Issue #79 - January/February 1983
by Marc Bristol
In my last column (as most of you will remember), I introduced you to Craig Rusbult, a bamboo-flute-maker extraordinaire. And that particular article went on to detail some of the basics of Craig's technique . . . with the aim of allowing you to craft a primitive flute of your own.
We've already discussed where to find the right bamboo for the job . . . how to cut it and remove the central membrane . . . and how to position — and form — the mouthpiece and fingerholes. However, although that column did provide all the information necessary to produce a "playable" instrument, the piece didn't include (because of space limitations) the "three F's" of bamboo-flute construction: fine tuning, finishing, and fingering . . . and I aim to remedy that situation here and now.
In the first part of this article I explained the importance of enlarging each hole in gradual increments, in order to "sneak up" on the right pitch . . . but there are some other tuning pointers that I think will also prove helpful.
For example, if you drill a small starter hole that produces an on-pitch but relatively weak note, you can obtain a clearer, more open sound by slightly enlarging the opening on the side closest to the flute's open end. And if a hole produces a very flat note, you can increase its pitch significantly by gradually expanding the opening on the side nearest the mouthpiece.
Of course, there's always the danger of making a hole too large . . . and therefore too sharp. If you find yourself in that situation, you may want to imitate a trick of Craig's: He stands his flute on end (mouthpiece down), applies a little white glue to the upward-facing edge of the offending opening, and allows it to dry. By building up this surface slightly, he's able to lower the pitch produced by the hole.
You'll likely be glad to know (if you don't already) that your homemade flute is capable of producing a second octave, which is played by simply blowing harder than usual into the instrument while using the same finger positions as those employed for the "normal" scale. Once you've shaped the holes to your satisfaction, then, you'll want to check the tuning of those higher notes. If your bamboo's natural taper is just right — that is, if the tube's inside diameter decreases very uniformly from its closed to its open end — the upper octave may be naturally in tune.
Chances are, though, that at least some of the notes will be flat. To remedy the situation, carefully sand all, or a portion of, the area inside the tube between the mouthpiece and the hole closest to it (use the same dowel-and-sandpaper tool you made to smooth the interior while making your flute). If all the notes are flat, of course, you'll have to work on the entire gap . . . if the three notes closest to the blow hole are the bad ones, sand just that half of the region closest to the mouthpiece . . . and, likewise, if the three notes farthest from the mouthpiece are flat, smooth the other half of the area. Again, always proceed gradually, and check the flute's performance frequently as you make your adjustments.