The design of the Wood-n-Bone's Doulbe Ocarina
I describe the conclusion first.
As compared with the four holes double ocarinas of other ateliers, Wood-n-Bone's four holes double ocarina had sufficient quality. Wood-n-Bone should abandon the design of five holes, and should adopt the design of the previous four holes.
Nobody can make a perfect double ocarina.
A standard double ocarina expresses one octave by four finger holes. Therefore, concert pitch is expressed as an approximate value.
Increase of pitch follows an exponential function. Therefore, it is impossible to express it correctly by addition and subtraction of finger holes. It is mathematically and physically impossible to express the exact pitch by four finger holes.
Although five finger holes are more exact than four holes, it is by no means perfect.
We select important notes.
Nobody can make a double ocarina of perfect concert pitch. Regrettably we have to make severe choice. We should adopt the notes which we often use and should abandon the seminotes which we rarely use.
The followings are nine important notes. They are an diatonic and one seminote. Other seminotes are abandoned.
4 holes double ocarina is sufficient quality.
All over the world, three ateliers are making a double ocarina which expresses one octave by four finger holes. In order to express one octave by four finger holes, concert pitch is certainly an approximate value. However, the qualities are practical enough. Many amateur and professional players in the world are supporting these.
On the contrary, the quality beyond these is superfluous.
The quality of the Wood-n-Bone's double ocarina is enough.
Wood-n-Bone's double ocarina expresses one octave + one note by four finger holes. The range of tones is wider than that of the ocarina of other ateliers. This is the big strong point.
The approximation accuracy of the Wood-n-Bone's double ocarina is completely equivalent to the approximation accuracy of the double ocarina of other ateliers. Therefore, if it is evaluated that the double ocarina of other ateliers is practical, it should be evaluated that the Wood-n-Bone's double ocarina is also practical.
And the quality beyond it is superfluous. There is no reason for adopting the design of 5 holes.
Proof of quality
The range of tones of the Woo-n-Bone's double ocarina is wider than that of the double ocarina of other ateliers. Nevertheless, mutual quality is equivalent. The following is the proof.
The mutual fingering is completely the same. Therefore, those approximation accuracy is also completely equivalent.
Mutual fingerings differ. In the double ocarina of other ateliers, the hole of index finger is opened. On the other hand, in the Wood-n-Bone's double ocarina, it is closed.
However, in the Wood-n-Bone's double ocarina , if the finger hole of thumb is enlarged enough, it can show the same effect as the fingering of the doulbe ocarina of other ateliers. That is, also in here, mutual approximation accuracy is completely equivalent.
Only the Wood-n-Bone's double ocarina can sound this note.
As an extreme talk, the pitch of this note may be inaccurate. It is a global standard to express one octave by four finger holes. The Woo-n-Bone's double ocarina has already cleared this standard. Even when the pitch of Re is inaccurate, it is no reason for evaluating the Wood-n-Bone's double ocarina low.
The Wood-n-nBone's double ocarina of 4 holes had cleared the global standard. Wood-n-nBone should abandon the design of 5 holes, and should adopt the design of the previous 4 holes.
Of course, approximation accuracy equivalent to the product of other ateliers should be required. The beauty of the tone should be required. However, the quality beyond it is superfluous.
The Wood-n-Bone's double ocarina of 4 holes can play range of tones wider than the product of other ateliers. It is tunable. It is a wonderful musical instrument.