Noise

Noise ( noise ) is a collective term for all auditory sensations that can not be described as sound, sound, clay mixture, harmony or sound mixture. Cause of a noise is vibration processes, which do not extend generally periodic and can change over time in their structure.

Characterization

For a more detailed description of a sound play, inter alia, the time course, its tonality ( the sound spectrum ), the interference effect and its origin a role. Many sounds have special names (see also Category: noise).

The public spheres of research classified as components of a soundscape basically three different types of noise: fundamental tones, signal sounds and orientation sounds. Basic tones are sounds that ( traffic, etc. ) and the weather will be determined by the scenery, the wildlife, the environment and therefore are rapidly listening habits. Signal sounds are clearly outlined noises can be transmitted with the help messages (for example, hunting horn sounds, chimes, sirens ). Finally orientation sounds are characteristic noise, which, although not transmit any special message, but have properties that make them a people identifiable and worthy of note, for example, the swelling sound of a truck or the strumming of a piano.

Time course

After the type of the time course over time stationary and nonstationary noise can be distinguished.

• A stationary noise does not change its character over a long period of time, or very little. Examples are: sound of a waterfall, falling rain, noise of a fan.
• Change with time non-stationary noise its character with time or are available only for a short time. Examples: dogs barking, hammer blows, sound of a roaring engine.

Tonality and range

The spectrum of a sound describes the frequency components are included in the noise. We can distinguish tonal and broadband noise.

• In a tonal noise is dominated by a frequency. Why can assign a pitch. Examples are: a steam locomotive whistle, propeller noise, pan flute.
• Broadband noise have no dominant frequency. Often, however, certain frequencies are more pronounced, so that a sound to be played with. Examples: roll of thunder in a storm ( dull tone), hiss of a snake (light tone), the ocean (It can not be assigned to timbre. )

Disturbance

From a noise may pose a mental disorder. The disturbing effect of noise depends primarily on whether it is desired or wanted. But it can be perceived as pleasant and desired or disturbing for example one and the same noise ( noise as a motor ). Unwanted noise is called noise. The interference effect of increasing, in particular with the volume. But rising tonality ( a tonal noise is disturbing ), with increasing unsteadiness ( a temporally fluctuating noise disturbs more ) and the information content (eg, speech or music ) can increase a disturbance.

As noise designated sounds are not often earmarked as heating fan, dishwasher, rustling leaves and chirping birds. Nevertheless, even music or a speech by outsiders in the environment can be perceived very well as a sound or even as noise.

Origin

Noises can occur both outside ( usually ) and within the hearing.

• Within the hearing resulting noise is usually a malfunction thereof. One example is the so-called ringing in the ears ( tinnitus).
• Resulting Outside the hearing noises have a physical cause, usually an air - borne noise source. After the emergence can be distinguished here: aerodynamic sound generation (eg, fans, wind noise, wind instruments )
• Mechanical sound production (eg hammer, squealing brakes, drum instruments)
• Thermodynamic sound production (eg, welding torch, explosion)
• Unknown origin of the sound generation, examples: Hum phenomenon (eg Stuttgart), Bloop, Train, Julia and Upsweep