Etude 4: Bamboo Tones

The Etude 4 deals with another most fascinating technique, the bamboo tone. Compared to the difference tone of the previous chapter, the bamboo tone offers us a totally different sound experience and will open a most delicate world, full of nuance, color and wonderful sounds. At the same time, like many of these extended techniques in the etude book For the Contemporary Flutist, it is again another valuable and enjoyable tool to help us further develop the control of both the body and the flute sound.

It is not easy to describe the sound of a bamboo tone by words: enchanting, vague, covered, misty, relaxed, a mixture or a pastel…? But for sure, a bamboo tone is different from how we all know the flute: a clear, open sound. To distinguish this traditional type of sound from other sounds we can speak about the ‘Bel Canto flute sound’ (bel canto = Italian for "beautiful singing"). Why actually this clear and open flute sound is indeed so clear and open? The answer is simple: because all the air inside the flute tube is vibrating the same way. Every air-molecule inside the tube is vibrating the very same pitch in a perfect unison. All air-molecules agree to vibrate over the same length (length = pitch!). There is no disturbance, no discussion, no desertion, only perfect harmony. It’s like the perfect blue sky, just blue without any cloud (even no airplane disturbing the blue). This perfect situation exists for example when all tone-holes are closed: in this situation all the air stops vibrating at the very end of the flute. This perfect bel canto situation also exists in an open string, vibrating between two clear point. All ‘string-molecules’ will swing over the same full length of the string, all with the exact same pitch. That is why most string instruments have a really open and clear sound.

Theobald Boehm (1794-1881) of course also knew about the air-molecules. When he designed his flute he had to take into account the recent developments and the musical desire of his time with louder and denser orchestral music, performed in bigger theaters. How the delicate flute sound could possibly cope with these developments?

Boehm found a solution by redesigning the flute and by making the tone holes as big as possible. Why? Well, when you open a tone hole and the tone-hole diameter is larger, clearly more air-molecules will be able to understand that they can escape and finish vibration (for closed tone holes there is no difference between large and small tone holes: they are just closed and air can't get out). When all air-molecules vibrate over the same length in the tube and go out from the same tone-hole we will get the clearest sound. So since Boehm intended to create a clearer flute sound he decided to make the tone-holes as big as possible, nearly as big as the diameter of the tube. Since these large tone-holes could impossibly be covered by the fingers - like typical for the older types of flutes - he had to develop a new key-system: the Boehm-system.

Let’s imagine now you too are an air-molecule vibrating inside the tube. While you travel through the tube you should vibrate constantly! Imagine, inside the tube it is dark and really humid. Yes, it must be a dirty and tough task! Having started your vibration from the embouchure hole, you will be glad when you finally reach the first open tone-hole. You will understand - since you are a really intelligent air-molecule - that this is your chance to escape and to finish the dirty work! So that’s great for you. But what about the less educated air-molecules? Or those distracted by chatting or partying? They probably miss the opportunity to escape through the first open tone-hole. Especially when the tone-hole is a kind of small, like for example on a bamboo flute(!) or on a baroque traverso. On these flutes the tone-hole diameter is obviously limited to the thickness of the finger. In any case, our less educated air-molecules, who missed the first tone-hole, may now try to escape through the next tone-hole. But what to do if the next tone-hole is closed? Then these air-molecules have no other possibility than to continue vibrating, in darkness and high humidity, until they finally reach a next open tone-hole from where they can get out and finish their vibration.

So what does this mean for the sound-quality? Since the less educated air-molecules will travel a longer way, they will create a different vibration than the intelligent air-molecules. Consequently, the sound result will be a mixture, a little vague, misty… indeed, a bamboo tone!

One can say that with a bel canto sound the air-molecules go out all at the same spot. But with a bamboo tone the situation is different. Now the fingering, in combination with the tone-hole diameter, creates a kind of intelligence test which makes the less educated air-molecules vibrate for a longer distance, before leaving the flute at another spot than the intelligent molecules. Finally, this mixture of vibrations is responsible for the typical bamboo tone quality.

Typically a bamboo tone is not that loud and more often will have a kind of timid character. But that doesn’t make it less important! Timid characters can also be beautiful, attractive and certainly of great importance. We can see the importance of a variety of characters if we look to the drama or opera. Some characters are prominent, loud or even obtrusive, while others are shy or introvert and may use more delicate ways to reach their goals. In a similar way, we can regard all the sound - including the bamboo tone, the wind tone, the harmonic, the bel canto flute sound and so on - as characters in a drama, all with its own unique qualities, personalities and importance.

We can divide the fingerings on the Boehm-flute into two categories. (This division is really helpful to get more understanding of the bamboo tone, but also about the multiphonic, which we will discuss in the next chapter):

1. Basic Fingerings: all tone-holes are closed until a certain spot, whereafter all tone-holes are open. Most of the traditional fingerings in the first two registers of the flute belong to this category. A basic fingering creates a clear ending of the vibration and will always have a bel canto sound quality. Also it will have the harmonic series as we discussed with Etude 2: Harmonics (octave; octave+5th; etc.).

2. Fork-Fingerings: all tone-holes are closed until a certain spot, whereafter one or more tone-holes are open, followed again by one or more closed tone-holes. We may know the fork-fingering from the recorder. A fork-fingering on the flute creates an diffused and mixed ending of the vibration, so it will always create a less clear sound: a bamboo tone. Also it will have some unexpected series of harmonics, totally depending on the exact fingering (and there are thousands of fingering possibilities!).

To play a bamboo tone with an attractive character we cannot just use our standard embouchure. The most important tool to develop an adequate embouchure is the vocalisation, as mentioned already in the article on Etude 2: Harmonics (this article also has attractive sound samples of vocalisation). Develop your bamboo tone by concentrating on the acoustic of your mouth cavity. You can do so by pretending or imagining that you are singing a vowel and by experimenting with changing between different vowels. In general, bigger vowels like [o] (in ‘york’) do work very well for bamboo tones, but also vowels like [ee] (like in ‘cheese’), [a], [i], [oo] and others can be most useful. We also can use a combination of vowels, like [o] and [ee], where we imagine the [o]-sound in the lower part and [e]-sound in the higher part of the mouth cavity. Furthermore, and most important, the bamboo tone can be best studied softly, but with a focus. Also, you can experiment with a flexible vibrato.

In the note sample below you can find various bamboo tone fingerings (also for closed-hole flutes). Just give them a try and intend to add character to each sound using the above mentioned instructions.

As mentioned before, Boehm made the tone-holes as big as possible. But for those with an open-hole system on their flute, there exists actually another type of tone-hole, which can extend the possibilities for bamboo tone fingerings remarkably. On a flute with an open-hole system we can depress only the rim of an open-hole key, without covering the centre hole. This will create a small hole, of the similar size as the trill keyholes. And small holes will further deceive the ‘less educated’ air-molecules and intensify the bamboo tone quality. So that is why it is advices to use an open-hole flute if you are really interested into performing lots of bamboo tones. That's also why my Etude 4: Bamboo Tones is for only open-hole flutes.

A similar contrasting alternations between bamboo tones and bel canto tones appears in my composition Honami (Zimmermann, ZM30730). As you can see in the score excerpt above, the B is alternating between bamboo and bel canto. To support the sound changes adequately, one has to alternate the embouchure on each note really quickly. By the way, Honami is a piece which combines various techniques. The middle part has lots of harmonics in a really melodious and attractive cantabile and with the special instruction ‘with an irregular motion’.

To study the bamboo tone and to learn to give each of them its own character using vocalisation will be of great value for your flute playing. After some time you will be more conscious and able to vary your sound by using vocalisation also in your most favourite flute music. Your music will never be the same again!

Another flute solo with lots of bamboo tones is Tsuru-no-Sugomori (ZM33720). This is originally a traditional piece for the Japanese shakuhachi flute (see the sound sample somewhere above). My transcription of Tsuru-no-Sugomori is based on an interpretation by the shakuhachi master Katsuya Yokoyama. With its flexible sound (e.g. in dynamic, timbre, intonation and wind-’noise’), the intense use of the breath and its deep-rooted history the shakuhachi has been attracting the interest of many flutists around the world. Some of the sounds in this traditional flute music may be regarded by Western flutists as ‘modern’ or ‘new’. However, the shakuhachi player seems to concentrate on his breathing, accepting the sound itself as a natural consequence. Typically, the shakuhachi player doesn’t use any tonguing, but instead starts a sound from the breath and sometimes in combination with the finger (the so-called finger-tonguing!). Especially characteristic are the numerous vibrato techniques (including pitch-bending, glissandi and portamenti). Below you can see a video of my performance of Tsuru-no-Sugomori. Offermans recorded 'Tsuru-no-Sugomori' on the CD Luna y Sierra.