Revisiting the Xiao

Fixing the unfixable

Shop Notes Blog

I began making Xiao (a Chinese end-blown flute) back in 2008, modeling my first attempts on a Chinese-made bamboo xiao from a famous craftsman. This Chinese flute is a superb example of it’s kind, with a rich voice and excellent tuning, so it provided a valuable point of departure for my own experiments.

Over the years I tried many variations on the design, experimenting with bore sizes, finger hole placements and mouthpiece designs. What I learned was that the makers in China, after evolving this flute over literally millennia, had pretty much dialed it in already. There wasn’t much room for what I would call “improvement” (I reference this in my previous blog, “What’s With All The Optimization?”).

And while it is true that I have never managed to create anything better, I have discovered many shades of different, and have come to appreciate some of these differences, and to even prefer them.

My last blog on the subject of the kaval touches on my collaboration with Ashley Jarmack, an avid world flutes player. In the course of our collaboration, she had occasion to test drive one of my xiao—the design I’d been using for years. She really liked it, which was encouraging, but she did intimate that she still preferred her favorite xiao from China. This intrigued me, because I had so far not encountered any other xiao I liked as well as my own Chinese-made version. Her xiao was from another famous maker and she tried to describe how it was different from mine, and even took the trouble to record some sound samples to demonstrate the differences. Well, as is the case with many recordings, it was not so easy to hear the differences she spoke of, in part because she is a good player who manages to make the instruments behave themselves, regardless of their idiosyncrasies! After some discussion, she volunteered to simply send me her xiao to examine.

There is no substitute for direct experience. I was able to play her bamboo xiao alongside my original bamboo xiao and there were distinct differences. The nuances that she had tried to describe, and which were not as easy for me to discern in a recording, became much more apparent when I played the flute myself. First of all, the timbre of the flute was different. She described her flute as having more “core”. After playing it I understood what she meant, and I would describe it as a type of harmonic reinforcement (which is a fancy way of saying that it has some real “mojo”—more on that later—but “core” was a good descriptor). Additionally, the tuning balance was a bit better on hers, and the second and third octaves were a bit more responsive.

Now, we are talking about subtle differences here. To a beginner or intermediate player, these differences might not be super obvious, but they were certainly there. So I set about examining the flute in some detail to determine the source of the differences.

Since both flutes were made from black bamboo (called “Purple” bamboo in China), the materials were virtually identical, so that was not a significant factor. It was all design-related. I measured the bore, the finger holes and examined the mouthpiece. All along the way were small but important variations.

First of all, her xiao had a narrower bore. They are both in the key of C (tonic F), but my xiao had a wider bore for the same key. And on her xiao, the blowing notch was a tiny bit narrower (a mere .03”) and the “window” (the aperture below the notch) was also smaller. These were the important factors. Finger hole size and placement was similar enough that it only played a minor role. But using a narrower bore for the key and making the mouthpiece less generous in it’s dimensions had a very sublime effect.

This is a subjective area. I preferred her xiao on many levels. Not all xiao players are going to agree with me, for a few reasons. There are certainly a number of objective differences that influenced my preference, including the improved intonation and the responsiveness of the higher octaves. But in exchange for these improvements there are a few trade-offs. First of all, I think it takes a little bit more skill and embouchure development to take advantage of the narrower bore/smaller mouthpiece. The “sweet spot” is a teensy bit smaller, requiring more focus from the player. This is most noticeable on the lowest note. My old xiao had a fuller and more robust C note, easier to push and hold with strength, and it was a larger target, so to speak. There is a free blowing feeling to the larger bore which is very pleasing, particularly in the first octave. These qualities are very nice, and depending upon individual player, they might be considered more important than the intonation issue or the response in the higher octaves. Again, the differences between the flutes is not radical, so whether the objective improvements resulting from the smaller bore outweigh these favorable qualities in my older xiao is an open question.

However, I found my personal preference lining up with Ashley’s in this case, favoring the smaller bored version. As mentioned previously, it has mojo, or a certain type of response that I like. Ashley called it “core”, and I’ve heard players of Irish flutes call this type of response “resistance” or “push-back”. My friend Blayne Chastain once described this desirable trait to me by saying that when one has such a flute, they can lean into it. The player can play a note softly, but when they start to really push it, bearing down on it with their embouchure, the note seems to compress and gain power without breaking up. It’s not easy to describe the experience, and it’s not as if one of these xiao has this quality and the other does not. I just think the narrower-bored version has a bit more of it. Classical xiao has a “reedy” tone at times, and it’s easier to achieve this tone on a flute with a slightly narrower bore.

Theobald Boehm, the creator of the modern silver flute that is so ubiquitous, originally preferred his creation with a 20mm diameter bore. He thought that the wider bore made for a sweeter tone. But he also knew that professional orchestral players at that time needed the flute to play accurately in the third octave (this was very important to them), so to achieve this he reduced the bore diameter to 19mm. He traded down a little bit on the tone to achieve the tuning accuracy and range, and that is what is going on between these two xiao.

What this experience did was inspire me to redesign my entire line of xiao, implementing these slightly different characteristics to achieve a xiao design that seems a bit nearer to my personal ideal for the instrument. In this case, I think that my ideal is going to harmonize with the ideals of other xiao players who use the instrument in ensemble settings where intonation is particularly important.

This leads to the final aspect of the xiao redesign: chambering. I’ll explain what that is, but first a quick note about the scale of the xiao. As most players know, the Chinese don’t reference the key of the xiao, but rather the tonic note (this is also true of the Indian bansuri). So if you go shopping in China, you’ll find xiao in F and G, instead of C and D. They describe the flute using the tonic note because that’s the root note of the primary scale they use. The idea being that it gives the flute some range, allowing the player to drop down to some lower notes when needed. So if you are playing a xiao in the key of C (tonic F), and running up and down the F major scale, you have the option of using four notes that are below the tonic note. I don’t know that many players choose to play this way, but I believe it’s how the xiao was intended to be played, at least most of the time. Though of course I’m simplifying a bit. Naturally an F xiao can be played in the key of C, but there is nowhere to go below that C note.

What this means is that on a tonic F xiao, the F major scale is very important, and to play it you need to be able to hit the Bflat note. This is a cross-fingered note, typically played thus:

O X X X O O X O (the hole to the far left indicates the thumb hole).

The second octave version of this note is played thus:


On virtually every xiao I’ve ever played these notes are the trickiest to play in tune, especially the second octave note. It’s not a shortcoming on the maker’s part, but rather just a part of the physics of a cylindrical bore instrument being played with cross-fingered notes. Some xiao are more accurate on this note than others, but all of them are a bit off. A good player can compensate by lipping the notes into tune, but this changes the tone color (which is already inconsistent as a result of cross-fingering) so it does not match the rest of the scale and the note is usually a bit weaker.

For years now I’ve been experimenting with ways to correct (or at least reduce) this discrepancy. I won’t enumerate here the multitudes of experiments I’ve done along the way (again, this is touched on in my “optimization” blog). My success was patchy and never really achieved the desired result. Usually this note is reasonably accurate in the first octave but quite sharp in the second, and a tuning gap of 40 cents between the octaves is not unusual. That’s a big gap to try to close by lipping the flute! I knew that if I could tame the first octave note a bit and reduce that gap to 20 cents or less, it would be a big deal for musician’s who desire more tuning accuracy.

So I began experimenting with chambering, exploring ideas with Michael Prairie of Norwich University, an avid xiao enthusiast and high-level thinker when it comes to instrument physics. The upshot of the many ensuing experiments was that I introduced a “wide spot” in the bore at a fixed location relative to the thumb hole of the flute. It’s just a subtle bulge in the otherwise straight cylinder, and the result of it’s implementation was that it flattened the rogue note sufficiently that it was much easier to play in tune and it’s tone color matched the scale much more closely. This is by no means an original idea! Flute makers have been doing this for centuries to great effect, though I don’t know if anyone has attempted it on the bei xiao. But given the history of the instrument and the many talented makers that have undoubtedly experimented with it, it seems impossible that somewhere along the line this method was not employed. Introducing this chamber during construction is it’s own challenge, and part of flute maker voodoo that we like to be mysterious about!

For the dedicated xiao player, this new design might just be the answer to their prayers, providing a highly responsive instrument with improved intonation and consistent tone color. Will the differences be obvious? I think so, but I described the changes as being subtle, which they certainly are. But subtle differences are what makes a player choose one instrument over another, and the differences between good and great, or great and amazing are often very small.

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Published Sunday, May 23, 2021