Acoustics: the vocal tract and the sound of a didgeridoo.
The Australian didgeridoo (or yidaki in the Yolngu language of northern Australia) is a simple musical instrument that, at the lips of an experienced player, is capable of a spectacular variety of timbres--considerably greater than those that can be coaxed from orchestral instruments, for example. To understand this phenomenon, we simultaneously measured the sound produced by the didgeridoo and the acoustic impedance of the player's vocal tract. We find that the maxima in the envelope of the sound spectrum are associated with minima in the impedance of the vocal tract, as measured just inside the lips. This acoustic effect is similar to the production of vowel sounds made during human speech or singing, although the mechanism is different, and leads to the surprising conclusion that experienced players are subconsciously using their glottis to accentuate the instrument's tonal variation.
School of Physics, University of New South Wales, Sydney, New South Wales 2052, Australia.
Alex
A
Tarnopolsky
Neville
N
Fletcher
Lloyd
L
Hollenberg
Benjamin
B
Lange
John
J
Smith
Joe
J
Wolfe
D000162:Acoustics; D001315:Australia; D006801:Humans; D008046:Lip / Q000502:physiology; D009055:Mouth / Q000033:anatomy & histology / Q000502:physiology*; D009146:Music; D012137:Respiratory System; D014059:Tongue / Q000502:physiology; D014197:Trees; D014934:Wood