Taming the Mando X-braced Beast
Yet another dulcimer has emerged from the Stephens Lutherie Skunkworks. To satisfy my curiosity, I whipped up a new instrument that steals elements from both my steel string and nylon string designs. Like the nylon string, the top is the soundboard and the neck/fretboard is elevated above the top on posts so that the entire top can vibrate freely. Unlike the nylon string, the strings do not terminate at the bridge, but attach to the tailpiece like on a flat top mandolin (and my standard steel string). From my most recent steel string designs comes the bracing system (a modified X-brace) and the floating bridge. For reference, the body and sides are maple and the top is western red cedar. The top is much thinner than usual, about 0.100 inch thick, which yielded 1.5 times my normal longitudinal deflection.
It’s always exciting to take the first strum across the strings of a new design. You never really know what to expect other than it is likely to be different than previous models. The first strum was done with steel strings and the sound was startling, both because of the volume and the tone. It was clearly the loudest dulcimer I have ever built. This was not anticipated. The relatively small downward force (approximately 8 pounds) seemed like it would pale in comparison to the massive torque (approximately 50 inch-pounds) put on the top when the strings stop at the bridge. Nevertheless, this dulcimer is a bit of a beast. In its raw form the tone was over the top in your face with more attack than was listenable. My initial thought was that there was so much volume available to work with that I could make modifications and still have a very loud dulcimer. My bolt on neck allows testing with the top clamped on so that it can be removed for additional work prior to gluing it in place. This approach has many benefits, especially in development work. I removed the top and added additional braces to the initial pure X configuration. Upon reassembly, I found that the tone had moved in the right direction, but the attack was still very strong for steel strings. I found that plugging both sound holes with foam improved the tone. I will have to try a dulcimer with no sound holes. From tests on this instrument, it seems that the sound holes have little, if any, affect on volume, but do impact the tone significantly.
When I reported my findings to Aaron O’Rourke, he suggested I try it with nylon strings in baritone tuning. I had been fixated on steel strings and was overlooking the possibilities with nylon strings. As usual, Aaron’s instincts were right. It showed real promise as a baritone with the nylon strings, retaining most of its volume and the tone was quite acceptable.
The black material is carbon fiber to stiffen the notched brace at he main joint.
Having heard it with the lower pitched strings, I moved on to standard pitched nylon strings. In this configuration it has a very crisp tone with plenty of attack on each note. I think it could work well for fast fingerstyle play where you want to hear each note. Probably not suited for slow play with lots of chords.
That is where the instruments is at this point in its development. I am encouraged by the volume level and the fact that it responded so well to changes in the bracing system. I think the basic design could have a bright future as Aaron and I continue to tweak it for specific applications. I am hoping to get the dulcimer into Aaron’s hands some time next week and then the real fine tuning will begin.