Any musical wind instrument that sounds when the player's breath or air from a wind chamber causes a reed (a thin blade of cane or metal) to vibrate, thereby setting up a sound wave in an enclosed air column or in the open air.
Reed pipes have single or double reeds. A double reed, as in the oboe or bassoon , consists of two cane blades tied together that beat against each other. A single reed may hit against a frame (beating reeds), as in the clarinet or saxophone , or it may vibrate freely through a closely fitting frame (free reeds), as in a harmonica or accordion . Beating reeds in woodwind instrument s depend on the pipe's sounding length (as determined by the fingering) to determine the pitch. Free reeds have their own single pitch, determined by their thickness and length. See also English horn ; shawm .