drone
A sustained or repeated note, usually in the bass, that persists throughout a passage or piece.
In Depth
A drone is a continuous pitch that sounds beneath or alongside the melody, providing a fixed harmonic reference point. Unlike a pedal point, which is a compositional technique within tonal harmony, a drone is often a fundamental feature of the music itself — the harmonic world is built on top of it.
Drones are central to many musical traditions worldwide. The Indian tanpura provides the drone for classical ragas. Scottish bagpipes have dedicated drone pipes that sound continuously. The hurdy-gurdy has built-in drone strings. In Western art music, drones appear in medieval organum and have been revived in minimalist and ambient music. The drone creates a hypnotic, meditative quality that many listeners find deeply immersive.
The tanpura, which provides the drone in Indian classical music, is always the first instrument to start playing and the last to stop — the drone literally frames the entire performance.