Mujitsu and Tairaku's Shakuhachi BBQ

Hi everybody.

In Ken La Cosse “How to make shakuhachi” we can read next:
“Keep in mind that each hole drilled will slightly flatten the pitch of the holes below. To compensate, the first hole can be tuned a bit sharp, the second less sharp, the third less sharp than the second, the fourth less sharp than the third, and the fifth on exact pitch.”

I was never giving heed to this effect before in my small flutemaking practise. I was working with non root bamboo with thin(near 4mm) walls, but now I have some root-end pieces with 6-7mm walls. And I think it’s time to pay more attention to this effect.

I’ve read some about pertrubation theory in navaching.com. So I’ve made some simple graph’s to understand the effect Ken talk’s about. The blue colour matches the zones there substracting material in the bore causes notes pitch flattening, and the green – pitch sharpening. To look how holes bumps affect on the notes pitches I’ve made some approximate computations. So I assumed the coordinate system from -10 to +10, it is the abstract units that hole bump can affect on the note pitch. So positive value matches the pitch sharpening, and negative value matches pitch flattening. In every case I sum all values to appraise approximately how all holes bumps affect on the note pitch.


Ro

2,3,4,5 holes flatten’s the pitch of Ro, 1 hole sharpen’s the pitch of Ro

Next are the approximate values that every hole bump affect on the Ro pitch

1 hole = +2
2 hole = -4
3 hole = -6
4 hole = -8
5 hole = -6
In sum we have -22 Ro pitch flattening

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Tsu

3,4,5 holes flatten’s the pitch of Tsu, 2 hole sharpen’s the pitch of Tsu

2 hole = +4
3 hole = -1
4 hole = -6
5 hole = -9
In sum we have -12 Tsu pitch flattening

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Re

4,5 holes flatten’s the pitch of Re, 3 hole sharpen’s the pitch of Re

3 hole = +4
4 hole = -3
5 hole = -7
In sum we have -6 Re pitch flattening

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Chi

5 holes flatten’s the pitch of Chi, 4 hole sharpen’s the pitch of Chi

4 hole = +3
5 hole = -4
In sum we have -1 Chi pitch flattening

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Ri

5 hole sharpen’s the pitch of Ri

5 hole = +2

We have +2 Ri pitch sharpening

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Go No Hi


There is no holes to affect the pich of this note

It is just very approximate computations, but they show the general tendencies in the gamefield.

So we can see that hole bumps flatten most the pitch of Ro, then less the pitch of Tsu, more less the pitch of Re and so on. And to bring notes in their correct places we have to tune Ro most sharp, Tsu less sharp, Re more less sharp and so on. I can suppose that Ken was talking about this, and that he numbered holes from bottom(Ro) hole. I hope my computations and reasonings are in correct way.

I want to ask makers to share their expierience in this practice. So my questions are next. How much pich of Ro flattens then all flute holes are made. How sharp do you tune Tsu? How sharp do you tune Re? And another notes. To be more concrete we can talk about 1.8 shakuhachi. Of course there is no constant values, because every bamboo piece is unique, and of course the situation depends on a hole sizes, but we can talk about some middle values.

And one more little question. In my computations we can see that thumb hole can sharp the Ri note. Does it happens in practice?

Last edited by dreamofnobody (2008-06-05 06:11:10)