The Sorna is an ancient Iranian woodwind instrument. The word sorna is a Pahlavi derivative of Surnay (literally "strong flute"). A small amount of air is forced under pressure through a small metal tube called the staple which serves to hold the reed and match it to the bore. This requires the player to make sure, as in oboe playing, that one also empties the lungs of stale air when taking a new breath. Often Sornas were played in pairs, with a melody and a drone player. This drone may move to different notes during a piece of music, changing at prescribed places in the composition.