How Length Affects a Didgeridoo’s Note, Pitch and Resonance

Didgeridoos come in a huge range of sizes, from very large instruments to quite small ones, and that size has a direct effect on the note each one plays. This video from the Didgeridoo Buyers Guide, presented by Benny from Didgeridoo Breath, covers the basic relationship between length, pitch and resonance. This article summarises the main ideas.

The general rule: longer means deeper

A didgeridoo is essentially a tube. When the player buzzes their lips into one end, the column of air inside resonates at a particular frequency, and that frequency is heard as the drone note. As with other wind instruments, a longer air column resonates at a lower frequency, so a longer didgeridoo generally produces a deeper note and a shorter one a higher note.

The video shows this using a PVC didgeridoo. Because plastic pipe has a uniform shape along its length, it isolates the effect of length clearly: as the tube is made longer, the note drops.

How the player’s lips respond

The lips have to match the instrument. On a didgeridoo with a lower note, the lips vibrate more slowly. On a small didgeridoo with a higher note, they vibrate faster. This is why different instruments can feel quite different to play, even for an experienced player.

Why natural didgeridoos are less predictable

Traditional didgeridoos are made from eucalyptus that has been hollowed by termites, so no two are alike. The inside of the trunk is irregular, and as the video explains, a variety of factors play into the note a natural instrument produces. Length is still a useful guide, but it is a generalisation rather than a precise measurement you can convert into a note.

Length and resonance

Length affects more than pitch. The video makes the point that two didgeridoos can play the same note, for example F, while one is long and the other very short. In that case the longer instrument tends to be more resonant. The explanation given is that the resonant frequency has more room to develop along the longer bore, which produces a fuller, richer sound.

So when people describe a didgeridoo by its note alone, they are leaving out part of the picture. Two instruments in the same key can still sound noticeably different in depth and fullness.

Which length suits a beginner?

A common question is what size of didgeridoo a newcomer, such as a child starting to learn, should begin on. The advice in the video is to avoid the extremes at either end. A very deep instrument and a very high one both make the basic drone harder to find. Something in the middle of the range is the usual recommendation. Beyond that, there is no single correct answer, since what suits one player may not suit another.

Summary

• Longer didgeridoos generally play lower notes; shorter ones play higher notes.
• The player’s lips vibrate more slowly on low instruments and faster on high ones.
• Natural eucalyptus instruments vary, so length is a guide rather than a rule.
• At the same note, a longer instrument usually sounds more resonant.
• Beginners are generally advised to start with a mid-range instrument.

For structured instruction on playing once you have an instrument, Didgeridoo Dojo offers online lessons for all levels.