Especially nowadays, noise is deeply-rooted in every individual. Being the unquestionable protagonist of our daily life brings two consequences: one is the development of a particular interest in noise as point of departure for different studies, and the other is the stratification of these studies and opinions. They overshadow the possibility of alternative readings and the rediscovery of the phenomenon with all its qualities.
Besides the medical analysis of noise and its consequences, in recent years the studies about noise grew exponentially. They can be inscribed in two main groups: the noise in contemporary society and the noise in contemporary aesthetics.
The documents that analyze the occurrence of noise from an historical sociological point of view are related to the first group; the analysis of the relationship between noise and the development and evolution of taste is related to the second group.
It is probably necessary to make a step back to rediscover noise and silence, to listen to them with new ears and read them as a new aesthetic opportunity. In this regard, by seeking a different way to talk about noise and analyse it, we’ll try to highlight some of the interpretations that have been made. We’ll investigate the relationship between noise and silence as it emerges from Luigi Nono’s work, one of the most authentic examples of aesthetic of noise and silence
The Industrial Era: the cradle of noise
The Industrial Era and the entrance into the twentieth century have a pivotal role in the history of the relationship between silence and noise. In his book “Il secolo del rumore” recently released by Il Mulino, Stefano Pivato explains this parental relationship with great sensitivity and a detailed bibliographic in-depth examination. This book represents the last, or one of the last witnesses of a research tradition that propose an historical-sociological approach to the matter.
Pivato tries to position noise in a particular context by giving it a date and a place of birth, which would be easily located in a crucial historic period between the nineteenth and twentieth century. Industrialization and combustion mechanisms introduced the loud voice of engines, which could be confused with something purely mechanical and inhuman. Something important however needs to be highlighted: in that period man started to feel involved, to be a glad witness, at a higher volume, of the advent of a new tool or invention. Centuries of new noisy inventions are greeted with enthusiasm. Noise becomes the acoustic symbol of progress.
Pivato quotes Attali: “For twenty-five centuries the Western culture has tried to look at the world. But it hasn’t understood yet that the world is not to see, it’s to hear. It is not to read, it’s to listen to. Our science always wanted to control, count, abstract and limit the senses, forgetting that life is noise and only death is silence.”
The society that Pivato describes tends toward a future in which noise is life. The author focuses on the celebrative aspect of noise as a lively and bright element. Exemplary is the story of Ferraris’ owners who loved so much the noise of their cars’ engine to record it on a CD.
The Nineteenth century was not a century of silence, of lack of sounds. The difference between the twentieth century however, as Pivato tells us, is that in the nineteenth century noises were all constrained within working schedules and time, were all enclosed in the rhythm of life. In the twentieth century is exactly the opposite. Noise is spread, aesthetically celebrated and philosophically justified.
The first celebration of noise and his first philosophical justification started with the Futurism: the sound of moving forward and the sirens of the progress became art, became a true hymn to reality, so celebrative that is deeply mimetic. Sounds are not perceived like sublime metaphors of world’s experiences and noises any longer, and the attention starts focusing on noises organized in artworks, brought by the external world into the internal world of art.
This dialectic between art and life, between noise and musical sound allows us to move from the sociological and historical level to the aesthetic one. But before approaching the aesthetic level a terminological premise and an in-depth examination about Paul Hegarty’s book Noise/Music are required. 
A premise about the meaning of aesthetic seems necessary, both to talk about the aesthetic of noise and to understand the mechanisms of perception at the core of Nono’s theory about the relation between noise and sound. The term aesthetics was coined by Baumgarten in 1735. He deepened it afterwards, in 1750,  by writing a book entitled Aesthetica in which he explicitly tries to establish an inferior epistemology, which is to say a science that could be source of endless knowledge able to shape the sensory perceptions that, according to Descartes, are still not clear. Aesthetics, then, is the study of the sensitive perception, of the senses and the relation between senses and logical knowledge. It is also, however, the study of art as a set of disciplines directly related to senses.
Baumgarten‘s analysis focuses on the five senses, leaving sight and hearing at last. To hearing is then assigned a particular task: it is the bridge between rationality and sensitivity. Hearing is in fact a sense that is tied to the body and the feel, in the way that it allows to perceive our own living body’s vibrations.
This combination of rationality and sensibility is the right way to approach Aesthetics meant as the taste of an epoch. In this sense the noise as a cultural phenomenon becomes alive in Hegarty’s research. Hegarty decided not to focus on the category of noise music, which he considers a category proper for records shops. What interests Hegarty is the cultural phenomenon of the tolerance to noise, of artistic appropriation, of noise perception as a value and not as undesirable act of acoustic overpower. If by definition noise is usually opposed to silence and music, according to Hegarty noise and music have a symbiotic relationship, which makes them deeply related. In his book there are different kind of music, from those who make noise as an aesthetic, intellectual and refined trace, to groups that seek the noise or situations in which noise is pre-conceptually conceived as symbol of life.
According to Noise/music, the fact that noise is considered something difficult to identify and understand could create a problem on sound and musicality and force people to question whether they are a matter of taste and habit, or something related to a universal order.
Let’s try to question everything again and analyze the first part of the inquiry about the noise-sound-silence triad. First of all we can try to give a definition, at least physical, of sound. Sound is a phenomenon that includes on one hand the extension curve from silence to noise and on the other hand it outlines an acoustic data in the perception.
Sound is one of the sensitive phenomena that is closer to our direct experience. Sound is a rapid variation of pressure, produced in an elastic medium by the vibration of a material body, called sound source, that is perceived by the organs of the human hearing. In other words, a body that vibrates transmits its own vibration to the elastic material that surrounds it, air or water for example, which then spread the vibration. This vibration, perceived by human hearing, is sound.
Usually, to establish a definition of noise and sound, the point of departure is the perception of noise as an annoying and unexpected sound, often extremely intense, different from music, that generally disturbs communication. In acoustic, noise is first of all a sound, something moving, that progresses in time; something that could be idealized in the white noise, a chaotic but continuous set of vibrations in which every vibration has more or less the same size.
As Helmholtz, one of the greatest scholars of the nineteenth century that studied the perception of sound, pointed out the lack of a regular element is what makes the noise, acoustically and perceptively, to be something anonymous and indistinguishable. In fact, it is the oscillation period that indicates the progress of the vibration, which gutters the energy, makes it sound and gives it a shape.
A different approach to the topic.
Noise as experience and endless opportunity.
After defining noise physically, and after showing different points of view, it is interesting to step back and suggest the interpretation of noise given by Luigi Nono. Nono, one of the most important composer of the late twentieth century, understood how to use technologies to create a musical current of thought that had at its core the investigation of the relationship between silence-noise and sound.
Let’s begin by saying that for Nono silence and noise are not opposed. In his aesthetic noise is not a celebration of life but a closer level to senses and sensitivity, more than to the symbolic value. Therefore, to decode Nono’s dialectic it is necessary to depart from a focal point: the communication data. According to Nono, silence is everything that communicates a clear nothing. Void, absence of vibrations, also on-going noise, is silence. Nono brings up the example of traffic in the tube. Noise in the tube is so perpetual and unclear that it doesn’t communicate anything, which means it can be considered silence.
Noise becomes a valuable phenomenon: its being unclear and vague is a form of silence. According to Nono an acoustic void and shapeless group of vibrations without periodicity have two things in common: the lack of a message, of any sort of communication, and the possibility, due to the lack of a shape, to become anything.
Nono keeps contextualizing sound and noise over and over. In this way sound and noise gain an always deeper perceptive-communicative role. Silence is the stage before sound and the lack of information in the chaotic sum of vibrations of noise. This is not a trivial concept. On one hand he avoids the naturalistic component and the component of stillness. On the other hand he relates silence to noise within the lack of communication and the expressive capability.
From a purely aesthetic point of view, Nono’s way to think of silence is also important for what concerns the direction of perception. In his works, the silent/noisy connotation of musical instruments’ emission contributes to conduct an easy reversal of the subject’s attention. In the past, the pause was an element/point between two hold sounds. Now two long situations of lull surround the emission of a point/sound which at the same time breaks the perception of a rhythmic scanning of music.
Making it simple, if in 4 ’33’‘ – the famous silent piece by John Cage – the pursuit of silence leads to the listening of the richness of sounds-noises of nature, in Nono the pursuit of silence allows to perceive the noisy and lively nature of which sound is made of.
Since space is always present in Nono’s work, to better explain the relationship between sound-silence and noise we could venture the following guess. Let’s imagine a ball which great circle is crossed by a thin membrane. The membrane is extremely flexible, able to vibrate and to change its shape and the shape of the half-spheres that it ties together. Let’s suppose that one half-sphere is completely empty and the other one is completely full of vibrations, and that the sound is like the thin membrane that determines subtle shifts between what is empty and what is full, between acoustic void and white noise. The entire sphere is the silence in which homeostasis is kept.
The sound comes from a movement within the stillness of silence. Silence is the deadlock that cannot be achieved upon the membrane, which admires the total absence of information and the perfect balance and separation between void and noise. Silence stands exactly like one of these moments, a complex and sophisticated situation that needs to be managed and listened to in order to communicate something. Silence is the emptiness where nothing exists, but that can host a sound, dishing the membrane that divides the half-spheres. It can also be a dense fullness that, at some point, clears its mesh until something comes out, dishing the same membrane seen from a different angle.
The sound becomes a small projection of the original silence, a puff that could be heard between void and noise. The rest of the sphere that represents silence remains in a sort of stillness that vents out, in the tension of the membrane, the two opposites of which is made of.
Silence and noise are not opposed. Noise can be read as part of silence, which, through the tension with the void, originates sound.
Silence, sound and noise become the keystones of a naive approach to the sound material, which goes beyond the stratified cultural datas. The aim is to return to the endless acoustic, artistic and emotional possibilities of listening.
 – Pivato, Il secolo del rumore, Il Mulino, Bologna 2011, p. 8.
 – Hegarty, Noise/Music. A History, Continuum Publishing 2008
 – Su questo cfr, Ophaelders, Filosofia arte estetica, Mimesis, Milano 2008, pp. 50 segg