The Australian didgeridoo or yidaki is a simple wind instrument, yet a good player can coax from it a variety of timbres greater than that of many an orchestral instrument. It can produce a huge variety of different timbres, despite it usually playing only a single note. A study of the vocal tract and lip contortions necessary for this feat tells us a lot about how music is made.

To understand this phenomenon, researchers led by Joe Wolfe of the University of New South Wales in Sydney simultaneously measured the sound produced by the didgeridoo and the acoustic impedance of the player’s vocal tract. What they found was that a skilled player alters the acoustics inside their mouth to set up strong resonances at certain frequencies. Players enhances certain frequencies while inhibiting others, much as different vowel sounds are produced by adopting different positions for the tongue and vocal cords. In other words, experienced players are using their glottis to accentuate the instrument’s tonal variation.

Skilled didgeridoo players do this subconsciously, Wolfe says: “None of the players to whom we’ve spoken is aware of it.” But the creation of these characteristic frequency bands, called formants, is what gives their playing expression and variety. “It’s easy to make a basic sound,” Wolfe says. “Then you have to learn circular breathing. Learning to make strong formants takes a while. Other techniques involve vocalizing and playing at the same time: one gets interactions between the vibrations from the lips and from the vocal cords.”

via news@nature.com, PhysOrg, Acoustics: The vocal tract and the sound of a didgeridoo (Abstract)

Why I blog this? Over the past few months I have been learning about as much as I can take in about acoustics, synthesizers, and music in general, so this article instantly grabbed my attention. Also, a good friend of mine has been playing didg for a number of months now, and I have been able to watch the dramatic improvement in her playing skills during that time. Thus, this story about the acoustics of the didgeridoo was quite interesting to me.

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 Tags: didgeridoo, acoustics