A week or ten days in the field is rarely enough. Animal activity isn’t framed by human time: mostly their hours to sleep, forage, and hunt differ widely. Instead, intervals are determined by the cycles of seasons, the amount of daylight or darkness, the passing of weather, the dappled shades of light on the forest floor as the day progresses, and the distinct fragrances that arise at various times. Of course, the combination of all these elements manages to evade complete capture on audio or video media. But after being present below the canopy of an equatorial rain forest for a very long time, we find that the tactile, aural, and visual elements eventually unite into a single, overall impression. Only at that point might someone begin to hear the phrases that motivate the nearby hunter-gatherers to begin an ancient chant. The forest becomes a place of worship, and we start to imagine what it must have been like to be part of the creature world. In fact, nothing can replace the experience of being there—but it’s our presence itself that’s turning out to be perhaps the most formidable hurdle of all.
CHAPTER SEVEN
The Fog of Noise
It’s late at night, and I’m sitting in my studio listening to a recording. My working space isn’t big—maybe large enough to accommodate the footprint of two medium-size cars tightly packed—but with the special techniques I’ve used to record my soundscapes in the field, the illusion created by the playback fills the room way beyond the reaches of its design. I’m auditioning a recording that was made in Yellowstone National Park during a fall afternoon—one exquisitely active with birds. It’s a single long take, maybe an hour in length. The texture at the beginning of the recording is as delicate and lovely as a piece of fine Irish lace—an expansive sonic fabric that sucks me deep into the time and space of the original moment, as only sound can do.
A raven calls out intermittently, inscribing a horizontal path across the stereo space with a flight beginning in the left-hand side of the field and moving to the right. As it does, the illusion is suddenly broken by what sounds like a small private or military jet heading northbound, maybe twenty thousand feet above my mics. The noise reverberates in thundering waves, back and forth across the valley. It takes six or seven minutes to fully disappear. Meanwhile, during the flyover, the bird biophony quiets down to almost nothing. After ten more minutes the natural soundscape is just beginning to return to its pre-jet level of quality when the low-frequency whomp-whomp-whomp of a distant helicopter intrudes. The birds become quiet again. Really silent this time.
The late Gregory Bateson used to tell his graduate students a story about the venerated philosopher Alfred North Whitehead. Invited to join the Harvard faculty shortly after World War I, Whitehead accepted the position on the condition that he could bring along his great friend and collaborator Bertrand Russell, with whom he had coauthored the ambitious three-volume Principia Mathematica. Newly appointed faculty members were required to present a lecture on their subject of choice, and Russell chose to clarify Max Planck’s quantum theory. It was a hot August night in 1919, and the auditorium near Harvard Yard was filled with eager faculty and, as Bateson told it, the bluest bloods in Boston. After laboring for ninety minutes without a break, a sweat-drenched Russell finally concluded his remarks and returned to his seat to polite applause. Whitehead, who had been sitting patiently on the dais, stood and walked slowly to the podium. When the applause died down, he intoned in his high-pitched English voice, “I’d like to thank Professor Russell for his brilliant exposition. And especially for leaving unobscured the vast darkness of the subject.”
I tell this story because Russell’s efforts parallel how I feel when trying to define noise. The turn-of-the-last-century wit Ambrose Bierce once called it the “chief product and authenticating sign of civilization.” Les Blomberg, of the venerable Noise Pollution Clearinghouse, defines noise as “aural litter” or “audible trash.” The cause of most noise—from the viewpoint of the natural world, at least—is anthrophony. Altogether, biophony, geophony, and anthrophony make up the soundscapes of the world.
Anthrophony comprises four basic types of human-generated sound: electromechanical sound, physiological sound, controlled sound, and incidental sound. Electromechanical noises are produced by our means of transportation and the loud tools of various trades, including aircraft, pile drivers, snowmobiles, leaf blowers, automobile and truck sound systems, motorcycles, generators, cell phones, TVs, boom boxes, refrigerators, pencil sharpeners, dishwashers, air conditioners, microwave ovens, and many other complex technologies—such as the relentless clicking of the keyboard on which this book is being written or the faint continuous whisper of my laptop’s cooling fan (although most current ones are inaudible beyond a few inches from the source). Physiological sounds—coughing, breathing, body sounds, sneezing, and talking, for example—tend to be much more subdued and localized. With a bit of mindfulness and consideration, we can manage our controlled sound, such as live or recorded music or theatrical performances, particularly when it comes in conflict with a sensitive biophony. Incidental sounds are made up of noises such as footsteps or clothes rustling and scratching; these, too, are controllable and localized.
Noise by itself attracts attention without delivering much useful information. It’s wasted energy; if loud enough and in an enclosed space, it generates a small but measurable amount of heat. Hearing that claim in a physics class long ago, I subsequently imagined that, given what we endure in our cities, we might be able to create enough noise-related heat to wean us off fossil fuels, if we could only figure out how to rechannel it without a net loss.
If our goal is to communicate a clear unimpaired signal containing useful information—assuming, of course, that the source is providing an unambiguous message and the receiver is distortion-free—we must realize that we and other living organisms can accomplish this only if acoustic channels are unimpaired. This applies as much to the creature sounds in a biophony as to, say, communicating on a mobile phone via a cellular network. Good signal exchange means that the transmission is useful, pertinent, and relevant to the moment and that the recipient clearly gets the message. It is not corrupted by other acoustic, tactile, olfactory, or visual sources. This is referred to in the trade as a “clean” signal. In video parlance, signal refers to a perfectly clear series of images focusing on one or two subjects. In music, it usually represents clearly expressed thematic patterns of consonance or dissonance that evoke a wide range of emotional responses. Noise occurs when a clear signal is somehow compromised—usually by a number of competing and uncorrelated signals or distortion. A common expression in acoustics, the signal-to-noise ratio refers to a signal’s power relative to the amount of background noise.
I think of noise as an acoustic event that clashes with expectation—loud heavy-metal music in an intimate restaurant is noise (or, for that matter, music in almost any restaurant). A straight-piping motorcycle gunning its way through the delicate landscape of Yosemite Valley shatters the numinous experience for both visitors and animals. When there are discontinuities between visual and aural content, aural and aural content, or visual and visual content, these breaks are usually received by us as various kinds of noise—in an extreme example, a contradiction such as a gentle classical guitar sound track set against a violent scene in a Terminator movie, unless the offset is meant as a joke. In the heart of many urban settings, acoustic noise can also be chaotic, disassociated sound, including that of car alarms, sirens, jackhammers, air brakes, downshifting diesel truck engines, and boom systems in cars.
I was not surprised to read that a sound-industry manufacturer’s award was given in 2003 for the loudest documented sound system ever produced for the interior of an automobile. To my knowledge and as of this writing, few have matched or beaten the winning delivery technology, one designed to generate 130,000 watts of power driving nine fifteen-inch subwoofers, with a sound pressure level of 177+ dBA at a sustained intensity. That is more than twice as loud as a .357 Magnum pistol being shot off next to your ear,
and a factor of seven louder than a Boeing 747 at full takeoff power—when you’re standing ten yards from the jet. The NASA space shuttle launches typically registered between 160 and 180 dB on takeoff. Let’s not forget that this car system was installed inside a Dodge Caravan.
Schafer tells us in The Tuning of the World that humans like to make noise to remind themselves that they are not alone (and to remind others, with whom they may have only a passing relationship, that they exist). The general presence of noise itself becomes really apparent when we introduce a microphone into the equation. A microphone, as an extension of our ears but very different in function, does not discriminate between useful sounds and noise. It will pick up every acoustic signal within its range and unique detection pattern. If you want to know how much noise there is in your environment, just plug a mic into a recorder and put on a set of headphones for a minute. Try this in a habitat that you consider to be “wild nature.” After just a few seconds, the results will amaze you.
Sound in our human world is broken down into two general types: desirable and undesirable, or, in the field of bioacoustics, information versus uncorrelated acoustic debris. Although in the process of listening we often don’t recognize noise—what the author Joachim-Ernst Berendt refers to in his book The Third Ear as “acoustic garbage”—it has detrimental effects on us. Unconsciously, our brains are hard at work filtering out undesirable sounds so that we can process the information that is beneficial. Broadly speaking, in most of our industrial societies, signal and noise are constantly competing for our acoustic or visual attention, and we spend a great deal of mental energy sorting out noise from the signals that more affably engage us.
We’ve all had the experience of talking with a companion in a noisy restaurant or on a crowded street. As we gaze at the source of the sound, we think we are hearing everything he or she is saying clearly. However, what we hear is largely filtered through what we see. Without that synchronous sight and sound, we’d probably get little useful information from the exchange. Our ears receive many sounds, but our brains do the heavy lifting, combining sounds with visual cues. Hard at work filtering out the background noise, it tricks us into thinking that the interference doesn’t matter.
This signal processing (filtering) goes on whether or not we are conscious of it. Weimin Zheng, associate fellow in experimental neurology at the Neurosciences Institute in San Diego and one of the few researchers to consider the idea, reports that relative brain activity allotments…
are not a question that can be addressed directly, but can be inferred from behavioral observations at the system level. Even in a quiet environment, in order to understand the speech, attention has to be focused on the task. Attending a single task requires “actively” decreased performance in some regions of the brain and increased activities in others…. In a noisy environment, greater effort (attention) is needed and often engaging other sensory systems, particularly the visual system for lip-reading. Thus, overall brain energy consumption will be increased…. So, overall, brain activity will be greater in a noisy rather than in a quiet environment because of the engagement of other systems.
Donald Hodges, Covington distinguished professor of music education and director of the Music Research Institute at University of North Carolina, Greensboro, reminded me that loud noise was used to flush Manuel Noriega, military dictator of Panama, from his residence during the U.S. invasion in 1989, and that highly focused loud noise is employed by the military and police to break up unwanted gatherings of demonstrators.
Our auditory processing system is conditioned over time to know which signals are meaningful and which are not. Yet even as our attention is focused on what we see, our brains are working overtime to retrieve and process desired information, eventually causing a consequential effect such as the onset of weariness. In a 1998 Swedish noise study of fifty thousand state employees, twenty thousand of the respondents working in environments where the random background noise level was measured between 60 and 80 dBA—considered moderate (like an average residential city street) in the United States—commonly complained of fatigue and headaches, even after just a couple of hours of exposure.
In addition, researchers have shown that fatigue and stress are significant by-products—resulting from an increase in glucocorticoid enzyme levels that may escalate as much as 40 percent—of trying to separate noise from signal. It turns out that most of us find noise intrusive, repellent, or stressful—or all of the above.
Unwanted sound in our lives—sometimes referred to in the current literature as ISE or irrelevant sound effect—induces multiple kinds of physical and psychological reactions, many of them unhealthy, especially when the noise persists. And when noise obliterates the subtle sounds of natural soundscapes, we can detect reactions in a wide range of living organisms. For humans, the consequences of harmful noise—including nervous tension, fatigue, and irritation—can be found everywhere from our biggest cities to our offices to surviving tribal groups such as the Ba’Aka, who are drawn to the interior of their remaining forests, as far away from human industrial noise as they can, to mend.
Three separate studies by Anders Kjellberg, Per Muhr, and Björn Sköldström, and confirmed by other researchers more recently, found that even moderate noise in a workplace caused measurable exhaustion, blood pressure elevation, and negative attitudinal shifts after only a few days of exposure.
Beginning in the early 1980s, the relationship between exposure to urban noise and increased human stress levels has attracted a growing amount of research. One of the first landmark studies linking noise and stress took place in Strasbourg, France. Researchers invited three men and three women to sleep in a specially designed laboratory, where they were subjected to different sound and noise experiences each night over a period of several weeks. Wired to stress-level instrumentation that measured heart rate, finger-pulse amplitude, and pulse-wave velocity, each test subject was monitored throughout the night. For the first few nights, they experienced uninterrupted quiet. For the following two weeks, they were subjected to recorded traffic noise. All of the stress indicators dramatically increased when the traffic was introduced—even at relatively low levels. Upon waking, participants completed questionnaires. After two to seven nights of noise, the subjects reported that they were no longer aware of being disturbed. Each person had become used to it. However, the measured physiological stress levels were consistently as high as when the traffic sounds were first introduced. Despite the small size of this study and the fact that it was carried out nearly thirty years ago, it is still considered significant—while the minds of the subjects rationalized that there was no noise effect, their bodies told very different stories.
Noise has also long been understood to detract from a child’s ability to concentrate and learn. In a recent article in Noise and Health, authors Maria Klatte, Thomas Lachmann, and Markus Meis show that there is a direct relationship between noise in a child’s environment and his or her task performance. When a particular task requires high levels of concentration and unrelated distracting noise intrudes, a greater allocation of attention—often beyond the child’s ability to engage—will measurably interfere with execution. And a 128-page World Health Organization E.U. study titled “Burden of Disease from Environmental Noise” released in March 2011 stated that, with children ages seven to nineteen, “Tasks affected are those involving central processing and language, such as reading comprehension, memory, and attention. Exposure [to noise such as that of auto traffic and aircraft] during critical periods of learning at school… impair[s] development and [has] a lifelong effect on educational attainment,” sometimes affecting IQ by between five and ten points. After the noise sources were mitigated (e.g., the relocation of an airport farther from a school), the noted learning disabilities disappeared. The report went further, concluding that exposure to excessive noise not only impairs learning in young humans but can also—due to epidemiological level increases in blood pressure and release of st
ress hormones—lead to heart attacks, a negative environmental condition rated second only to air pollution.
In our industrialized world, there are times when mechanical noise is welcome and, in some cases, becomes “art.” A well-placed noise cue crafted by a film or video sound designer that punctuates the narrative of a film for effect can be a creative use of noise. For others it could be the reassuring sound of a subway train approaching a station platform. It could be an oil well belching out percussive intervals of its diesel-powered drivetrain somewhere on the High Plains of Wyoming; the firing of a military cannon; or the deafening roar of a NASCAR event. People on the ground may not be so thrilled when pilots fly multiengine aircraft into their acoustic space, but the sound of synchronized engines—those that run at the same number of revolutions per minute and consequently generate equal pitch and power—is a steady beatless hum of the sweetest and most reassuring “music” the person at the flight controls can imagine.
Ocean and lakeside waves, the effects of wind, and the sound of streams contain elements of white noise. Analogous to white light, this class of sound is made up of an infinite number of audible frequencies that are distributed over the entire audio spectrum. Each frequency appears at random and, over time, has equal power. Naturally generated white noise provides a number of positive effects and is, more often than not, pleasant to our ears and relaxing to the psyche. The Wy-am once heard the natural geophonic white sound of Celilo Falls as a recognizable signal replete with profound practical and spiritual significance, just as the Nez Percé heard music on the wind in the reeds at Lake Wallowa. Yet, in settings where we have tried to harness white noise by reproducing it artificially, it often works to our disadvantage.
Whether conscious of the experience or not, most of us have visited offices where white noise has been integrated into the ambient design of the working spaces to mask conversation in nearby zones with open partitioning. With similar sales pitches to those used for marketing elevator or background music, slews of web advertisements claim that office white-noise installations are calming and relaxing, and are effective masking tools to keep one from hearing conversations in the next separated space. The intent is to increase productivity—the false premise being that any white noise sounds natural.
The Great Animal Orchestra Page 15