Slit gong

Why would this elegant instrument sometimes be called a “talking drum”? Technically speaking, it’s not a drum—it has no membrane, the sound emanating instead from a narrow slit in the hollowed-out center. But slit gongs were used to communicate, as the sides of the instrument were made of slightly different thicknesses to produce two different pitches—a high tone and a low tone—when struck by mallets or bare hands. This contrast can mimic the words of a tonal language, essentially “talking.”