Mujitsu and Tairaku's Shakuhachi BBQ

Hi kel

Karmajampa wrote:

My question is 'what causes a bright tone or dark tone in a Shakuhachi ?'

It has been said many times that a flute is incomplete without it's player.  That being said, it is true that some flutes can exhibit strong, insistent character.

My first observation is that it seems that a flute with a wide bell will give a bright tone and a narrow bell will give a darker tone. I think a bright tone is giving greater volume to the harmonics of that note. In a dark tone the harmonics are subdued.
What has just happened to me making a 2.0 flute with an aspect ratio of 29, the flute measures 617mm with a nice taper and about 14mm choke and maybe 16mm bell, Ro was 'dark', Tsu was dark then Re comes out bright. Holes initially 10.5mm dia. and bevelled. Chi darkish, also with Ri.
But the brightness of Re is a bit of a mystery.

If the other holes are the same size and finished the same way, then one of the resonance spots in the bore for Re might be a bit narrow.

It seems now that I can't have a dark toned flute, that I have to bring up the brightness of the darker notes, I opened the bell a bit, from the end to the choke, plus there is a node between holes 1 and 2, so I have tried to make sure this is not choking also. This, I think has balanced things a bit but not enough. It is possible to adjust one note for timber or tone color. the obvious place would be at the finger hole. How the hole is fashioned - undercut, beveled smooth, rough - walled etc... - affects the tone color to some degree.

A few weeks ago, I had a repair come in with very dirty finger holes. They were encrusted with years of oil and dust build up. Once I sanded the crust off, the notes sounded brighter.


Heres the hole after I sanded the crust off.


After the coat of urushi, I noticed a brighter sound. One way to make RE darker may be to do something to the hole itself or in the bore just inside the hole.

Why does one hole suddenly have a totally different tone. It seems easier to brighten a note than darken it. I am referring to the Otsu register, Kan is balanced and easy to get. I am thinking that those particular harmonics are being boosted by the area between the choke and bell, relative to the flute length, perhaps this section is slightly narrow and those frequencies are amplified. Interesting.

Could be, lots of fascinating things happening in the bore, especially with different finger combinations. (notice how Ou feels different with the different fingerings).  All I can say use a tuning bead or small wet pieces of paper and poke around to see what happens.

That's always good for a few hours (or days) of fun!
Namaste, Perry

I'm not sure what is meant by brighter and darker, so I'll speak in terms of harmonics.

Generally I find that smaller bores are more reedy (stronger harmonics).  Conversely larger bores may be louder but have weaker harmonics. 

The largest square bore I tried (1 inch square) was especially dead sounding on the lowest note (D).  I made a bell (funnel) for the end which perked up the D considerably.

I also perked up D on a 7/8" round bore flute the same way.

Conversely I made a 0.94" square bore flute which had an excessively reedy D.  In fact it was somewhat raspy.  I cured that with a plug in the end which reduced the last half-inch of length to half-inch diameter.

In all of the three examples above, I was only modifying the lowest note, though in all cases D sounds through an unreachable D hole, not just the open end of the flute.

As I mentioned in a post in the new members section, I've lately been adding an unreachable C# hole below the D hole.  Thus all notes (even the lowest) sound through at least two holes.  So far I've not had to resort to bells or plugs with this scheme.

Best,

Alan

I think I understand. The C# hole if closed will sound a C#. However, since it's unreachable it's always open and placed such that a D will sound when it's open.

I'm not sure that what Alan is doing with shakuhachi in this respect is desireable. With all holes closed on a traditional shakuhachi the Ro (D on a 1.8) sounds fatter than all the other notes. In an ideal world, all the notes on the shakuhachi would sound like that. But it's not an ideal world and shakuhachi players have grown to accept that Ro is the fattest note and like the idea that they have at least one big, fat note on the instrument. Basically what you have done, Alan, is to take away from the best note to make all the notes sound the same.

Shakuhachi music is very tolerant of and even plays with the fact that not all the notes sound the same. This is unlike Western silver flute where the player has goal is to make all the notes sound the same. The way you do that is not by playing the naturally stronger notes weaker, but by playing the weaker notes stronger. This is a skill the silver flute player strives to develop. Traditional shakuhachi, with only 5 holes, will never be able to play all the notes as evenly as silver flute that has lots of large holes and keywork to open the correct ones, and that is accepted.

I tend to think that if you want the shakuhachi to play more evenly, rather than making the strongest note weaker you might want to make the weaker notes stronger. You could do this by using larger holes, but without covering them with keys you're pretty much limited to the 10 or 11 mm found on traditional shakuhachi because most peoples fingers can't cover anything much larger.

One thing I notice about your experimental shakuhachi is that they look an awful lot like pennywhistles. You might want to prototype one that plays a D diatonic scale and get it to a shakuhachi playing penny whistler, there are I think at least a couple here on the forum, to see what they think of it.

Alan Adler wrote:

To be precise, when my D hole is closed, the open C# hole sounds C#.  It's true that I was stiving to make the timbre of all my notes more similar.

OK, so I guess it's not a traditional shakuhachi tuning, maybe it wasn't a good idea to assume that it was considering they are experimental flutes. From what you're saying the note that sounds when you have all the reachable holes closed is a C#, and when you lift the bottom-most finger a D sounds. Some of my confusion stems from the fact that some people would call the D hole the hole that you close to get a D while others would say that the D hole is the one you open to get a D. I'm not sure which is more correct.     

Alan Adler wrote:

But despite my efforts and extra holes, my lowest notes still have a richer, more powerful and more resonant timbre.  They are the most pleasing notes produced by my flutes.

But is that because low notes in general are more pleasing or is it the nature of the flute? The test for this to determine if the second register note with all holes closed sounds better than the note below it with all holes open. If it does, as with most flutes, it's the flute and not the common opinion that lower notes are more pleasing. If it doesn't, I'd say you at least partially succeeded in your attempt to make the notes even in tonality across the range of the flute.   

Alan Adler wrote:

With regard to pennywhistles:  They rely on cross-fingering.  My flutes do not respond well to cross-fingering.  When I cover the hole below the sounding hole there is very little pitch change, although the sound is seriously muted.

I do not completely understand why my flutes respond so slightly to cross-fingering.  My large bore is one factor.  But I also think that cross-fingered instruments suffer from muting of the cross-fingered notes.

The explanation I heard as to why cross-fingerings work on baroque flutes but not Irish flutes is that baroque flutes have small holes. I read in another one of your posts that you have worked with a baroque flute maker, you could always verify that with him. 

I still think it would be great if you could get a penny-whistle/shakuhachi hybrid to work. I have an Irish-flute/shakuhachi hybrid that is great for slow Irish airs. I have problems with holding the flute vertically and reaching the holes that are placed for Irish flute diatonic tuning though. I can do it, but it hurts and because of that I never played the flute all that much.

BTW, some penny-whistles respond better than others to cross-fingerings and even the ones that respond well often work best with different cross-fingerings than work best on other penny-whistles that respond well to cross-fingerings. Also, the only cross-fingering you need to get working on a penny-whistle is the one to bring the "all holes open" C# down to a C. That enables the player to be able to play in both D and G. It's really the only commonly used cross-fingering and the only one that would be a requirement for most players.

The fixed jet length and aspect of a fipple make it a much less flexible sound generator than the mouth embouchure of either end-blown or transverse flute. The geometry of every fipple must be a compromise, and I don't think you are going to be able to improve established design in one area without making it worse in another.

The question of tonehole lattices is quite complex, but it is certain that smaller holes have a higher impedance and less energy is radiated from the first open tonehole, making the intonation more dependent on the lower open holes. Smaller holes also lower the tonehole cutoff frequency making the sound less rich in harmonics (and also seriously limiting maximum dynamics).

Larger bores have weaker higher harmonics, smaller bores weaker lower harmonics and fundamental. Cross fingerings respond not so much to hole size as the ratio of hole size to bore size. The inverted cone of the shakuhachi (and recorder) have a lot to do with the response to cross fingerings, as well as stretching the ratio of resonances of the tube.

Toby

Last edited by Toby (2009-03-11 00:23:47)

Let's not forget the role of wall thickness which lengthens the hole "chimneys".  It was Mujitsu who recently reminded me of that a few weeks ago.

Just a few days ago, I tried a D Pentatonic major flute with a 1.0" ID and 0.16" thick wall.  This scale dictates a 3" space between the A and the next lower hole F#, which is three semitones lower.

When I played "A" the pitch was correct but the timbre was muted - like cross fingering.  I presume that was because the next lower hole was 3" distant.

I tried countersinking the region around the 3/8" hole with a 5/8" ball mill.  That helped slightly.  But the problem went away when I made the same flute with an aluminum tube having the same ID, but only .062" wall.

As I've mentioned in another post, Arthur Benade has written about what he calls "cutoff frequency", which limits harmonics.  Cutoff frequency diminishes as the chimneys become longer.

Best,

Alan

Last edited by Alan Adler (2009-03-12 01:58:39)

For those interested in these acoustical questions, please see:

http://ccrma.stanford.edu/marl/Benade/

Writings>70s

1977: Acoustical evolution of wind instruments

On pg 43 a section on the flute has some relevant information, and there is more basic stuff at the top of the paper.

Cutoff frequency is a function of both diameter and hole length. Larger holes and shorter holes radiate high frequencies better, and also allow higher maximum dynamics. The cutoff frequency itself is exactly that: a cutoff above which high frequencies get attenuated by (IIRC) 18 dB/octave. You can read about cutoff frequencies here:

http://www.phys.unsw.edu.au/jw/fluteaco … tml#cutoff

There is also a nice section on cross fingerings.

There are no "rules" regarding hole/bore diameter ratio, but there are formulae to figure out the effects of hole sizes for a given bore size (at the position of the hole). This is also frequency dependent, so it is true that lower holes should be larger to achieve the same tone color and response, but this is not really essential, and was eventually dropped on the Boehm flute when it was seen that two sizes were enough. I can post the formula when I get back to Tokyo next week, but you need a pretty good mathematical foundation to really understand it.

The only "rule" is that there should be no sharp edges anywhere in the bore. Undercutting of finger holes is highly recommended, as well as slight rounding of the top edge of the finger hole. The same goes for the inside edge of the tenon joint and the end hole.

Toby

Alan,
a lot has changed since 1973, but Middle Earth is still green.
I am a Potter and in this industry a 'ball mill' is a tumbler that is used to crush material.

Do I understand you correctly in that you are thinning the hole from the outside, as a countersink, rather than the inside of the bore, as an undercut?

The physics of acoustics is tough going for me but I stumble onto some concepts eventually that I can hear and see in effect in my own flutemaking.

Kel.