What makes the sound of Stradivarius violins so special? Musicians and collectors have long prized Italian violin maker Antonio Stradivari’s instruments. “The 1726 Belgiorno Stradivarius is one of the great violins of the world and carries all of the trademarks of Stradivari’s inimitable artistry; the tone is exceptional in its brilliance, and it has a spectacular palette of colours and expressions,” Australian Chamber Orchestra principal violinist Satu Vänskä said earlier this year when the orchestra acquired the almost 300-year-old instrument. “Owning a Stradivarius is practically impossible for my generation of musicians, so to be the custodian of an extraordinary instrument such as this one is the opportunity of a lifetime. But what makes this instrument so special is that, like all of Stradivari’s best instruments, it has a soul and a personality of its own.”

Stradivarius, Research, Australian Chamber OrchestraAustralian Chamber Orchestra principal violinist Satu Vänskä. Photo © Nic Walker

According to a team of researchers in Taiwan, while “the construction methods of Amati and Stradivari have been carefully examined, the underlying acoustic qualities which contribute to their popularity are little understood.”

The team’s study, published in Proceedings of the National Academy of Science has shed some light on this mystery, based on baroque violinist Geminiani’s claim that the ideal violin sound should “rival the most perfect human voice”. The research team, consisting of Hwan-Ching Tai, Yen-Ping Shen, Jer-Horng Lin, and Dai-Ting Chung has published the findings of a study comparing 15 antique Italian violins with eight male and eight female singers.

The researchers observed, by examining factors such as frequency response and harmonics, that early Italian violins emulated the vocal tract resonances of male singers, particularly basses and baritones, while “Stradivari pushed these resonance peaks higher to resemble the shorter vocal tract lengths of tenors or altos”. The Stradivarius violins also exhibited vowel qualities corresponding to “lower tongue height and backness”.

“The unique formant properties displayed by Stradivari violins may represent the acoustic correlate of their distinctive brilliance perceived by musicians,” the researchers wrote. “Our data demonstrate that the pioneering designs of Cremonese violins exhibit voice-like qualities in their acoustic output.”

The findings may have ramifications for future advancements in instrument making. “Pushing violin formants even higher to mimic mezzo-soprano or soprano voice types, beyond what Stradivari has achieved, could be a new challenge for 21st-century violin makers,” the researchers wrote. “Additional research is required to understand the physical and material factors that influence formant properties in violins, and how voice-like formants are perceived by listeners. It remains to be explored whether this design concept is also applicable to violas and cellos, or even other string instruments across different cultures.”

Not everyone is convinced by the sound of Stradivari’s instruments however, with some studies suggesting audiences and, indeed, violin soloists are unable to distinguish between the sound of a Stradivarius and that of a modern instrument at better than chance levels.