If you know only one thing about violins, it is probably this: A 300-year-old Stradivarius supposedly possesses mysterious tonal qualities unmatched by modern instruments. However, even elite violinists cannot tell a Stradivarius from a top-quality modern violin, a new double-blind study suggests. Like the sound of coughing during the delicate second movement of Beethoven's violin concerto, the finding seems sure to annoy some people, especially dealers who broker the million-dollar sales of rare old Italian fiddles. But it may come as a relief to the many violinists who cannot afford such prices.

"There is nothing magical [about old Italian violins], there is nothing that is impossible to reproduce," says Olivier Charlier, a soloist who participated in the study and who plays a fiddle made by Carlo Bergonzi (1683 to 1747). However, Yi-Jia Susanne Hou, a soloist who participated in the study and who until recently played a violin by Bartolomeo Giuseppe Antonio Guarneri "del Gesù" (1698 to 1744), questions whether the test was fair. "Whereas I believe that [the researchers] assembled some of the finest contemporary instruments, I am quite certain that they didn't have some of the finest old instruments that exist," she says.

The study marks the latest round in debate over the "secret of Stradivarius." Some violinists, violinmakers, and scientists have thought that Antonio Stradivari (1644 to 1737) and his contemporaries in Cremona, Italy, possessed some secret—perhaps in the varnish or the wood they used—that enabled them to make instruments of unparalleled quality. Yet, for decades researchers have failed to identify a single physical characteristic that distinguishes the old Italians from other top-notch violins. The varnish is varnish; the wood (spruce and maple) isn't unusual. Moreover, for decades tests have shown that listeners cannot tell an old Italian from a modern violin.

Still, the belief in the superiority of the rare old Italians persists: Even if listeners can't tell the difference, players can, adherents say. But that position has also come under fire. In 2012, Claudia Fritz, a musical acoustician at Pierre and Marie Curie University in Paris; Joseph Curtin, a violinmaker from Ann Arbor, Michigan; and colleagues published a study in which 21 violinists compared three old Italian violins and three new ones and were unable to tell the two types apart. However, critics noted that only six instruments were compared; the players were not top-flight soloists; and the test was conducted in a hotel room, close quarters that should make any violin sounds vibrant.

Now, Fritz, Curtin, and colleagues have performed a larger study that addresses those concerns. During 1 week in 2012, they invited 10 professional soloists to Vincennes, a suburb of Paris, and assembled 13 new violins and nine old Italians, including six Stradivariuses and two made by Guarneri del Gesús. The researchers did not tell the musicians that they would be playing old and new instruments and instructed them to suppose they were picking an instrument to use on a tour.

The violins were winnowed to six old and six new in a double-blind listening test judged by the soloists. Then, each of them donned dark goggles so they couldn’t distinguish the instruments by sight and tested out these top fiddles in two 75-minute sessions, one in a small room and one in a 300-seat auditorium. (Soloists could also play their own instruments for comparison.) After each session, the soloists picked his or her four favorites fiddles and rated them on scale of zero to 10 for qualities such as articulation, projection, and playability. Finally, after the second session, each subject had to guess whether instruments in a small selection that included some of their favorites were old or new.

The consistency of results from session to session showed that soloists could definitely distinguish one violin from another. However, the soloists seemed to prefer the new violins, the researchers report online today in the Proceedings of the National Academy of Sciences. In their lists of favorites, new violins outnumber old ones roughly 3-to-2, and the most popular violin by far was a new one, denoted N5. Musicians rated qualities of new instruments higher, too. And when it came to telling old violins from new, the soloists did no better than if they had simply guessed.

Fritz cautions that the study cannot be generalized to draw broader conclusions about all new or old violins. "Our observation is about these 12 violins," she says. "Maybe if we had done this with 12 other violins people might have been able to tell the difference, although I don't see any good reason why they might." One aim of the study was to determine what violinists look for in an instrument, which remains hard to quantify scientifically. "I don’t like violins that are too direct," says soloist Solenne Païdassi. "I like a sound that's more diffuse."

Still, several of the players involved in the study say they now think there is no reason to believe that a new violin cannot produce the same qualities of sound as an old one. And that's a very good thing for young musicians, they say, given the enormous expense of old Italian violins. This June, a Stradivarius viola will go to auction for $45 million, and a Guarneri del Gesú recently sold for $16 million. In contrast, the record auction price for fiddle by a living maker is $132,000. "I grew up thinking that if I am going to be a soloist, I really need to play an old Italian violin in order to be successful," says Giora Schmidt, who participated in the study. "I tell my students that's no longer true." Schmidt has played old Italians in the past but now plays a modern violin made by Hiroshi Iizuka.

Not everyone is convinced that there isn't something special about the old instruments. Hou says she found the study somewhat artificial in that choosing an instrument for one tour isn't the same thing as choosing one to use for the long haul. A modern instrument may sound better right away, she says, but an old Italian may be able to produce more colors of sound that only become apparent after months of use. "I played the Avery Fisher Stradivarius for 6 years," she says, "and it took me 3 years just to get accustomed to it."

Even if new violins can rival old Italians, that fact won't bring the price of old violins down, musicians predict. Stradivariuses and Guarneris are works of art by the masters who essentially defined what a violin is, says Elmar Oliveira, a soloist who participated in the study and owns a Guarneri del Gesú worth millions but often plays a modern replica in concert. "You'd pay $250 million for a painting by Matisse," Oliveira says. "Why wouldn't you pay $25 million for a Stradivarius?"

The issue of finding an instrument is real and pressing, violinists say. For example, Païdassi now plays a violin by Lorenzo Storioni (1744 to 1816), but will have to return it next year to the foundation that owns it. "I have no idea what I will do," she says. "Maybe I can find out what that N5 is." But violinmaker Curtin is sworn to secrecy.

*Correction, 7 April, 4:39 p.m.: The story was changed to correct the numerical scale for judging instrument properties.

*Correction, 9 April, 3:04 p.m.: The story has been changed to correct the length of the testing session and to indicate that the identities of the instruments will never be revealed.

*Correction, 9 April, 4:42 p.m.: The story has been changed to better reflect Fritz's thoughts on the significance of the results.