A blind listening test at a forestry conference suggests that foresters, at least, prefer a modern violin made from fungus-treated wood to an original Stradivarius (an example of a Strad, played by Janine Jansen on the left).
Last year Francis Schwarze of the Swiss Federal Laboratories for Materials Testing and Research in St Gallen published results suggesting that treating wood with fungus might help recreate the unusually low density that prevailed when Antonio Stradivari carved his legendary instruments. (Nature News, 16 June 2008)
Schwarze teamed up with luthiers (violin-makers) to build violins with the treated wood, along with some control copies made from untreated wood. At a blind competition in the German city of Osnabrück on 1 September this year, 180 attendees of a German forestry conference (Osnabrücker Baumpflegetagen) rated the test violins and an original Stradivarius played by British violinist Matthew Trusler (World Radio Switzerland, 1 September 2009). One of the fungus-treated violins, called "Opus 58" garnered 90 votes for the best sound, with the Strad second at 39, according to a press release.
Blind violin identification is notoriously difficult: In a BBC test in 1974, experts were only able to correctly identify 2 of 4 instruments, and confused a modern instrument with a Stradivarius. Schwarze noted that the fungus treatment might make violins which sound like Strads, at least to foresters, for as little as 25,000 Swiss francs (World Radio Service, 10 September 2009).
For centuries, the perfect tone of a Stradivari violin, such as the one played by Anne Sophie Mutter at the recent Lucerne Festival, fascinated many music lovers. At the last Empa science forum in late August 2006, two scientists and a violin maker took the audience on the lookout for the secret of Antonio Stradivari.
Did the great violin maker use a special primer or varnish, did he treat the woods he used with minerals, or it was a fungus that gave the wood tone its special characteristics? Ever since, violin makers have tried to find the reason behind the differences in tones and paid careful attention to the quality of the wood used. But only ten years ago, scientists have become interested in the resonance properties of spruce fir, which is the most commonly used wood in violin and piano construction.
Wood - a material with many faces
Christoph Buksnowitz of the Agricultural University in Vienna, explained to about 150 participants of the forum, that spruce wood is used in tone instruments since it contributes a lot to the development of sounds and because it was available in large quantities in close proximity to the early factories of musical instruments. Spruce fir used in violin making must have certain physical characteristics. Thus, for example, the diameter of the tree trunk must be at least 40 centimeters in order to allow for the size of boards needed in violin making. Tree rings must be evenly spaced about 5 millimeters apart in order to allow for perfect propagation of sound. Therefore, growth conditions play an important role, Busnowitz noted. Only wood from those spruce trees growing at their typical range and at heights of about 1.000 meters are therefore suitable. Too much light or wind from one side cause Uneven growth and therefore the wood is of lower quality. In order to remove tensions in the wood, the trees must be dried naturally for some years.
All these factors influence the formation and shaping of the most common cells of the spruce fir, the tracheids. When the cell walls of these tracheids become thin then wood density is reduced, and the wood becomes less heavy. Such a result is wished for in the making of violins because it allows for better resonance properties and sound radiation. However, this kind of wood is at the same time also less firm and this may negatively impact the stability of the violin. It appears then that the acoustic of a musical instrument is influenced by the cell structure of the wood. Experienced violin makers recognize the tone quality of the wood by its color. Thus, for example, the yearly formation of growth rings or a fungal decay of a tree will change the color.
One may be tempted to ask therefore, why violins are still made out of so complicated a material with resonant wood and not out of a less variable material such as carbon fibers. Dr. Busnowitz thinks that «a lot of tradition is tied in with the resonance wood of the spruce tree, which is unique and individual in its form and tone features».
Fungi as useful helpers
In the past, it was thought that a fungal decay of a tree brings about damaging effects altogether. Melanie Spycher in PhD work at Empa tried to show that this must not necessarily be the case to the Tonal quality of the wood.
Empa test of spruce wood infected with fungi
She Sterilized infected spruce and maple wood pieces with different kinds of wood decaying fungi and these fungi allowed to grow for periods of from four to twenty weeks in a climatically controlled chamber.
So far, the interim results of this probe are astounding, as Melanie Spycher puts it: 'Different fungi work differently on various woods.
With the split gill fungus, Belonging to the group of the soft rot fungi, we could achieve suitable for violin making changes in the wood structure. »In June of this year, a patent was applied for.
This maple tree had Thicker cell walls before it was infected with fungi. The fungus reduced the cell wall thickness of the wood without impairing its firmness. Thus, the density of the wood was reduced thereby making the violin lighter Tonal and improving its quality. Yet, the necessary firmness of the instrument was maintained.
A Soulless violin
Michael Rhonheimer's profession of violin making could soon be impacted through the ongoing research in the resonance of spruce wood. Even today, Rhonheimer constructs resonant Baden Masterworks in his workshop, using nearly the same tools as were used in the 16th or 17th centuries, such as CHISEL, tuning hammer, saw, plane and the botanic horsetail. Wood alone, however, does not determine the quality of a violin's sound. Other details, such as the Curvature of the upper and lower plates of the violin and the positioning and size of the "F holes" play a role as well. Until in this manner through handicraft and costly new violin finally makes its sounds, one year goes by and the master violin maker has spent at least 300 hours producing the instrument.
Rhonheimer did make it clear that the quality of new violins is comparable to that of old ones. While older musical instruments are valued because of the passage of time and the culture of music, new ones have the advantage in their construction that the artist's wishes can be taken into account. Nevertheless, the master violin maker does not have a high opinion of machine made violins. 'Contact with the material is lost, and thus for example a carbon fiber violin sounds Soulless ». On the other hand, biological modifications in the wood used for violin construction are less Objectionable for the purpose of building future violins again in the manner of Stradivari.
The 'master fungus »discovered by Empa, may soon find its way to the workshops of the violin makers and help construct violins which may compete with the one now played by Anne Sophie Mutter. (EMPA press release 4 September 2009)