The didgeridoo is a wind instrument rich in overtones and is considered a traditional musical instrument of the northern Australian Aborigines. In the traditional context, it is usually made from a trunk of local eucalyptus species hollowed out by termites and serves as a predominantly rhythmic accompanying instrument for chants and dances. The tonal and rhythmic variety is created through combinations of mouth movements, breathing technique and voice effects, based on a fundamental tone that is only slightly varied in pitch and overblown tones. The mouthpiece only consists of a wax ring to protect the lips, which can also be missing on inexpensive or well-made instruments. In addition, the naturally given diameter of the wooden pipe is narrowed to a diameter that is comfortable for the player.