String Theories: Chemical Secrets of Italian Violins and Chinese Guqins

Abstract

The most valuable musical instruments in the world are 17-18th century violins from Cremona, Italy (made by Stradivari and Guarneri), and Chinese guqins (7-string zithers) from the 8-13th century. Today, musicians still prefer these antique instruments for their superior acoustic qualities that cannot be reproduced by later makers. Over the centuries, many theories have been proposed to explain the unique playing properties of famous violins and guqins, but most are based on conjectures rather than factual evidence.

Analysis of the Anisotropy of Sound Propagation Velocity in Thin Wooden Plates Using Lamb Waves

“…Both nowadays and in the past, stringed musical instruments were covered with varnish to protect them from variations in atmospheric humidity and dirt [ 31 , 32 , 33 ]. Current studies with modern methods of determining the chemical fingerprint of the varnish layers on old violins have highlighted the fact that luthiers used recipes based on alcohol-solvent resins, with oils, or the wood was treated with salts like borax and the sulfates of Zn, Cu, Cr, Na, and Fe [ 32 , 34 ]. Based on these considerations, currently, the most well-known types of varnishes used for maestro- and professional-level musical instruments are those with an oil-based solvent and those with an alcoholic solvent (spirit) [ 32 , 33 , 34 , 35 ].…”

“…Current studies with modern methods of determining the chemical fingerprint of the varnish layers on old violins have highlighted the fact that luthiers used recipes based on alcohol-solvent resins, with oils, or the wood was treated with salts like borax and the sulfates of Zn, Cu, Cr, Na, and Fe [ 32 , 34 ]. Based on these considerations, currently, the most well-known types of varnishes used for maestro- and professional-level musical instruments are those with an oil-based solvent and those with an alcoholic solvent (spirit) [ 32 , 33 , 34 , 35 ]. Not only is the chemical composition of the surface treatment important but also the thickness of the varnish film and the varnish–wood interface, aspects highlighted in studies [ 36 , 37 , 38 ].…”

Tunable Acoustic Properties Using Different Coating Systems on Resonance Spruce Wood

“…[17] However, in the literature, there are controversies on the chemical fingerprints of old varnishes, especially regarding the preparation of recipes. Although some researchers consider that the varnish system is responsible for the acoustic quality of antique violins, Cai et al [18] proposes the analysis of cellulose rearrangement patterns as a result of both wood aging and longterm exposure of musical instruments to vibrations. It is certain that, regardless of the varnish used, the film thickness (number of applied layers) and the wood-varnish interface lead to changes in the elastic and vibrational properties of the resonance wood used as a support.…”