Mujitsu and Tairaku's Shakuhachi BBQ

Hmmmm.....I may have a similar challenge, I have not yet drilled any hjoles but this one plays ro kan with ease but ro otsu does not want to join in.
No obvious reason to me yet, though the bore may be narrow around hole 1-2 and the choke. So I am thinking to begin opening this slowly.
I would be interested to know how you get on Michael.

K.

madoherty wrote:

I am not sure that I am going to touch it to tell you the truth.  It is a Gyokusui.  If it is more than adding a bit of wax here and there (which it is) I will have it repaired professionally (which I will).

OK, I was assuming it was one you are making.
I have a Kono Gyokusui 1.8 - nice bottom end quite tight but blows a nice honking Ro.

K.

Yeah - I did.  It revealed that I would not be able to do much about it without cutting into the bore.  Not comfortable with doing that myself on this flute...

Update: I tried a bit of paper about an inch below the tenon, as suggested in another thread, and it cleaned up my ro no otsu... and tsu.  It did not effect tuning much, though it did raise my tsu no otsu a touch (which was in fact flat a bit).

Last edited by madoherty (2009-12-14 23:21:21)

madoherty wrote:

Any pointers for areas of the bore to look at for un-focused and non-expansive ro no otsu and ro no kan?

If both otsu and kan are weak, you should explore the areas 1/4 the length from each end, or thereabouts. Use Neptune's wet paper method: stick some little squares to the walls at these points and see if it improves. If yes, material needs to be added here. If it gets worse, then material needs to be removed. If nothing happens, we need to think again...

Benade explains it as "regimes of oscillation". When you play a note, the air column vibrates at the dominant resonant frequency of the tube, but that's not all there is to it. A bore does not only have one resonance, it has a whole series of them, at what frequencies depending on the shape. Ideally, you want those resonances to fall at integral relationships to each other. Playing ro otsu, you want the primary frequency to be 293.66 Hz. Ideally, then, your higher resonances would fall at 587.32 (ro kan), 880.98 (chi kan), 1174.64 (ro dai kan)--these are integral multiples of the fundamental: the harmonic series--the octave, twelfth, 2nd octave, etc on up.

In any real-world instrument, the resonances are not going to be exact harmonics for many reasons. But for a note to sound continuously--for the standing wave to regenerate--all these ducks have to be in a line. A continuously sounding note will achieve perfect harmonics through a process called "mode-locking". If the resonances are close to the correct frequency, they will be able to provide a lot of energy to the harmonics near them; but the farther they are away from those integral relationships, the less energy the corresponding harmonic will have in the sound of the final note. So if you have a strong ro otsu, but the second resonance does not match it at exactly twice the frequency, the note will have primary energy from the fundamental only, with little help from the octave. In that case it will be dull and somewhat weak.  The more you can get the resonances of the tube aligned with the actual harmonics, the stronger, more stable and harmonically richer the note will be, and this applies very much to the initial transient of the attack, before all the modes have become locked together.

That's not all. The strongest resonance does not have all the say as to what the sounding frequency will be. If you have a strong second resonance point at, say, 600 Hz instead of 587, it will pull the sounding frequency up somewhat. It is all about each resonance having its say depending on its strength. So this adds a new wrinkle.

Acoustically, each harmonic increases as the power of its order as a note is blown harder. So, for instance if you blow a note twice as hard, the intensity of its second harmonic increases 4x, that of its third harmonic 9x, etc. That accounts for most of the difference in tone quality in notes as the dynamic changes. If you have seriously screwed-up harmonics, but are playing softly, the fundamental will rule the roost. But as you blow harder, the out-of-tune second resonance (and/or third, fourth and on up) will progressively exert more and more influence, trying to pull up (or down) the final frequency. This will cause the note to be progressively more unstable, and might even lead to an oscillation between two competing regimes of oscillation, or "motorboating" as we call it in the sax world.

This is not the only cause of an unstable note, but it is a main cause. If you can get your resonances aligned (primarily the first three or four, which are the strong ones), you stand a much better chance of getting a good solid note that speaks easily.

Is that reasonably clear? There is a good but relatively complex paper online by Benade in pdf format. Worth reading for believers in acoustic science. It applies to "normal woodwinds" but the principles apply to the shakuhachi as well, especially the extensive writing on the tuning of the clarinet. Go to:

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

Writings>70s>1977 and download "Acoustical evolution of wind instruments"

HTH,

Toby

Last edited by Toby (2009-12-18 09:08:58)