What Is An Irish Flute?
An Irish flute is a simple-system flute made of wood (typically African blackwood, cocus, rosewood, boxwood, and ebony). These conical-bore flutes were originally used by concert musicians before the adoption of the Boehm system flutes in the middle of the 19th century. As the simple-system flutes were discarded by concert flutists, folk and traditional musicians adopted them. A number of makers produce Irish flutes today, most commonly out of wood, but also out of more modern materials like Delrin and PVC.
What's the difference between an Irish Flute and a Boehm Flute?
The differences between an Irish flute and a Boehm flute are mostly in the scale of the instruments. A simple-system Irish style flute's scale is in the key of D; the Boehm's scale is in the key of C. Most of the basic fingerings between the two flutes are the same, except for the XXX XOO fingering, which is F# on an Irish flute (and tin whistle) but is F natural on a Boehm system flute.
Additionally, Boehm flutes introduced a cylindrical bore with larger tone holes for optimal tone, which is why keys are used to cover the tone holes. Irish simple-system flutes have a conical bore and holes are covered by a player's fingertips.
Mike Rafferty - Irish Flute