Uilleann pipes being the less famous Irish cousins of the Great Highland Pipes, what exactly is the difference between the two? This question is a variant of this question.
First the similarities: Both types of bagpipe have a bellows or bladder which is filled by the player blowing air into it. The bellows/bladder is pressed by the player's elbow. The air then goes to three drones, tuned in octaves (two tenor drones tuned in unison and a bass drone an octave lower) and a 'chanter' which the player fingers like a flute.
In the case of the Scottish Great Highland pipes a bladder holds the air and a simple unkeyed chanter is used, which produces a one-octave mixolydian scale.
In the case of the Irish Uilleann pipes the air is blown by bellows. In addition to the drones there are three additional pipes, known as 'regulators' which have keys and can provide notes or chords as an accompaniment. The chanter is more complex and has keys. It can be overblown and produce two chromatic octaves. The Uilleann pipes have a sweeter, more melodious tone than their Scottish counterparts and are more suited to playing together with other instruments in an ensemble.
Bag pipe is used for such a wide range of instruments, that any match is more remarkable than a difference.
- base tone (even the octave of it may differ)
- number of drones
- pitch and interval between them, tunable yes/no
- chromatic yes/no (no much more likely, which poses further questions)
- inflated by mouth piece/bellow
- indoor/outdoor volume class