"Avalanche of decibels: beware, danger"

Eighth interview of the series Alain Gerber × Alfred Tomatis in SON Magazine. In no. 37, April 1973, Tomatis treats of dangerous sounds and urban sound ecology. At a time when the auditory disorders of adolescents have tenfolded in fifteen years (Swedish survey 1956-1970), he recalls his founding research at the Aeronautical Arsenals on occupational deafness (book co-written with Robert Maduro and Maurice Lallemant), expounds the mechanism of the scotoma at 4,000 Hz (the C above the C of the flute), pathognomonic of sound trauma, and warns of the ravages of rock at 8,000 watts (Grand Funk), of symphony orchestras (130 dB), and of prodigy-conductors withdrawn too early from the bill on account of deafness.

“SON” Magazine — no. 37 — April 1973
Dangerous Sounds
Alfred A. TOMATIS: “AVALANCHE OF DECIBELS: BEWARE, DANGER”
Interview gathered by Alain Gerber

Presentation

Pollution and nuisances are the bugbears of the twentieth century… It is true that noise, in large doses, kills the ear… What is very important is that the auditory apparatus is not the only one affected: the action of noise may have repercussions on the psyche, on blood circulation, on the respiratory rhythm, on memory… Professor Tomatis enjoins you to beware of the excess of decibels…

The Beelzebubs of the 20th century

Marked by the industrial and technical civilisation, our age has fashioned itself myths to the measure and image of its realities. The man of today designates, in the aggressions he daily endures, new demonic figures destined to replace the old, which now hardly frighten any but small children.

Nuisances and pollutions are the Beelzebubs of the 20th century, and gifted journalists succeed in persuading us that, in the midst of them, we live in a hell. Hell of atmospheric corruption, hell of “denatured nature”, hell of decibels. The last interested us most particularly. We decided to go and see at closer hand, by once again questioning Professor Tomatis, whose first research, some twenty years ago, bore precisely on this problem.

Pieces of the dossier

But can one speak of a problem? In truth, the matter seems simple and the case decided in advance. Noise, the intensity of which keeps increasing in the cities, is dangerous both for the organism and for the psyche of the individuals submitted to it. It is clear, neat and beyond reply. The testimonies abound and all lead to the same conclusions. A few pieces of the dossier? Here they are. Everyone knows for example that young people listen to the music they love (pop in particular) more and more loudly; now a Swedish survey has revealed that in 1970, auditory disorders through sound aggression were ten times higher in adolescents than in 1956!

Yet a French popular-science journal had to underline that to these optional aggressions one must add those from which no one can shelter:

pneumatic drill: 120 decibels
motorbike: 110 decibels
Métro at Place de la Concorde: 90 decibels
heavy trucks, alarm clocks: 80 decibels
telephone: 70 decibels

In flats, the rubbish chute, or the waste-disposal unit, the refrigerator, the mixer, the coffee grinder, the washing machines for clothes and dishes, add from the inside to the residues of the noises from outside which one has tried, badly, to suppress through a few sound-insulation measures. In short, we are no longer in a position to preserve our hearing, as is still sometimes the case in certain remote countrysides or in certain Andean tribes where only persons afflicted with a hereditary affection of the ear and the elderly, whose decline in hearing is the result of a natural physiological senescence phenomenon, have difficulty in hearing well into their hundreds…

The founding research at the Arsenals

These observations are overwhelming. However, one must distinguish between what, while incontestably constituting a nuisance, can be borne by the organism at lesser cost (we shall see how), and what causes lesions duly verifiable and sometimes irreversible. On this point, serious and objective research is fairly recent. One can say that before the Second World War, the noxiousness of noise was but a vague idea in the minds of scientists and physicians.

“The notion is old,” Alfred A. Tomatis observes, “but for a very long time it was little or ill defined. In times past, all that was known was that members of certain professions, the coppersmiths for example, were submitted to sound intensities such that their ears risked being damaged. The phenomenon was the object of certain research in France — I note in passing that it was the French who invented the audiometer — around 1934. But all this very quickly came to nothing, and it was only after the war that the problem was taken up again. I had the chance at that time of being part of the Air personnel, and I was asked at the Arsenals to conduct a study on the lesions provoked by noise.”

“This research had nothing disinterested about it: it was a matter of knowing whether the people working on the engines should receive a compensation, as the Americans had launched the idea. Ten thousand people exposed to noise had to be examined. The inconvenience is that they all tried to escape the examination, or at least to cheat when they finally submitted to it: everyone was afraid of being found deaf and consequently dismissed!”

“With great difficulty, I had had an audiometer brought from the United States, but it was almost useless to me, for I had to beg people to take an audiogram! In three years, I was able to examine no more than 1,300 people; these observations nevertheless allowed me to write, in collaboration with Robert Maduro and Maurice Lallemant, a book on occupational deafness which was the subject of a congress. The result was not slow in coming: the Arsenals personnel said that if there was occupational deafness, there were no doubt compensations to be had, and this time there was a veritable rush! People jostled to take an audiogram! Demand was such that we could not meet it. We were installed in a coal bunker and we did what we could…”

The role of the psyche in deafness

“What it was interesting to observe is the change of attitude between those who came to see us before the publication of the book and those who came after: while the first made desperate efforts to hear, the second did everything in their power to understand nothing! And the most curious thing is that in many cases this manoeuvre was not really deliberate, not really conscious. This allowed me to realise the importance of the psyche in this affair. A subject full of goodwill, but with the idea of being recognised as deaf at the back of his mind, could have his auditory threshold actually shifted by ten, twenty and even thirty decibels.”

The 4,000 Hz scotoma, pathognomonic signature

“When you plunge an individual into noise (120, 130 decibels or more in certain Aeronautics workshops), immediately the ear undergoes damage. I say immediately, for it makes itself felt from the first day; if you do not relieve the subject, after a month the lesion becomes irreversible. This damage is called a scotoma: it always sits in the same place (it is even one of the rare fixed signs of medicine) and consists in a lesion that occurs at 4,000 hertz (the C above the C of the flute), with a few exceptions at 2,000 and 6,000. Subsequently, this fault will open out into a fan, and one will have a progressive degradation both towards the high and the low frequencies.”

“At 4,000 hertz, hardly anyone realises the deficiency, because such sounds are not commonplace, but the degradation will progressively reach the zone of the hearing of language, of intelligibility, and the subject will suffer from a deafness specific to sound aggressions: he will always hear, but he will no longer understand anything.”

Vicious circle and aggravating factors

It should however be specified that, if an intensity of 120 decibels is painful, an intensity of 80 decibels sometimes suffices to make disorders appear. Moreover, intensity is not the only factor: the duration of exposure to noise, its frequency, its more or less unexpected character influence first and foremost the nature and importance of the damage caused. It is also known that pure sounds are more harmful than complex sounds, and that the appearance of a lesion leads in very many cases to the establishment of a veritable vicious circle: the more one listens loudly, the more deaf one becomes, and the more deaf one becomes, the more one needs to listen loudly to hear.

Noise affects the whole organism

The auditory apparatus is not alone affected. This cannot surprise when one knows, thanks to Professor Tomatis, the central place it occupies in man and the very close links it maintains with the other physiological apparatuses and with the psyche. The action of noise may have repercussions on the functioning of the heart, blood circulation, the respiratory rhythm, intestinal transit, hormonal life, vision, the central nervous system, memory, intellectual and mental equilibrium, etc.

Sound engineers and the myth of deafness

It is therefore not exaggerated to say that, by their very activity, certain individuals find themselves in danger. Which ones? First, all those who, professionally, are subjected to intense sound exposure. For example, the workers on engines, the occupants of control towers, the sound engineers. The latter listen at very high intensity to the tapes on which they exercise their talents. Alfred Tomatis offers a simple explanation of this phenomenon: “People always wonder at this listening at great power; however, for the one doing a mix, if he is not ‘in’ the orchestra, all work becomes impossible. He is obliged to hear the same fullness as if he were in the centre of the formation, otherwise he cannot exercise his competences. Listen to Richard Strauss at low intensity: the music loses all its value and all its meaning. Does this mean that these engineers become deaf? Absolutely not. I know some who have done this trade for a very long time and who hear marvellously. To a certain extent, the sound engineer with damaged hearing is a figure of legend.”

Rock at 8,000 watts

However, the editors of SON have often had the opportunity to meet members of this profession who complained of experiencing certain auditory disorders. It must be said that these were specialised in so-called “rock” music. Now in such a context, the one who must re-immerse himself in the original conditions of sound emission exposes himself to particularly violent aggressions. The “hard rock” trio Grand Funk, for example, develops 8,000 watts when it is on stage!

In addition, a veritable ideology of sound power has been born in the public of these groups: it is no longer a matter only of hearing the music but of feeling it; the bass frequencies must make the air vibrate and shake the floor; one must be able to experience in one’s body their muffled breathing, etc. The amplifier, the theoreticians explain, is henceforth a full-fledged member of the orchestra. The others content themselves with affirming that this debauch of decibels contributes to the “kick” they seek and allows the listener to enter all the more easily into the music since the music finds itself all around him! The fact is, there is a pleasure (perverse perhaps, but that is not the question) in listening “too” loudly. Especially this music.

Most people, however, after a quarter of an hour or half an hour of this regime, tire of it. Others, for all sorts of reasons that it is not for us to analyse, resist and soon find themselves drawn into a kind of masochistic escalation in intensity.

Like it or not, the musicians must be at the head of the pack in this absurd race. They are therefore the first victims, and the most severely affected, of a murderous fashion to which they have largely contributed in launching: many become totally deaf, a few are so distressed nervously that psychiatric treatment is required. But alongside the lesions from which certain sound engineers devoted to rock artists suffer, there is another that lies in their age. Most of those who look after the music of the young are themselves fairly young.

Why youth is more vulnerable

“Now,” Alfred Tomatis explains, “the younger a subject is, the less capable he is of relaxing. I realised this at the time of my first work. When a worker of mature age was assigned to engines, he had generally followed a progression in relation to sound exposure. He had first worked in the workshops, then on more powerful engines, and so on… There had been over time an education such that he behaved like a true athlete in his spontaneous and automatic defence against noise. By contrast, the one who arrived there all fresh, all pink, and received the thunder on his head in one go, found himself crushed. On such a subject, one could observe serious lesions; the hammer blows of the stapes had torn the basilar membrane, for example.”

“Same phenomenon among musicians and singers. A great opera singer develops about 150 decibels in his skull when he is in full action. Fortunately, he has learned to hear himself in a very damped way at the moment when he sings, as if, in a way, he closed his ear to his own emission. If a young vocalist tries straightaway to sing at the maximum, he breaks his own ear, in the literal sense of the term!”

The prodigies withdrawn too early

“The same goes for a musician who would be plunged too early into a symphony orchestra. The public sometimes wonders why certain young prodigies, conductors admired before even having entered adolescence, have been suddenly withdrawn from the bill: it is because they have become deaf!”

“In a symphony orchestra, the sound intensity is often 130 decibels, and the human being is not made to live in the midst of such noise, unless one has learned to defend oneself through one’s natural means; how could a young musician, like most pop artists, playing at full power on an instrument amplified to the maximum, in the midst of other musicians no less keen on producing as many decibels as possible, fail to undergo significant auditory damage in the end?”

“And what shall it be if this musician is a percussionist! For percussion instruments are capable of provoking, on a sound curve, untimely spikes which it is not possible to measure exactly but whose consequences on the auditory apparatus and the nervous system are particularly redoubtable.”

Place of this interview in the series

This interview is the eighth of a series of fifteen. For the complete contents, see the mother-article of the series.

Source: Alain Gerber, “Dangerous Sounds — Alfred A. Tomatis: Avalanche of decibels, beware danger”, SON Magazine no. 37, Paris, April 1973. Digitisation: Christophe Besson, June 2010.