Trough zithers are a group of African stringed instruments or chordophones whose members resemble wooden bowls, pans, platters, or shallow gutters with strings stretched across the opening. A type of zither, the instruments may be quiet, depending upon the shape of the bowl or string-holder. Sound is often amplified with the addition of a gourd resonator. Instruments have been classed into five different types, based on shape. The resonator is most commonly a gourd, but tin cans have also been used. * * * *