Tom Service discovers endless variety in music based on a drone - from rustic dance to mystic religious ecstasy. Medieval Christian music used a drone to provide support for their liturgical chants; old country dances went with a swing to the drone of bagpipes and hurdy-gurdy.

Much Indian classical music builds elaborate melodic variations over a drone. Minimalist composer Lamonte Young has a never-ending drone piece playing in his loft in New York; and rock band The Velvet Underground brought psychedelic drones into the pop scene of the late 1960s.

Tom talks to Northumbrian piper Kathryn Tickell about the drones on her bagpipes, and to American minimalist composer Phill Niblock about his use of microtonal drones in his music.