The marimbaphone is an obsolete tuned percussion instrument, developed by the Deagan company of Chicago, Illinois, U.S.A. in the early 20th century.
The marimbaphone had shallow steel bars arranged chromatically with a tube resonator under each bar. Its timbre was similar to the celesta, and it was used mainly by marimba bands and as a solo instrument by stage artists (Blades 2001).
In addition to being played with mallets in the conventional way (as in the playing of a marimba or vibraphone), the marimbaphone was designed so that its bars could be rotated from a horizontal position to a vertical position, allowing them to more easily be played with a bow. To further facilitate bowing, the ends of its bars were concave rather than flat. A single marimbaphone could be played by more than one performer, allowing both techniques to be used simultaneously.
Although the instrument has been comparatively little used in art music (Percy Grainger was one of only a few composers ever to call for it), the name is found in many scores where the ordinary marimba is meant (Blades 2001).