Noise (related to "noise" ) is a collective term for all auditory sensations that cannot be described as sound , tone , mixture of sounds , harmony or mixture of sounds . A sound does not have an exactly definable pitch . The cause of a noise are vibration processes mediated by elastic bodies , which are usually irregular, not periodic and can change in structure over time.
For a more detailed description of a sound play u. a. the temporal course, its tonality (the sound spectrum ), the disruptive effect and its origin play a role. Many noises have special names (see also Category: Noise ).
The sound sphere research basically classifies three different types of noises as components of a sound sphere : basic tones, signal sounds and orientation sounds. Fundamental tones are sounds that are determined by the landscape, wildlife , the environment (traffic, etc.) and the weather and therefore quickly become listening habits. Signal sounds are clearly contoured noises with the help of which messages can be transmitted ( e.g. hunting horn sounds , bells ringing, sirens). Finally, orientation sounds are characteristic noises that do not convey a special message, but have properties that make them identifiable and noteworthy for a person: for example the swelling noise of a truck or the clink of a piano.
Noises, especially from technical devices, have a historical context, as the production and use of the devices are limited to specific periods of time.
- A stationary noise changes its character only very little or not at all over a long period of time. Examples are: sound of a waterfall, falling rain, sound of a fan.
- Temporally unsteady noises change their character over time or are only present for a short time. Examples: dog barking, hammer blows, the sound of a roaring engine.
Tonality and spectrum
The spectrum of a noise describes which frequency components are contained in the noise. Tonal and noise-like broadband noises can be distinguished.
- In the case of a tonal noise, one frequency dominates. Therefore, a pitch can be assigned. Examples are: the whistle of a steam locomotive , propeller noise , panpipes .
- Broadband sounds do not have a dominant frequency. Often, however, certain frequency ranges are more pronounced so that a timbre can be assigned.
- The transition area between noise and tone is called tonality from the perspective of noise and particularly affects periodically working machines.
A noise can cause a mental disorder. The disruptive effect of a noise depends primarily on whether it is wanted or wanted. So z. B. one and the same noise (such as a motor noise or the noise of analog sound technology ) can be perceived as pleasant and desirable or as annoying. Unwanted noise is called noise . The disturbing effect mainly increases with the volume . But also increasing tonality (a tonal noise is more disruptive), with increasing unsteadiness (a noise that fluctuates over time is more disturbing) and with the information content (e.g. in the case of speech or music) can increase the disruptive effect.
In some cases, previously disturbing noises are synthetically generated after reinterpretation, which counteracts aspects that previously reduced the disturbing noise:
- Electric cars that are actually very quiet are operated with engine noise in order to compensate for safety in traffic through better audibility.
- Actually noise-free digital sound recordings are retrospectively provided with the noise of analog sound technology or the crackling of records or the pitch is changed in the manner of a magnetic tape with a feed speed that does not move constantly, e.g. B. low fidelity .
As a sound described sounds are often not earmarked, such as heating fans, dishwashers and rustling leaves. Nevertheless, music or a speech from bystanders in the environment can very well be perceived as noise or even as noise.
Noises can arise both outside (as a rule) and within the hearing .
- Noises arising within the hearing are usually interpreted as a malfunction of the same. One example is so-called noises in the ears ( tinnitus ).
- Noises outside the hearing have a physical cause, usually an air or structure-borne sound source . A distinction can be made between the following:
- aerodynamic sound generation (e.g. with fans , wind noise , wind instruments )
- mechanical sound generation (e.g. hammer blow, brake squeal, percussion instruments )
- thermodynamic sound generation (e.g. welding torch , explosion )
- unknown origin of the sound generation, examples: humming sound phenomenon (e.g. Stuttgart), Bloop , Train , Julia and Upsweep
- Tonality (music)
- Disturbance of the peace
- noise protection
- Noise (music)
- Noise instruments
- Sound effect
- Room volume
- Jürgen H. Maue, Heinz Hoffmann, Arndt von Lüpke: 0 decibels plus 0 decibels equals 3 decibels . Schmidt, Berlin 2003, ISBN 3-503-07470-8 .
- Roberto Casati and Jerome Dokic: Sounds. In: Edward N. Zalta (Ed.): Stanford Encyclopedia of Philosophy .