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Mujitsu,
I have noticed you undercut the fingering holes on your Taimu a lot. More than the average maker, I'd say without having looked scientifically at it.
What do you find undercutting, to the extent you do, make of changes in the flute you are making?
Volume, timbre the way a note catches on and disappears when blowing.... anything?
You once explained that you have learned about undercutting by observing Edo period shakuhachi. If you look at jinuri shakuhachi they seem not be have as much undercutting in the fingering holes as the old flutes. I read in an article by the expert on acoustics, Ando that undercutting make the air move through the tube less efficiently (sorry don't have the article here so no source or explanations). Do you agree?
Please add comments anyone
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I made a couple of shakuhachi from PVC but only followed very basic instructions and did not undercut any holes. However, I've also made a couple of Irish 6 hole flutes, and the instructions that I followed spelled out undercutting as part of the tuning process to regulate the upper octaves. These instructions said that the under cutting is only necessary on the edge of the hole that is closest to the embochure.
I wondered if this is the same for shakuhachi.
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Kiku Day wrote:
Mujitsu,
I have noticed you undercut the fingering holes on your Taimu a lot. More than the average maker, I'd say without having looked scientifically at it.
What do you find undercutting, to the extent you do, make of changes in the flute you are making?
Volume, timbre the way a note catches on and disappears when blowing.... anything?
You once explained that you have learned about undercutting by observing Edo period shakuhachi. If you look at jinuri shakuhachi they seem not be have as much undercutting in the fingering holes as the old flutes. I read in an article by the expert on acoustics, Ando that undercutting make the air move through the tube less efficiently (sorry don't have the article here so no source or explanations). Do you agree?
Please add comments anyone
Hi Kiku,
The first wide bore shakuhachi with severe undercutting I noticed was a big Gudo Ishibashi flute that Tairaku brought over once. I experimented with severe undercutting on the Taimu that we were developing at the time and found that large holes plus undercutting dramatically gave the tone more power, volume as well as a more pronounced foghorn like tone. It also gave the flutes an "outward" rather than "inward" sound. Of course there are different approaches for different preferences but we realized that a big sound was the direction that we wanted to go.
Big holes and severe undercutting seem to be easier to get away with on wide bore shakuhachi. It can still be done on conventional width shakuhachi but it can be a more delicate matter. That makes sense since there is a small window of change on thinner bores before it affects other areas of the flute.
As far as undercutting making the air move through the tube less efficiently, I don't know. It makes sense intellectually. Perhaps that is happening with thinner bore shakuhachi with severely undercut holes? I imagine Nelson has that covered on his site.
Hope this helps.
Ken
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In general acoustic terms undercutting (or chamfering) reduces turbulence in the bore and leads, as Ken notes, to the possibility of higher sonic output. The scientists who have studied woodwind acoustics recommend chamfering of all the tone holes, as any sharp edges in the bore introduce turbulence and reduce acoustic efficiency.
FWIW,
Toby
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