Saturday, August 11, 2012

The Soundboard Barring for the Jauch Baroque Lute

In my last post I cambered the neck and glued on the 2mm thick ebony fingerboard. Now it was time move on to barring and fitting the soundboard. This is one of my favorite and most satisfying lute making activities. I spend a lot of time comparing barring patterns used by historical makers, reviewing what I have done before on similar lutes and thinking about the approach I want to take.

Ivo Magherini, who provided me with the drawing and photos for this lute, was also able to get a glimpse of the interior.












Ivo Magherini photo
Even though the original lute is intact there are several large cracks through which "it was possible to assess part of the barring layout," Ivo reported.
The first bar is 32mm in front of the bridge (measurements are taken from the middle of each bar). The second bar is 76mm from the first. The third bar is 59mm from the second. The fourth bar is 50mm from the third. This bar is the center of the rose.  There is one bar that runs from the curved edge of the belly to under the treble tip of the bridge. There was no trace of a J bar (bass bar) It was not possible to determine what the arrangement of bars was like in the area above the rose. For reference, the front of the bridge is 101mm from the rear of the belly.

 I think of the three bars between the bridge and the rose  as primary bars. Their placement and size control the strength and evenness of the tone. At 32 mm from the bridge the position of the first bar provides strength. The location of the second bar, unevenly spaced closer to the third than the first deserves comment. Friedemann Hellwig in his important article, On the Construction of the Lute Belly, Galpin Society Journal XXI, 1968, describes the division of the lute belly by 16th and 17th century lute makers into equal parts with the bridge and bars placed proportionally. I followed this method when I first started building but I had problems with overly assertive notes or weak ones. Eventually I attributed this to equal spacing and when I moved the second bar the tone evened out. Jauch placed his second bar more unequally than I would but I decided to follow his example - after all, these guys knew what they were doing.  The barring I used to support the triple rose area is not the only solution but one that is found in many lutes. Since my client for this lute plays with light tension strings I decided to use only two bars between top of the rose and the front block rather than three. Also, I always make this area of the soundboard thicker than elsewhere, around 2.0 - 2.1 mm. So I didn't think it needed extra support.
The barring pattern in the area around the bridge that I used is typical of Jauch's era. The size and exact placement of the individual bars is based on my experience. I alter dimensions and placement to fit the requirements of individual clients. I drew the diagram from the finished belly. I have made one for each of my lutes dating back to the mid 80s. The belly thickness is listed in 1/1000 inches. So "74", for example, is 74/1000 or about 1.9 mm. I'll continue with a short explanation  to help you decipher the diagram. The first finger bar on the treble side (right) measures 7.5mm high at  the hash mark and tapers in both directions to 0.0 under the tip of the bridge and 2.0mm where it glues to the rear of the bowl. It is 3.9mm wide. The first harmonic bar is 4.2mm wide and 15.8 high. The hash mark near the end denotes the beginning of the scallop. The bar as it glues to the rib is 6 mm high.
Throughout the process of shaping the bars - rounding the tops and cutting the scallops - I listen to tap tones. Not necessarily the pitch but the clarity and strength. It changes as the bars are shaped, changes again when the bridge is glued on and then again when the belly is glued to the bowl. I make adjustments to maintain the strength and clarity. I always string up my lutes before varnishing to see what  how it turned out. More than once I've opened a lute and moved a bar or added a "sweetener".

To finish this post here is a photo of the bridge. Because there is a fourteenth course the bridge is a little wider. To compensate,  I shortened the bridge tip.

Before gluing the belly on the bowl I was careful to make sure the bar ends fit snuggly against the edge ribs and by stretching a piece of sewing thread from the bridge to the nut I assured myself that the neck was in proper alignment.

Next time I'll describe making the triple nut extension.

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