Uilleann pipes are the Irish members of a widespread family of bagpipe-like instruments that can be found across the British Isles and continental Europe. These Irish national pipes, sometimes referred to as union pipes, differ from most of its relatives in that the bag is inflated by bellows rather than a blow pipe. With origins in the early 18th century, the modern instrument was not refined until the late 19th century when tuning was standardized. Unlike Scots highland pipes, uilleann pipes are ordinarily played indoors and the piper performs while seated.
Pronounced roughly as "ill-yun" in English, uilleann pipes derive their name from the Irish word for elbow — the part of the arm used to pump the bellows. The bellows are strapped around the waist and right arm of the piper, allowing him or her to sing while piping. The melody pipe, also called a chanter, has a chromatic two-octave range and produces tones many consider to be sweeter and more mellow than those of its cousin, the more familiar Scotch highland pipes. The chanter is equipped with drones as well as regulators that have closed keys, which, when opened, produce simple chords, offering harmonic and rhythmic accompaniment possibilities. By blocking the bottom tone hole of the chanter with the piper's thigh, a staccato, rather than legato, effect can be produced by closing each tone hole before opening the next.
Among bagpipes, the lower volume and sweeter tones of the uilleann pipes lend themselves to a highly melodic repertoire. Modern pipes are usually tuned in D, although other "flat" tunings are available with which to accompany the various fixed tunings of tin whistles and other instruments. It was not until the late 19th century that louder pipes tuned to concert pitch appeared in the United States in answer to the acoustic demands of larger halls. Some modern solo players continue to favor the older "flat" pipe sets for their rounder, more mellow tone. While guitarists and fiddlers can "tune down" to the flat pipes, other instruments such as accordions ordinarily only accompany concert-pitched uillean pipes.
Because of the complexity of a full set of uillean pipes, beginners often learn on a partial set of pipes called a "practice set." This minimalist set consists of the chanter without drones or regulators, plus the bag and bellows, and are available in both concert and "flat" tunings. Once the student has mastered the process of simultaneously inflating the bag, regulating its pressure, and fingering the chanter, he or she usually moves on to a "half set" that includes three drones. Once the drones have been incorporated into the student's playing technique, he or she will move on to a full set of uillean pipes that includes the regulators necessary for playing highly complex melodic music.