Monday, December 30, 2013

Checchucci Guitar - The Harmonic Barring

I always string up and play my instruments "in the white" as soon as it is practical to do so. You can see that I haven't inlaid the edge purfling or applied the moustaches to the bridge. With the guitar in this semi-completed state I can still judge the quality and strength of tone and the guitar's playability. If changes need to be made, it is easier to do them unencumbered by varnishes and decorative appurtenances.

I was impatient to hear what my Checchucci sounded like. The harmonic barring of the original is minimal and somewhat unusual. Photos taken during the restoration of the guitar show only three harmonic bars; one between the rose and the neck, a second immediately to the bridge side of the rose and a third about half way between the rose and the bridge. Both of the last two bars are angled off the horizontal by about seven degrees.
Photo: Checchucci, MFA, Boston
The unusual feature is that these bars slope from higher on the treble side to lower on the bass. This is the reverse of what is usually seen on period guitars.  I found this puzzling. To make matters more confusing I wasn't convinced that the positions of the bars were original. A faint trace of a glue line is visible at the waist, below the rose hole, that suggests an angled bar that sloped in the opposite direction - the direction that I would expect. If the third bar, the lower bar, is original there is no indication that it has been moved.

The Museum of Fine Arts, Boston has an audio recording attached to the guitar's webpage   but it was no longer functioning when I last tried it. This is unfortunate because there are few opportunities to hear original instruments. Hopefully, the malfunction is temporary.

My Voboam barring pattern

I couldn't decide whether to use the barring design as it is appears in the restoration photo or to adapt some features of it or to use another system all together. Players have told me that they distinguish between styles of baroque guitars; in general preferring vaulted back guitars for strumming and flat back ones for plucking. I agree, but I think it is possible to expand on this perception.  In today's period guitar world vaulted back guitars are usually represented by Italian models that were built in the first half of the 17th century. Flat back guitars are often patterned after French examples from the 1670 - 1690  (I know there are popular exceptions and guitars by Stradivari and Koch are examples).  Furthermore, it seems that guitars dating from later in the 17th century were fitted with additional struts such as those from the Voboam family (see my post from March 6, 2012). These features coincide with the era from composer-guitarist Corbette to Visée when a premium was placed on instruments that were ultra-responsive and well-balanced.

Photo: MFA, Boston
 But what to make of the Checchucci barring pattern -- what was he trying to accomplish? I think the key to understanding his intent is to be found in the shortened neck. It has only nine frets above the neck joint which is certainly not enough range for a virtuoso who would be unlikely to own such an ornate guitar. There are other clues; the width of the neck at the nut is among the widest measuring 47mm while the width at the joint with the body is only 53mm which doesn't provide much space for the strings to splay out at on the bridge. The bridge is a modern replacement so it is not possible to know the original string spacing, but it must have been narrow. However, the combination of a wide nut and a narrow bridge allow for easy left hand chording and effortless strumming. The barring, being the reverse of the pattern that supports and enhances the treble, in this case, accentuates the bass. These features suggest to me that the guitar was built as a sort of 17th century "rhythm guitar" affording the amateur guitar connoisseur the opportunity to jam with his musicians -- pounding out a ground in the same way the rhythm guitarist did in the Swing Band era.

My Checchucci barring solution

Although I know of no historical examples of two angled harmonic bars * (see edit) I am familiar with variations on the idea. Two examples come to mind; the Ashmolean Stradivari built in 1688 has a single bar angled toward the treble but placed further away from the rose and many makers, through several centuries, have used a straight bar or angled bar placed just above the bridge. I have used both previously, on guitars from various eras, but never together.

My solution to barring my Checchucci was to acknowledge his contribution by placing two bars in the same positions that he chose but angling them toward the treble instead of the bass. In order to keep the total barring light I again followed Checchucci's example and omitted the second strut that I usually put across the upper bout and installed a single "finger" directly under the first string instead of the flat wood plate (which may not be original) to support the belly frets.

When I strung my model and played it in my limited way, it was fully resonate across its register with strength and clarity in the treble and a measure of silvery lightness throughout. I thought that it should have a different combination of attributes than my Voboam, Koch and Oth models and it does.

Now I am ready to inlay the "ivory" lozenges that make up the border of the soundboard. But while I'm working on that I'll describe assembling the neck and peghead in my next post.

All of December has been very festive and I'm enjoying the holidays and the opportunity to spend the days with family and friends and activities that I seldom have time for.

So, Happy New Year and wishing you all a healthy, happy and prosperous 2014!

*  I was leafing through my copy of the catalogue of Royal College of Music, Museum of Instruments, Part III, European Stringed Instruments, and found an x-ray photo of RCM 22, an unattributed baroque era guitar. The x-ray clearly shows two diagonal harmonic bars tilted toward the treble in much the same location as I chose. Since I examined this guitar in 2006 I must have been aware of the barring pattern but allowed it to drift too deeply into my subconscious.

The catalogue is available from;

January 25, 2014.

Wednesday, December 11, 2013

Checchucci Guitar Update

My progress on the Checchucci guitar has been slowed by commitments to other projects and by my decision to  completely re-do the vaulted back and to add inlaid triple fillets to the side ribs. You'll remember in my post from June 18 that I described repairing a collapsed portion of the vault and commenting on the hazard of copying a historical design.

I re-shaped the lower portion of the mould so that the vault was a little more pronounced in the problem area. The rib lines of the last three ribs were almost straight as you can see on the vaulted back on the left. The corresponding ribs on the new back (top right-hand corner of the photo) show a definite curve that strengthens the vault.

Guitar body before making the changes

While I was building the new back I was also thinking about inlaying a triple fillet into the side ribs. I had considered this before I started building the guitar but I couldn't figure out how to do it. Baroque guitar sides are usually assembled from multiple strips glued edge to edge forming the necessary height and then bent to the proper contour. Had I followed that procedure the result would have been side ribs with odd wavy inlaid lines because the ribs are not perpendicular to the soundboard but are angled in from the down towards the back.

Letting an idea ferment for a while can yield results. I suddenly had the idea of combining the principles of a marking gauge and a veining tool into one and cutting the groove for the inlay right into the finished sides of the guitar. The idea was to scribe two parallel lines, 2 mm apart, into each side of the guitar and then to scrape or gouge out the material between the lines. The procedure would require multiple passes, cutting deeper into the wood with each pass, so firmness of touch and complete stability of the tool and guitar were essential.

I cut a piece of  2 mm thick tool steel, ground a knife edge  single bevel on one end and a slightly angled but blunt scraping edge on the other end and tempered both ends. The cutting tool was mounted in a simple, but precisely made wooden block.

In order to provide stability to the guitar body, I glued a close fitting temporary front into the body and levelled the side ribs on a sanding board. Working on a flat surface, I held the guitar firmly under my fore-arm and pressing the scribing tool block against the flat work board I drew the  tool from one end of the guitar to the other, multiple times. The second parallel line was cut by flipping the blade in the tool holder and repeating the process.

 Once I was satisfied with the depth of the parallel lines I fixed the blunt scraping end of the tool in the wood holder. Although I took photos of the cutting and scraping process I can't find them.  They must have vaporized.

The side ribs are only 1.2 mm thick so I was worried that the pressure of the scraping tool would cause the rib to bow and subsequently throw the tool out of line, ruining the groove.

But all went well, although I did scrape through the side ribs in several places, and after test fitting I was able to glue the first fillet in place. In the areas where I installed the fillets I papered the inside of the ribs when all was finished.

 I liked the results and so much and since I was confident in the method I decided to add a second fillet. I made an extender block of the necessary height and screwed it to the bottom of my tool holder. Installing the second fillet went as smoothly as the first.

I am well along in assembling the neck and peghead with their unique veneer design. As soon as I have glued the neck to the body I'll report on my work again. In the meantime here are several photos of the Checchucci guitar to date.

Wednesday, October 30, 2013

Schreiner's Lute and Guitars -- Update

If you are wondering what has happened with the Checchucci guitar here is the latest view. I have made progress but it has been slowed by other commitments. I'll continue my reports on this instrument as I will soon have more time to concentrate on it.

The Koch theorbo (posts from Sept. 20 and April 19) was delivered earlier this month to the student baroque ensemble of Adlai Stevenson High School, located in a Chicago suburb. I believe it is important to promote Early Music particularly theorbo among young musicians so I was enthusiastic about being part of this project.

Much of my time the last few months has been taken up with repairs. I repair my own instruments and those by other makers that belong to my clients. Some of this work can be arranged in advance and I include it in my schedule. Others things arrive on short notice with tight deadlines. The owner of the first lute I want to show you contacted me in April. I was told it was from 1975 so I was looking forward to seeing it when it arrived last month.

The action had gotten far too high so I dis-assembled it and put it back together in proper alignment.

I like re-visiting my earlier work, not to see what I've done, not to be critical, but to see the story that belongs to each instrument. The bowl wood is Brazilian Rosewood. I found a plank of it at a neighbourhood lumber yard in East End Montreal around 1972 when I was living there. Wondering where there might be more I was sent to a warehouse in the suburbs. I found an aircraft hanger size building crammed floor to ceiling with the wood! The species is endangered and is now banned in international trade.

after Benedid 1783, Schreiner 2003
Other instruments unexpectedly develop problems and need to be looked after quickly. This photo arrived in an email Sunday night and the owner is now arranging to come to Toronto and to stay over while I fix it.

Unfortunately, some repairs that initially appear to be straight forward turn out to be nightmares.

 This is the neck block of a small theorbo with the neck and belly removed.  It is not one that I built but it belongs to one of my clients so I agreed to work on it.  I thought that only the neck joint had broken open, but it turned out that five of the eleven ribs of the bowl had, over time, come loose from the block. The lute had slowly folded up and become unplayable. While I worked on it one unwanted discovery led to another and what I scheduled as a simple repair -- wasn't!

Last month a lutenist who had recently moved to Ontario from Italy got in touch. The movers had damaged his archlute and he has a show scheduled for the middle of November.

The bowl was cracked through on the bass side of the end clasp leaving a jagged break and there was a nasty split in a soundboard. I removed the soundboard and carried out the repairs. I am just now touching up the varnish.

I still have two lutes waiting for my attention.
I have inserted knives to demonstrate the open joints
 One of my Kaiser theorbos (built 2000) was mistreated by baggage handlers on a flight to Charleston SC.  The neck joint popped which is fairly common and easy to fix. But the violence separated the soundboard tongue from the neck surface. They are both clean breaks but I will have to remove the soundboard in order to do the repair.

after Gerle, Schreiner 1996
 Good grief, how did this happen?

The rose is damaged but the broken parts will glue back without much trouble and the bridge is intact. The soundboard is a write-off. I'll salvage the rose and set it into a new soundboard.

 Also, I have gotten started on a special project. Toronto lutenist/guitarist Lucas Harris obtained an 1831 Giovanni Guadagnini guitar and I agreed to restore it. The work on this will go on for several more months. I am documenting everything so I will report on it in two or three posts when I am further along.

Next, I will finish the Checchucci guitar and in the coming months I'll finally get to work on new lutes; a couple of ten courses lutes, another Koch theorbo and a baroque guitar in A. That is the plan anyway.

Sunday, September 29, 2013

The 'Warwick' Frei Lute

I recently finished a model of the 'Warwick' Hans Frei lute. The original is conserved in the Market Hall Museum, Warwick UK. Although it has been one of my favorite models I didn't blog about building it because it, or rather I, literally fell victim to fate when I broke my knee (requiring surgery) just after I finished assembling the bowl. This happened before I started blogging. Unable to complete the lute, I fitted a false top to the bowl so it would retain its shape and placed it on a shelf in my studio to await a better day. But I wanted to blog about the lute and decided to focus on the original. So this post is shaped in part by my thoughts, but also by responses to queries that I made to fellow lute makers and lutenists.

I recently found out that at much at the same time as I was finishing my model, Adam Busiakiewicz, a curator  and lutenist at the museum were the Hans Frei is conserved, announced the idea to organize a lecture/mini recital about the Warwick Frei. . Although Adam was to play on his own Frei copy, the museum agreed to display their original Hans Frei which had not been seen in public for many years. This took place on September 10 and I am sorry not to have known about it earlier. I did confirm with the museum that the Frei will be on display until October 19. .

The Warwick Frei has long been a popular model for contemporary lute makers as a visit to any maker's website will attest. The history of its conversion from a renaissance to a baroque lute is frequently noted. But little has been written about it and few photos appear in the public domain. Adam posted this photo  of the lute being played in the 1950s.

My favorite article and the one I re-visited for this post is: Michael Prynne, Galpin Society Journal, vol. 2, 1949 that described the Frei with measurements and four excellent photos. Online, this article can be downloaded from JSTOR,

When I started building lutes no plans were available for the Frei, so I scaled up one of the photos from Prynne's article. For many builders this was the only available option. When plans were published in 1979 I bought those, but they are now in tatters. I just ordered a new set from The Lute Society:

The Warwick Frei was in playable condition in the 1950s  and presumably it still is. Prynne wonderfully describes the tone; "The tone of the lute is sweet, though quite small, with a rather reedy quality in the lower register. The notes hold out for a long time, and the richness in overtones and comparative weakness of the fundamental note produce to a marked degree the very intimate and sympathetic tone which is the lute's essential character."

Prynne's remarks are revealing because they relate to a curious feature in the graduation of the thickness of the Frei soundboard. It tapers in thickness from the area behind the bridge where it is unusually thick to the area around the neck joint where the thickness is more normal. In my opinion this thickness is responsible for the richness, intimate and sympathetic tone but not for the smallness of tone. The treatment of the harmonic barring, size, shape and placement  regulate the strength of tone. That is what I found in building models of the Warwick Frei and I think it is also true for other historical instruments that have unusually thick soundboards.

I discovered that Jacob Heringman owned a Warwick Frei six course built by Michael Lowe with the original soundboard graduation. When I contacted Jacob he generously provided a lengthy account of his experience with the lute that includes a link to several tracks of his  Josquin des Prez CD where he uses his Frei. Jacob relates that Michael Lowe built the Frei six course with the graduated soundboard as an experiment and asked him to try it out before applying the finish with the intention of thinning the soundboard if he did not think that it worked. Jacob said:" My strong feeling was that he should definitely finish the instrument off leaving the soundboard as it was, without making any further changes. It felt pretty good right from the start, but I had the strong hunch that, because of the amount of wood in it, the instrument would take a long time to develop ... When the instrument was still brand new, I recorded several of the tracks on my CD of Josquin intabulations on it. It sounds striking and remarkable already on that recording  Now, fourteen years on, it sounds even better, and it has certainly become more responsive and more nuanced as time has gone on... in my own collection, it's my favourite -- my 'desert island lute' and I'm so pleased that we kept our nerve and went through with the 'experiment'."

Building copies of historical instruments requires some detective work. Writing about them requires witnesses. I would like to thank David van Edwards, Bruce Brook and Tony Johnson : whose remarks I did not use but who pointed me in the right direction.

Friday, September 20, 2013

Theorbo after Christoph Koch

I finished my first model of the Christoph Koch theorbo, Venezia 1650, Number 3581, Musikinstrumenten Museum -- Staatliches Institut für Musikforschung, Berlin. Earlier this year I travelled to Berlin, examined the instrument and reported on my study in this Blog on April 19, 2013. I spent the summer analyzing the templates that I made of the bowl and turning them into a workable mould. I was surprised by the lack of symmetry and I mentioned this in my earlier post but I wasn't ready for the problems this would cause in constructing a mould. Since I had wanted to replicate the shape of the lute's bowl accurately I was willing to put up with mis-alignments of individual ribs and I intended to include these features.

However, when I assembled the cross-sections and proceeded to check the rib contours with a flexible ruler, I could see that the irregularities would be a major problem. (My procedure for laying out rib lines is described in detail for another mould in two posts on May 8 and 17, 2012). On the original lute bowl the rib widths at any cross-section were approximately the same, but to maintain this uniformity, the edge contours were distorted.

 I pondered this difficulty for some time considering whether it was possible to remove the irregularities from the rib lines while maintaining the uniformity in width without altering the shape of the bowl. I decided that it wasn't. My solution was to start over.

Most of the irregularities are found on the bass side of the bowl. The treble side is  accurately assembled. I decided to make the bass side a mirror image of the treble side. If the lute bowl had been symmetrical in the first place this would have been the case. I assembled a new mould using the treble side contours. I felt this would result in a bowl that, while not a replica of the original, was representative of it.

 I constructed the bowl with East Indian rosewood ribs that I cut from the remains of a log that I have had since 1983. The triple spacers between the ribs are made of holly/ebony/holly.

The low profile of the bowl is obvious in this view. I was pleased that the contour lines of the ribs of my model are a close match with the original.

The Koch bowl is constructed with kingwood ribs
with triple spacers of ivory/kingwood/ivory.

This photo of my Koch shows the flow of the ribs over the rear of the bowl. When I examine an original lute I carefully measure and plot the position of each rib as it disappears under the end clasp. This is an important aid in reproducing this difficult area of the bowl shape.

I chose not to use as deep an end clasp as on the original. This doesn't alter the flow of the rib lines. Note that the angle between the fourth and fifth ribs (the first and last ribs are not visible) on each side is significantly tighter than the others. The angle on the bass side of the original is tighter than that on the treble. This feature is, in part, the reason that I had such difficulty in constructing the mould.

Note too, that the center rib is narrower than the others. These factors lead me to believe that the original bowl was not assembled on a mould but assembled from templates and not starting from the center and working outward, one rib after another, as is the method today but from each edge inward.

When I constructed a symmetrical mould by altering the bass side it affected the line of the ribs, not the contour of the face which was retained. By comparing the two photos you can see the slight different in the curving line through the middle third of the face and that in the lower quarter of the face from one side to the other.

I used 10 year old Italian spruce for the top, thinning it to just under 2 millimeters on the treble side, a little thinner on the bass and down to 1.1 millimeter around the rose area. I do not know the barring arrangement in the Koch theorbo so I assumed it was similar to that found in his archlute, E.546 Musée de la musique, Paris which is a standard design and similar to what I described in my post on the Kaiser theorbo from November 7, 2011.  Plans for the Koch archlute are available from the museum.

The distance that the bridge and rose are placed from the rear of the face affect the instrument's tone. I think it is important to respect the original location of these elements. Theorbo bridges are often off-set to the bass side as a result of balancing the alignment of the extension. I routinely set my theorbo bridges off center by 5 mm or so. The Koch bridge is off-set much more than this.  Although I chose to not to duplicate this feature, I did roughly follow the design and dimensions of the bridge.

The tips are missing from the wings of the original bridge so I finished my bridge in a design that could have been a continuation of the original.

Notice that the top front edge of the Koch bridge is smoothly canted back. I believe this was done to accommodate the metal diapasons that risked breaking if bent over a rounded but more abrupt edge. I liberally rounded the front edge of my bridge.

The rose is beautifully cut but the detail is somewhat obscured
by an accumulation of wax. I cut a different but similar design using the same location on the face and the same diameters as the original.

The neck and extension of the original theorbo are veneered with kingwood and elaborately inlaid with ivory arabesques. I used ebony and rosewood thinly cut to veneer the neck and extension. The latter I edged with holly/ebony/holly banding front and back.

The fretted string length of my Koch model is 84.6 centimeters with diapasons at 167.5 centimeters in a disposition of 7+7.

All photos by the author.

Tuesday, August 13, 2013

The Checchucci Guitar Rose -- An Inlaid Ring of "Ivory" Triangles

It was never been my intention to build an elaborate copy of the Checchucci guitar, but I did want to include those features that characterize its design. In my model I have preserved the inward sloping side ribs and the seventeen piece vaulted back of the original, but I laid aside the idea of producing the inlaid arabesques. For the soundboard I decided to replicate the ring of ivory triangles around the tiered rose. This presented several challenges both in the choice of materials and technique. The original design is created with ivory set in a black paste. Nowadays ivory is a prohibited material in many countries and substitutes are available so there is no justification for using it.

I used bleached cow bone purchased from a guitar supply company and sold as over-size blank saddle bone. For the black paste I used carbon black mixed with slow setting epoxy. This mixture flows into crevices, levels itself, dries to a low sheen and shrinks very little. It does have the potential to stain surrounding material that might be porous. I took precautions against this.

To begin, I routed a recess in the soundboard a little more than 1mm deep and with hide glue, glued two 1.5mm wide black/white/black strips of purfling to each side of the recess. I filled the recess between the two strips with lengths of plastic purfling material. This kept the black/white/black strips snuggly against the walls of the recess while the glue set but was removable because plastic doesn't stick well to hide glue.

There are thirty-two white triangles embedded in the ring. A close look reveals that they are not uniformly shaped. Some larger and others smaller, some are clearly right angles and some not. Certainly these were cut by hand and fitted individually. I intended to follow a like procedure but I wanted to be a little more accurate.

The first thing I did was to devise a way to lay out the spacing for the thirty-two triangles. The right hand figure is a circle divided into thirty-two  equal segments. I drew this with a rule and compass by dividing the circle into quarters and each quarter in half and so on until I had thirty-two segments. They were not quite equal. Sue had a better solution using Excel to make an accurately segmented pie chart.

I cut out the center of the diagram and taped it top the soundboard. This provided a clear guide to position each triangle. The recess for the triangles is 5mm wide so I prepared several strips of bone saddle material 1.2mm thick and 5mm wide. The triangles are not right triangles so there was no easy way to set up a cutting jig to insure accuracy.

Earlier in the year I bought a minature -- the table measures 10x12 inches -- precision table saw to make custom purfling strips. The machine is designed for model wooden boat builders and works perfectly for fine inlay pieces for lutes and guitars. I experimented with various angles on the cross cut guide until I found the one that resulted in the proper fit.

After that, the assembly of the ring went fairly quickly. The triangles fit snuggly but I glued them in place with a tiny drop of hide glue. I mentioned previously that the black paste I wanted to use to fill the recess around the triangles had the potential to stain both the soundboard and the bone. I masked the exposed soundboard and brushed a thin solution of lacquer over the top and edges of each bone triangle in order to seal them.

Then I mixed a paste of carbon black and slow setting epoxy and dabbled it around the triangles, pushing the paste into the corners with a tooth pick. I was careful to insure that the level of the paste was at least equal to the top of the triangles. Once the paste  dried I levelled the assembly with files.

The finished ring turned out quite nice. Tiny air bubbles formed in the corners of several of the triangles -- something I half expected. Before I finish the guitar I will dab some black paste into the offending holes and re-level them.

Next, I will construct the neck and peghead, assembling the guitar and stringing it for a trial before I apply the inlaid bone and black paste edging to the soundboard.

The tiered parchment rose is by Elena Dal Cortivo.