The Soundscape: Our Sonic Environment And The Tuning Of The World (34 page)

Noise

When I first discussed the outline of this book with several publishers they were quite enthusiastic. “A book about noise pollution would be very timely,” they said. I pointed out that I had already dealt with noise pollution in another publication
^v
and that anyway there were already a large number of good books on the subject. When I went on to discuss the book I wanted to write, they grew uneasy. I insisted that the only realistic way to approach the noise pollution problem was to study the total soundscape as a prelude to comprehensive acoustic design. They assumed my interest was academic. I further suggested that multitudes of citizens (preferably children) needed to be exposed to ear cleaning exercises in order to improve the sonological competence of total societies, and went on to describe how, if such an aural culture could be achieved, the problem of noise pollution would disappear. They concluded I was a dreamer. Nevertheless, after years of association with the noise pollution issue, I have come to the realization that there are only two ways to solve it: the way I have just described, or a worldwide energy crisis. The largest noises in the world today are technological; thus the crack-up of technology would eliminate them.

Throughout this chapter I will draw extensively on a World Soundscape Project study in which we examined by-laws and antinoise procedures from over two hundred communities around the world. The help of countless municipal officials who sent copious information in reply to our inquiries is gratefully acknowledged. The purpose of the survey was not to draft a model by-law (though we could probably do that) but to study the question of what constitutes noise in as many varied cultures as possible. Noises possess a great deal of symbolic character as sound phobias; and, in fact, the test of a good noise by-law would seem to be whether the most displeasing sounds of a given locale are effectively dealt with in the law. Before introducing this survey, however, some preliminary questions must be discussed.

The Evolving Definition of Noise
     The increase in sound in he modern world has given rise to a change in the meaning of the word
noise
. Etymologically the word can be traced back to the Old French word
noyse
and to the eleventh-century Provencal words
noysa, nosa
or
nausa
, but its origin is uncertain. The suggestion that it may have originated in either of the Latin words
nausea
or
noxia
has been rejected.
Noise
has a variety of meanings and shadings of meaning, the most important of which are the following:

1. Unwanted sound
   . The Oxford English Dictionary contains references to
   noise
   as unwanted sound dating back as far as 1225.
   
2. Unmusical sound
   . The nineteenth-century physicist Hermann Helmholtz employed the expression
   noise
   to describe sound composed of nonperiodic vibrations (the rustling of leaves), by comparison with musical sounds, which consist of periodic vibrations.
   Noise
   is still used in this sense in expressions such as “white noise” or “Gaussian noise."
   
3. Any loud sound
   . In general usage today,
   noise
   often refers to particularly loud sounds. In this sense a noise abatement by-law prohibits certain loud sounds or establishes their permissible limits in decibels.
   
4. Disturbance in any signaling system
   . In electronics and engineering,
   noise
   refers to any disturbances which do not represent part of the signal, such as static on a telephone or snow on a television screen.
   

The matter is more complex than this. For instance, while the word
noise
was first used in English to imply “unwanted sound,” it frequently took on a richer meaning and was sometimes used to imply “an agreeable or melodious sound.” Chaucer uses it this way in his translation of the
Roman de la Rose
.

Than doth the nyghtyngale hir myght

To make noyse and syngen blythe. (11. 78-79)

Of whiche the water, in rennying,

Gan make a noyse ful lykyng. (11. 1415-16)

The King James version of the Bible also employs the word
noise
in a broad sense:

Make a joyful noise unto the Lord, all ye lands. (Psalms 100:1)

While this wider connotation has disappeared from the English word today, it still exists with the French equivalent,
bruit;
for the Frenchman may still refer to the
bruit
of the birds or the
bruit
of the waves, as well as to the
bruit
of the traffic. One of the difficulties in dealing with noise internationally is that the word has slightly different nuancing in each language. I have also employed the word in a wider context in the expression “Sacred Noise” (see pages 51-52 and 114-115).

Of the four general definitions, probably the most satisfactory is still “unwanted sound.” This makes
noise
a subjective term. One man’s music may be another man’s noise. But it holds out the possibility that in a given society there should be more agreement than disagreement as to which sounds constitute unwanted interruptions. “To disturb the public” then means to disturb a significant portion of the public, and it is in this manner that traditional legislation usually deals with noise problems. Such noise legislation may be called qualitative, inasmuch as it involves public opinion.

This contrasts with another type of legislation called quantitative. Such legislation sets decibel limits to specified undesirable sounds. If, for instance, a regulation states that the permissible level for an automobile is 85 decibels, an automobile producing 86 decibels is noisy while one producing 84 decibels is not noisy—or so the law would have us believe. The quantitative measurement of sound is thus tending to give noise a meaning as “loud sound.” This is unfortunate because, as we know, not all irritating noises are necessarily loud, or at least loud enough to show up effectively on a sound level meter. Noise has come to be evaluated quantitatively owing to the risk of hearing loss, a matter about which enough is known for definite prevention criteria to have been established. It is, therefore, a subject that should be clearly understood.

The Hazards of Noise
     Medical science has determined that sounds over
85
decibels, heard continuously over long periods of time, pose a serious threat to hearing. The resulting malady is often referred to as boilermaker’s disease, because the earliest known victims were workers in factories where metal boilers were riveted together. Prolonged exposure to sound beyond this level may result, first, in temporary threshold shift (or ITS as it is sometimes called). TTS is an elevation of the threshold of hearing so that after being subjected to a very noisy experience, all sounds heard afterward seem fainter than usual. Normal hearing returns after a few hours or days. With further exposure, permanent cochlear damage may take place, resulting in permanent threshold shift (PTS). When this loss occurs in the inner ear, it is incurable.

Authorities concerned with industrial hygiene are now attempting to fix and enforce hearing risk criteria. In the U.S.A. a great step forward was taken when the Walsh-Healey Act of 1969 stipulated that no government contracts would be awarded to industries not respecting the established criteria. These were somewhat above the recommendations of the American Otological Society, and represented a compromise between the ideal and the immediately practicable. These recommendations parallel criteria already in effect in numerous European countries.

Permissible Noise Exposure

as Established by the Walsh-Healey Act (1969)

The threat of industrial hearing loss is now being resisted and is therefore not a concern of these pages. But PTS and TTS are by no means limited to these precincts. For instance, some researchers have found that exposure to levels as low as 70 dBA for 16 hours daily may be sufficient to cause a hearing loss. This is substantially lower than curbside traffic on a busy street. The term
sociocusis
has been devised to refer to non-industrial hearing loss, and a large number of examples could be given in illustration. For instance, it has been established by audiometric examination that persons operating power lawnmowers averaging 97 dBA suffer a temporary hearing loss after 45 minutes of exposure. We have already encountered a similar problem resulting from snowmobiles (Chapter Five) and amplified music (Chapter Seven). When Dr. George T. Singleton tested 3,000 public school children in Florida, he discovered a marked decrease in high-frequency hearing as the student progressed from the sixth to the twelfth grade, a period during which students had been exposed to rock bands, motorcycles and other “recreational” noises. Dr. Singleton and others found that the hearing ability of college freshmen who had attended rock concerts often deteriorated to that of sixty-five-year-olds.

Because sound is vibration it affects other parts of the body as well. Intense noise can cause headaches, nausea, sexual impotence, reduced vision, impaired cardiovascular, gastrointestinal and respiratory functions. But noises need not be intense to affect the physical state of humans during sleep. Russian researchers have found that “the level of thirty-five decibels can be considered as the threshold for optimum sleeping conditions …” and that “when noise is at a level of fifty decibels … there are fairly short intervals of deep sleep … followed, on waking by a sense of fatigue accompanied by palpitations.”

Everyone’s hearing tends to degenerate a little with age. This happens very gradually and begins first in the high frequencies, which is the reason older people sometimes complain “everyone mumbles nowadays.” This gradual loss of hearing acuity due to age is called presbycusis. It has always been assumed that presbycusis was a natural result of aging, like gray hair and wrinkles. This is now being challenged. A study on a tribe of Mabaan Africans in the Sudan showed very little hearing loss due to presbycusis. Africans at the age of sixty had as good or better hearing than the average North American at the age of twenty-five. Dr. Samuel Rosen, a New York otologist under whose supervision the study was made, attributed the superior hearing ability of the Africans to their noise-free environment. The loudest sounds the Mabaan heard were the sounds of their own voices singing and shouting at tribal dances.

How Fast Is the Ambient Noise Level Rising?
     In chapter Five we saw how the noises of technology rubbed their way into both urban and rural life and how they were sanctioned as “progressive.” By 1913 Luigi Russolo was able to point out that the new sensibility of man depended on his appetite for noise. Today, as the machines whirl in the hearts of our cities day and night, destroying, erecting, destroying, the significant battleground of the modern world has become the neighborhood Blitzkrieg. It is another reminder of the truth of Constantin Dox-iadis’s statement that for the first time in history we are less safe inside the city gates than outside them.

Precisely how fast the ambient noise level of the modern city is rising has been difficult to estimate. The figure of one decibel per year has frequently been given, but this seems excessively high when we remember that the decibel is a logarithmic term, so that a mere three decibels is approximately equal to a doubling of sound energy. In recent years, a great number of acoustical engineering surveys have been carried out in various cities in an attempt to determine the present noise level. It is an expensive proposition to do this properly, for thousands of readings must be taken by skilled workers using expensive equipment.

In order to point up the shortcomings of such surveys I will mention only one, though it is typical of them all. In 1971 Vancouver commissioned an extensive survey in which some ten thousand readings were taken over a grid stretching across the whole city region. The report concluded (in almost the only paragraph intelligible to the general public): “Traffic noise is the most significant noise source at all times. During the day hours local traffic noise was found to be responsible for 40% of all noise sources while distant traffic constituted some 13%. At night the corresponding values were 30% and 26%.” Comparing their findings to those of similar surveys conducted elsewhere, the researchers concluded that the noise in Vancouver was some 6 to 11 dBA worse than that of some American cities in 1954. That would be an increase of about half a decibel per year. But this is not particularly meaningful comparison, and the survey will only become useful if it is repeated in Vancouver in an identical manner at some later date. Given the rapid refinements of technical measuring, however, it is doubtful whether this will ever happen. Even then, without an integrating social survey to discover what the public thinks about the changing soundscape, the value of any engineering survey will remain under suspicion.