How are Musical instruments tuned

How are Musical instruments tuned??

              All musical instruments produce sound by vibration of something a string , a membrane or a column of air. A good musical tone is produced when the vibrations have the right frequency(pitch) and right amplitude (loudness). When a musical instruments  is out of tune, it fails to produce sound of the right frequency and unpleasant sound is produced these instruments are tuned by making some adjustments.in stringed instruments, the string(wires) are re tuned by tightening or loosening them so that they vibrate with the  right frequency when plucked. similarly, in case of a percussion instruments, like tabla, the tension or tautness of the membrance can be adjusted to produce the right sound when stuck by hand.