Sonic Boom: Trevor Cox and ‘The Sound Book’

After you read this paragraph, pause for a moment. Close your eyes and listen to the sounds around you: What do you hear?

I hear the hum of my laptop, the vibrating drone of construction equipment working outside my window, the gentle whoosh of distant traffic.

If Trevor Cox had his way, we’d all be much more aware of our sonic surroundings. Cox, a professor of acoustic engineering at the University of Salford, in Manchester, England, has dedicated himself to expanding beyond academia’s echo chamber to bang the drum for sound in print, on radio and TV, and via blogs and social media. Now he aims to open our ears with his new book, The Sound Book: The Science of the Sonic Wonders of the World.

“The dominance of the visual has in fact dulled all of our other senses, especially our hearing,” Cox asserts in the book’s prologue. Like the Soundkeeper in The Phantom Tollbooth, he writes, he’s detected in those around him a distinct “lack of appreciation of subtle sounds and an increase in discordant noises.”

But where Norton Juster’s whimsically tyrannical character responds by locking sounds away from ungrateful listeners, Cox’s remedy is “to seek out, experience, and celebrate wonderful aural effects” so that we learn “how to listen better.” And by becoming more attuned to the sounds around us, he hopes, we may become not only more grateful for them but also, perhaps, more willing to preserve them.

Cox’s search for ear-inspiring sonic phenomena takes us from the stinky sewers under London, which he found inspiring, to an underground oil storage tank in Scotland, where he had to squeeze through an eight-foot wall via an eighteen-inch-diameter pipe. (He was rewarded with the discovery of an echo that earned him a spot in Guinness World Records.) He slid down sand dunes on his bottom in the Mohave Desert to make them “sing”; clapped hands, burst balloons, and crooned Barry White songs to test acoustic resonances in ancient burial mounds; and mounted rickety staircases, braved caves, and ducked under bridges and arches in pursuit of aural curiosities.

Cox paused in his peripatetic audio adventures to sit quietly and take our questions over email. — Amy Reiter

The Barnes & Noble Review: Given that your book is all about sound, it seems strange to conduct this conversation in a silent medium. What sounds can you hear around you right now?

Trevor Cox: The clunk of a car door in the street, a distant plane approaching Manchester airport, a child’s voice outside, the clatter of my keyboard, and the whirr of the computer fan. I’m hoping to hear the sound of someone bringing me a cup of coffee in a moment.

BNR: You begin the book by describing an interlude in which you climb, somewhat anxiously and reluctantly, into a fetid sewer beneath the streets of London, in search of an echo. Is there anywhere you wouldn’t go in search of an interesting new sound?

TC: I’m not rushing to go down a sewer again. But providing it’s safe, I’m probably up for going anywhere to capture a sound. I’d love to hear the sounds of Antarctica.

BNR: While in the sewer, where, apparently, despite your initial reservations, you lingered for some time, you had an “acoustic epiphany,” prompting you to explore the world’s sonic wonders  –  the beautiful and the ugly. What’s the most terrifying place your sonic tourism has taken you? The most disgusting? The most unexpectedly beautiful?

TC: Some people would find the entrance to the [now-empty underground oil] storage tanks in Inchindown [constructed to store a humongous bombproof supply of oil during World War II], terrifying. The entrance wall is eight feet thick, and the only way in is through the eighteen-inch-diameter pipes that were used for pumping shipping oil down to the naval anchorage in the Cromarty Firth. It was worth suffering the claustrophobic entry, however, because the thunderous reverberation was astonishing. My measurements inside the tank provided evidence to extend the Guinness record for the “longest echo” by a minute.

Some of the best sounds in my home city of Manchester can be found underneath the arches and bridges that were built during the Industrial Revolution. Smelly, graffitied corners hide fluttering echoes, whispering arches and zinging sounds. I’ve spent a few hours playing my saxophone under the arches of a dingy car park to sample the echo, much to the amusement of the attendants.

BNR: What are some of the most mind-blowing sounds you’ve ever heard?

TC: Animals make an incredible range of sounds, and for me the most surprising is the lyrebird. The male lyrebird builds a stage in the rainforest from which he sings an amalgamation of everything he has heard before. They can impersonate the calls of about twenty other species, including whipbirds and kookaburras, and even mimic man-made sounds such as camera shutters, car alarms, and foresters’ chainsaws.

BNR: You bemoan the fact that visuals get so much attention, yet the world’s aural wonders are often overlooked. Why do you think that is? What is the effect of this “dominance of the visual” and what can be done to correct it?

TC: It is hard to describe aural wonders to people, and in the past there was no simple way for most of us to record the sounds. This means in the past it was hard for people to share their sound experiences. This is now changing as digital technologies allow video soundtracks to be recorded on mobile phones, tablets, and cameras. So I’m hopeful that sound will play a more important role in the future as we have common technologies to capture it and people seem to want to share their experiences through video on social media and Internet sites such as YouTube.

BNR: Can you explain what “ear cleaning” is and why you think it’s a useful exercise, if in fact you do? It has nothing to do with Q-tips …

TC: Ear cleaning is a process whereby listeners improve their hearing skills. While some acoustic ecologist believe this needs a set of prescribed exercises, I found that just taking a little time to listen to the sounds around me was all that was needed. It is about paying a little more attention to sounds we encounter every day.

BNR: Let’s talk a little about “endangered sounds.” What sounds are you worried we’re currently in danger of losing, and what should be done to preserve them?

TC: I am most concerned about how birdsong is being drowned out by the smog of man-made noise in cities. We lose out because we don’t get to hear a natural sound that helps reduce stress. But more important, we affect bird species that struggle to be heard above the traffic din. If birds cannot hear each other sing, then how are they going to find mates?

BNR: What do you think makes a sound rise to the level of “sonic wonder of the world”?

TC: During my research l relied in part on my gut reaction as a trained acoustician: What was surprising enough to make me stop and wonder? One example might be the glissandos made by bearded seals under the arctic ice, a sound that is like a UFO coming in to land in a sci-fi movie. Or perhaps a sonic wonder was something that took me back in time to the experiences of our ancestors, such as the acoustics of Stonehenge. Sonic wonders might also have been very rare acoustic effects: Only a few sand dunes sing, droning like a propeller aircraft.

BNR: You use some unusual methods to assess acoustics — not just clapping and yelping but also popping balloons, playing an instrument, even singing Barry White. What are you looking to discover with each of these different tools?

TC: Making a loud, short, sharp sound by bursting a balloon is a great way of revealing patterns of reflections in architectural spaces. I would capture these on a digital recorder so that later I could analyze what was going on. But to experience some sonic wonders, a more subtle sound was needed. From near the center of the radome at the Teufelsberg Cold War listening station in Berlin, I experimented with whispering into my own ear using the reflections from the spherical walls.

BNR: You mention that some animal noises, even some birdsongs, which we often think of as a tranquil noise, are more relaxing than others. What makes some animal noises relaxing and others irritating? And what animal noises has research found to be more relaxing, and which less so? Are city noises ever as relaxing as nature sounds?

TC: Common sense holds that natural things are good for our health and to be encouraged, and unnatural sounds are harmful and to be abated. But this is an oversimplification that researchers are starting to pick apart. While the pretty warbles of songbirds are good for helping us to de-stress, this can’t be true of all animal calls. The roar of tiger is a danger signal and makes us jump and prepare to fight or flight. I can’t think of a study that has found city noises to be relaxing. However, I have a theory that the sound of some crowds, like the gentle hubbub in a café, might be good for us. The idea is that being among people must be a pleasant experience for us. Some of my project students at Salford University are currently carrying out experiments to test this idea.

BNR: How much does our own individual experience color our response to sounds, and to how great a degree are our responses shared or universal?

TC: We have some universal responses, such as the sound of someone vomiting prompting a disgust reaction to discourage us from getting too close and potentially catching an illness. But some responses are very individual. Take the example of whether musical notes that are played at the same time sound pleasant or unpleasant together. It seems that early in life, we all find some combinations of notes more pleasant than others, but this innate preference can be changed by the music that we hear during our lives, starting with what we hear in the womb during the third trimester.

BNR: We may think of underwater as being silent, but you note it’s actually far from it. What sorts of noises can be heard underwater, and how have we discovered them?

TC: The artist Lee Patterson showed me that even a small fishing pond can teem with sonic delights. All you need to reveal them is a good quality hydrophone (underwater microphone). When I put on Lee’s headphones to listen to what his hydrophone was picking up, I had the unnerving experience of hearing animals munching in my ears. These were the amplified sounds of tadpoles scraping away at the hydrophone looking for food.

BNR: What do we know about how sound differs in space?

TC: The sonic environment inside a spaceship is unpleasant because the machines that keep the astronauts alive are noisy. Outside a spaceship, the only sound at audible frequencies is found on planets and moons with atmospheres. Scientists have put microphones on spacecraft such as the Huygens probe to Saturn’s moon Titan. As the probe descended through the atmosphere, recordings were made of the wind buffeting the microphone.

BNR: We think a lot about how air pollution is affecting our planet, but you observe that noise pollution is also having an effect. What’s happening, and what should be done about it?

TC: Noise pollution raises lots of concerns as it has detrimental effects on health. It also causes problems in schools. Many scientific studies have demonstrated that noise affects the performance of pupils because the students need to be able to hear the teacher and have a certain amount of quiet to learn. The solution in the case of schools is to design and build them well, something that isn’t always done.

BNR: You set out to differentiate myth from reality when it comes to echoes. What surprised you the most about your experiments with echoes?

TC: In the past, naturalists wrote about old echoes, documenting and cataloguing them as they would have done for any natural phenomena. Some of the old tales seem unlikely to be true, like the echo that turned a single word into a whole sentence. I was surprised to find, however, that much less has been written about echoes in modern times. This made it very difficult for me to find sites with extraordinary examples.

BNR: You also discuss the tricks your mind can play with those satanic messages people sometimes hear when they play rock songs backward. What’s going on there?

TC: One of the best-known examples is the suggestion that Led Zeppelin hid satanic messages in “Stairway to Heaven.” If you play the track backward, you supposedly hear, “Oh here’s to my sweet Satan.” Scientific experiments have shown, however, that if you listen to “Stairway to Heaven” backward with your eyes closed, what you hear is just gibberish. These satanic lyrics are heard only if you have a printed version in front of you. The brain mistakenly matches the printed satanic lyrics to the otherwise incomprehensible backward murmurings.

BNR: Some sounds are easier for our brains to ignore than others. Why do you think that is?

TC: Our hearing is partly an early-warning system to pick up signs of danger. Consequently, our brains are listening out for changes in sound, like the crack of a twig, which might signify a foe creeping up on us. To maximize the chance of hearing danger signals, the brain needs to block out constant sounds, such as the wind moving through trees, or in modern life, the hum of the computer fan.

BNR: You mention that people often respond strongly to the anechoic chamber at your university. What does total silence sound and feel like?

TC: The best anechoic chambers are designed to be so quiet that no sound enters your ear canals. The only things you hear are generated by your own body. You might hear blood moving through your head and a high-pitched hissing originating from spontaneous firings on the auditory nerve. But the extraordinary quiet isn’t the main reason why some visitors ask to leave the chamber. The walls, floor, and ceiling are covered in absorbent wedges that mean no sound reflects back to you when you talk. Some visitors find the disjoint between the visual and aural unsettling. This is a room that has obvious walls to your eyes but can’t be heard by your ears.

BNR: Do you think silence is undervalued or overvalued? Is complete silence good? What about the noise of life?

TC: Although cities thrive on human activity, vibrancy, and excitement, studies have shown that people need relatively quiet places for respite from the hustle and bustle. When visitors have been surveyed about what draws them to the countryside, a key feature is tranquility. But that isn’t silence. What people want are places where nature can be heard and man-made noises are minimized.

BNR: You describe an interesting experiment in which people listened to the same sound but were given visual cues to make them think the sound was either the whoosh of traffic or the whoosh of sea. What are the lessons from that experiment? What role does vision have in our perception of sound?

TC: The experiment showed that connectivity in the brain is altered if people think they are processing man-made noise from a road, compared to natural waves on a beach. Like many current studies in neuroscience, knowing that the connectivity changes in the brains doesn’t explain why this is happening or what the changes in the brain mean. But we can draw one important conclusion from the study as it demonstrates that tranquility is not just about what we hear; it’s also affected by what we can see.

BNR: What are “soundmarks”? Why are they important?

TC: Soundmarks are keynote sounds that define a place. They can be as varied as landmarks: In Vancouver, Canada, the Gastown steam clock marks time not with bells but with whistles; on the Orontes River in Hama, Syria, ancient waterwheels called norias let out loud groans as they slowly rotate; and my travels in the southwestern U.S. were punctuated by the dissonant hoots of Amtrak trains. Globalization risks homogenization of what we hear; we need to celebrate and preserve sounds that make places unique.

BNR: What are some of your favorite sounds?

TC: The musical road in [Lancaster] California was one of my favorites from my travels. As you drive over the pattern of grooves cut into the road, the vibration of the car wheels creates the “William Tell Overture.” It’s a terrible rendition of the melody because it’s badly out of tune. But despite this, it made me smile.

BNR: What effect would you like to have on your readers? What do you most want them to take away from your book?

TC: I would like readers to be a bit more aware of the sounds around them. A lot of noise problems we face, like the tinny music leaking from someone’s headphones, are caused by people being inconsiderate of other peoples’ aural environment. If we all listened to and cared for the sounds around us, we would start to build a better-sounding world.

BNR: What are your hopes for the future of sound?

TC: As an acoustic engineer, I know that quite a lot of the acoustic defects we have to put up with on a daily basis need not exist. I hope that reading my book will raise awareness of this among the general public who will then demand better acoustics.

BNR: I understand that, at one point, you held the Guinness World Record for the world’s largest whoopee cushion. Do you have any plans to reclaim your record?

TC: The world’s largest whoopee cushion was built as a prop for a science show I presented at the Royal Albert Hall in London. The physics of a whoopee cushion is similar to what happens in the mouthpiece of a saxophone, and so it was used to illustrate how wind instruments work. A friend of mine broke the record, and I have no plans to break his record.