Music style characterized by the use of sustained sounds and notes. Originally, a drone is a low-pitched sound supporting the main patterns of the musical piece, most typically in bagpipes.
In its purest form, a drone music piece will consist of a few notes continued for several tens of minutes with only very slow distortions (for instance, The Hafler Trio's Trilogy, Cleave, No Man Put Asunder and No More Twain, Of One Flesh).
Drones are also used in Doom Metal, where the bass line remains unchanged for several minutes while sometimes lacking any tempo (for instance, Earth and Sunn O)))).
Drones also feature in Noise and other experimental recordings, where the hypnotic and sometimes jarring effects of sustained notes are applied to the listener for an extended period of time (for instance, Nackt Insecten's Sick Animal Eyes, Time Machines' self-titled album, and Keiji Haino and Sitaar Tah!'s collaborative album, Animamima.)