The vibraphone or in some circles simply 'vibes' are a percussion instrument of the idiophone family. Similar in appearance to the xylophone and marimba as it uses tuned metallic bars arranged in the chromatic scale and also hollow tubular resonators beneath the note bars to amplify the sound when they are struck. However, the vibraphone also incorporates a motor which drives a spinning valve which is mounted on a common shaft at the top of the resonators. This produces the vibraphones distinctive a tremolo/vibrato effect. The vibraphone also has a sustain pedal much like a piano which when depressed engages a damper bar to produce a shorter sound. The vibraphone originates in the United States in the early 1920s.