Jonathan Sterne (Sterne 2003: 95) describes how this double reduction managed to effectively free sound recording from the noise problem, Michel Serres (Serres 1995; Serres 2008) unanimously argues that the preconditions underlying the concepts of “noise” and “signal” in information theory not only provide the framework for noise reduction, but also show that noise reduction is never complete or successful. In addition, it turns out that noise reduction not only creates its own idea of noise, but also inevitably affects the signal itself. The output of noise reduction – a particular type of silence – can be considered a false signal: arises from noise reduction and presentation as information. Various techniques can be used to reduce noise before, during or after recording. The most advanced of these are double-end noise reduction technologies. Based on an earlier technique called “pre-accentuation/undressing,” inventor and engineer Ray Dolby developed a process called “companding” in the early 1960s: a contraction in which the amplitude of the signal is compressed at the time it is recorded, and then extended during playback. High-frequency and low-volume passages are pressed into the volume by compression, which effectively “masks” the high noise of tape noise. In the extended state, the amplitude range is reset to its original level, and with the volume of previously compressed passages, the noise level is significantly reduced. Therefore, most of the noise is now masked by the louder signal and becomes virtually inaudible. In a professional recording process, compression or “encoding” takes place during recording between the sound source and tape; The extension or “decoding” takes place during the production of the master tape. Noise reduction is a strategy to imbue sound recordings with a significant false silence that suggests an orderly, delimited and clear meaning. But according to Serres, given its idealized status, it remains a fundamentally temporary, unstable and, above all, precarious order, exemplified by the song of Orpheus rather than the cunning of Ulysses.

Or, as Stäheli (Stäheli 2003:244) writes: “It is precisely the functioning of the order that produces its own noise that makes impossible […] order. Information theory itself undermines the distinct difference between signal and noise. No matter how quietly claims that noise reduction cleverly reduces a clearly defined object and produces a supposedly clean “original”,” that object is always only negatively defined by what it is not. Sound researcher Mack Hagood (Hagood 2011) describes a similar silence in his analysis of Bose QuietComfort Acoustic Noise Cancelling headphones. Just like noise reduction, these headphones separate, in the words of Bose founder Dr. Amar Gopal Bose (Bose quoted in Hagood 2011: 575), “the things you don`t want from the things you want.” To do this, they actively create silence in places where noise is actually abundant. Headphones and noise reduction act as a support, reducing noise and creating a reconstructed sound image of an imaginary original, artificially inducing silence. This imbues the silence with a special meaning and sense of agency: it is carefully constructed and potentially meaningful like any sound. In clinical audiology, pure tones are used for pure tonal audiometry to characterize auditory thresholds at different frequencies. Localizing sound is often more difficult with pure tones than with other sounds. [2] [3] In the second half of the nineteenth and the first half of the twentieth century, the concept of noise underwent several profound changes that led to the predominance of three major conceptual currents. First, as described in Jonathan Sterne`s seminal book, The Audible Past (Sterne 2003), nearly a century of research and experimentation on the physical nature of sound and hearing has redefined the traditional hierarchy between musical “sounds” and non-musical “noise.” Amid numerous studies in acoustics, medicine, engineering, and physics, the famous German physicist Hermann von Helmholtz applied Fourier analysis to the study of overtone series and the sound structure of sounds and coined the term “tonal color” (Evens 2005: 3-6; Kursell 2006: 216-221), but also inspired a new idea of noise.

[4] Vibration, the attraction of hearing, consists of a series of pressures made up of normal air that can be called waves. Sound waves have three properties, each with psychological involvement, each amplitude, frequency and purity. Larger wave amplitudes are associated with higher volume; The frequency of the waves is associated with the height, and the purity of the waves correlates with the timbre. From the early days of sound recording, listeners were trained to separate the foreground from background noise or, in terms of information theory, to separate the signal from the noise.