The uilleann pipes originally known as the Union pipes, are the characteristic national bagpipe of Ireland. The uilleann pipes bag is inflated by means of a small set of bellows strapped around the waist and the right arm. Found in other European bagpipes (ex. Northumbrian pipes, Scottish smallpipes), the bellows not only relieves the player from the effort needed to blow into a bag to maintain pressure, they also allow relatively dry air to power the reeds, reducing the adverse affects of moisture on tuning and longevity. Some pipers can converse or sing while playing as well.
The uilleann pipes are distinguished from many other forms of bagpipes by their sweet tone and wide range of notes — the chanter has a range of two full octaves, including sharps and flats — together with the unique blend of chanter, drones, and "regulators." The regulators are equipped with closed keys which can be opened by the piper's wrist action enabling the piper to play simple chords, giving a rhythmic and harmonic accompaniment as needed. There are also many ornaments based on multiple or single grace notes. The chanter can also be played staccato by resting the bottom of the chanter on the piper's knee to close off the bottom hole and then open and close only the tone holes required. If one tone hole is closed before the next one is opened, a staccato effect can be created because the sound stops completely when no air can escape at all.
The uilleann pipes have a different harmonic structure, sounding sweeter and quieter than many other bagpipes, such as the Great Irish Warpipes, Great Highland Bagpipes or the Italian Zampognas. The uilleann pipes are often played indoors, and are almost always played sitting down.
The word uilleann comes from the Irish word uillinn, meaning elbow, emphasizing the use of the elbow when playing the uilleann pipes. However, the pipes were originally called "Union pipes," the first printed instance of this at the end of the 18th century, perhaps to denote the union of the chanter, drones, and regulators. Another theory is that it was played throughout a prototypical full Union of England, Wales, Ireland, and Scotland. This was only realized, however, in 1800, with the Act of Union; the name for the bagpipe slightly precedes this. Alternatively Union pipes were certainly a favourite of the upper classes in Scotland, Ireland and the North-East of England and were fashionable for a time in formal social settings, where the term Union pipes may also originate.
The term "uilleann pipes" came into use at the beginning of the 20th century. William Henry Grattan Flood, an Irish music scholar, proposed the theory that the name "uilleann" came from the Irish word for "elbow". He cited to this effect William Shakespeare's play The Merchant of Venice published in 1600 (Act IV, sc. I, l. 55) where the expression "woollen pipes" appears. This theory originated in correspondence between two earlier antiquarians, and was adopted as gospel by the Gaelic League. The use of "uilleann" was perhaps also a rebellion against the term "union" with its connotations of English rule. It was however shown by Breandán Breathnach that it would be difficult to explain the Anglicization of the word 'uillin' into 'woollen' before the 16th century (when the instrument did not exist as such) and then its adaptation as 'union' two centuries later. See Folk Music and Dances of Ireland, Cork, The Mercier Press, 1971, p. 77. A much more likely explanation is the fact that many bagpipe bags of that earlier type were made from goatskins which still had the fur attached.
The first bagpipes to be well-attested to for Ireland were similar, if not identical, to the Highland pipes that are now played in Scotland. These are known as the "Great Irish Warpipes". In Irish and Scottish, this instrument was called the píob mhór ("great pipes").
While the warpipe was alive and well upon the battlefields of France, the warpipe had almost disappeared in Ireland (as a result of its outlaw by the English). The union or uilleann pipe required the joining of a bellows under the right arm, which pumped air via a tube to the bagpipe under the left arm, with bellows. The uilleann or union pipes developed around the beginning of the 18th century, the history of which is here depicted in prints of carvings and pictures from contemporary sources. At about the same time the Northumbrian smallpipe was evolving into its modern form, early in the 18th century; a tutor of the 1750s calls this early form of the uilleann pipes the "Pastoral or New bagpipe." The Pastoral pipes were bellows blown and played in either a seated or standing position. The conical bored chanter was played "open," that is, legato, unlike the uilleann pipes, which can also be played "closed," that is, staccato. The early Pastoral pipes had two drones, and later examples had one (or rarely, two) regulator(s). The Pastoral and later flat set Union pipes developed with ideas on the instrument being traded back-and-forth between Ireland, Scotland and England , around the 18th and early 19th century.
The earliest surviving sets of uilleann pipes date from the second half of the 18th century but it must be said that datings are not definitive. Only recently has scientific attention begun to be paid to the instrument and problems relating to various stages of its development have yet to be resolved.
The D pipes are most commonly used in ensembles, while the flat-pitched pipes are more often used for solo playing — often a fiddler will "tune down" their instrument to play with a piper's flat set, but the inflexibility of other instruments used in Irish music (accordions, flutes, etc.) usually disallows this. It is noteworthy that Irish music was predominately solo music until the late 19th century, when these fixed-pitch instruments began to play more of a role. Like pipe organs, uilleann pipes are not normally tuned to even temperament, but rather to just intonation, so that the chanter and regulators can blend sweetly with the three drones. Equal temperament is almost universal with the fixed pitch instruments used in Irish music, which can clash with the tuning of the pipes.
In order to play the uilleann pipes effectively, students must learn to pump the bellows steadily while controlling the pressure on the bag and playing the chanter simultaneously. Therefore, beginning students often play on practice sets until they become comfortable with those basic mechanics. Despite their name, however, practice sets are used not only by beginning players but also by some advanced players when they wish to play just the chanter with other musicians, either live or in recording sessions. In these instances, the practice sets can be tuned to equal temperament if needed.
The drones can be switched off. This is made possible by a key connected to the stock. The original design of the stock was a hollow cylinder, with two metal tubes running through it to both hold the regulators, and independently supply air to them. Thus the regulators could be played with the drones silenced. In the late 19th century it became more common to build the stock from a solid piece of wood, with 5 holes bored through it end-to-end. This was less susceptible to damage than the earlier design. The piper is also able to switch on and off various drones individually (applying slightly more pressure to the bag and tapping the end of a drone), which is generally used to aid in tuning (a technique used in almost all bagpipes which have drones) or all of them at the same time using this key. This makes the instrument more versatile and usable not only as a half set, but also to allow playing the chanter by itself. The drones use a single-bladed reed (the actual part creating sound), unlike the double reed used in the chanter and the regulators. These drone reeds were generally made from elderberry twigs in the past — cane began to be used in the late 19th century.
A "full set", as the name implies, is a complete set of uilleann pipes. This would be a half set with the addition of three "regulators". These are three closed pipes, similar to the chanter, held in the stock. Like the drones, they are usually given the terms tenor, baritone, and bass, from smallest to largest. A regulator uses keys (five on the tenor and four on both baritone and bass) to accompany the melody of the chanter; these keys are arranged in rows to give limited two note "chords," or, alternatively, single notes for emphasis on phrases or specific notes. The notes of the regulators, from highest to lowest (given a nominal pitch of D) are as follows: Tenor: C, B, A, G, F#. Baritone: A, G, F#, D. Bass: C, B, A, G. The tenor and baritone regulators fit into the front face of the stock, on top of the drones; the bass regulator is attached to the side of the stock (furthest from the piper), and is of complex construction.
Another method of using the regulators is to play what are referred to as "hand chords": when the melody (usually in a slower piece of music such as an air) is being played on the chanter exclusively with the left hand, the right hand will be free to create more complex chords, using all three regulators at once if so desired. Many airs end a section on a G or A note in the first octave, at which point a piper will often play one of these hand chords for dramatic effect.
The difficulty of playing a melody, pumping the bellows, keeping constant pressure on the bag and playing the regulators at the same time, precludes most pipers from using the regulators much; some pipers have played for years and years yet have little ability to use them. Some pipe makers also add another regulator with one key to play an E (a tone above the chanter's lowest note); this allows a whole tune to be played with the regulators, which was occasionally mentioned in old accounts of pipers. Sometimes this E key is added to the tenor regulator, or, more rarely, the baritone. Another addition is a "double bass" regulator, giving the notes F#, E, D, below the bass regulator. The regulators use the same double-bladed reed as the chanter. A final occasional variant, the three-quarter set, omits the bass regulator. The pipes evolved from one regulator, to two, to three, which became a de facto standard in the early 19th century.
One characteristic of the chanter is that it can produce staccato notes, because the piper seals it off at the bottom; with all of the finger holes closed, the chanter is silenced. This is also necessary for obtaining the second octave; the chanter must be closed and the bag pressure increased, and then fingered notes will sound in the second octave. A great range of different timbres can be achieved by varying the fingering of notes and also raising the chanter off the knee, which gives the uilleann pipes a degree of dynamic range not found in other forms of bagpipes. Pipers who use staccato fingering often are termed "closed-style" pipers. Those who use legato fingering more predominately are referred to as "open-style" pipers. Open piping has historical associations with musicians (often Irish travelling people) who played on the street or outdoors, since the open fingering is somewhat louder, especially with the chanter played off-the-knee (which can, however, lead to faulty pitch with the second octave notes).
A type of simultaneous vibrato and tremolo can be achieved by tapping a finger below the open note hole on the chanter. The bottom note also has two different "modes", namely the "soft D" and the "hard D". The hard bottom D sounds louder and more strident than the soft D and is accomplished by applying slightly more pressure to the bag and flicking a higher note finger as it is sounded. Pipemakers tune the chanter so the hard D is the in-tune note, the soft D usually being slightly flat.
Many chanters are fitted with keys to allow accurate playing of all the semitones of the scale. Four keys will give all the semitones: F natural, G sharp, B flat, C natural. The C natural key is essential for obtaining this note in the second octave, and is the key most commonly fitted. Older chanters usually had another key for producing d3 in the third octave, and often another small key for e3, and another for D#' (as opposed to the E♭ fingerhole, which could be slightly off-pitch). Most uilleann chanters are very responsive to "half-holing" or "sliding", which is the practice of obtaining a note by leaving a fingerhole only half covered. This is why many chanters sold in Ireland are sold without keys. With this technique and some practice, many pipers can accurately play the semi-tones which would otherwise require a chromatic key to be installed. The exception is the C natural, which in the second octave, cannot be cross-fingered or half-holed, and requires the key. This is why it is the most commonly fitted key.
The chanter uses a complex double reed, similar to that of the oboe or bassoon. Unlike most reed instruments, the uilleann pipe reed must be crafted so that it can play two full octaves accurately, without the fine tuning allowed by the use of a player's lips; only bag pressure and fingering patterns can be used to maintain the correct pitch of each note. It is for this reason that making uilleann pipe chanter reeds is a demanding task. Uilleann pipe reeds are also often called "the piper's despair" for the immense difficulty of maintaining, tuning and especially making the double reed of the regulators and, most importantly, the chanter.