Drone music is a minimalist musical style that emphasizes the use of sustained, repeated sounds, notes, or tone-clusters called drones. Music that is based on drones can consist of pure drones, slowly changing drones, or drones augmented with more transient sounds. It is typically characterized by lengthy audio programs with slight harmonic variations throughout most pieces.
The preeminent innovator in drone-based music is composer La Monte Young, who, in the 1960s, composed very long pieces for clusters of sustained tones; Young himself defined drone music in 2000 as “the sustained tone branch of minimalism”. The style of drone music exemplified by La Monte Young is usually classified as being part of the minimalist genre of post-classical music.
Another style of drone music has developed out of the heavy metal genre. Usually referred to as drone metal or drone doom, it is characterised by electric guitar and bass guitar played at very slow tempos, and by a focus on very low, and loud, bass tones. Many drone bands focus on the ability of their sound to create a feeling in the listener of trance or ecstasy, instead of on harmonic variation or intricate song structures. This drone music has strong relations to doom metal, and its style has also been integrated into the music of some electronic and post-rock artists.
Not all drone music is slow and relying on one note held indefintely; drone can also involve more active music that uses repetition of notes. 60's psychedelic rock would often chime a drone note and/or have a persistent drone bassline in the style of Eastern raga music. Jams would revolve around this drone, sometimes utilising dissonance in the other lead lines played against it, rather than the music consisting solely of one note/ chord stretched out in time. .