Building a Ukulele: Voicing is at the Heart of Volume and Sound Quality
BY AARON KEIM | FROM THE WINTER 2018 ISSUE OF UKULELE
I have a fondness for objects that last, the kinds of things that are made to outlive their first few owners while also looking and feeling beautiful. When we talk about a ukulele, we add the condition that it must also excel in quality—and quantity—of sound. If it’s built too lightly, it may have volume but not fortitude; if it’s stout enough to withstand abuse, it may live its life tucked away in a case due to its weak sound.
“Voicing”—the process by which a luthier thins and braces an instrument’s top during construction—has been the heart of the matter for hundreds of years. I am by no means an expert on the history and science of voicing, but I have learned about what has happened in the past, and I watch carefully as others take this practice to new places.
My experience is a unique one that unfolded over eight years as I braced and carved tops for over 1,500 instruments at Mya-Moe and Beansprout. After inheriting a traditional bracing pattern from Gordon and Char Mayer at Mya-Moe, I slowly and subtly developed ways to alter and apply that pattern to different sizes, top-woods, playing styles, as well as the tone and volume needs of the player. As part of my daily workload, I braced two ukes and strung up a third that had been braced a couple of weeks earlier. This meant that I still had memories of the voicing process of each uke and could hear the results rather quickly, speeding up the slow process of refining the voicing of our entire output. We always had the same goal—produce a durable instrument that also sounded its best.
So, let’s get to it. I start with the top and back with the soundhole cut, rosette inlaid, and sanded on a drum sander to .080–.085 inches thick for the top and .085–.090 inches on the back. This thickness varies according to species of wood, the stiffness of a particular board, and even the pitch the wood makes as it goes through the sander. (This is just one of the many times that a musician’s ears can help during this process.) The idea is to leave the back stiffer than the top so it reflects the sound that the top produces. For this instrument, we are using old growth Douglas fir for the top and Oregon walnut for the back and sides. Figure 1
Next, I use a template to trace the bracing pattern onto the top and back—two cross braces and back strip for the back, and a bridge plate, three fan braces, and two cross braces for the top (Fig. 2). Bracing patterns are a deep rabbit hole to go down. I have seen builders try to learn and refine several patterns at once, which distracts them and slows down their progress. I suggest picking one and slowly refining one aspect at a time, giving you better data to use for future builds.
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I use Sitka spruce for the braces, which is sawed from chunks I split from larger billets. They start out 3/8-inch high and 1/4-inch thick and I work them down from there. Before they are glued into place, the back braces are hand planed and then rubbed on a radiused sanding dish to help introduce a subtle arch into the back, making it stronger (Fig. 3). The ends of some braces are then scalloped on a jig on the sander (Fig. 4), to be refined with a chisel later.
The braces (Fig. 5) are then glued on using a go-bar deck: two wooden boards held together by a steel rod with fiberglass kite rods as clamps (Fig. 6). This step must be done pretty quickly so that I have time to scrape glue squeeze-out before it dries.
After several hours of drying time, I take them over to a board at my bench that is flat on one side and radiused on the other; it holds the plates for the next steps. I then use a small plane to taper the braces into a V-shape and a chisel to finish scalloping the ends, leaving a careful curve from full height to paper thin at the ends. (Fig. 7)
This is where I really start listening to the top, holding it near my ear and tapping it to listen for the two main musical pitches. (Fig. 8) Every stroke of the plane or chisel lowers the main sustained pitch away from the percussive tap, working towards a harmonious goal that is difficult to describe with words. I know from experience that carving too much off the top bracing to chase a lower pitch will eventually lead to a weak top with a “floppy” tap tone. You just need to know when to stop! Keep in mind that the braces still need to be sanded and the top will later get sanded from 220-grit up to 600-grit, also lowering the pitch a little.
When I am happy with the top, I sand the braces to remove tool marks and scrape off any dried glue with a razor blade. I am now ready to glue it to the sides and complete the body. Fig. 9
The bracing is just one of the many mundane steps that eventually add up to a finished instrument, but I always look forward to it, and I would argue that it is one of the most important for the instrument’s sound and durability. Like any other task in building an instrument, it really benefits from practice and experience. Just give me another 1,500 ukuleles, and maybe I’ll begin to figure it all out.
Aaron Keim is a luthier at Beansprout Musical Instruments and also a busy educator, historian, writer, and performer. He performs with his wife Nicole in the Quiet American.
