The human voice is one of the most versatile musical instruments in the world, and we’ve all got one.

Some voices are stronger than others (just watch those Pop Idol auditions!) but whether they’re singing, speaking or shrieking, the inner machinery is the same …

What’s a set of bagpipes got to do with your beautiful singing voice? More than you may think – they’ve got a lot in common! Read on …

		Why it’s good to be full of hot air
		The Voice Box
		Perfect Pitch
		Say ‘Ah’

Why it’s good to be full of hot air

All sounds are produced by vibrations that travel through the air.

There are lots of ways of creating vibrations to make sound. You can hit things, pluck things, blow raspberries through things – lots of options.

For the human voice to make sound though, there has to be a source of air, and some moving part that can get that air to jiggle.

click to view animation. (flash format in pop-up)

Every time you breathe in, you draw air into your lungs which is then potentially available to make sound (oh, and to keep you alive). Certain muscles in your torso contract and make your chest bigger. This lowers the pressure inside your chest relative to the atmosphere, and so air rushes in. it travels down your windpipe (trachea), into your bronchi, and finally into your lungs.

When you breathe out, your muscles of respiration relax. Your chest shrinks back to its original size, pushing air out of your lungs in the process.

So your torso acts a bit like the bag of a bagpipe, supplying air. And somewhere in the middle of this flow of air would be a good place to put the thing that can vibrate and create varying sound waves, right? Right.

The Voice Box

The vibrations come from your voice box or larynx.

The larynx is a structure made mostly of cartilage that sits at the top of the trachea. Air can pass through it from the trachea to the nose and mouth.

Inside the larynx are the vocal cords. These are two small flaps made of muscle and mucous membrane which stretch across the passage in the larynx that air passes through.

Click here to see the larynx in action. (1mb Quicktime movie in pop-up)

Make a sound and place your hand gently on your larynx – you’ll feel the vibrations.

The vibrations also spread to air cavities in the body, especially the sinuses in the head and face. The air in these cavities resonates, and this contributes to the loudness and timbre of the vocal sound

The handy thing about the vocal cords is that they can be relatively far apart, allowing air to pass through. But they can also, with the help of a few muscles inside the larynx, be brought together, obstructing the flow of air through the voice box.

The vocal cords probably first evolved as a valve, to stop unwanted particles from travelling down the windpipe into the delicate lungs. There’s a reflex that provides this protection, and if you’ve ever drunk something that’s ‘gone down the wrong way’ and ended up coughing violently, you’ll know what it feels like. When this happens, instead of travelling down to the stomach as it’s supposed to, liquid tries to go into the lungs, but is stopped in its tracks by the vocal cords closing.

Perfect Pitch

If the vocal chords couldn’t change shape, they’d only be able to produce one note – not very interesting (Simon Cowell wouldn’t be impressed).

But when you adjust the cartilage and muscles in the larynx, you can change the length and tension of the vocal cords, and create a whole range of different notes. Not just the different notes of a ‘doh ray me’ style musical scale, but all the pitches in between as well. Try for yourself – sing from a low note up to a really high one.

By regulating the flow of air using our breathing muscles we can also make sounds louder or quieter. So it’s getting pretty musical, but there’s still something important missing.

Say ‘Ah’

What really sets us apart from musical instruments and animals is our ability to form words and language with our voices.

Raw noises from the larynx can be transformed into a huge number of different sounds simply by changing the shape of your mouth (and the bits inside it). This is called articulation.

By changing the shape of your lips and moving different parts of your tongue and jaw you alter the shape of the space occupied by the vibrating air inside you.

Say ‘ah’. Your lips are probably reasonably open and your tongue is quite flat on the floor of your mouth.

Now say ‘ee’, like in ‘wee’. Your lips are probably stretched wider than for ‘ah’, yet are closer together. The middle bit of your tongue will have moved up towards the roof of your mouth.

The amount of physical movement between the mouth shapes for ‘ah’ and ‘ee’ is pretty small. But the difference in sound is significant. 

The human voice is unique, because we have such incredible control over the sounds we make – and the emotions we can express. Not only that, but every voice is slightly different.

Singing lessons can help make your voice even more powerful – but you don’t need to have lessons to LET RIP!

So go on, enjoy yourself!