Wednesday, February 8, 2012

Building a Baroque Guitar after Jean Voboam

In one of my early posts ( Sept 10) I mentioned that I usually work on two instruments at once in order to be economical with my time. I had been working on a French guitar after Jean Voboam but I had reached the stage where I needed the tiered parchment rose that I had belatedly ordered from Gianluca Ceccarini. 




The second instrument was the Kaiser theorbo that became the  focus of this blog at the end of last year. As I commented once, it is more difficult to blog about instrument making than it is build the instruments. And it certainly takes longer to get the posts finished.The theorbo was finished in October and the guitar in December. I wanted to keep my blog current, but it doesn't seem possible. So now, six weeks after finishing the guitar, I'll pick up the story where I began taking photos for my blog, part way through the guitar's construction.






By early September I had assembled the neck, side ribs and back for the body. The photo at right shows the "slipper foot" construction -- the neck, heel and interior block are assembled forming a single unit. At this stage it is convenient to have the neck nearly finished, that is, completely contoured and veneered, and it is, except that I don't have a photo to show you. 


The ebony side ribs are let into slots cut in the side of the slipper.  The mass of the slipper is reduced to a minimum. I cut the slots for the ribs as tight as possible and chastise myself when I have to tighten the joint by adding shims. 




The rear block is shaped in such a way as to reduce the gluing surface of each of the three elements that are attached to it -- belly, back and ribs. The narrow foot of the rear block mirrors the slipper on the neck. Internal features of baroque guitars are difficult to ascertain. I consulted two sources for the design of the  slipper and the rear foot.








This photo, taken by Viola d'Amore player 
Thomas Georgi, of a Voboam guitar conserved in the 
Smithsonian National Museum of American History,
Washington, D.C. shows both the slender profile
of the slipper and the triangular foot; evidence of a
desire not only to reduce mass but also to firmly anchor the back.




As you can see in the next photo, also taken by Thomas, the back was constructed without supporting bars. The thickness of the wood was considered sufficient to maintain stability.   
























I am not convinced. I added three struts to my back even though it is nearly 3mm thick. I feel that an unsupported back is tempting fate --  risking stability problems when the guitar is thousands of miles away in the hands of a disgruntled owner. 

On the other hand, current research, particularly by Daniel Sinier and Françoise de Ridder, in their article Voboam: Inside perspective demonstrates that Voboam guitars were originally built with a minimum of internal barring and support on the back and ribs resulting in a distinctive sound that has been obscured by subsequent modifications.

The easiest way to access this important article is to search "Voboam inside perspective" and view the PDF as a Quick View. 

The Smithsonian website is difficult to navigate, but finding more photos of the the Voboam guitar pictured above is rewarding. In your search engine type Smithsonian ID number MI*65.0591 and follow the results.



















2 comments:

  1. Michael, I'd like to thank you for taking the time to blog about your instrument making. It's really educational and eye opening. I made a grand total of one classical guitar through a course I just finished and it was immensely rewarding. I think there's already enough classical guitars around but not even one baroque guitar in my town. So I got greedy and my next project will be a very simple baroque guitar. I'm really excited about it and blogs like yours provide lots of very useful information. Thanks again!

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