Drone

Continuously or repetitively sounding tones or noises which seem to have little or no variation in time.

See: Hum, Lo-Fi, Redundancy, Stationary Sound, Tape Loop. Compare: Glissando, Grain, Tempo.

In music, the drone functions to stabilize the tonic, and as such serves a harmonic function. See: Harmony, Keynote Sound.

In an environment, drones serve no function, and are almost always the acoustic by-product of some electrical, mechanical or aerodynamic process. Usually, such sounds are monotonous and boring, but when they contain sufficient internal dynamics and harmonics, or when they are environmentally altered or enhanced (for example, by phasing, Doppler shift, reverberation or wind gradients), they can become interesting to the ear, and evoke positive images and feelings. Also called steady state sound.

Envelopes of two recorded sounds showing relatively constant or repetitive intensity levels that are characteristic of drones.