eolian sound, sound produced by wind when it encounters an obstacle. Fixed objects, such as buildings and wires, cause humming or other constant sounds called eolian tones; moving objects, such as twigs and leaves, cause irregular sounds. A wind that flows over a cylinder or stretched wire produces a sound the frequency (pitch) of which is a function of wind speed and the diameter of the cylinder or wire; it is independent of the tension, composition, and length of the wire.