The xylophone (from the Greek words ξύλον—xylon, "wood" + φωνή—phonē, "sound, voice", meaning "wooden sound") is a musical instrument in the percussion family that consists of wooden bars struck by mallets. Each bar is an idiophone tuned to a pitch of a musical scale, whether pentatonic or heptatonic in the case of many African and Asian instruments, diatonic in many western children's instruments, or chromatic for orchestral use.
The term xylophone may be used generally, to include all such instruments, such as the marimba, balafon and even the semantron. However, in the orchestra, the term xylophone refers specifically to a chromatic instrument of somewhat higher pitch range and drier timbre than the marimba, and these two instruments should not be confused.
The term is also popularly used to refer to similar instruments of the lithophone and metallophone types. For example, the Pixiphone and many similar toys described by the makers as xylophones have bars of metal rather than of wood, and so are in organology regarded as a glockenspiels rather than as xylophones. This misnomer was also popularised by the Sooty show, in which the metal-barred instrument he plays is always described as a xylophone.
The modern western xylophone has bars of rosewood, paduk, or various synthetic materials such as fiberglass or fiberglass-reinforced plastic which allows a louder sound. Some can be as small a range as 2½ octaves but concert xylophones are typically 3½ or 4 octaves. The xylophone is a transposing instrument: its parts are written one octave below the sounding notes. Xylophones should be played with very hard rubber, polyball, or acrylic mallets. Sometimes medium to hard rubber mallets, very hard core, or yarn mallets are used for softer effects. Lighter tones can be created on xylophones by using wooden-headed mallets made from rosewood, ebony, birch, or other hard woods.
Concert xylophones have tube resonators below the bars to enhance the tone and sustain. Frames are made of wood or cheap steel tubing: more expensive xylophones feature height adjustment and more stability in the stand. In other music cultures some versions have gourds that act as Helmholtz resonators. Others are "trough" xylophones with a single hollow body that acts as a resonator for all the bars. Old methods consisted of arranging the bars on tied bundles of straw, and, as still practiced today, placing the bars adjacent to each other in a ladder-like layout. Ancient mallets were made of willow wood with spoon-like bowls on the beaten ends.
The instrument has obscure, ancient origins. According to Nettl, it originated in southeast Asia and came to Africa c. 500 AD when a group of Malayo-Polynesian speaking peoples migrated to Africa. One piece of evidence for this is the similarity between East African xylophone orchestras and Javanese and Balinese gamelan orchestras. This, however has been questioned by ethnomusicologist and linguist Roger Blench who posits an independent origin in Africa.