Monday, April 30, 2012

Fickle fipples

The Durham spring Art Walk was this past weekend, and I spent a few hours on Saturday in front of Claymakers, providing wheel demos for passersby. I made chickens: they're quick and cute, and they offer great opportunities for one-liners. I used to demo chicken rattles, but of course this year I made chicken whistles, which facilitated pleasant cooing interactions with some morning doves in the awning above the door.

By the end of the afternoon, I had a bat full of chickens waiting to be transformed from single-note birds to full-octave gals, so on Sunday I spent a few hours on voicing.

The only annoying thing about making  full-octave ocarinas is that while an ocarina might start out with a lovely clear tone and might hold onto that tone through the addition of a few finger holes, at some point you cut one hole too many and the clear tone vaporizes: poof, gone. The quickest fix is to plug the last hole, but that's not an option if you need the hole for building a diatonic scale.

Ocarina fipples* are fickle, fickle, fickle, and predicting and diagnosing fipple problems is difficult because so many variables are involved: number of holes in the resonating cavity, hole sizes (a hole that is too small can muffle the tone), distance from windway exit to labium,** bevel angle, bevel thickness, windway channel shape/size, changes in the fipple due to condensation (when you blow through the mouthpiece to test the tone, water from your breath condenses onto the clay), stray clay goobers that obstruct the windway, etc. Once a chicken becomes breathy, it's often easiest to fix tone problems by hand-building a mouthpiece and attaching it to the bird butt, rather than trying to adjust a built-in windway (i.e. a windway that is one with the chicken), but attached mouthpieces sometimes shift during drying, and even a slight change in angle can obliterate the tone again.

Recently I've been having pretty good luck with built-in windways, but I still lose the tone around the sixth or seventh finger hole. Today it finally occurred to me how to fix the problem.

Several online ocarina-making instructions say the bevel angle should be 45o, which in practice isn't the case--certainly not when an ocarina produces just a single tone. However, because the bevel is the thinnest part of the fipple, it dries faster than the rest of the ocarina. I noticed that ocarinas that had been well tuned were turning breathy after drying a bit, and guessed that the drying bevels might be shifting upwards, changing whatever angle happened to be working when the chickarina was first voiced. Gently pushing the bevel down fixed the problem. I transferred that solution to the chickarinas that were losing tone quality with the addition of finger holes and discovered that pushing the bevel down usually repairs the sound. When that fix doesn't work, an added mouthpiece does.

I expect this is going to save me hours of mouthpiece futzing. Another trial-and-error breakthrough in the geek lab, where I continue to fill gaps the world never knew it had.

*Another bonus of making ocarinas is getting to use technical terminology like fipple and labium.
**Monday night update: According to the Wikipedia article on fipples, the bevel of a fipple is called the labium lip. The term labium lip is redundant, of course, since labium is Latin for lip, so I'm editing the term down to just labium. I suppose I could pare it down to lip instead, but labium and fipple sound intriguing together, while "lip and fipple" sounds like a '70s comedy team.

1 comment:

Bernadette said...

Agree; "lip and fipple" don't work. Even saying it in my head made me want to insert 'flipple'. Personally I enjoyed the intrigue. Love these Latin cognates.