Researchers from the Massachusetts Institute of Technology (MIT), discovered that the Stradivari family made the best-sounding violins in the world because of the thicker back plates and longer sound holes. The study was published in the journal Proceedings of the Royal Society. (citation below). Craftsmen from the Italian factories of the Stradivari and Amati families made some of the most beautiful violins. They were created in both the 17th (and 18th) centuries. The Cremonese period was the golden age in violin-making, and their violins are now worth many millions of dollars. The instrument holes have evolved over 8 centuries from a simple circular shape to the modern f-shape. (Image: MIT). Violin-makers from the North Bennet Street School, Boston, and fluid dynamicsists, and acousticians, at MIT, analyzed hundreds of Cremonese violins. They sought to determine the key features of each instrument’s design that give it its acoustic power or volume. Violins have a loud sound because of the shape and length of the “f-holes”. The shape is where air escapes. A violin will produce more sound the longer these holes are. An extended sound hole is a smaller size than a regular sound hole, but still produces a rich sound. Researchers found that this sound hole was much more efficient than earlier instruments like medieval rebecs or lyres. The thickness of a violin’s back plate can also increase its acoustic potential. Wooden instruments are very elastic. As it makes sound, the body of a violin may react to vibrations from air. A thicker backplate could improve a violin’s sound, they discovered. Nicholas Makris (MIT professor of mechanical engineering and ocean engineering) and his colleagues discovered that violins were first created by Amati, Stradivari, and then Guarneri. As a result, the f holes became longer and thicker. Did the violin designers change deliberately? To find out if the three families responsible for making violins had deliberately changed their designs to produce a louder sound, the team began to investigate. The team used the data from thousands of Cremonese violins to create an evolutionary model. The only reason for design changes was craftsmanship errors, which they called “natural mutation”. Antonio Stradivari (1644-1737) improved sound quality in the violins that he made, probably through accident. The result was thicker sound holes and thicker back plates. Professor Makris stated that the development of thicker back plates and longer sound holes was accidental. However, it is not clear whether the violin-makers had a better ear to determine which design features were associated with stronger sounds. Professor Makris stated that people had to listen and pick the most efficient instruments. We don’t know if they could understand that “Oh, we must make [*] more slender,” but we do not know. They knew which instrument was better. He recalls, “I’m going to just play the thing.” This pledge didn’t last very long. After speaking with players and lutemakers to gain a better understanding of the instrument that was once Europe’s most beloved, his curiosity in its acoustics increased. The violin sounds louder than the guitar. It has a lute with f-shaped sound holes. The interior of the lute is also round. These intricate carvings are inherited from its Middle Eastern ancestor, the oud. A well-known player of lutes asked Professor Makris years ago whether the lute’s sounds were affected by the carvings. Professor Makris noticed that the frequency of sound produced by a lute was in the same range as the fluid flowing through the sound hole. He asked Yuming Liu (principal research scientist, Department of Mechanical Engineering, MIT) to assist him in this endeavor. Researchers modeled airflow through two holes, one simple and one with a different pattern. They found that air flows fastest around the perimeter of both holes. Airflow was not affected by the interior or exterior of the hole. An 8-century study. The simple question of the lute player turned out to be a seven year project. It was designed to examine the acoustic dynamics over time for several instruments. This included the Middle Eastern oud to the medieval fiddles and the guitar. Roman Barnas (director of violinmaking at North Bennet Street School and an expert in the early construction of instruments), urged researchers to also include analysis of the violin. The team observed a change in sound-hole shapes over the past eight centuries. It went from a simple round hole to one that was semicircle-like. This eventually led to the formation of a c shape, which became longer and finally took on the shape of the violin’s f-shape. The perimeters of these shapes grew steadily, while the inner void gradually got smaller. The researchers discovered that earlier instruments had evolved in a similar fashion to the Cremonese period. However, their overall shapes were more powerful and acoustically more efficient. This was not an intentional change. Professor Makris stated that these modifications are possible due to natural mutation. We’ve modelled all of the subtle parameters of the shape and were able to predict the effect on power and frequency. Prof. Makris hopes that the findings of the study will help violin-makers who want to produce more powerful instruments. However, he acknowledges that it is not enough to adjust a few parameters in order to make a high-quality violin. Professor Makris stated that “mystery is good and there’s magic violinmaking.” It’s an art form. “Some makers I don’t understand how to do it. Each maker has their own methods and techniques. However, we believe it is important to be as scientifically informed as possible.” This study was partially funded by the Office of Naval Research. Citation: “The evolution in air resonance power efficiency for the violin and its ancestral instruments,” HadiT.Nia, Yuming Liu, Mohammad-Reza
