Tuesday, December 11, 2012

Variation on a Theme - A New Voboam

I just finished a new baroque guitar after the 1690 Jean Voboam, E.2087 Musée de la musique, Paris. Since I published four posts earlier this year ( Feb 8, 27 and Mar 6, 15) on a similar guitar I will only describe the variations that I made on this one.

I usually sculp the edges of my pegheads with one of the characteristic Voboam designs, veneer them in ebony and leave it at that. But with all of the repair work that I have had to do this year I have been feeling frustrated and depressed. I decided that I needed to make something elaborate and challenging.

René, Alexandre and Jean Voboam often decorated the pegheads of their elaborate guitars with parallel lines of ivory and ebony chevrons mounted by a panel inscribed with their name, place and date. The peghead photo at left is of the Jean Voboam guitar, E. 2087 that I model. I used the same general lay-out as Jean but I reversed the sequence of the ivory and ebony chevrons and omitted the border around the inscribed panel. Various combinations of these elements are found on other Voboam guitars. I also used holly, a fine textured white wood in place of ivory.  I cut the  straight letters with micro chisels and the curved ones with gouges after having made many practice samples.

Original bridges and their flourishes often have not survived. This photo of Royal College of Music No. 32 London, attributed to René Voboam, shows a replacement bridge with original flourishes. I liked the ornate delicacy of this example and decided to model it.

I drew an approproximate likeness and re-sized it to fit my guitar. I glued the pattern on a thin plate of ebony .8mm thick. Since there are many delicate elements in this design, I backed the ebony plate with a layer of paper for added security. Usually, I glue two plates of ebony together sandwiching a slip of paper between and then saw two flourishes together, carefully separating them when finished. In this way I am assured that the two flourishes will be symmetrical. But this time I sawed out each flourish separately and purposely altered the design slightly. Adding a top plate of holly and ebony parallelograms completed the design.

Inside, I made a significant change. In my post from February 8 I commented on current research that suggests that later additions made to the barring of the back and belly and the re-inforcements of the side ribs of Voboam guitars obscures the makers' original intent and affects the sound of the guitars if these additions are copied by modern makers.

Here I am concerned with the barring of the back. The back in this photo of the Smithsonian Voboam, MI*65.0591 taken by Thomas Georgi has no braces and the continuous re-inforcement strips over the joints suggest that it never did. 

When I examined E. 2087 in 2008 I was curious about the location of the braces on the back and by listening to tap tones I decided there was a single bar located across the lower bout. I have ignored this information but I this time I changed my mind. Making the back a little over 3mm thick I included a single bar and a number of small short tabs. The latter secured and maintained the back's outline.

The treble side is left.

I strung the guitar and tested it before I applied any finish. It responded with the usual silvery warmth, quickness and volume level that I expect, but with a degree of responsiveness that I found disturbing. I attributed this to the freely vibrating back. I wanted to retain the quality of sound that I could hear  the back was contributing, but some control needed to be added. I believe that musical instruments, at least lutes and guitars, are counter-intuitive. I lifted the belly and inserted a thin moderating bar behind the bridge as shown in the diagram. It is 70mm long, 3.8mm thick and 4.3mm high. It is located 58mm from the rear of the belly. The bridge is 104mm from the rear. It did the trick.

All photos by the author unless otherwise noted.