What is the didjeridu?
The didjeridu (also known as a didgeridoo or didge, yidaki) is a wind instrument developed by Indigenous Australians of northern Australia possibly 40,000 years ago and is still in widespread usage today both in Australia and around the world. It is sometimes described as a natural wooden trumpet or “drone pipe”. Musicologists classify it as an aerophone. The instrument is traditionally made from Eucalyptus trees which have had their interiors hollowed out by termites or died of other causes.
There are no reliable sources stating the didjeridu’s exact age, though it is commonly claimed to be the world’s oldest wind instrument. Archaeological studies of rock art in Northern Australia suggests that the Aboriginal people of the Kakadu region of the Northern Territory have been using the didgeridoo for at least 1,500 years, based on the dating of paintings on cave walls and shelters from this period. A clear rock painting in Ginga Wardelirrhmeng, on the northern edge of the Arnhem Land plateau, from the freshwater period shows a didgeridoo player and two songmen participating in an Ubarr Ceremony.
A modern didgeridoo is usually cylindrical or conical, and can measure anywhere from 1 to 3 m (3 to 10 ft) long. Most are around 1.2 m (4 ft) long. The length is directly related to the 1/2 sound wavelength of the keynote. Generally, the longer the instrument, the lower the pitch or key of the instrument.
Authentic Aboriginal didgeridoos are produced in traditionally-oriented communities in Northern Australia or by makers who travel to Central and Northern Australia to collect the raw materials. They are usually made from hardwoods, especially the various eucalyptus species that are endemic to the region. Sometimes a native bamboo, such as Bambusa arnhemica, or pandanus is used. Generally the main trunk of the tree is harvested, though a substantial branch may be used instead. Aboriginal didgeridoo craftsmen spend considerable time in the challenging search for a tree that has been hollowed out by termites to just the right degree. If the hollow is too big or too small, it will make a poor quality instrument.
When a suitable tree is found and cut down, the segment of trunk or branch that will be made into a didgeridoo is cut out. The bark is taken off, the ends trimmed, and some shaping of the exterior then results in a finished instrument. This instrument may be painted or left undecorated. A rim of beeswax may be applied to the mouthpiece end. Traditional instruments made by Aboriginal craftsmen in Arnhem Land are sometimes fitted with a ‘sugarbag’ mouthpiece. This black beeswax comes from wild bees and has a distinctive aroma.
Cultural Significance
Traditionally and originally, the didgeridoo was primarily played as an accompaniment to ceremonial dancing and singing, however, it was also common for didgeridoos to be played for solo or recreational purposes outside of ceremonial gatherings. For surviving Aboriginal groups of northern Australia, the didgeridoo is still an integral part of ceremonial life, as it accompanies singers and dancers in surviving cultural ceremonies. Today, the majority of didgeridoo playing is for recreational purposes in both Indigenous Australian communities and elsewhere around the world.
Pair sticks, sometimes called clapsticks or bilma, establish the beat for the songs during ceremonies. The rhythm of the didgeridoo and the beat of the clapsticks are precise, and these patterns have been handed down for many generations. Traditionally, only men play the didgeridoo and sing during ceremonial occasions, whilst both men and women may dance. Female didgeridoo players did exist, although their playing generally took place in an informal context and was not specifically encouraged. Linda Barwick, an ethnomusicologist, says that traditionally women have not played the didgeridoo in ceremony, but in informal situations there is no prohibition in the Dreaming Law. On September 3 2008, however, publisher Harper Collins issued a public apology for its book “The Daring Book for Girls”, scheduled to be published in October, which openly encouraged girls to play the instrument.
Physics and Operation
A termite-bored didgeridoo has an irregular shape that, overall, usually increases in diameter towards the lower end. This shape means that its resonances occur at frequencies that are not harmonically spaced in frequency. The second resonance of a didgeridoo (the note sounded by overblowing) is usually around an 11th higher than the fundamental frequency (a frequency ratio somewhat less than 3:1).
The vibration produced by the player’s lips has harmonics (i.e., it has frequency components falling exactly in the ratio 1:2:3 etc.). However, the non-harmonic spacing of the instrument’s resonances means that the harmonics of the fundamental note are not systematically assisted by instrument resonances, as is usually the case for Western wind instruments (e.g., in a clarinet, the 1st 3rd and 5th harmonics of the reed are assisted by resonances of the bore, at least for notes in the low range).
Sufficiently strong resonances of the vocal tract can strongly influence the timbre of the instrument. At some frequencies, whose values depend on the position of the player’s tongue, resonances of the vocal tract inhibit the oscillatory flow of air into the instrument. Bands of frequencies that are not thus inhibited produce formants in the output sound. These formants, and especially their variation during the inhalation and exhalation phases of circular breathing, give the instrument its readily recognizable sound.
Other variations in the didgeridoo’s sound can be made by adding vocalizations to the drone. Most of the vocalizations are related to sounds emitted by Australian animals, such as the dingo or the kookaburra. To produce these sounds, the player simply has to use their vocal chords to produce the sounds of the animals whilst continuing to blow air through the instrument. The results range from very high-pitched sounds to much lower guttural vibrations. Adding vocalizations increases the complexity of the playing.