How it works and sources
The calculator models the flute as a tube of air and solves for where each hole must go. The starting proportions come from experienced makers, mostly as collected by Flutopedia.
The acoustics, briefly
- The sound chamber behaves like a pipe open at both ends. Its lowest note has a wavelength twice the chamber's acoustic length.
- The acoustic length is longer than the wood: air vibrates a little past the foot (about a third of the bore, per Flutopedia) and past the sound hole (computed from the sound hole's size against the bore).
- Each open hole is treated as a short side branch of the air column, so its position depends on its size, the wall thickness and the open holes below it. The calculator solves for each position, from the bottom hole up.
- The speed of sound depends on air temperature, and A4 can be set to any pitch.
- Bores follow Flutopedia's published table from A3 to C5 and extend it for bass and high flutes.
The model was checked against Flutopedia's worked G4 example (3/4" bore, 15.2" sound chamber); it comes out within about 1/8". Real wood varies, which is why holes start small and are tuned up.
Sources and credit
- Flutopedia, the encyclopedia of the Native American flute by Clint Goss: bore recommendations, acoustic length and end correction, sound hole, flue, slow air chamber, ramp and splitting-edge dimensions, and the Mode 1 fingering chart from its NAFlutomat calculator. Much of this site's starting data comes from Flutopedia's dimensions, bore diameter and acoustic length pages.
- Makers whose measurements Flutopedia collects: Russ Wolf (sound hole, flue, ramp and splitting-edge angles for a G4 flute), Vance Pennington (slow air chamber), Joe Nulph (breath hole), Prairie (sound hole to flue ratio, edge lift), and the Stanford 2008 and Wolf 2001/2004 bore tables.
- The tone-hole model follows the classic woodwind acoustics of Arthur Benade and Cornelis Nederveen.
This site is independent and not affiliated with Flutopedia or the makers named here.