Violin’s secrets come out of the woodwork

Scientists are leaving no string untuned in their attempt to unravel the secrets of the Stradivarius. They’ve analyzed varnishes, types and densities of wood, the shapes and thicknesses of the plates that make up these highly prized, centuries-old violins. Now a research team from Leiden University in the Netherlands and Borman Violins in Fayetteville, Ark., says it has found clues within the wood’s annual growth rings.

The duo compared two Stradavarius and three Gesu violins to eight modern ones, using computer densitometry – a noninvasive technique for measuring changes in a material’s density on a fine scale. It’s most often used for medical imaging. The researchers say they found little or no difference in the overall average density of the wood used in the classical and modern instruments. But once they looked at the wood’s growth rings, they saw a striking difference. Wood in the annual rings showed significantly wider differences in density at the beginning and at the end of a growing season in the modern instruments than they did in the classical ones. Those differences among violin generations could help explain the difference in sound, they conclude, either by directly affecting the way the wood vibrates or by affecting the way it dampens the sound.

The means the masters used to achieve the narrower density differences remains a mystery. The team notes that several approaches would achieve this result, including fuming the wood with nitric acid or ammonia. The duo offers up its observations in the hopes that today’s luthiers can come closer to matching the tonal quality of the old masters. The results appear in the current issue of the Public Library of Science’s PLoS ONE.