Noise as undifferentiated sound. This is the starting point: 'We might assume that it is possible to distinguish between musical sound and noise in acoustic terms: musical sound results from regular, periodic vibrations; noise results from non-periodic vibrations ... The distinction is based on the opposition between 'pure and simple sounds' on one hand and 'complex sounds' on the other' (Nattiez, p.45). Nattiez comments that the French language even employs an official physical definition of noise: noise is an erratic, intermittent or statistically random vibration. A sound has been considered as noise for a long time if its originating frequency was non-periodic and therefore of no determinate pitch. (Theodore Gracyk speaks of the doctrine that certain timbres are inappropriate for music making. He refers to the 19th century ideal of 'purity in articulation' where any richness of the contributing overtones was considered unwelcome noise (cf. Gracyk, p.114).) Non-periodic vibrations. Complex sounds. I call it noise as undifferentiated sound. As a starting point.
 Futurist Luigi Russolo was one of the first in the early 20th century to put the institutionalized division between music (Russolo mostly uses the term 'sounds' instead of 'music') and noises on the agenda. Russolo's essays on modern music all revolve around the main statement of his 1913 L'Arte dei Rumori. Manifesto Futuriste [The Art of Noises: Futurist Manifesto]: 'We must break out of this limited circle of sounds and conquer the infinite variety of noise-sounds' (Russolo, p.25). His main and simple question: If music is sound, then why does not music employ all the varieties that sound has to offer? According to Russolo, the traditional division between music and noise is based on the notion that music is a succession of regular and periodic vibrations. Noise, in contrast, seems irregular and fragmentary. Russolo questions this sharp distinction between music and noise and provides two arguments to support his position. The first concerns duration. 'The production of a sound requires not only that a body vibrates regularly but also that these vibrations be rapid enough to make the sensation of the first vibration persist in the auditory nerve until the following vibration has arrived, so that the periodic vibrations blend to form a continuous musical sound. At least sixteen vibrations a second are needed for this. Now, if I succeed in producing a noise with this speed, I will get a sound made up of the totality of so many noises - or better, a noise whose successive repetitions will be sufficiently rapid to give a sensation of continuity like that of sound' (Russolo, p.37). Here, Russolo tries to overcome the idea that musical sounds are continuous while noise is discontinuous. He undermines the sonorological difference between music and noise with respect to duration. By doing so, he is effectively introducing noise into the musical realm. The emancipation of noise has assumed an acoustic legitimization where noise is understood as a special kind of musical sound.
 Noise as undifferentiated sound. The idea that musical sounds result from regular, periodic vibrations and noise from non-periodic vibrations has remained widespread until long after Russolo's death in 1947 (to date?). However, 20th century electro-acoustic research reveals that the spectrum of most musical sounds is non-periodic. This means that noise may well have the same acoustic structure as musical sounds (cf. Nattiez, p.45-6). Furthermore, there is a reciprocal relationship between volume and sound quality. Increasing the amplitude of a sound wave alters its characteristic pattern and thus its timbre. It exposes more overtones, both harmonic and non-harmonic; the sounds become more complex (cf. Gracyk, p.109). Musical sounds become noise (from 'simple' to 'complex' sounds) when the volume increases. The alleged opposition between music and noise based on physical differences becomes less clear; it becomes less of an opposition. When we attempt to exclude noise from the realm of music on physical grounds, when we try to assess the essential difference between the two as accurately as possible, the difference dissolves and disappears. The boundary between music and noise becomes uncertain and undecidable. This also happens when we try to restrict ourselves to a single tone. The tone, or, rather, the sinusoidal tone, is the smallest musical unity to which all sounding phenomena can be retraced. However, we cannot perceive sinusoidal tones. Unavoidable, there are always overtones present due to the space in which the tone necessarily resounds, and because of the way our ear functions. (A tone constantly fluctuates; it continuously differs from itself. Therefore, in its vibrating quality, a tone is nothing but a changing quality, Derrida explains in D'un ton apocalyptique adopté naguère en philosophie, p.18-26.)
 I stop here. No more examples although the list could be extended. The boundary based on a physical difference between music and noise is constantly transgressed. Each sound immediately proves to be pervaded by noise; noise is at all times a part of every musical sound. If noise is the outside and music the inside, we must conclude that the outside is always already on the inside. And this conclusion (which is not a conclusion in the conventional meaning of the word, not the final word, the definitive outcome) goes beyond the idea of the emancipation of noise, the extension of the concept of 'music' as an acceptance of sounds that were previously rejected as noise, beyond the idea that no sound can any longer be excluded from the domain of music. Noise was and is always already part of musical sounds. That's a difference between deconstruction and emancipation.