malletjazz.com FAQ pages
Whats the difference between a xylophone, a vibraphone, and a marimba?
The main differences are range, and the material used to craft the bars. Of those three mallet instruments, the xylophone has the highest range (covering 2-1/2 to four octaves), and the bars are either made of rosewood or some sort of synthetic material. The marimbas bars are also made of rosewood or synthetic materials, or sometimes a less expensive wood like Paduk.
Marimbas range from three octaves to five (or even a few notes beyond that!); 4-1/3 octave instruments are probably the most commonly-found range today, as this was the standard concert range for the instrument for many years - but in the past decade or so, five octaves has become the standard range for concert marimba repertoire, and five-octave instruments have become much more commonly used by professionals and college music programs.
Vibraphones have bars made of metal rather than wood,and thus the bars on a vibraphone sustain far longer than those on a marimba or xylophone; this is why vibraphones have a damper pedal (similar in function to the damper pedal on a piano). The standard range of the vibraphone has been three octaves (F-F) for many decades, but recently manufacturers have started to offer extended range vibraphones, extending down to C for a 3-1/2 octave range, or sometimes adding notes to the upper range to create a four-octave vibraphone.