The aboriginal didgeridoo (didjeridu, dijeridu, yidaki) is a long, wooden wind instrument or horn used traditionally by the aboriginal people of Northern Australia. Rock paintings on caves have established that the didgeridoo has been used as a musical instrument for at least 20,000 years. It is made from a tree branch, usually eucalyptus, hollowed out by termites. Branches cut into varying lengths produce instruments with different pitches. The mouthpiece is usually made of beeswax or resin.
The haunting tones of the didgeridoo are created by the vibrating of the player's lips. Since every branch has its own unique shape, no two didgeridoos sound exactly alike. The didgeridoo is almost unique in the world of music in its use of a technique called circular breathing. This allows the player to breathe while producing continuous sound. During this process, the player allows his cheeks to fill with air, like a bellows. Then, in one quick step, the player releases that stored air while quickly inhaling through the nose, refilling the lungs. This breathing technique is often used along with subtle tongue and lip movements and the voice to create energetic rhythmic patterns.
The sound of the didgeridoo can be very powerful, often inducing the Trance State in the player as well as the listener.