The didgeridoo is a wind instrument coming from the Arnhem Land in Northern Australia. Naturally, it is created from tree trunks and limbs hollowed by termites. It produces a resonant low sound with complicated rhythmic pattern. This makes it suitable for chant and song accompaniment. It is also said that it is the sound of Australia, the voice of the earth, and probably the world’s most ancient musical instrument.
The acoustic guitar is hollow-bodied and uses only acoustic techniques to produce sound which means it does not have electric amplification. Its name is a retronym of the electric guitar to differentiate them from each other. Its strings could be made of steel or nylon while its top plate could be made of cedar or spruce. At the top is a circular hole with a diameter of 3.25 inches to 3.5 inches which strengthens and reinforces the produced sound.
The trombone is a wind instrument that is a member of the brass family. The differentiating characteristic of the trombone is a telescope-like slide which is controlled by the player to change pitches with the exception of the valve trombone with three valves. Similar to other brass instruments, the vibrating lips of the player makes the air inside the trombone to vibrate and this produces sound.