Vessel flute

A vessel flute is a type of flute with a body which acts as a Helmholtz resonator. The body is vessel-shaped, not tube- or cone-shaped.

Most flutes have cylindrical or conical bore (examples: concert flute, shawm). Vessel flutes have more spherical hollow bodies.

The air in the body of a vessel flute resonates as one, with air moving alternately in and out of the vessel, and the pressure inside the vessel increasing and decreasing. This is unlike the resonance of a tube or cone of air, where air moves back and forth along the tube, with pressure increasing in part of the tube while it decreases in another.

Blowing across the opening of empty bottle produces a basic edge-blown vessel flute. Multi-note vessel flutes include the ocarina.

A Helmholtz resonator is unusually selective in amplifying only one frequency. Most resonators also amplify more overtones. As a result, vessel flutes have a distinctive overtoneless sound.

These flutes have a fipple to direct the air at an edge.

A referee's whistle is technically a fipple vessel flute, although it only plays one note.

These flutes are edge-blown. They have no fipple and rely on the player's mouth to direct the air at an edge.

The shepherd's whistle is an unusual vessel flute; the fipple consists of two consecutive holes, and the player's mouth acts as a tunable vessel resonator.

Sound is generated by oscillations in an airstream passing an edge, just as in other flutes. The airstream alternates quickly between the inner and outer side of the edge.

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