Xylophones produce sound when their metal or composite material bars are struck using a mallet. The pitch produced depends on the bar's length: short bars tend to have a higher pitch while long bars have a deeper pitch.
The sound is amplified through resonator tubes underneath the bars. Air is pushed into the tubes resulting in more vibration, but at a similar pitch produced by the bar struck. A cord is placed across the middle of the xylophone to lift the bars from the frame, allowing them to vibrate freely. The bars are usually arranged on a frame like a piano keyboard and are tuned to the same 12-note chromatic scale.
Xylophones are categorized as percussion instruments, which are musical instruments that have to be shaken or struck to produce sounds. Within the larger percussion category of musical instruments, xylophones are further classified as idiophones. This uniquely distinguishes them from membranophones, which are musical instruments that have a membrane, such as a drum.
The xylophone is believed to have originated in Oceania or Southeast Asia. It produces a unique brittle metallic sound. The quality of sound produced by a xylophone typically depends on the skill level of the player. The mallet is also crucial to the sound produced; mallet grip is an important technique for playing the xylophone.