These occur mainly at the start of a sound, e.g. when a stringed instrument is plucked or a cymbal is struck. These starting transients are also characteristic of the instrument producing them. Sound equipment must be able to cope with these high frequencies otherwise the tonal quality of the sounds will be altered. Cymbals, for example, can produce frequencies around 20kHz to 25kHz. Noise is an integral part of much music.
Periodic motion is movement that is regular and repeating eg.
A musical note is produced by periodic motion at an audible frequency. Non-periodic motion is perceived as a noise. In music, the range of sounds is divided into sections known as octaves . Each octave consists of seven different notes and eight intervals or spaces between the notes. The seven notes are named A to G and the eighth note is the A of the next octave.