Chromatic Flutes/Whistles

[Daniel Bingamon]

I have a spreadsheet to share:
http://www.kingsmills.us/flute-chromatic.xls
This calculates toneholes for flutes/whistles that have a mixture of open holes and normally closed keys like the 19th century flutes. Cylindrical bore - doesn't do conical.

Note: It does assume that you know some of the basics regard bore diameters, wall thickness, etc.

Data entry columns in yellow.
Here is how you use it:

1. Enter the wall thickness in inches, Col A7
2. Enter the bore diameter in inches, Col D12
3. Enter the frequency of the bell note, Col C23.
(Note, you can click on the 'Frequencies' spreadsheet tap to look it up.
4. This version assumes a length/width embouchure. If your mouthpiece is a round hole (like a flute) use whatever makes the total are equivalent to your flute or modify it to your liking.
5. Columns F12-F22 is where you put in your hole diameters. Note that the normally closed holes of these kind of instruments are generally smaller and the normally open (key covered) holes.
Try to keep the "cutoff ratios" of adjacent holes on the graph from being excessively low or from being greatly varied - consistency of the cutoff makes the instrument sound consistent between holes.
Toneholes are adjusted for the compromise between fitting human hands and sound quality - that's your job.
6. "Window to End of Tube" is approximate. Physically tune your tubes length beforehand. Geometry from mouthpieces vary greatly which makes this difficult to predict. Once you have your own design down, you can calculate a "bias" adjustment for future instruments.
7. Columns D44 give the position of the tonehole from the bottom of the instrument in millimeters.

Note, there are color markings around D27 that will help you quickly find left-hand and right-hand spacing.