The marimba is like a xylophone. It is made of a set of wooden bars with tubes below called resonators. The bars are struck with mallets. It has a deeper sound than a xylophone.

The bigger, thicker and longer bars make the deeper notes, and the smaller, thinner and shorter bars make the top notes. To tune the bars, material is scraped from the underside of the bar.

The resonators add richness and volume to the marimba's sound. They are tubes made from aluminium, each hanging below a bar. Vibrations from the bars pass through the tubes, making them vibrate (resonate), amplifying the sound in the same way as a soundbox on a violin. In the most traditional versions, natural gourds are attached below the bars to act as resonators.