Like xylophone and marimba, the xylorimba consists of a series of wooden bars laid out like a piano keyboard with a compass sufficiently large to embrace the low-sounding bars of the marimba and the highest-sounding bars of the xylophone. The lower notes of the xylorimba sound like a xylophone rather than a marimba on account of the bars being thicker and narrower than those of a marimba (the bars of the xylophone and the marimba are shaped differently to emphasize different overtones) and of the different size and shape of the resonators. The usual playng range of a modern xylorimba is five octaves: from the C one octave below middle C to the C four octaves above middle C (C3 to C8). It is a transposing instrument, since music for xylorimba is written an octave lower than it sounds, using a grand staff with both bass and treble clefs.
As the marimba-xylophone it was a popular instrument in the 1920s and 30s, particularly in vaudeville. As the xylorimba (or, less commonly, the xylo-marimba) has been used in a number of 20th century classical works. The terms have been a source of confusion. Many composers have called for ‘xylorimba’, including Alban Berg, Pierre Boulez and Olivier Messiaen, but invariably the parts were written for a four-octave xylophone (C4 to C8, nowadays the standard range for a concert xylophone). However, Pierre Boulez wrote for two true xylorimbas (each of five octaves) in Pli selon pli.
Compositions including xylorimba (both four- and five-octave instruments):