Vocal box holds key to ancient instrument

The didgeridoo is an aboriginal instrument traditionally made from a tree trunk hollowed out by termites. It can produce a wide variety of timbres, though usually playing only a single note.

A skilled player alters the acoustics inside the mouth to set up strong resonances at certain frequencies, the Journal Nature reported.

This is done by moving the glottis, the part of the windpipe that contains the vocal cords, say researchers led by Joe Wolfe of the University of New South Wales in Sydney.

This enhances certain frequencies while inhibiting others. It's easy to make a basic sound. But learning these strong formants takes a while.

Skilled didgeridoo players do this subconsciously, Wolfe says. "None of the players to whom we've spoken is aware of it."

Copyright 2005 by United Press International