The Sound Book: The Science of the Sonic Wonders of the World

by Trevor Cox

  I turned my mountain bike off the road and onto forest trails, trying to get as close as possible to the most tranquil spot. I parked my bike, put on walking boots, and started the long trudge cross-country. As I left the trees behind, I entered one of the Kielder Mires, the local name for peat bogs covered in moss and heather. The ground was very uneven, and my feet kept disappearing into dips and gullies and getting soaked. I had previously thought of asking the CPRE if I could publish the location of the quietest place. But I now realized this would be a bad idea. If lots of people put this on their rambling bucket list, then this delicate wetland terrain would be damaged.

  Fortunately, no one was logging in the forest, and the military were having a day off. It really was incredibly quiet, with the only sound coming from my pounding heart, heavy breathing, and rhythmic squelching from my boots. After an hour I judged I had reached the final location, and I turned on my phone to check the GPS coordinates. A beep announced the arrival of a text message. There was no other sound, no visible sign of human activity, and yet I had decent mobile phone reception!

  To capture tranquillity, I decided to try my sound-recording equipment. Even with the gain on my recorder turned up to its highest setting, there was nothing to be captured apart from the dull background hiss of electrical noise from within the equipment, and the occasional flapping sound as I tried to kill the midges that were feasting on me. Just then, a few birds flew by in the distance, called out using rapid staccato chirps, and quickly disappeared before I could spot what they were.

  This was not a very serene, rejuvenating, or relaxing silence. I was exhausted, my feet were drenched, and I was unable to sit down in the wet peat bog. The mild anxiety that the military might turn up and arrest me for trespassing did not help. But I was surprised and impressed that I had found complete silence in the English countryside. For me, the lack of animal sounds detracted from the experience, reminding me that the surrounding monoculture of conifer trees is not good for biodiversity. Complete silence in a natural setting is not necessarily wonderful. I wanted to hear birds or the trickle of a stream; even a buzzing fly would have been good—some sound that signified life.

  More than half the world’s population now lives in cities. Is it possible to find some form of tranquillity in an urban environment? Engineers have been working hard to make cars quieter, but with more traffic on the road, average noise levels in cities have stayed the same.29 And considering only an average of the noise level overlooks a crucial trend. As motorists try to avoid traffic by leaving for work before or after rush hour, their noise pollutes peaceful times of the day. As drivers try to avoid gridlock, they turn calm back roads into rat runs, ruining quiet places. Although cities thrive on human activity, vibrancy, and excitement, people need relatively quiet places for respite from the hustle and bustle.

  Policy makers are interested in how tranquil refuges can be preserved, but achieving such protection is turning out to be difficult.30 The ideal would be to craft a simple metric that could be measured on a sound-level meter or predicted in a computer model. A scientific report once suggested that areas with sound levels below 55 decibels (a level you might hear from a cheap refrigerator) should be designated quiet areas; another, that man-made sounds should be below 42 decibels (a typical level for a library).31 By those criteria, there are no tranquil areas in major cities like London, which is nonsense. Like all world capitals, London is a noisy place, but turn a corner and go down a back street and often you find a quiet square where noise is distant and less intrusive. This just illustrates the problem of trying to reduce human perceptions to simple numbers.

  In a city, what matters is relative quiet rather than absolute loudness. As in the countryside, man-made sounds need suppressing, but they do not have to be inaudible. Songbirds, rustling leaves, and moving water need encouraging, because studies have shown that tranquillity in towns is greater when natural sounds are louder. Other senses need to be considered: research suggests that places with more hard landscaping need to be quieter than greener refuges, and certain smells, especially the stench of street urination, do not aid tranquillity.

  How might you make such an acoustic oasis? Layout is very important because a noise source out of sight is usually quieter. The piazza in front of the British Library in London is an interesting example. Facing onto a very busy street, it is still possible to find some quiet in this pedestrianized square because a high wall hides the road. Unfortunately, bass sound carries over the wall more easily than higher frequencies, so the rumble of waiting buses is still overpowering from time to time, but a higher wall placed closer to the road could solve this problem.

  In quiet back streets, it is actually the buildings that often act as barriers to noise. Hildegard Westerkamp, a world-renowned composer, radio artist, and sound ecologist from Canada explained to me on the London soundwalk that this “quiet stone sound of back streets” is heard only in old cities where roads are narrow and buildings close together.32 In North America, where most of the streets are wide, it is also hard to escape the hum and whine of ventilation fans. Since lowering sound levels at the source is the most effective strategy, having fewer, slower cars is good, as is reducing rolling noise through better asphalt and tire design.

  As for promoting desirable sounds, water features and fountains create likable babble and splash that can also mask unwanted traffic noise. Hong Kong is incredibly crowded and noisy. Even so, close to the center there is a park with a giant aviary where man-made sounds are completely absent and the songs of the birds can be enjoyed. The traffic noise is inaudible because the babbling of a stream helps hide the sound of the roads. Sheffield in northern England was at the heart of the UK’s steel industry and famed for its high-quality cutlery. Nowadays, it may be better known as the setting of the film The Full Monty, a black comedy about former steelworkers, unemployed and desperate for money, forming a striptease act. At Sheffield train station there is an enormous fountain (Figure 7.2). It is on a size and scale that I expect to see only on the grounds of a grand, stately home. I travel to Sheffield often and had noticed this huge water feature being built, but I did not realize the subtleties of the acoustic design until they were pointed out to me by Jian Kang, a soundscape guru from one of the local universities. The high-sided walls of shimmering water serve as a noise barrier shielding the square from traffic. In addition, a series of large pools stretches downhill with water flowing between them. If you stand in the right place, the waterfalls between the pools imitate the chuff-chuff sound of steam trains because the water stops and starts. This irregular flow draws more attention because it is harder to tune out intermittent sounds than continuous ones. The fountain makes the traffic less perceptible by both physically blocking the sound and generating pleasant, distracting water sounds.

  Figure 7.2 Part of The Cutting Edge, a fountain by Chris Knight of Si Applied, acting as a noise barrier outside the Sheffield railway station.

  I talked to a colleague from Salford University, Bill Davies, about the large research project he had conducted investigating positive sound design in cities. Appropriately, he is the most soft-spoken person I have ever met—so quiet that his speech becomes almost inaudible at times. Bill and his collaborators took people on soundwalks and asked them about their impressions of city squares; they also played sounds to subjects in the laboratory and asked which ones they preferred. The results showed that vibrancy and pleasantness are important.33 A busy piazza can be buzzing with people, yet there is a pleasant calmness if you are slightly distant—say, in a café on the edge of the square watching the crowd go by. This may be true even if cars are present. In contrast, a city square that is little more than a traffic rotary lacks the babble of the crowds. The noise from cars is just unchanging and unpleasant.

  Researchers have demonstrated the health benefits of natural sounds, but I think Bill’s finding on vibrancy and pleasantness indicates that scientists are overlooking an important sound that could also be good fo
r us. Perhaps hearing human activity reduces stress. The quiet chatter of people in a café is relaxing and not too alerting. Furthermore, one should have a positive emotional response to being surrounded by other people in a friendly atmosphere. After all, being a social animal has been a vital part of our evolutionary success. Maybe this is an avenue for future research.

  One thing is certain: perception of silence is highly subjective. In Kielder Forest I felt there should have been natural sounds, and the lack of them made the place seem barren. On the Mojave dunes, the enveloping silence seemed appropriate and peaceful. Looking out over the vast, barren valley, I could imagine the complete quiet extending for miles. The silence waxed and waned as the wind came and went, creating a gentle whooshing past my ears, or the occasional insect buzzed, or I heard the beating sound of bird wings. These aural accents made the silence seem very natural.

  An ex-colleague of mine, Stuart Bradley from Auckland University, has visited Antarctica, another place devoid of vegetation where silence can be heard. Stuart is a tall New Zealander, sporting a fine mustache like a soccer player from the 1970s. Ironically, what Stuart does in Antarctica is make noise and briefly ruin the pristine natural soundscape. He uses a sodar (a sound radar system) to measure weather conditions, sending up strange chirps that bounce off of turbulent air in the atmosphere before returning to the ground to be measured. I asked Stuart if he had experienced silence in Antarctica, and he told me about his time in the dry valleys, possibly the most barren places on Earth, which lack snow and ice cover: “Sitting up on the valley wall on a still day, there was no sound I could identify (except heartbeat? breathing?). No life (apart from me). So no leaves either. No running water. No wind noise. I was certainly struck by the primeval ‘feel.’ ”34 Stuart commented on how different this was to the sound of a silent laboratory, “I didn’t get the claustrophobic feel one can get in an anechoic chamber . . . I suspect this is because, although it was incredibly quiet, it was also a very, very open vista (the valley walls were 1,500–2,000 meters [5,000–6,500 feet] high and the visibility was amazing!).”

  Getting away from normal existence and civilization is an important part of silent retreats. John Drever, the acoustic ecologist who had taken me to hear bitterns (see Chapter 3), suggested that I needed to experience a retreat to truly understand silence. So I signed up for three days of Buddhism in an eighteenth-century manor house out in the English countryside for a month before I went into the desert. Only when I arrived did I realize that this Buddhist weekend would involve fifteen meditations a day, challenging my inflexible, middle-aged body to adopt an unfamiliar posture for hours. It was a great relief when the gong sounded to end each backaching session. I needed to have done some training to be better prepared for the static gymnastics.

  Just before silence started on the first day, we were asked to tell a fellow retreatant why we were there. I said I was researching silence for a book, my fellow retreatant announced she was struggling with a bereavement, and then we were told to be silent. That bombshell, that glimpse into her heart, was left hanging in the air for three days. The only two words I said in the next twelve hours were “compost bin?” as I searched the kitchen during my work hour. The only other talking I did over the following three days was during two brief question-and-answer sessions with the teachers.

  On the first evening, I was struck by how odd it was going around the house without talking. There were about fifty of us, so I was constantly passing people in the corridors, or waiting in line for food and the bathrooms, but no words were exchanged. I did more smiling at strangers in one day than I normally do in a whole month, but eye contact alone seemed odd and awkward.

  Sitting down to our simple Buddhist meal of split-pea soup and whole-wheat bread (maybe not the best choices for maintaining bodily silence), I found myself directly opposite a woman in her midforties. I did not know where to look. We were close enough to be invading each other’s space, but being unable to say hello made the proximity seem exceptionally intrusive. It was weird not being able to engage in small talk. The retreat teachers encouraged us to find comforting community in the shared experience and something supportive in the silence. For me, however, it was a struggle, and I had a strong feeling of cold isolation.

  The room where we meditated was the size of a small church, and we sat or knelt in regimented rows on mats. Everyone had a personalized nest shaped from cushions, blankets, and tiny wooden stools to make the sitting more bearable. At the front the teacher sat mostly in silence, occasionally giving instruction. As I settled down for the first sitting, I realized that not only was I physically ill prepared, but I also did not know how to meditate. “How do you know you have a body, right now . . . how is your breath?” the teacher queried precisely and slowly. I learned self-hypnosis twenty years ago, and around the same time I had practiced the Alexander technique to improve my posture, so I did my best to meditate by mingling these techniques with hints picked up from the teacher.

  The teacher asked how we knew we were “inhabiting a body.” Apart from discomfort and breathing, the awareness came from the sounds around me. This was hardly a silent retreat! Above the meditation hall was a large rookery, and the loud squawks and squeals as the rooks fed their chicks rang out across the hall, interspersed with the soft, warbling tones of blackbirds and the cooing of wood pigeons. Less poetic was the gurgling pipework—from stomachs and radiators—and coughs as people cleared their throats. As I was to learn over the next few days, part of meditation is accepting these sounds and incorporating them into the practice.

  On the way to the retreat, I had read some scientific papers about how brain networks are altered by mindfulness techniques, and these accounts helpfully described the stages of focused-attention meditation, which I then copied.35 You start with a focus—say, your breath passing through the nostrils. Inevitably, your mind wanders. When you become aware of being distracted, you need to shift attention back to the focus. Different brain regions are involved in each of these stages. In an experiment carried out by Wendy Hasenkamp, subjects meditated for twenty minutes in an fMRI scanner to measure brain activity. The subjects were asked to press a button whenever they realized their mind had wandered, before returning to their breath focus. Experienced meditators had more connectivity across networks of brain regions that might be used for maintaining attention and avoiding distraction.36 This increased connectivity might have been in place before the people started their years of practice, in which case it might be evidence that they were well suited for meditation. Alternatively, it could be evidence that meditation changes neural structures. Attention is not just important to meditation; it plays an important role in cognitive processing. Many aspects of it—alerting, disengaging, reorienting, maintaining attention—are also useful elsewhere in life.

  Having survived the first few meditations, I grabbed a quick barley-and-chicory coffee substitute (I bet your mouth is watering!) and retired to the lounge. It was like a dreadful retirement home when the television is broken. Chairs were pushed against the walls and we all sat there staring at our cups, at the walls, or through the windows into the darkening green hills outside. I decided to go to bed early. I was sharing a room with two strangers, and I could not even say good night. It was like a scene from a 1970s sitcom where a marriage had gone wrong—or in this case, a same-sex three-way civil partnership. We padded around the bedroom not looking at each other or talking, passing like ships in the night.

  For some there is joy in this communal silence—the freedom from having to put on an act. The silence creates anonymity, since you do not know people’s names, where they come from, what jobs they do, and so on. Taking a break from being mindful at breakfast, I glanced around and tried to guess who everyone was, but the loose, formless meditation clothes offered few hints. A young man sat in a fleece sarong and woolly hat, a thirty-something woman had a tie-dyed top and leggings, and an older man sported a goatee and looked as though he played in a traditional jaz
z group. It was like living in a whole-food shop.

  Half of the sessions were walking meditations, which were better outside, even when it was drizzling and cold. The idea was, while walking, to notice how the feet struck the ground and how the lower legs moved and were braced for each step. A cyclist passed on the lane just outside the grounds and stared as the retreatants walked purposefully and incredibly slowly in random directions. Adding to the chorus of birdsong, a malevolent hum came from a tree in full blossom as insects buzzed about pollinating, and wing-beat noise was just above my head.

  Maintaining silence between meditation sessions encourages continuous mindfulness. At the time, I was so busy being mindful that it was hard to judge what effect all this silence might be having on me. Only after leaving the retreat did I notice the effects. The sandwich I bought at the railway station while traveling home tasted exceptionally strong.

  The idea that meditation can change basic perception is gaining traction in the scientific literature, although not many results are available yet, and there is nothing on taste or sound. Katherine MacLean and collaborators have looked at one aspect of vision, testing people on a three-month Buddhist samatha meditation retreat in a remote mountain setting in Colorado. They had retreatants look at different-sized white lines on a black screen and categorize each line as long or short. By the end of the retreat, compared to a control group, retreatants had improved their ability to discriminate different line lengths, and five months later they still demonstrated improved acuity.37

  My family laughed at me when I arrived home from the retreat because I spoke in an uncharacteristically soft voice and walked about at a snail’s pace. Immediately after the retreat, I felt it had been an interesting experience but not one to repeat. In the weeks and months that followed, however, I had a lingering desire to spend another weekend in that noisy silence, to take the time to rediscover the peaceful state in which I had arrived home.