The "didgeridoo" (sometimes didjeridu) is an Australian Aboriginal wind musical instrument. They were used by the Yolgnu people of Arnhem Land. They can be quite long, anywhere from long. Most are around long. The longer the instrument, the lower the pitch or key of the instrument. They are a hollow wooden tube, which can be either cylindrical or conical in shape. It is best described as being a wooden trumpet or drone. Musicologists say it is a brass aerophone.