See also: Silence (homonymy)

The silence is the absence of its. The opposite of silence is the Bruit or the sound.

Physical definition of silence

Silence is not the complete absence of its or acoustic vibration, but the absence of perception of a sound by an human being.

A silence known as perfect corresponds to 0 dB but in general an audio signal is regarded as silencer if its noise level is in lower part of 40dB.

The mathematical reference of 0dB, in other words no sound can be perceived, is theoretical. Silence in the environment can be of ~10dB (A) in high mountain and ~20dB (A) in a peaceful campaign.

The sound is propagated through the air which surrounds us, or more precisely by using the vibrations of the molecules. The fact of being in a private space of air, as in space, would mean the absence of sound. It is thus impossible for us or the Spationaute S of an orbit station, to hear an explosion taking place on the the Moon, because of the vacuum which separates the transmitter from the receiver. What invalidates, in particular, film sound effects as Star Wars where the vessels emit noises of engines and explode in a deafening noise.

Biology

An human being perceives a certain beach of vibratory frequency and it was issued that physically silence would be what is beyond and in-on this side this human perception.

Measuring devices, " sonomètres" were gauged on the human frequencies of perception, but it is possible to detect and measure molecular vibrations beyond good and in-on this side measurements in decibels associated with the frequencies and perceptible by our ears. Therefore, silence does not exist on our planet ground.

To be convinced some, let us observe a dog. We see it drawing up the ear and listening to something which we do not hear. It does not have the same limit of silence as us. In the same way, the Chauve-souris move by echolocation by means of inaudible Ultrasons for us, and the elephants communicate by Infrason S quite as unperceivable by the human ear.

Music

Silence is with the music what the calm one is with the storm.

Alive silences between two successive notes of music take part in the formulation of the message and the feeling. An uninterrupted succession of notes without silence would amount reciting a text without marking spaces between the words!

This apparent paradox (because it is not one) is an important parameter in the design of a good room of music or theater: while having the times of reverberation adapted to their use (theater, symphonic music, etc), their acoustic geometry must be such as silences become perceptible (see opera of Bayreuth).

Le Monde of Silence

In its famous documentary of 1956, the Commander Cousteau calls the sea Le Monde of Silence , because it is frequently believed that the sound is not propagated there. They is of course false: in addition to one uses Sonar S there (artificial or natural, like those of the Cétacés), the sea is full with the noise of the Vague S, of the Pluie, the movements of ground or of the Tectonic plates, the animals like the Crevette S, etc Certaines layers of water even phantom Bruits retain. It a poetic license thus should be seen there.

See too

• Noise
• Quiet, device aiming at decreasing the sound
• Soundproofing
• soundproof Room
• 4 ' 33, work " silencieuse" of John Cage
• the silence of Lazare of Jean-Marc Rouvière, Desclée De Brouwer-DDB, Paris 1996
• S! lence, the monthly review of association S! lence
• the way of silence