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#1 2010-02-12 18:27:46

Matt Lyon
Member
From: North Eastern Oregon
Registered: 2009-06-30
Posts: 92

Choke point and Taimu.

This question is probably directed more at Ken but if anybody else has some input please feel free to chime in.

I am about to start hacking up some bamboo and I had a question regarding the choke point. I have a 2.3 Taimu and it doesn't have a traditional choke point. The bore tapers down and then ends without flaring back out.

My questions are:

Is this common on wider bore flutes and other Taimu?

Also, What is the reason for doing this? How does it affect the flutes in general when the choke point is atypical?

thanks,

Matt

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#2 2010-02-12 18:46:35

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

Re: Choke point and Taimu.

Hi Matt,

I don't recall making any Taimu without some kind of a reverse taper past the choke point. But now you have me thinking! Sometimes it's difficult to detect visually that a bore flares out slightly. Especially when the choke point is relatively wide. Sometimes it looks like there is no reverse taper when only the very bottom end is closed down slightly. Feel free to email me a photo for reference.

On a tapered bore shakuhachi, the absence of a reverse taper will generally deaden the bottom end. It's not something I would imagine would be desirable. If the choke point is relatively wide, the result is often a quick, breathy attack with less resistance. If the very end (last cm.) of the flute is closed down it can give it an interesting internal playability. As you know, Kiku, Kodama, Okuda and Alcvin have made flutes with that feature.

Ken

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#3 2010-02-12 20:23:43

Matt Lyon
Member
From: North Eastern Oregon
Registered: 2009-06-30
Posts: 92

Re: Choke point and Taimu.

Ken,

I sent you an email with the pics. I didn't post them because of their size. If you wanted to post one for others feel free.

I don't see much of a choke point if there is one. The end of the flute definitely is smaller and does not flare out. I think that I would be able to see a choke point that has a reverse taper especially since it would have to come back in again as this flute ends with the bore tightening. Then again you are the expert and I am just learning and training my eyes.

I bought the Taimu from you around thanksgiving 2008 when they were on sale if that helps your memory.

Matt

Last edited by Matt Lyon (2010-02-13 00:57:04)

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#4 2010-02-13 04:24:07

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

Re: Choke point and Taimu.

Actually, there is no real acoustic reason to widen out after the choke point. No other reverse-taper flute (old-style concert, recorder, modern piccolo) does that. I suspect that the real reason for widening out has to do with symmetry at the root end. A non-widened end would have to be somewhat shorter for ro to be in tune, and that might mean cutting off that aesthetically-all-important last root ring...

Toby

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#5 2010-02-13 12:41:13

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

Re: Choke point and Taimu.

Matt Lyon wrote:

I sent you an email with the pics.
I don't see much of a choke point if there is one.

Thanks Matt,

A photo of the exterior would help as well. One possibility that comes to mind is if the end has only one or two root rings. That automatically widens the usual choke point area. When that is the case, it's very difficult to judge a reverse taper. Basically, what I do is open up the bottom end slowly, judge how the tone gradually improves, then stop before going too far. Most, if not all times, that means some kind of reverse taper.


Toby wrote:

Actually, there is no real acoustic reason to widen out after the choke point.

That's an interesting idea Toby. What do you mean by "no real acoustic reason?" Perhaps it is subjective. In my experience, the area below the choke point is critical. A flute will play without a reverse taper, but for my subjective ear, the depth, volume and glow improves dramatically as the reverse taper widens. Too far and problems are invited.

One situation I've experienced when a reverse taper is not as critical is on shakuhachi with very wide choke points and very slight taper. And of course cylindrical bores.

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#6 2010-02-13 12:50:40

Matt Lyon
Member
From: North Eastern Oregon
Registered: 2009-06-30
Posts: 92

Re: Choke point and Taimu.

Ken,

I just sent you a couple of more pics.

Matt

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#7 2010-02-13 13:38:09

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

Re: Choke point and Taimu.

Matt Lyon wrote:

Ken,

I just sent you a couple of more pics.

Matt

Thanks Matt. That helps a lot. 

Looks like there are a few variables at work with this flute regarding the degree of taper from the choke point.

First, a naturally wide choke point to start. (Notice how the choke point does not fall on a node) Also, the concern not to raise ro too much by opening up the bottom end dramatically which would drive hole one too close the node.

What is fun about jinashi making is that each piece is different and the challenge is finding the most efficient way of balancing all the variables offered. 

Good luck!

http://www.mujitsu.com/images/matttaimuforum.jpg

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#8 2010-02-15 14:40:50

Matt Lyon
Member
From: North Eastern Oregon
Registered: 2009-06-30
Posts: 92

Re: Choke point and Taimu.

Ken,

Thanks for clearing that up for me. I see what you mean now by a wide natural choke point.

One last question: I understand opening up the bottom would raise ro but it sounds like it also changes the effective length of the whole flute too. Is this correct? If so, then how do you calculate where to drill the holes?

This actually brings up another question: When do you work on opening up the root end? It seams like it would have to be before the holes are drilled.

Matt

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#9 2010-02-15 18:49:09

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

Re: Choke point and Taimu.

Matt Lyon wrote:

I understand opening up the bottom would raise ro but it sounds like it also changes the effective length of the whole flute too. Is this correct? If so, then how do you calculate where to drill the holes?

This actually brings up another question: When do you work on opening up the root end? It seams like it would have to be before the holes are drilled.

Matt

Matt,

It's easier for me to open up the bottom end and get the tone where it needs to be before drilling the holes. Drilling holes does change the bore profile but I've found it's not enough to to cause problems. The holes could be drilled before opening up the bottom end but I find that more complicated.

Any hole movement is calculated by educated guess depending on the degree of the opening at the bottom end. A very wide opening requires the holes to be moved a bit North. (Is that what you mean by effective length?) The holes don't have to be moved that much. After a handful of flutes it becomes clear how far to cheat. Larger holes are more forgiving. By starting small there is more pitch wiggle room to enlarge them in either direction. Enlarging North raises the pitch a lot. Enlarging South raises the pitch a little.

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#10 2010-02-15 19:20:31

Matt Lyon
Member
From: North Eastern Oregon
Registered: 2009-06-30
Posts: 92

Re: Choke point and Taimu.

Mujitsu wrote:

A very wide opening requires the holes to be moved a bit North. (Is that what you mean by effective length?) The holes don't have to be moved that much. After a handful of flutes it becomes clear how far to cheat. Larger holes are more forgiving. By starting small there is more pitch wiggle room to enlarge them in either direction. Enlarging North raises the pitch a lot. Enlarging South raises the pitch a little.

Ken,

Yep, that is what I meant. It is nice to know that it only makes a slight difference.

A couple of the culms that I am going to start in on have hole placements that are a little lower than I was wanting. I was planning on shortening the culms but I looks like I will want to see how the root end behaves as I open it up. It sounds like they might end up being naturally higher after I get into it.

Many thanks for the info,

Matt

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#11 2010-02-15 20:11:12

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

Re: Choke point and Taimu.

Mujitsu wrote:

Toby wrote:

Actually, there is no real acoustic reason to widen out after the choke point.

That's an interesting idea Toby. What do you mean by "no real acoustic reason?" Perhaps it is subjective. In my experience, the area below the choke point is critical. A flute will play without a reverse taper, but for my subjective ear, the depth, volume and glow improves dramatically as the reverse taper widens. Too far and problems are invited.

One situation I've experienced when a reverse taper is not as critical is on shakuhachi with very wide choke points and very slight taper. And of course cylindrical bores.

This is a bit complicated. First, why do we have a reverse taper at all? Acoustically, a reverse taper (as compared to a straight cylinder) does two things. First, it somewhat attenuates the higher resonance points (minima) in the bore, leading to a somewhat duller or darker sound. Second, it makes the minima slightly lower in frequency and offsets them as compared to the maxima, which somewhat lowers the frequency of the sounding note, but also makes the pitch more stable at higher blowing dynamics. The shakuhachi shares a reverse-conical bore with several other types of flute, including the South American quena, the recorder, the old-style concert flute and one species of the modern piccolo. Actually, it should be completely possible to build a well-playing cylindrical shakuhachi, but it would take a complete rework of the fingerhole sizes and positions.

Now, let's get back to our standard bore: the choke point is actually the end of the reverse taper, and then we have a positive taper. This is very unusual among woodwinds with reverse taper--most keep the reverse taper until the end of the bore, except for a few old flutes, which have a very small flare at the very end.

Acoustically speaking, there is no real reason for the opening after the choke point. Nothing "new" happens in that area, so to speak. One possibility is that the widening acts as a sort of "bell", but with flutes there is no real need for a bell (as opposed to a reed woodwind). The only other possibility I can see is that the widening serves only to slightly raise the pitch of ro, allowing the root end to be a bit longer. Of course it goes without saying that as soon as a couple of fingerholes are open, the size of the end hole makes no difference at all.


I have a wonderful old half-jinashi flute by one of the original Tozan makers (I forget his name, damn), with no widening at the end. Ro is about 20 cents flat, but the flute is a monster, and I note no weakness or other compromise in the lower notes nor in any other part of the scale.

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#12 2010-02-16 07:21:22

Musgo da Pedra
Member
From: South of Brazil
Registered: 2007-12-02
Posts: 332
Website

Re: Choke point and Taimu.

Hi Toby!

Toby wrote:

Nothing "new" happens in that area, so to speak. One possibility is that the widening acts as a sort of "bell", but with flutes there is no real need for a bell (as opposed to a reed woodwind). The only other possibility I can see is that the widening serves only to slightly raise the pitch of ro, allowing the root end to be a bit longer.

Can the above paragraph be changed if the below quote have the showed features of resonance points changed due to the bottom widening, since it will not have an entirely conical bore?

Toby wrote:

This is a bit complicated. First, why do we have a reverse taper at all? Acoustically, a reverse taper (as compared to a straight cylinder) does two things. First, it somewhat attenuates the higher resonance points (minima) in the bore, leading to a somewhat duller or darker sound. Second, it makes the minima slightly lower in frequency and offsets them as compared to the maxima, which somewhat lowers the frequency of the sounding note, but also makes the pitch more stable at higher blowing dynamics.

What I mean is: the widening at the bell can make diference in the maxima and minima (the widening after some point down in the bore will make the top conical part of the bore smaller - what will make the area of actuation of the minima/maxima idea just for the top part of the bore - , allowing other part of the bore to act diferently I think. How this works in theory?)? If so, it makes diference to the sound we hear right?

I am not sure if my post is clear and sorry if the questions souns fool...


A big hug!


Omnia mea mecum porto

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#13 2010-02-16 08:06:22

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

Re: Choke point and Taimu.

Basically the impedance maxima and minima are only going to change for 'ro' if you change the bore below the choke point, because once you open even one hole then you are mostly 'short-circuiting' the bore below that hole. There will be a small change for the max/minima for 'tsu' and almost none above--BUT--there can be a change if one uses cross-fingerings and there could be some changes up in dai-kan where the frequency is near the cutoff. In the higher notes end correction increases and more of the bore below open holes becomes significant. When holes are small, as in the shakuhachi, this means that strange things can happen when you shade or close holes below an open hole.

Does that answer your question?

Toby

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#14 2010-02-16 10:56:49

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

Re: Choke point and Taimu.

Toby wrote:

Actually, it should be completely possible to build a well-playing cylindrical shakuhachi, but it would take a complete rework of the fingerhole sizes and positions.

Has anyone done this? It's an interesting idea because it could potentially save shakuhachi makers a lot of headaches. After experimenting with clean and adjusted/treated cylindrical bores the last few years I've discovered that it is possible to make a relatively decent playing, clear, pure toned shakuhachi this way. They have a fast attack and are surprisingly easy to play. However, after a number of bore experiments I have yet to discover the glow, depth, sweetness and complexity of tone that appears more often in tapered bore shakuhachi. I don't know of anyone who has done that. For me, that is the difference between a shakuhachi that can more or less do the job and one that is exceptional.

Again, it suggests it comes down to the subjective ear. Dull and dark = Mysterious and alive. Mechanical and uninteresting = Beautifully pure.

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#15 2010-02-16 15:18:01

Tairaku 太楽
Administrator/Performer
From: Tasmania
Registered: 2005-10-07
Posts: 3226
Website

Re: Choke point and Taimu.

Mujitsu wrote:

Toby wrote:

Actually, it should be completely possible to build a well-playing cylindrical shakuhachi, but it would take a complete rework of the fingerhole sizes and positions.

Has anyone done this? .

Has anyone? Has anyone not? Wouldn't a PVC shakuhachi fit this description? They're nice but they go flat in kan above re and lack some other good characteristics.


'Progress means simplifying, not complicating' : Bruno Munari

http://www.myspace.com/tairakubrianritchie

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#16 2010-02-16 16:15:12

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

Re: Choke point and Taimu.

Tairaku wrote:

Mujitsu wrote:

Toby wrote:

Actually, it should be completely possible to build a well-playing cylindrical shakuhachi, but it would take a complete rework of the fingerhole sizes and positions.

Has anyone done this? .

Has anyone? Has anyone not? Wouldn't a PVC shakuhachi fit this description? They're nice but they go flat in kan above re and lack some other good characteristics.

I mean a PVC or any other cylindrical bore shakuhachi that HAS those "other good characteristics" of exceptional shakuhachi. I've tried and have been unable to pull it off. Some tuning issues can be addressed but tone remains an issue. They can be decent flutes but the tone does not measure up to the better tapered bore shakuhachi.

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#17 2010-02-16 16:26:03

Tairaku 太楽
Administrator/Performer
From: Tasmania
Registered: 2005-10-07
Posts: 3226
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Re: Choke point and Taimu.

Mujitsu wrote:

I mean a PVC or any other cylindrical bore shakuhachi that HAS those "other good characteristics" of exceptional shakuhachi. I've tried and have been unable to pull it off.

PVC flutes just take the air in and let it out without much resistance. I think there's something about proper shakuhachi bores which keeps the sound inside the bore longer and let's you play around with the tone. This keeps things interesting. Although I'm sure Toby will be able to explain how I'm deluding myself and this phenomenon is an illusion. wink

Regarding opening up the end hole, we have experimented with that as before/after principles in both directions and opening up the hole a bit creates more volume and a stronger tone. But there is a wide range of what makes for a good tone in terms of the size of the end hole.


'Progress means simplifying, not complicating' : Bruno Munari

http://www.myspace.com/tairakubrianritchie

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#18 2010-02-17 09:08:03

Yungflutes
Flutemaker/Performer
From: New York City
Registered: 2005-10-08
Posts: 1061
Website

Re: Choke point and Taimu.

Hi Guys,

Toby wrote:

Mujitsu wrote:

Toby wrote:

Actually, there is no real acoustic reason to widen out after the choke point.

That's an interesting idea Toby. What do you mean by "no real acoustic reason?" Perhaps it is subjective. In my experience, the area below the choke point is critical. A flute will play without a reverse taper, but for my subjective ear, the depth, volume and glow improves dramatically as the reverse taper widens. Too far and problems are invited.

One situation I've experienced when a reverse taper is not as critical is on shakuhachi with very wide choke points and very slight taper. And of course cylindrical bores.

This is a bit complicated...

To say the least! Toby, I've always read your posts with great interest and learn much from them. But I'd like to offer another view.

Acoustically speaking, there is no real reason for the opening after the choke point. Nothing "new" happens in that area, so to speak. One possibility is that the widening acts as a sort of "bell", but with flutes there is no real need for a bell (as opposed to a reed woodwind). The only other possibility I can see is that the widening serves only to slightly raise the pitch of ro, allowing the root end to be a bit longer. Of course it goes without saying that as soon as a couple of fingerholes are open, the size of the end hole makes no difference at all.

The area under open holes still affect the performance of a shakuhachi because of the cross fingerings. Many of you know that if you have a flat Go no HI, it can sharpen by opening one or both of the bottom holes.  In regards to the Choke point and the bell opening, those areas have a great affect on the over all tone color or character of the flute, which can be huge deciding factor when one chooses a shakuhachi. Many experienced players, choose a flute by it's ability to produce a range of dynamic tone color within the style of music they play. This is where it gets difficult, as you mentioned above. There are many styles and many ways to play a shakuhachi. Without having a specific flute to talk about, we can only talk generally. In general, the choke point is one area (among others) that affects the response of Tsu greatly, which is very important to classical shakuhachi players as it's meri notes are used very often. To make things more difficult, different schools have different ways of hearing the different Tsu meri (s). This is subtle stuff but a large part of the art of playing and making shakuhachi

I can't stay on the computer long enough to do this topic justice but can only say that the construction of the shakuhachi evolved side by side with the music over centuries and that is the reason why the bore is what it is today. A cylindrical plastic PVC will do the job just fine. Here's a posting on how to make one: http://www.shakuhachiforum.com/viewtopic.php?id=3500
But as Brian pointed, they are only good for so much. Mainly, they are lacking in dynamic response and tone color. (That criteria is based on the particular Ryu).

Lastly, I get a lot of bore refurbishing work and I always compare the bore of a great flute that comes in with my bore measurements (from Kinya Sogawa).

http://www.yungflutes.com/logphotos/guages.jpg
http://www.yungflutes.com/logphotos/guages4.jpg
http://www.yungflutes.com/logphotos/guages3.jpg
Here, different lines remind me of the bell dimensions of certain flutes I liked. Aside from influencing the pitch, volume and tone color of RO,  the opening can also have a great impact on the kind of Honk a flute can produce, which is quite important to those who like to honk (you know who you are)smile

I have a wonderful old half-jinashi flute by one of the original Tozan makers (I forget his name, damn), with no widening at the end. Ro is about 20 cents flat, but the flute is a monster, and I note no weakness or other compromise in the lower notes nor in any other part of the scale.

I bet if you enlarge the opening, Ro will sharpen, the tuning will be in line and it will become even more of a beast!

We really can not talk specifically until we all sit in a room with the same flute. I do this with players who need tuning adjustments. We sit together I show show them what happens with their flute if we do a adjustment.  I would love to sit with you one day. Do you ever get to New York City?


"A hot dog is not an animal." - Jet Yung

My Blog/Website on the art of shakuhachi...and parenting.
How to make an Urban Shakuhachi (PVC)

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#19 2010-02-17 09:36:21

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

Re: Choke point and Taimu.

Tairaku wrote:

Mujitsu wrote:

Toby wrote:

Actually, it should be completely possible to build a well-playing cylindrical shakuhachi, but it would take a complete rework of the fingerhole sizes and positions.

Has anyone done this? .

Has anyone? Has anyone not? Wouldn't a PVC shakuhachi fit this description? They're nice but they go flat in kan above re and lack some other good characteristics.

Actually this is a good point. The Boehm flute has a curve to the headjoint in order to stop the upper modes from becoming flat. This happens because to play higher the air jet has to be shorter (at least to play higher easily without blowing your head off), and the extra shading of the top increases the end correction of the embouchure hole and so the instrument plays flat.

That being said, my Okuralo is COMPLETELY cylindrical and it plays great, except that it goes quite sharp around the middle of the third octave, which is a characteristic of all end-blown flutes. This may be the best reason to have a reverse-conical bore, to keep the very top notes in the dai-kan from going too sharp.

I do agree with Perry that any changes in the bore will have complex effects, especially as regards higher modes and cross-fingerings. The latter particularly is not a consideration on the Okuralo, and the toneholes make it a completely different animal than a shakuhachi. Still it is pretty interesting just how much shakuhachi character is retained even in a full Boehm flute with a shakuhachi utaguchi.

Toby

Last edited by Toby (2010-02-17 09:41:02)

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