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#1 2008-05-29 10:04:35

jaybeemusic
Member
From: Moncton, New Brunswick, Canada
Registered: 2006-06-22
Posts: 145

Question on hole placement/bore adjustment.....

Hi there

This is kind of an odd question and i'm not sure if i'll be able to explain it properly but here goes....

it seems to me that the prescribed order of things would be to mark out the hole locations and "then" adjust the bore" to tweak any tuning problems.

what would happen if you reversed the order...   mapped out the "pre-existing" bore profile and then modified the hole positions "before" you drilled them so they would be in tune (supposedly).   could it be possible to compensate for most/all bore problems by moving the holes?   


maybe i'm putting the cart before the horse so to speak,

just a thought....

jacques


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#2 2008-05-29 11:22:55

Mujitsu
Administrator/Flutemaker
From: San Francisco
Registered: 2005-10-05
Posts: 885
Website

Re: Question on hole placement/bore adjustment.....

jaybeemusic wrote:

what would happen if you reversed the order...   mapped out the "pre-existing" bore profile and then modified the hole positions "before" you drilled them so they would be in tune (supposedly).   could it be possible to compensate for most/all bore problems by moving the holes?

Jacques,

Do you mean tweaking the bore first so it gives you a better idea of exact hole placement?

In some ways, that is what is happening when casting a bore. And to some degree when hand filling a bore to exact specs. With this method, the hole positions become relatively fixed after many generations of flutes. After repetition you know where they are going to be located.

With jinashi, I think it helps to do a lot of bore work before drilling the holes so ro plays very well. I think that also gives you a pretty good idea where the holes will go, but maybe not quite as exact because of the variables involved. So, with bore work and observation, hole placement becomes a very well educated guess.

Does this address your question?

Ken

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#3 2008-05-29 12:00:38

jaybeemusic
Member
From: Moncton, New Brunswick, Canada
Registered: 2006-06-22
Posts: 145

Re: Question on hole placement/bore adjustment.....

thanks for your reply ken

that's not exactly what i meant.  I don't want to work the bore "at all"

let's set up a hypothetical situation....     before you drill any holes..... 

1.  check the 1/4, 1/2 and 3/4 spots in the bore for hole #1

2.  assuming the bore is out a bit...  from where it "should be",   the "perfect hole position" will create the wrong note and need bore work to compensate.  (am i correct on this point?)

3.  My ideas is........could you not just re-position the hole placement a bit further south/north to compensate for inherant bore weaknesses and make it more in tune.  and require less or possibly no bore work at all.   

I'm trying to see how far you could go with little or no bore work at all...... as raw as possible...   

Hope this is more clear.

Lemmie know...


It's better to keep your mouth closed and let people "think" that you're stupid, than to open it, and remove all doubt.

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#4 2008-05-29 13:06:18

Mujitsu
Administrator/Flutemaker
From: San Francisco
Registered: 2005-10-05
Posts: 885
Website

Re: Question on hole placement/bore adjustment.....

jaybeemusic wrote:

thanks for your reply ken

that's not exactly what i meant.  I don't want to work the bore "at all"

let's set up a hypothetical situation....     before you drill any holes..... 

1.  check the 1/4, 1/2 and 3/4 spots in the bore for hole #1

2.  assuming the bore is out a bit...  from where it "should be",   the "perfect hole position" will create the wrong note and need bore work to compensate.  (am i correct on this point?)

3.  My ideas is........could you not just re-position the hole placement a bit further south/north to compensate for inherant bore weaknesses and make it more in tune.  and require less or possibly no bore work at all.   

I'm trying to see how far you could go with little or no bore work at all...... as raw as possible...   

Hope this is more clear.

Lemmie know...

Ok, I see your point. Interesting. It seems your idea is to get as much information from the bore (as is) to figure how to tweak hole placement. Why not go for it and test it out?

It makes sense theoretically. I can't say I've approached it quite that way. My feeling is that there are more accurate hole placement clues available by paying attention to the general characteristics of the bore. General aspect ratio, bore end opening width, etc. I think these clues are accurate enough so there is rarely a need to adjust the bore to fix tuning errors (on conventional width shakuhachi). Adjustments can easily be made by undercutting holes. Wide bore flutes are another thing, but for conventional width shakuhachi, I think bore work is predominantly for tone and not pitch.

Results from 1/4, 1/2 and 3/4 points can be sketchy. In my opinion, I don't think you get the best hole placement information by studying these points alone. However, don't let my observations stop you. We're all different. Take whatever clues you can find that make sense to you!

Ken

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#5 2008-06-16 04:33:02

Toby
Shakuhachi Scientist
From: out somewhere circling the sun
Registered: 2008-03-15
Posts: 405

Re: Question on hole placement/bore adjustment.....

No, your idea doesn't work, because generally a problem with the bore detunes the octaves by throwing out the partials. Both parameters have to be correct: the hole placement and the bore profile, or one or the other note of overblown octaves will not be in tune. Small problems with intonation due to tone hole placement can be corrected after drilling by undercutting on the upstream side of the hole if the note is flat and vice versa if the note is sharp, along with closing the upper side of the hole by making a crescent inside with ji and urushi in that latter case. But if the bore geometry is not correct your octaves will not be in tune.

Toby

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