Learn to play the didgeridoo
The first and hardest thing to do with the didgeridoo is to make a noise and produce a sound.
I know several people who have struggled and not been able to make any sound at all when trying to play the didgeridoo. Once you are able to produce a sound and make a noise, the rest is learning how to change and regulate that sound.
The drone is what distinguishes the didgeridoo (ok so there's circular breathing but that's the next bit), it's what makes it different from every other instrument I have ever heard and is the name given to the sound produced by a didge when being played.
What makes a drone sound the way it does? When a didgeridoo is played air travels down the bore of the didgeridoo, and is under pressure, it bounces off the walls creating a wave - a wave of sound if you like. The main sound wave is called the fundamental note and will be the pitch or key the didge plays at, however there are a range of sound waves that travel down the didge. It is the combination of these waves bouncing off the walls of the didge that create the unique and individual sound.
You can liken it to humming a tune. The main drone or fundamental is the main note but other tones both higher and lower occur and can be controlled.
Embouchure simply refers to the shape and tightness of your lips when playing an instrument. To play brass instruments such as the trumpet and bugle, the lips need to be quite tight, or tense. Compared with the trumpet and bugle, the embouchure for a didgeridoo is much looser, and more relaxed, however, with total control.
The important thing to remember is to make sure that your lips are able to vibrate inside the mouthpiece with an airtight seal. The didge does not have to be pressed hard against the lips to effect this. If air escapes because there is not an air tight seal, it will be harder to produce a good clear drone.
Mouthpiece's on didgeridoos vary in size/diameter, from very small (22-25mm, 7/8"-1" - and I've seen smaller) and tight, to very large (35-40mm, 1 ½" and I've seen larger), some are oval, some round. There is not set rule and is completely down to the preference of the player.
As for positioning the mouthpiece - in the middle, or to the side of the mouth - it is what suits you and is most comfortable. Personally I have found that playing with the didge mouthpiece in the middle, to be more versatile as you benefit from being able to use both sides of the mouth evenly i.e. cheeks and tongue.
When starting to learn to play I would recommend trying as many different positions and sizes etc as possible as it will help you find what is best for you and also help you to understand what the differences are.
Blowing a Raspberry
The most obvious analogy of how to play the didgeridoo is to blow a raspberry down it. If you can blow a raspberry with your lips, you can play the didgeridoo. Another way of looking at the shape of the lips is to imagine that you are about to have your first big kiss and you 'pukka' your lips forward as if to make a large sloppy kissing noise. Instead of making the sloppy kiss noise, blow air through your lips but retain their shape. You should achieve a quite high pitched raspberry noise. You could even think of it as saying 'BRRRRRR' like when saying 'Brrrrrrrr, its cold'.
Practice without the didge a few times to help get your mouth cheeks and lips in the right position then place the didgeridoo to your mouth and try again.
The pressure will change when you place your lips on the didgeridoo mouthpiece (the amount will depend on the type of didgeridoo you are playing), but will increase because the air that you are blowing out is now restricted within a chamber. Make sure the seal is air tight with no gaps for pressure to be reduced. Some quite funky effects can be achieved by leaving a small gap when playing but when starting out, try to ensure your lips fit snugly on the mouthpiece.
Once you have done that, well done, you have made your first sound with the didge. Repeating the exercise a number of times, you will start to become familiar and find your facial muscles will automatically adopt the right position.
Remember - the harder you try the harder it is - there is no need to blow as hard as you can - it is a gentle process.
I've mentioned back pressure and about creating an air tight seal on the mouthpiece, here I explain a little more about what it means. When you blow air down the bore of the didgeridoo it is under pressure and as the air reaches the end of the instrument, the air escapes the bore and pressure is reduced. This will create a backward wave (think of it as a shock wave or ripples on water rebounding back towards their source).
If a didge has a narrow neck blowing the same air as a wide necked didge will result in higher or greater back pressure. Didges with a higher amount of back pressure lend themselves to quick staccato rhythms and are more percussive in the way they sound.
Losing air from not having an air tight seal will reduce the back pressure and alter the sound of the instrument on top of which it will be harder to produce a decent sound.
Blowing to hard and/or to quickly is a common problem for people learning to play the didgeridoo.
Blowing to hard (apart from being a strain) will not produce a drone but something called an overtone or toot. This tooting noise can and is used to great effect in playing but needs to be controlled.
The reason the tooting or overtone noise is produced is that too much pressure is being blown or forced down the didgeridoo and instead of travelling at its normal speed and therefore producing the drone, the air produces a higher note. Also your lips will not be able to vibrate freely if there is to much pressure so instead of producing the drone the result is more like that of playing brass wind instruments like the trumpet or bugle.
Blowing air out to quickly often results in a 'blow out'. Instead of the air travel down the didgeridoo evenly and therefore producing the drone, the air travels in a mass with a sudden release as it exits the bell. Relax and blow softer, slower, like the breathing exercise previously mentioned. The amount of air need to produce a note or drone is incredibly small considering the comparative volume. Blow soft and little making the breath last. In the same way as talking, you do not need to shout all the time and talking at a normal level will mean that your sentences sound better and last longer without the need to take a breath mid sentence.
Hints and Tips
Relax, chill and try not to try to hard. Before blowing down the didge make the shape with your mouth and blow to get used to the process and when sufficiently relaxed and confident place the didge on your lips and try again.
Don't try and be a virtuoso straight away - good didgeridoo players will have spent a lot of time over many years to perfect their playing - don't try to run before you can walk. Focus on making a noise every time you pick up a didge to play. Once you can do that then think about improving it.
Above all, do not be down hearted if you are unsuccessful at first - practice is the key - just keep trying and you will get it!