Futurist painter and composer, Luigi Russolo firmly believed that the Industrial Revolution had meant that there was no longer silence in the world; the noises that now filled the air came from the technology that was developing at an incredible rate.
In 1913, Russolo published his manifesto, The Art of Noise in which he explained his theory:
In antiquity, life was nothing but silence. Noise was really not born before the 19th century, with the advent of machinery. Today noise reigns supreme over human sensibility. For several centuries, life went on silently, or mutedly. The loudest noises were neither intense, nor prolonged nor varied. In fact, nature is normally silent, except for storms, hurricanes, avalanches, cascades and some exceptional telluric movements. This is why man was thoroughly amazed by the first sounds he obtained out of a hole in reeds or a stretched string.
This led him to consider how noise could be recovered and transformed into music.
To excite our sensibility, music has developed into a search for a more complex polyphony and a greater variety of instrumental tones and coloring. It has tried to obtain the most complex succession of dissonant chords, thus preparing the ground for musical noise.
To create his ‘musical noise’, Russolo invented, what he called, Intonarumori; an acoustic contraption made of cogs, strings, drums that all made different sounds dependent on the construction.
A recreation of this can be seen in MART in Roverto, Italy:
Each sound carries with it a nucleus of foreknown and foregone sensations predisposing the auditor to boredom, in spite of all the efforts of innovating composers. All of us have liked and enjoyed the harmonies of the great masters. For years, Beethoven and Wagner have deliciously shaken our hearts. Now we are fed up with them. This is why we get infinitely more pleasure imagining combinations of the sounds of trolleys, autos and other vehicles, and loud crowds, than listening once more, for instance, to the heroic or pastoral symphonies.
In 1917, a performance using the machines was met with disapproval by the audience, not that Russolo was surprised. Today, this does not seem quite so strange. Check out this fantastic animation of Luigi Russolo and the Futurista Sound System:
For an informative study on Russolo and the Art of Noise, this article from History Today is worth reading.