A FEW years ago Francis Schwarze noticed something unusual. Dr Schwarze, who works at the Swiss Federal Laboratories for Materials Science and Technology, in St Gallen, knew that sound travels faster through healthy wood, which is stiff and dense, than it does through the soft stuff left by a fungal attack. But some fungi, he found, do not slow sound. Moreover, the acoustic properties of wood so affected seem to be just what violin-makers desire. So Dr Schwarze had some violins made from the infected wood and discovered that they sounded like a Stradivarius.

Dr Schwarze is now trying to standardise this fungal treatment in order to make what he calls “mycowood”. His hope is that it will endow modern instruments with the warm and mellow tones found in those made during the late 17th and early 18th centuries by Antonio Stradivari.

Exactly what makes a Strad so magical is contentious. Besides excellent craftsmanship, the master and members of his workshop in Cremona used different types of wood and, possibly, different chemical treatments. The period when they were active does, though, coincide with a cold spell in Europe’s climate that occurred between 1645 and 1715. In the long winters and cool summers wood would have grown slowly and evenly, creating a lot of stiffness. Which is exactly what a good violin needs.

Treating wood with certain fungi endows it with similar properties. The species Dr Schwarze lit upon are Physisporinus vitreus, a type of white rot, and Xylaria longipes, commonly known as Dead Moll’s Fingers. He applies them to Norway spruce (used for an instrument’s body) and sycamore (for the back, ribs and neck).

What is unusual about Physisporinus and Xylaria is that they gradually degrade the cell walls of the wood they infect—thinning them rather than destroying them completely. That leaves a stiff scaffolding through which sound waves can readily pass, without compromising the wood’s elasticity. When the fungi have done their work, Dr Schwarze treats the planks with a gas that kills the infection. He then hands the result over to Martin Schleske and Michael Rhonheimer, two master violin-makers, for conversion into instruments.

And it works. A blind trial conducted in 2009 by Matthew Trusler, a British violinist, for example, compared modern violins made with treated and untreated wood from the same trees with a Stradivarius made in 1711. A jury of experts, and also most of the audience, thought that the mycowood violin was the Strad.

Tonal quality is a subjective measurement, of course, and Stradivarius violins vary in their tones. But, in music, subjective experience is what actually counts. Readers may therefore exercise their own judgments by listening to the audio files below, and decide whether, in their opinion, Dr Schwarze has cracked a problem that has defeated instrument-makers for 300 years: matching, or even beating, the Master of Cremona.

These two recordings show the difference in tone between an untreated violin and one given nine months of fungal treatment.