Building a Balafon — The West African Gourd-Resonated Xylophone

The balafon is a xylophone of tuned wooden bars, but each bar hangs over its own tuned gourd resonator with a small buzzing membrane, giving it a warm, humming, buzzy voice.

Cut a set of hard, dense wooden bars in graduated lengths, longest to shortest, and dry them well. A shorter, thicker bar rings higher.

Tune each bar by shaving wood away: hollow the MIDDLE of the underside to lower its note, or trim the ENDS to raise it — the same two cuts as any xylophone or marimba.

Build an open frame — two long rails on legs — to carry the bars in a row with space beneath for the gourds.

Hang a gourd of the right SIZE beneath each bar — a bigger gourd for a lower bar. Each gourd's air cavity is tuned to its bar so it swells that note like a bottle blown at the right pitch.

Pierce a small hole in the side of each gourd and cover it with a thin membrane (traditionally spider-egg-sac film; tissue works). It buzzes when the bar sounds — the balafon's signature rasp.

Rest the bars on cords along the rails at their still points (nodes) so they ring freely, and strike them with two rubber-headed mallets.

The balafon is a tuned-bar idiophone, just like the gamelan's metal saron, and its bars follow the same physics: a struck bar bends and rings, higher when it is short, thick and stiff, and it is tuned by removing wood — hollow the middle to lower the note, trim the ends to raise it — while resting the bar on cords at its two nodes (the still points about a fifth in from each end) lets it ring freely. But the balafon differs from the saron in two ways. First its bars are WOOD, not bronze, giving a warmer, woodier tone. Second, and beautifully, every bar has its OWN resonator: a gourd hung beneath it whose air cavity is tuned to that bar's note, so it acts as a Helmholtz resonator (a bottle blown at just the right pitch) and swells that one note — exactly the job a marimba's metal tube does under each bar. And each gourd carries a small membrane over a side-hole that BUZZES sympathetically when the bar sounds, a built-in mirliton that adds the balafon's characteristic rasp, the same trick as the dizi's dimo. The balafon is ancient in West Africa — the Sosso Bala, a sacred balafon, is said to date from the thirteenth century — and it is a direct ancestor of the marimba, carried across the Atlantic and grown into the marimbas of Latin America.