What is music and harmony

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Sound pressure and frequency

The normal origin of sound is vibration. The vibration of the violin body is coupled into the air where it appears as cyclic pressure variations. Sound can also origin as oscillations of an air stream. This is how sound is created by a flute or a trumpet. The pressure changes are very small. Sound pressure is measured in Pa that is Newton/square meter The weakest audible sound is about 20 millionth Pa (0dB). When we play 20 people in folkets hus we often reach 1 Pa (96dB). The atmospheric pressure is about. 101.000 Pa. This means that you can hear noise about 100 trillionth of the atmospheric pressure. Sound is propagating as waves in the air with a speed of about 330 m/s (depending on air temperature). The oscillations are measured per second equal to Hertz (or Hz) The frequency range that children can here is between 16 Hz and 20.000 Hz. When we get older we will loose the ability to hear high pitches. Violinists are here in the danger zone. Not because we play loud, but because the instrument is so close to our ear, that the sound level that our ear is subjected to often gets above the critical level.