Bullroarer (music)
A
bullroarer or
turndun is an ancient ritual musical instrument and means of communicating over extended distances.
It consists of a longish piece of
cord fixed to an
oval piece of wood or other suitable material which usually is thicker in the center, and sharpish at the edges.
The cord is given a slight initial twist, and the roarer is then waved in a large circle in a horizontal plane. The
aerodynamics of the roarer will keep it spinning about its axis even after the initial twist has unwound. The cord winds fully first in one direction and then the other.
It makes a characteristic roaring
vibrato sound with notable modification from both
Doppler effect and the changing speed of the roarer at different parts of its circuit.
By modifying the expansiveness of its circuit and the speed given it, the modulation of the sound can be controlled, making the coding of information possible. The low frequency component of the sound travels extremely long distances, especially on the wind.
This instrument has been used by numerous early and traditional cultures in both the
northern and
southern hemispheres but in the popular consciousness it is perhaps best known for its use by
Australian Aborigines (it is from one of their languages that the name
turndun comes).
Bullroarers are still considered to be sacred/secret by some Aboriginal tribes and are not allowed to be shown to women, children or outsiders. They are used in men's initiation ceremonies and the sound they produced is considered to represent the sound of the
Rainbow Serpent.
The bullroarer is sometimes used as a means of demonstrating the
Doppler effect, by using sound. As the instrument travels round, its sound goes up or down according to its speed, and distance from the hearer.
