Chemical Detectives Unlock the Secrets of Famous Italian Violins

The Chimei Museum (奇美博物館) in Taiwan boasts a world-famous collection of antique Italian violins. The greatest makers were Antonio Stradivari and his neighbor Guarneri “del Gesù.” NTU researchers recently collaborated with Chimei Museum to solve their secrets hidden for 300 years—special chemical recipes for altering wood properties to achieve special sounds. This study, led by Hwan-Ching Tai (戴桓青), associate professor chemistry, has been published in the journal Angewandte Chemie.

Analyzing wood flakes collected during violin repairs, scientists revealed that Stradivari and Guarneri used chemically altered wood for both front and back plates. They probably learned the trick from their teacher, Amati, who added a little bit of chemical preservatives (like borax and copper sulfate) against worms and fungi. But Stradivari and Guarneri were brave enough to try acoustic tuning using much more aggressive chemical means.  They tried to make the wood more stiff: Stradivari added table salt; Guarneri added alum, KAl(SO₄)₂. They also tried artificial aging of wood by alkaline treatments: Stradivari used potash (potassium carbonate or hydroxide); Guarneri used lime, Ca(OH)₂.

The salt stiffened the wood by altering the distribution of water molecules in the wood, similar to the situation in salted meat. The alum stiffened the wood by forming chemical crosslinks between wood fibers. The alkaline treatments caused rearrangement of wood fibers. The hydrolysis of hemicellulose fibers under basic pH conditions allowed extra space for the remaining cellulose fibers to reorganize and form thicker bundles. On a side note, artificial aging of wood using lime has been recorded by ancient Chinese guqin makers. Prof. Tai also observed cellulose bundling in legendary Chinese guqins over 1000 years old. So the principles behind amazing instrument tones may be shared between different cultures.

These new discoveries will take us one step closer to reproducing the famous tonal quality of Stradivari and Guarneri violins. Prof. Tai believes that different chemical recipes are associated with distinct tonal colors of each master. Leading modern violin makers are incredibly skilled and they will probably surpass Stradivari once they master the principles of materials engineering for tonewood. Tai started this line of research when he was a PhD student at Caltech and paid a visit to Joseph Nagyvary, a biochemistry professor at Texas A&M who pioneered Italian violin materials research. Nagyvary took interest in violin research when he was a PhD student at University of Zurich, playing a violin formerly used by Albert Einstein. Tai is an avid collector of classical music CDs and hi-fi audio equipment including vacuum tubes, and plays on a Nagyvary-Chen violin made in 2009. When he is not fiddling around with music side projects, Prof. Tai applies his biochemistry training to understand tau proteins in Alzheimer’s disease and to develop corresponding antibody therapies.

Refer more：https://doi.org/10.1002/anie.202105252