By Ricky O’Bannon

Dan Chitwood is fascinated by shape.

As a biologist at the Donald Danforth Plant Science Center in St. Louis, Chitwood works to quantify the morphologies and architecture of leaves to better study the development of plants.

But Chitwood, a viola player, recently devoted many sleepless nights and his scientific expertise to see what patterns would emerge by analyzing the shape of 9,000 violins that span 400 years. The results of his study were published in early October by PLOS One, an online publication of peer-reviewed research.

“A real problem I think about a lot is that it’s really difficult to quantify the entirety of a shape,” he said. “Shape inherently carries so much information. In biology we often say structure is function.”

Chitwood manually cleaned up 9,000 pictures of instruments sold through Tarisio Auctions by digitally removing chin rests and the instrument’s neck to be able to run an analysis on the body shape.

Violin Mosaic Full
A mosaic of a violin comprised of the outline violin bodies. 
(Credit Dan Chitwood)
Cluster Graphic
A comparison of the four violin body-style clusters.

An analysis of those images showed the shapes of the violins formed four distinct clusters, which Chitwood named Stainer, Amati, Maggini and Stradavari after the well-known luthiers in each category.

Chitwood’s analysis also showed that the shape of modern violins converged on the shape qualities of the Stradavari cluster, named for the near mythical luthier Antonio Stradavari whose 17th-century instruments are the most desired and valuable in the world.

The easiest assumption about that trend would be other luthiers emulated the shape of the Stradavari design to get the desirable Stradavarius sound. However, acoustic engineers Chitwood spoke to during the peer review process said that might not be the case. The shape of a violin has a much smaller effect on the sound of the instrument than qualities like the thickness of the wood or its arching pattern.

Similarly, Chitwood pointed out that a recent blind listening test showed many violin players couldn’t tell the difference between, a Stradavarius, violins made by other 17th century masters or even some high-end modern instruments.

But because both the real and perceived qualities were desirable, traits from Stradavari’s design such as shape were passed down.

“It's almost like a self-fulfilling prophesy where because people made it important, it does become functionally important as it ended up shaping the modern instrument that we have today,” Chitwood said.

While Chitwood focused on the violin shape, his study also looked at the shapes of the viola, cello and bass. The latter two varied significantly in shape from the violin to best suit the range and performance of that instrument. The viola was for the most part virtually indistinguishable from the violin in shape.

From an evolutionary point of view, that fact makes violas the penguin of the stringed instrument world. In biology there’s a concept called developmental constraint.

“A constraint in biology is where you are stuck with a particular set of genes that is not ideal but you really have to make do with it,” Chitwood said.

For example penguins’ ancestors had wings, but penguins needed flippers not wings because of their environment and had to do the best they could with what they inherited. The viola, Chitwood said, probably needs to be bigger than can comfortably be played under a performer’s chin to best accommodate its range and tone.

The decision early on to model the viola after the violin has been passed down through generations, even if that results in a few back problems for viola players like Chitwood.

“For me the viola is a perfect example of [developmental constraint],” he said. “Nobody in their right mind is going to start making violas between their legs like a cello any time soon, so people have tried the best they can to come up with all of these compromises in how to allow for playability and not sacrifice tone.”

The full study can be read at PLOS One.