Come eliminare Marimba, Xylophone, Vibraphone

The Marimba is a percussion music instrument consisting of a set of wooden bars struck with yarn or rubber mallets to produce musical tones. Resonators or pipes suspended underneath the bars amplify their sound. The bars of a chromatic marimba are arranged like the keys of a piano, with the groups of two and three accidentals raised vertically, overlapping the natural bars to aid the performer both visually and physically. This instrument is a type of idiophone, but with a more resonant and lower-pitched tessitura than the xylophone. A person who plays the marimba is called a marimbist or a marimba player. Modern uses of the marimba include solo performances, woodwind and brass ensembles, marimba concertos, jazz ensembles, marching band (front ensembles), drum and bugle corps, and orchestral compositions. Contemporary composers have used the unique sound of the marimba more and more in recent years. (https://en.wikipedia.org/wiki/Marimba)

The Xylophone 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.
(https://en.wikipedia.org/wiki/Xylophone)

The Vibraphone is a musical instrument in the struck idiophone subfamily of the percussion family. It consists of tuned metal bars, and is usually played by holding two or four soft mallets and striking the bars. People who play the vibraphone are called vibraphonists or vibraharpists. The vibraphone resembles any keyboard instrument. One of the main differences between the vibraphone and other mallet instruments is that each bar suspends over a resonator tube with a motor-driven butterfly valve at the top. The valves connect together on a common axle, which produces a tremolo or vibrato effect while the motor rotates the axle. The vibraphone also has a sustain pedal similar to a piano. With the pedal up, the bars produce a muted sound. With the pedal down, the bars sustain for several seconds, or until muted with the pedal.
(https://en.wikipedia.org/wiki/Vibraphone)

The Glockenspiel is a percussion instrument composed of a set of tuned keys arranged in the fashion of the keyboard of a piano. In this way, it is similar to the xylophone, although the xylophone's bars are made of wood, while the glockenspiel's are metal plates or tubes, thus making it a metallophone. The glockenspiel, additionally, is usually smaller and, because of both its material and smaller size, higher in pitch.
In German, a carillon is also called a glockenspiel, while in French, the glockenspiel is often called a carillon. In music scores the glockenspiel is sometimes designated by the Italian term campanelli.