How It Works: Didgeridoos
By Anne Adapter
Used for more than 1,500 years, and therefore possibly the world’s oldest wind instrument, the didgeridoo creates a sound much like Marmite – you either love it, or hate it. But what’s the secret behind that unique drone?The traditional manufacturing process is unique in that it relies upon finding a suitable length of (typically) Eucalyptus tree that has previously been hollowed out by termites. The branch or length of trunk is trimmed, its bark removed and a rim of beeswax applied to the narrower end to serve as a mouthpiece.
To create a constant drone, a didgeridoo player must continuously vibrate their lips. To achieve this continuity the player must employ a special breathing technique called ‘circular breathing’ - inhaling through the nose whilst simultaneously exhaling through the mouth. It is far easier said than done. Excessively hard blowing (referred to as ‘overblowing’) and ‘vocalising’ are used to create dramatic effects.
| Didgeridoo maestro Ash Dargan. |
In the case of the didgeridoo, however, the sound wave also travels backwards into the player’s vocal tract, itself a resonator that amplifies or suppresses certain frequencies. The shape of the tract, especially the shape and position of the tongue, affect the frequencies at which the tract resonates. When playing the didgeridoo properly, then, the vocal tract is actually working backwards much of the time.
So what’s the difference between a simple length of plastic pipe and a didgeridoo? Well, a termite-bored didgeridoo has a very irregular internal shape. This, combined with its gradually increasing diameter, means the instrument’s natural resonances occur at frequencies that are not harmonically spaced. Therefore the sounds produced are not as pure as they would be in
a smooth-bored cylinder of the same length and diameter. Although some inexpensive, modern didgeridoos are now made from plastic tubing, experienced blow-hards say these cheap imitations just aren’t up to scratch.Get some more from the musically minded:
- Funny - Musical basters
- Cool - Sci-pop reviews
- Weird - Fire and pipes music
- Strange - Clenched your iPod
Share this
