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I recently listened to recordings of the bansuri, a bamboo flute used in Indian (Hindu) music, and I thought about trying to make one myself from scratch. A tutorial I found on wikiHow makes the process seem pretty straightforward, but it recalls using a flute calculator to make finger holes for the major scale while I would like to be able to play chromatic notes so I could modulate between different scales.

I play mostly guitar and I'm not really familiar with wind instruments, so I would like to know what could one do in the construction of a bamboo stalk to allow for all 12 tones, plus what dictates the range of the instrument (so it won't be only across a single octave). When I looked up videos about concert flutes, one explaining about the Bb thumb key made it seem like it just helps with achieving finger hole closures that would be awkward to perform without the thumb, but perhaps I misunderstood what's going on.

Thanks in advance.

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All woodwind instruments1 have a first octave, which then overblows to a second octave. Then, higher notes are possible through increasingly convoluted fingerings. So you don't have to do much to assure that the instrument will have more than one octave. Modern instruments have octave keys and other mechanisms that make this easier, but even the most basic instruments are capable of over two octaves.

Here is a fingering chart for fife and tin whistle. Look at the fingerings for notes in the D major scale, and ignore the others for now. Notice that it's one finger/hole per note. It would be great if we had 12 fingers, then we could simply have one finger/hole per note in the full chromatic scale, but alas we don't. So to get the notes in between, we have to use some trickery.

On the tin whistle/fife chart, you can see that most of the in-between notes are achieved by half hole fingerings. This is exactly what it sounds like--you cover the hole part way, and only some of the air can get out there, and some has to continue down to the next hole, so you get a pitch in between. This is as awkward and imprecise as it sounds.

Now consider recorder fingerings, especially the top half of the first octave. The finger holes on a recorder are much smaller, so it's as if the half-hole effect is present on every note. Even on a normal fingering, not all of the air gets out the first open hole, and we can exploit this in our fingerings. By fully covering holes after the first open tone hole, we can very precisely control the effective length of the instrument. Bending a pitch down in this manner is called shading, and a fingering that uses shading is called a cross fingering. So the in-between fingerings are much more precise, but they're still awkward. And now it's hard to figure out exactly where to put each hole, as every hole's placement affects every note above it.

So you have to decide which of these paradigms to use. Your instrument will either be fife-like, with big holes and half-hole fingerings, or recorder-like, with small holes and cross fingerings.

Either way though, it's going to be hard to play in any key. It will be easy enough to play in the scale that the instrument is designed around (the one where you just add or remove one finger at a time), and not bad in closely related keys, but playing in a distant key will involve some ugly transitions between notes.

Modern instruments have alleviated these issues with complex mechanisms. They do have one hole for every note (sometimes multiples, for alternate fingerings), and various holes are covered automatically when certain keys are pressed. One of the first improvements was made by Theobald Boehm for the flute, which was then used for clarinet and saxophone. With this system, the fingering that was F♯ for fife/tin whistle/recorder is now F♮, and between F and G there is an extra hole. Instead of covering it with a finger, a mechanism automatically closes it whenever any of the right hand keys are pressed2. So to play F♯, we leave the F hole open but press one of the lower keys in the right hand. Thus the F♯ pad is closed, but the F hole is open and F♯ sounds. Saxophone and flute use a similar mechanism for C♯ vs. C at the top of each octave.


1 Except clarinet. Clarinet operates on the same idea, but it only sounds its odd overtones, so the gap between the first "octave" and the second is actually a 12th.

2 Saxophone and flute use keys instead of covering tone holes directly. Clarinets do have holes that are covered directly, so modern instruments have rings that get pressed when you cover a hole.

  • This is a well explained answer about some of the woodwinds' aspects and their playability, but the part you eventually left out was the one I was most interested in. Even if it should in effect be too difficult to build for a hobbyist instrument maker (*everyone had to start somewhere, yes?), I would like to know WHAT are the mechanics of the chromatic keys, what are they doing when engaged which causes chromatic notes to play? – TLSO Jul 1 at 21:24
  • @TLSO elaborated – MattPutnam Jul 2 at 1:54
  • Thanks, I think it's more clear now! But just to make sure, as I'm not sure these are specifically interconnected from what I read elsewhere: the half-holing/shading technique specifically refers to partially covering finger holes while cross fingering refers to using intricate finger patterns that close holes both below and above an open hole? Regarding the amount of holes required – because I don't currently know what results from differently combined finger schemes, is it really required to have 12 different holes for 12 different possible tones? – TLSO Jul 2 at 4:59
  • Might also note that the saxophone has a complicated XORed pair of octave holes to ensure clean tone throughout the second octave. There are both closed-key and open-hole-key flutes; there are even a few closed-key clarinets (never made much sense but there they are) – Carl Witthoft Jul 2 at 13:03
  • @Carl Witthoft I'm not sure what an "XORed pair" means. Regarding the key construction, I think it would only make sense a flute I'll be making from bamboo will be open-hole. Perhaps if I'll add extra thumb keys (or whatever is called for, I'm still not entirely sure) to add chromatic notes, these would logically be closed by a mechanism and opened with pressed to raise the pitch. I'm treading into physics territory here, but I also want to make sure I get the pipe length correctly. I read the modern C flute is "about" 66 centimeters long (continue to next comment); – TLSO Jul 2 at 14:15

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