What is a tanpura?

A tanpura is a long-necked, unfretted lute that plays a steady drone behind a singer or instrumentalist. It usually has four metal strings, tuned to the tonic (Sa) and generally the fifth (Pa).

The tonic is the soloist's chosen base pitch, and every accompanist tunes to it. The tanpura is played to keep that pitch sounding under the melody. Each string meets a slightly curved bridge over a thin thread, and that contact makes the overtone-rich sound called jawari. Carnatic musicians call the instrument the tambura.