such multitasking, these tests demonstrate that such an ability is an illusion. We listen to one thing at a time and rapidly change our attention from one sound to another.

Consequently, back on Euston Road the only way to quiet the pneumatic drill was to focus very hard on another sound. I used two strangers having a boisterous conversation outside a pub. Trying to actively suppress the drill just made it louder, but switching my attention elsewhere meant I could exploit the brain's amazing cognitive ability to suppress background noise.

During the hours focusing on the soundscape around me, I heard the fleeting melody of birdsong, an unexpected hush in the piazza outside the British Library, an auditory sense of enclosure as I entered the tunnel under Euston Road, and the subtle squelching of an underinflated bicycle tire on pavement. Interesting sounds suddenly became more obvious and audible. I was amazed to hear how different railway stations sounded; the throb of idling diesel trains in King's Cross made that station seem more authentic than St. Pancras or Euston. Of course, it was not all positive; the clatter of cheap rolling suitcases being dragged along platforms and sidewalks proved intensely annoying.

Acoustic ecologists have amazing ears for such sonic subtleties, but soundwalking and ear cleaning can help anyone learn to consciously tune in to such previously overlooked delights. We have at our disposal immense cognitive power to analyze sound—after all, listening to and decoding music and speech is an incredibly complex task—yet it is something we take for granted. A soundwalk reveals that there are sounds in our everyday life that, if we choose to listen to them, will surprise us with their diversity and uniqueness. Even something as mundane as footsteps encompasses a huge range of sounds, from the clack-clack of high heels on marble, to the squeak of sneakers on a gym floor. If we can unconsciously learn to recognize colleagues approaching unseen along a corridor from the rhythm of their walking, what else might we be able to accomplish with dedicated effort? Our ears play an immensely important role in how we perceive the world. In this book I hope to show how we can filter things differently, to move us away from our overreliance on the visual, showing how diverting our attention in this way can enrich our enjoyment and understanding of the spaces we inhabit.

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coustic ecologists are also concerned with aural conservation. Soundscapes do not need to be preserved in aspic, but we need to make sure that great sounds are not lost through neglect—not just calls from endangered species, but also other sounds that are important to us. Not long after my first soundwalk, I interviewed artists in Hong Kong for a BBC program about endangered sounds. They lamented the loss of the bells in the tower at the Star Ferry pier in Kowloon in 2006, which used to play the Westminster Chimes. Redevelopment and well-meaning renovations can ruin precious acoustic effects, as happened about a century ago in the US Capitol in Washington, DC, when architects altered the dome and dulled the focusing that used to distort the speech of senators. Acoustic scientists and historians have only recently begun documenting, preserving, and reconstructing the acoustics of a very few important places. Combining the latest methods for predicting architectural acoustics, three-dimensional sound reproduction, and new archaeological research, scientists have begun to reveal some of the ancient sounds of Greek theaters and prehistoric stone circles.

Another major threat to the sonic landscape is the smog of transportation noise. Underwater, baleen whales have to sing louder to overcome shipping noise. In cities, birds such as great tits have changed their tunes to be heard above the traffic. Of course, humans suffer as well: Nearly 40 percent of Americans want to change their place of residence because of noise, 80 million EU citizens live in unacceptably noisy areas, and one in three UK citizens have been annoyed by neighbor noise.
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Unintelligible announcements in train stations, restaurants where you have to shout to hold a conversation, and annoying mobile phone ringtones—we unnecessarily suffer a large number of acoustic deficiencies.

Some of these sound excesses are of our own making. Many of us take a large daily dose of music and speech through headphones that isolate us from the sound of our environments. It has become part of our daily routine: compared with only five years ago, youngsters spend 47 more minutes a day listening to music and other audio.
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We drive around in cars cocooned in our own portable and controllable soundscape. But then we miss out on simple sonic pleasures: not just the twitter of a bird singing out defiantly against the roar of traffic, the laughter of schoolchildren in a playground, or a snippet of overheard gossip from strangers passing in the street, but the wonderful and unique acoustics of the places we wander through each day. City districts can be visually ugly, but even there, a dingy corner covered in graffiti can harbor the most extraordinary zinging sound effects.

For decades, acoustic engineers have been trying to reduce unwanted noise, but many attempts have been defeated by changes in society. A modern car is much quieter than an old clunker, but increased traffic means the average city noise level has remained about the same. As the rush hour extends and motorists seek out quieter roads, peaceful places and times are disappearing. What should we do about this noise? I believe that telling people to stop doing noisy things is futile. It is better to encourage listening and curiosity. Although technology often produces unwanted noise, new devices are also creating bizarre and wonderful sounds every day. Gadgets emit distinctive pings and buzzes that people will cherish and be nostalgic about. The chime of the pinball machine takes me back to hanging out with friends in my youth. My children will likely have fond memories of the iPhone click, long after the device has been supplanted by more sophisticated technologies. With better awareness of the sonic wonders, I hope people will demand better everyday soundscapes.

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ince the trip into the sewer, my hunt for sonic wonders has morphed into a full-blown quest. I set up an interactive website (SonicWonders.org) to catalogue my discoveries and serve as a forum for people to suggest enticing sounds for further investigation. After a talk at a conference in London, a delegate told me about a large, spherical room called the Mapparium at the Mary Baker Eddy Library in Boston, where even nonventriloquists can throw their voice. This illusion plays with the mental processing that allows us to locate sound sources, processes that evolved to protect us from predators creeping up on us from behind. A conversation during a TEDx event in Salford made me want to find out more about the moths that have evolved decoy tails to fool echolocating bats. Rummaging through old proceedings from academic conferences has revealed a gold mine of acoustic curiosities, neglected phenomena that devoted scientists have studied alongside their day-to-day research.

Friends and colleagues, and even complete strangers, have given me examples of quirky acoustics and fascinating science. My research has uncovered the ways in which sounds have inspired musicians, artists, and writers: how church acoustics had to be adapted when the liturgy moved from Latin to English, how writers portray subtle acoustic effects such as the indoor feeling at Stonehenge, and how sculptors have ingeniously made sonic crystals that reframe ambient noise.

As a scientist, I want to pick apart what is going on. I went on holiday to Iceland many years ago and marveled at bubbling mud pools, but now I wonder, what caused them to gloop? I have seen Internet videos of a giant Richard Serra sculpture in which a hand clap resounds like a rifle shot. What is happening there? Why does throwing a rock onto a frozen reservoir produce the most astonishing high-pitched twangs? Some of these questions have no readily available answers, but in searching for explanations, I hope to gain insight into how our hearing works, both in these special places and in our everyday lives.

What makes a sound so extraordinary as to be considered one of the sonic wonders of the world? In my quest for these aural gems, I will rely in part on my gut reaction as a trained acoustic engineer: What might be surprising or weird enough to make the experts stop and wonder? One example might be the sonic behavior in an old water cistern in Fort Worden, Washington, which one audio engineer described as “the most acoustically disorienting place I have ever visited.”
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Or perhaps it will be something that takes us back in time to the experiences of our ancestors. Were the Mayan pyramids in Mexico deliberately designed to chirp? Was this sound used as part of their ceremonies? Sonic wonders might also be very rare acoustic effects: Only a few sand dunes sing, droning like a propeller aircraft—a phenomenon that astonished both Charles Darwin and Marco Polo.

Travel guides will be useless. Like most of our texts, they privilege the visual, describing beautiful vistas and iconic architecture while ignoring sounds and unusual acoustics. I was delighted to find the whispering gallery in St. Paul's Cathedral featured in my London guidebook, but this is a rare exception. The whispering gallery appeals to me as a physicist because the movement of sound around the dome fools listeners into hearing mocking voices emerging from the walls.

Music will play an important role in the search, not least because it can provoke strong emotions. Listen to one of Mahler's grand symphonies in an auditorium like the Great Hall of the Viennese Music Association (Wiener Musikverein) in Vienna, and you might feel shivers down your spine. Music is a powerful research tool, used by psychologists and neuroscientists to tweak the emotions of humans to reveal the workings of the brain. Research into music has taught us a great deal about listening—why some things sound nasty or nice, and how evolution has shaped our hearing. Often the best scientific understanding of sound and how we perceive it comes from research into music. But music and speech engage us on a different level. Indeed, recognizable patterns in music and speech can
distract
us from acoustics and natural sounds. This book will thus go beyond music and oratory to discover sounds that are overlooked or neglected.

Inevitably, I will have to use words and analogies from the visual world to describe sonic phenomena; we have relied on the visual for too long for our language to have developed otherwise. A newspaper interview with the artist David Hockney once said something about
seeing
that has stuck with me:

We don't just see with our eyes, [Hockney] argues, we use our minds and emotions as well. That is the difference between the image which the camera makes—a split-second record from a fixed viewpoint—and the experience of actually looking, of passing through a landscape, constantly scanning and switching our focus. That is the difference between the passive spectator and the active participant he wants us to become. The latter sees not just geometrically, but psychologically as well.
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I want to explore what would happen if we transpose these ideas from the visual to the aural. To see what fascinating sounds reveal themselves, and discover what effect they have on us. This book is about the psychology and neuroscience of hearing as observed and explored by a physicist and acoustic engineer. And no other place embodies the combination of these disciplines better than a concert hall. Strangely, we know more about the human response to classical music in an auditorium than about many more common sounds. Why not, then, start with the most important quality of a concert hall: reverberation?