Marimba

Overview

A marimba is a large tuned percussion instrument played by striking wooden bars with mallets, each bar sounding a definite musical pitch. It is laid out like a piano keyboard so a player reads and plays it the same way, but its voice is warm and woody rather than struck-string. A bare bar gives only a short, quiet knock; the marimba's full, singing tone comes from pairing every bar with a tuned air column beneath it, so the instrument is really a row of small tuned resonators played through wooden keys.

The playing surface is the Tone Bar Set, a chromatic span of tuned Natural Tone Bar and Accidental Tone Bar keys. Under them hangs the Resonator Set, one tube per bar. Everything mounts on the Frame, the bars held by the Bar Suspension and the whole instrument rolling on its Locking Casters. It is struck with the Marimba Mallet.

How it works

Each bar is tuned by carving an arch out of its underside with the Natural Tone Bar and Accidental Tone Bar cut deeper for lower notes. The undercut lowers the bar's fundamental and, just as importantly, tunes its overtones into a harmonic relationship with that fundamental, which is what gives the marimba its rich pitch instead of a clangy one. The bars rest on the Bar Suspension: a continuous cord runs through holes drilled at each bar's vibrational nodes, the two still points where the bar barely moves, so the bar can ring freely without the frame damping it, isolated further by a rubber Bar Grommet.

Loudness and sustain come from the Resonator Tube hung directly under each bar. The tube is a closed air column tuned to the same pitch as its bar; when the bar is struck, the air inside resonates in sympathy and radiates far more sound than the bar alone could, while a Resonator Cap sets the tube's effective length so it stays matched. The Bar Suspension keeps the bar coupled to its tube and nothing else. The Frame carries it all at a Height Adjuster-set playing height, and the locking Locking Casters let a heavy concert instrument roll on and off stage and then stay put.