The breath of the angels; the hum of honeybees on a warm summer's day; the pounding heart of an expectant lover. All these words describe the sweet and vibrant sound of the Irish flute.

The Uilleann (pronounced 'uill-e-ann') pipes are another matter and while no serious musician would dispute that they are indeed the finest of all instruments, the sound is a little harder to put into words.

At their simplest a 'practice' set of uilleann pipes consists of a set of bellows strapped under one elbow. This is used to pump air into a leather bag under the other elbow. The bag acts as a reservoir for the air which is squeezed in a controlled fashion to the chanter, the part that plays the melody.

The first problem for any new piper is how to pump and squeeze with the arms in a controlled fashion whilst accurately fingering and lifting (1) the chanter with the hands connected to those arms.

The unique sound is formed by a double reed (like on an oboe) that sits at the top of the chanter and through which the air flows. The reed is a constant source of irritation until the piper learns to just play away and not constantly fiddle with the damn thing. For the audience however the reed remains a constant source of irritation.

The next step up from a practice set is achieved by the addition of three drone pipes, forming a half-set. These have a stop-cock that enables them to be switched off and on and they are able to play just one note each. As if the piper doesn't have enough to think about, he or she now has three extra reeds to control and supply with air.

Three more pipes - regulators - can be added to make a full set. These have keys controlled by the lower wrist and are used to form chords played along with the melody. The overall effect is a machine that resembles a gasworks in the control of a demented fool who could easily win any gurning competition.

A full set of pipes is therefore the equivalent of seven oboes joined together by a network of pipes, tubes and airbags under the questionable control of a madman/woman. Remember that next time you listen in awe to the haunting soundtrack of some dreadful Irish tourist board promotional video. Hey, at least your not listening to a banjo!

(1) As well as seven finger holes on the front and a thumb hole at the back, the open end of the pipe is used. Normally it is closed off by resting it on the knee, but by raising it off the knee the lowest note is blown.