Wind machine

 
The wind machine (also called aeoliphone) is a friction idiophone, which is a class of instrument which produces sound through vibrations within the instrument itself. It is a specialist musical instrument used to produce the sound of wind in orchestral compositions and musical theater productions.
Construction.
The wind machine is constructed of a large cylinder made up of several wooden slats which measures approximately 75–80 centimeters in diameter. The cylinder body of the instrument rests upon a stand and is typically covered with silk, canvas, or other material which is in a fixed position. A crank handle, used by the player to rotate the cylinder and create the sound, is attached to the cylinder.
Another method of construction implements an electric fan, which is fitted with lengths of cane, rather than blades. However, this method is less popular because it does not provide the player with the ability to control the speed of rotation.
Technique.
The wind machine is played by rotating the crank handle, which is attached to the cylinder, to create friction between the wooden slats and the material covering that touches the cylinder but does not rotate as the crank handle is turned. This friction between the wood and the material covering creates the sound of rushing wind. The volume and pitch of the sound is controlled by the rate at which the crank is turned. The faster the handle is turned, the higher the resulting pitch and the louder the sound. The slower the handle is turned, the lower the pitch and the softer the volume. The sound of the wind machine can also be controlled by the tightness of the fabric covering the cylinder.