Thursday, June 1, 2017

Sebastian Schelle Theorbo

    At the beginning of April I finished a model of the large bodied late baroque theorbo by Sebastian Schelle, 1728. Back in 2001 I built my first Schelle theorbo. That instrument was quickly followed by orders for a half dozen others. At the time I found this surprising because the Schelle is so different from other theorbo models. It isn't a flat back multi-rib triple rose striped yew job like the Italian instruments built a hundred years earlier. It is huge. The bowl is 11 wide ribs of bird's eye maple. The belly of the original measures 64.7 centimeters long x 40.2 wide while the bowl is 19.4 deep. The string disposition is 8x1, 7x2. The string lengths are 160 cm and 88 with10 tied frets on the neck. My model's string disposition is 8x1, 7x2 at 140 cm and a 9 fret neck with a fretted length of 86cm. The bridge holes can also accommodate 7 fretted singles, but more on that later.
A technical drawing of the instrument MI 574 is available from  German National Museum Nüremburg .

German National Museum Restoration Photo

After I had built the first two or three models I had the opportunity to visit Nüremburg and examine the lute.
Even though the technical drawing and descriptive notes are clear and thorough there were many features I wanted to view first hand.

The technical drawing and my photo show that the bowl is lop-sided. The second rib on the photo's left (lute's treble side) leans in while the corresponding rib on the opposite side has a straighter contour. The effect is particularly noticeable by the third rib on each side of the bowl. The measurable difference, comparing the two arcs, is 5-7mm.

Occasionally, I will incorporate features like this in my model since they obviously occur as part of the historical building process. But the difference was too large and I decided to make my mold symmetrical by using the fuller bass side contour (photo's right side).

The technical drawing provides six cross sections of the bowl. Having chosen to replicate the bass side I laid out the half sections along a central plywood spine.

Here I am using both clear plastic tape and duct tape to hold the rib joints together. I like the advantages of using clear plastic packing tape: I have a clear view of the joint, the tape is ultra thin so, with an open mold, I can feel the joint between my thumb and fore-finger and correct a mis-alignment if necessary.  Plastic tape however is not strong and in this situation I want the extra strength that duct tape offers.

Here's why. I want the ribs to develop a pronounced scallop effect across their width. This occurs naturally when the joints are papered over on the inside of the bowl. But it is possible to enhance this feature. I achieve this by chamfering the bottom edge of each ribs so that when they are assembled the joint is like an inverted 'V'. Closed and tight fitting at the top (the surface of the bowl) but open at the bottom or inside of the bowl. When the joints inside the bowl are papered over the drying glue and shrinking paper pulls the bottom edges together and forces the two sides of the inverted V upward, bowing the surrounding wood  and creating a more pronounced scallop.

The reflection of light on the rib joints accentuates this effect on the original lute.

The rose is set into the soundboard and is made of a wood other than spruce, perhaps basswood. This is noted on the technical drawing.

Apparently Schelle followed the traditional method in preparing to cut the rose. Once the blank disc of basswood (?) was inserted into the soundboard the rose pattern was glued on the inside covering the joint The pattern was then cut from the inside out. This is visible on a restoration photo of the inside of the soundboard showing that the paper pattern covered the joint of the soundboard and inserted rose.

Schelle's rose is not precisely cut nor is the drawing precisely rendered. The design is somewhat fanciful. I photocopied the rose pattern  from the technical drawing and using a light screen made a full size tracing, altering details as I went. I did not follow Sebastian's example and I cut my rose directly from the table but I did not carve a border.

The bridge is located close to the rear of the soundboard but its original position can be seen just forward of that. Apparently the bridge was relocated rather than re-glued in the original spot because the wood was too badly damaged. I do not know if this was done during restoration or at an earlier date.

There is little doubt that the Schelle bridge is original as the shape of the bridge tip matches the footprint of the original position on the right side.

   My client wanted a slightly wider spacing between courses and extra string holes so the lute could be single or double strung.  This increased the width of the bridge by more than a centimeter so I diminished the size of the bridge tips to help compensate.

The pegbox has 14 pegs for 7 courses although in this photo of the original lute the nut is grooved for a single first and the first bass peg does not carry a string.

The treble string is mounted in a bracket attached to the side of the pegbox. This style of side bracket is often a feature of swan neck baroque lutes as it allows the thinnest string to run straight over the nut rather than angling around the pegbox cheek and on to its peg.  It does not however alleviate he problem of  the build-up of string windings that jam into the narrow opening. Here a frustrated lutenists has chopped away the inner part of the pegbox.

For reference, here's a closeup of a similar bracket on the triple nut extension of a Jauch that I built several years ago. This bracket was constructed as part of the pegbox cheek and a rectangular slot was cut through for the string. You can see that it allows little room for string windings.

The Schelle theorbo is probably best known  for this feature - the neck  can be folded back on itself to allow for easy transport. The iron hinge is the center of a simple mechanism. The theorbo extension is in two parts connected by a simple half lap joint.

Note that this series of photos show the theorbo extension upside down.

Here is a closeup and you can see the half lap. The hinge pin sits toward the bowl.  Each half of the two part extension is notched so that one over laps the other. The hinge swings back on itself from right to left.

I photographed this while the lute was upside down on the table

The theorbo head is nearly 18 cm long so there is plenty of room for the eight diapasons.
The extension is constructed with two types of wood and although both are painted black the quality of finish is different.

For example, the peg box has a smooth satin finish and in areas where it is worn a nice patina has developed. In contrast, the finish on the theorbo head and its half of the extension is dull and rough. There are tool marks on the sides of the head.

Obviously I am fascinated with the historical theorbo and it has been my pleasure to share these photos from my time in the museum. I had intended to show more photos of my Schelle and I will.
There is more to say about this instrument too so I'll put that all together in my next post.
Also, the new Voboam and Stauffer are about finished so there will be stories about those.

All photos by the author except as noted.


No comments:

Post a Comment