Duct flute

Duct flute (Ger.: Kernspaltflöte), flute in which the air stream is directed through a narrow duct against the sharp edge of a lateral aperture. Ducts can be internal or external, terminal or central. Internal ducts are situated inside the tube and may be formed by a natural node, a block of wood, or of resin. External ducts are often formed by a ringlike sleeve (ring flute) tied around the wall of the tube. In flutes with terminal ducts the player blows directly into the duct; in those with…