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#1 2016-10-04 14:44:17

Andrew P.
Member
From: Cyprus
Registered: 2015-11-23
Posts: 8

About the inner nodes at root end.

Hello everyone!

These days i am working on a naturally matured piece i found wondering an a dried river bank
this flute is in " B " with average dimensions in centimeters
outer width is 3, inner is 2 (walls are 0.5) total length 62.5
i had to construct custom bent filers to work at the root point

http://i.imgur.com/mtDyfdX.jpg

http://i.imgur.com/ssyboMi.jpg


My general approach (at the present) is not to ad any foreign material,
i just remove slowly checking / double checking
up to the point i believe are the limits of the flute.

I am currently attempting fine tuning the second octave and i have been sanding a bit of everything
specially the end little by little to see the changes,
plus some 4th/5th hole enlargement (i cant keep doing that or they will be in bad analogy with the others).
as i am suspecting , bigger holes results to higher dynamics

It has helped to reach the last note of the second octave "A" (holes 1 and 2) before the fundamental (B) at the third octave


now i am working to find the third octave note
(it comes out faintly and in combination with another harmonic and only with my fingers on holes 2 and half covered 5)

i have not totally cleared the other nodes along the bore (maybe they are 0.1- 0.15 cm)
should i do that?

and these are the remaining nodes inside the root end

http://i.imgur.com/GQokk0z.jpg

as you can see there is a small bowl shape space in there

http://i.imgur.com/wXhUbps.jpg

should they be filed away also?

Or maybe a better question ,
will filing them , help in the third octave note ?


Art is to forget about errors and perfection.

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#2 2016-10-06 08:49:16

Andrew P.
Member
From: Cyprus
Registered: 2015-11-23
Posts: 8

Re: About the inner nodes at root end.

Turns out i should have done some more conical filing of the inner wholes and just a bit of the root for the reverce taper,
as well as softening the inner utaguch node and decreasing the angle slighly.

The "c#" harmonic along with the third octave "b" and  hole#1 and half fingering on hole#5 has changed to
just whole #1 and  all others open and the b note can be heard much better.


Art is to forget about errors and perfection.

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#3 2016-10-06 14:15:43

Mujitsu
Administrator/Flutemaker
From: San Francisco
Registered: 2005-10-05
Posts: 883
Website

Re: About the inner nodes at root end.

Hi Andrew,

A few thoughts. Some, or all of this may be redundant for you. I'll add for the sake of discussion.

Bamboo selection is half the battle.

A two centimeter bore is slightly on the thin side for a flute of that length. That often translates to a weaker bottom end and/or muffled tone. Node protrusions can compound this issue. Once you're on the edge or outside of the ideal aspect ratio window, issues begin to appear. Ideally, the natural bore should already fall within the AR window. Then, you can flare from the choke point to the root end. That usually takes care of octave tuning issues. Then, it's just a matter of hole placement for tuning and bore adjustment for tone.

In my experience, when working on a piece with those specs, I'd clear out all the nodes and bottom end first while testing for tone as well as ro otsu and ro kan tuning - proceeding to drilling the holes only after the tone and octave tuning is ideal. If I'm unhappy with the results before drilling holes, I've found it's often best to move on to the next piece.

That being said, if you are happy with the tone, maybe there is no need to proceed. If you think the tone could use some improvement. file away. Keep in mind opening up the bottom end will raise the pitch of ro. It might even help the third octave.

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#4 2016-10-08 05:13:40

Andrew P.
Member
From: Cyprus
Registered: 2015-11-23
Posts: 8

Re: About the inner nodes at root end.

Hello Ken,

Firstly i would like to say thank you for the "howtomakeshakuhachi" guide, it inspired me greatly.

Its my first time attempting a proper tapering while examining the behavior of the inner space
Yes, i should have tuned the otsu and kan more precise before i moved on.

For my first flutes  i did not know the importance of diameter/length aspect ratio, therefore didn't take it seriously.
(i could hardly make a proper utaguchi and only played first octave) and as a result
i harvested bamboo with wrong dimensions or used the bamboo the wrong way.
(the species i use is arundo donax - which is abundant here)

So for a less adventurous construction i should select a proper bamboo piece to begin with.
I did my math and used (average) AR's  of  1:27.25  for [inner_diameter/total_length] and 1:4 for [wall_thickness/inner_diameter]
(using your schematic)
i found for my length the inner diameter should have been about 2.29 and wall thickness 0.57

and with reverce calculations
with bamboo specs 2 (diam) and 3 (wall) i could have gone for a 54.5 length

does this seem right?


Art is to forget about errors and perfection.

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#5 2016-10-08 12:58:07

Mujitsu
Administrator/Flutemaker
From: San Francisco
Registered: 2005-10-05
Posts: 883
Website

Re: About the inner nodes at root end.

Exactly, Andrew. 2.0 is a good top bore diameter for a 1.8 D shakuhachi.

Here are some averaged bore profiles for different lengths. Sticking close to them will help eliminate major issues from the beginning. Then you'll be able to concentrate more on hole placement for tuning and subtle bore adjustment for tone.

Bore Profiles

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#6 2016-10-08 16:00:16

Andrew P.
Member
From: Cyprus
Registered: 2015-11-23
Posts: 8

Re: About the inner nodes at root end.

Thank you Ken

As soon as i have a descent flute ready, I will link a video of improvisation!


Art is to forget about errors and perfection.

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