Secrets of the Stradivarius

by Brian Dunning
September 18, 2012

She pushed the instrument into my hands, even as I held them up to ward it away. "No," I said, "Don't let that thing anywhere near me. I'll break it." But the violinist was insistent, and it was catch it or let it fall. I held it, and as it was the first violin I'd ever actually touched, I was amazed by its light weight and highly stressed rigidity. These thin sheets of wood, so cunningly curved and fitted and glued together, formed a box that seemed by all rights to be impossibly fragile, as if I could have crushed it with the slightest squeeze of my hand. But I couldn't have; the instrument was a living exercise in tension mechanics, its great strength coming from its highly stressed curves pushing back against the compression load from the tightly cranked strings. A perpetual battle in physics, with both sides deadlocked in dètente.

Mostly I remember looking down into the F hole and reading the original signature, elegantly inked by the hand of the luthier himself on the inside of the back plate, a sight that is etched in my memory as indelibly as it was on the instrument itself: Stradivari.

Antonio Stradivari was an Italian luthier — a maker of string instruments — who lived from 1644 to 1737. He's considered the greatest of all violin makers whose instruments are the finest in the world. He also built cellos, a few violas, and a very few guitars, harps, and mandolins. Surviving instruments are all named and generally played by the most prominent performers, such as violinist Itzhak Perlman and cellist Yo Yo Ma. They are fortunate to own their own instruments. Strads, as they're commonly called, can cost millions of dollars, and most are owned by foundations or wealthy patrons. The one I profaned with my grasp was used by a violinist with the Pacific Symphony and was on loan from a patron. Somewhere north of 1,000 Strads were ever made and about 650 survive, some 500 of which are violins. His so-called "golden age" when his best instruments were built is usually considered to be from around 1700-1720.

Stradivari (best known by the Latinized version of his name, Stradivarius) acquired his talent as an apprentice of Nicolaus Amati, one of a whole dynasty of luthiers whose instruments are also considered among the world's finest. But no violins, not those of the Amatis, or Da Salo, Guarneri, Bergonzi, or any other great names, have the reputation of Stradivarius. Even today, researchers subject the great instruments to CAT scans, chemical analyses, and supercomputer simulations to try and discover some elusive secret. What made his instruments so amazing? Was it the varnish? The glue? The design? The wood itself, or way the wood was cut, dried, or even treated? None who have so painstakingly replicated a Stradivarius using authentic materials and craftsmanship has yet recreated the unique tonal quality, that perfect sound attributable only to the instruments of the master himself. Or, at least, so pop culture tells us. Today Skeptoid is going to study not this question, but the assumption on which it is based: Is the sound of a Stradivarius truly up to its reputation?

A good sounding violin is not quite as subjective as, say, a good tasting wine. Taste is largely a matter of personal preference, and while the same goes for violins, violins do have certain quantitative aspects that are measurable. All sorts of tonal qualities over the frequency spectrum can be objectively assessed. And it's not entirely implausible for there to have been a certain period in history when violins were indeed "better" than could be reproduced today. An often-cited reason for this has to do with climate.

Toward the end of the Little Ice Age, roughly defined as around 1550-1850, came a period of extraordinarily low sunspot activity called the Maunder Minimum, between 1645 and 1715. Winters in Europe during this period were already bitterly cold, and whether the Maunder Minimum compounded that or not is a matter of some debate. Regardless, it coincides perfectly with the growth period for the wood that Antonio Stradivari was using in his instruments during his golden age; and the broader Little Ice Age covers virtually the entire span of all the great early luthiers of Italy. Trees grew more slowly in the cold, the rings were tighter, and the wood was more dense. If you tried to make a new violin now using the same type of wood as a Stradivarius, today's wood would be less dense and we'd have to expect different performance. In light of this theory, Francis Schwarze of the Swiss Federal Laboratories for Materials Science and Technology announced in 2012 that he'd developed a fungal treatment for wood that would increase its stiffness and make it comparable to the Little Ice Age wood. In 2009 he gave an informal demonstration where a violinist played both a 1711 Strad and an instrument made from his fungus-treated wood, and he reported that both the audience and a panel of experts thought his violin was the Strad.

And this is the perfect place for us to step back and ask not what makes the Stradivarius so special, but rather to ask first if it actually is special. A lot of time and energy has been expended trying to learn the secrets of the Stradivarius; but in my estimation, not enough energy has been spent first trying to determine whether the difference actually does exist in the first place.

When you have instruments that cost millions of dollars, you don't often get an opportunity to test a bunch of them head-to-head. But that's just what one team of researchers managed to do in 2010 at the Eighth International Violin Competition of Indianapolis. The owners of six extraordinary violins were persuaded to part with them for the purposes of the largest and best controlled test the researchers were able to assemble. The six violins included three old Italian classics, a circa 1740 Guarneri and a pair of Strads from circa 1700 and 1715 (the exact dates were not given to keep the instruments' specific identities unknown). Their collective value was about $10,000,000. Three top-quality new violins were also included, one of which had been completed only a few days before the test, with a collective value of about $100,000.

Twenty one violinists were rounded up to participate in the study. They were drawn from the competition itself, from its judges, and from the Indianapolis Symphony. All were talented and experienced players whose own violins — none of which were included in the study — ranged in value from $1,800 to $10,000,000. The only thing the participants knew is that they would be playing "a number of fine violins, including at least one by Stradivari." The most unique feature of this particular study is that it was truly double blinded; neither the participants nor the researchers knew which violin was being played at any given time. To accomplish this, the entire test was administered in a dimly lit hotel suite, with everyone wearing modified welder's goggles that eliminated their ability to see clearly. Each violin was daubed with perfume on the chin rest to mask its unique aroma. Players used their own bows.

Everything was properly randomized, and even the researcher who handed each violin to each player didn't know which instrument it was. The musicians, who all participated one at a time, had a number of tasks. Each had to try out ten pairings of instruments, playing each for 1 minute; and for each pair, evaluate which one they preferred. In a second test, they were given equal access to all six instruments for 20 minutes, and asked to evaluate which was the best and the worst in five categories: tone colors, playability, response, projection, and which one they'd want to take home and keep for their own.

So what were the results? They were indeed surprising. In the head-to-head comparison, five of the violins were preferred about equally often. But the sixth violin was the lone standout in the data; almost nobody ever preferred it. It was clearly the least favorite, and its identity? It was the 1700 Stradivarius, and was the one with the most illustrious history. Every pairing of violins not involving the 1700 Strad was split 50/50; but whenever the 1700 Strad was in the mix it was rejected 80% of the time. Although none of the participants knew it, each pair had one old and one new violin. All three new violins held their own head-to-head against the old Italian classics.

In the second test, in which participants picked their favorite and least favorite of all six in five categories, the results were equally unexpected. Four of the violins scored about equally, but once again, the 1700 Strad was the clear loser. There was also a clear winner, and it was not an Italian classic. It was one of the new violins, which was selected as the favorite in every category more than any other instrument. Of the three old violins, the Guarneri outscored both Stradivarius. There was no detected bias for musicians to prefer instruments that were similar in age or make to their own.

Seventeen of the twenty one took a shot at guessing the make of their most preferred instrument: Was it old, or new? Seven said they couldn't tell at all, seven guessed wrong, and only three guessed right. In this study, only 14% of professional, expert violinists, who themselves owned instruments worth up to $10,000,000, were able to correctly guess whether the violin they liked best was brand new or 300 years old.

Now this was only one study, and so cannot be considered the final word. But its results were quite clear, and the few similar studies that have been done aren't of comparable quality. What it did show is that whatever special glue, special varnish, or special wood was used in the shop of Antonio Stradivari was probably no better than what any other top luthier has produced over the centuries.

So what is the secret of the Stradivarius? The secret is that there is no secret. It is a high-end instrument, comparable to other high-end makes. The claim that there is any inexplicable superiority is simply not supported by data. If such a difference does exist, it's one that the limited number of high-quality studies has not yet found. There's no doubt that Stradivarius is the biggest name in the history of stringed instruments, and no doubt that they will remain at the top of the auction block for the foreseeable future. Only a small part of their price lies in the quality and the sound of the instrument; what's really valuable is the reputation, historical importance, and prestige. That's something that no amount of CAT scans or chemical analysis can recreate.

By Brian Dunning
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