Liutaio Mottola Stringed Instrument Design

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Lutherie Myth/Science:
Violin Plates are Symmetrically Arched and Thicker in the Center than on the Edges

The modern book The Secrets of Stradivari by Simone F. Sacconi features diagrams showing the cross sections of the plate arching of what are considered by some to be the best sounding instruments ever made. The arching diagrams show curves that are familiar to all makers of violin family instruments as well as those that build archtop guitars, mandolins, and other instruments derived from violins. The curves are invariably smooth, regular, symmetrical, and show the plates to be thicker in the center than they are at the edges. As such the book recapitulates information that has been known about the cross section of violin plates for hundreds of years, information that appears in many books on violin making and that is taught in violin making schools. But recent and compelling research indicates that this information concerning the arching of the plates of violins by Stradivari is quite incorrect. That the received wisdom is incorrect and has persisted for such a long time is a good example of why scientific skepticism is such a useful thing. It also tells us something about how erroneous information persists. And it may raise quite a lot of questions about the validity of a lot more of modern lutherie practice.

Last updated: Saturday, November 25, 2017

Everyone knows what the cross section of the plate (top or back) of an archtop instrument such as a violin looks like. It looks like this:

Disregarding my lumpy drawing, the basic properties are that the center of the plate is thicker than the edges, and that the arching is smooth and symmetrical. The received wisdom is that the plates are arched this way because this is the way the Cremonese master violin makers, including Stradivari, made their plates. Jeffrey S. Loen has published work in both the Catgut Acoustical Society Journal and the Journal of the Violin Society of America that provides hard evidence that this is not so1, 2. Dr. Loen's work indicated that most (60%) of the 105 plates of Cremonese master instruments he examined were thinner, not thicker, in the center than at their edges. Only a handful of the plates examined were thicker in the center of the arch. The other striking thing was how irregular and non symmetrical the arching on most plates was. The technique used in this evaluation was striking in its simplicity. Using a magnetic thickness gage made by Hacklinger the instrument plates were measured, and the data were recorded in a database. Not to trivialize the massive amount of work that went into (and apparently continues to go into) this research, but what was done was simply to measure the thicknesses of the plates, something apparently no one had ever done before.

So what does it tell us that Jeffrey Loen's work managed to turn over an enduring myth about the construction of instrument plates, a myth that has probably been around for a few hundred years? Probably that, until he started this effort, nobody bothered to look. It's not like the rest of us were all asleep at the switch mind you, it just didn't occur to us to take a long, hard look. I don't mean this to be as damning as it sounds. Scientific research is full of such cases, cases where someone made a startling discovery because they were interested enough to look. Here are just two examples, neither having anything at all to do with musical instruments.

In his popular press book The Promise of Sleep, sleep researcher William Dement tells how amazed he was that no one had ever noticed the hallmark eye movement that characterizes the stage of sleep known as REM sleep. Considered to be the father of sleep research, Dr. Dement's sleep lab was the first to notice this in the 1960's and in the book he wonders out loud why no one had ever seen this before, given the long history of human beings. Another example is the flying squirrel. It is well known that the forests of the northeast are thick with these animals, but at one time and not too long ago they were considered to be quite rare. What happened that changed the perceived size of the flying squirrel population? Someone took an interest in them and took the time to study them.

Examples of such discoveries are common, and in each case as in Dr. Loen's plate analysis someone was interested enough to do research that no one had done before. In the case of the plate thickness research one might wonder why it took so long to figure this out, what with repair people opening up these Cremonese master instruments for so many years. But consider that the violin making world had a plausible story for the arching of the plates even if it was wrong, so what would motivate someone to take a closer look? One motivating factor is scientific skepticism, a basic principle of scientific research. This is often misunderstood by non scientists to be the same as cynicism but it is hardly that. In this case as in most, scientific skepticism is nothing more than the willingness to pursue one's research to completion, even when it appears to contradict an established “fact.”

Consider the ramifications this discovery has for lutherie. The pursuit of the tone of Cremonese master violins has been elusive. Modern violin makers may begin to experiment with plates arched in the real manner of Stradivari. And if something as obvious as plate arching was so elusive, what else might we find out simply by taking other long and hard looks?

References and Suggestions for Further Reading

1. Loen, J. “Reverse Graduation in Fine Cremonese Violins”
CAS Journal, May 2003, p. 27.

2. Loen, J. “Thickness Graduation Mapping: Surprises and Discoveries”
Journal of the Violin Society of America, Vol. XIX, No. 2, p. 41.

3. Mottola, R.M. “Comparison of Arching Profiles of Golden Age Cremonese Violins and Some Mathematically Generated CurvesSavart Journal, Vol. 1 ( No. 1)

4. Mottola, R.M. “Visual Comparison of Ensemble Averaged Transverse Arching Profiles of Golden Age Cremonese Violins and Curtate Cycloid CurvesSavart Journal, Vol. 1 ( No. 2)