An African violin? New study tests which native woods could make o…
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Tonewoods are wood species that possess certain desirable similarities that make them appropriate for making musical instruments, such as woodwind or string instruments — like a flute or a violin. Any good tonewood should be radially cut, which method the lines formed by the year-rings are perfectly similar on the surface. It must have an already-grain structure, be defect free and not spread or expand noticeably with environmental changes.
The world’s violins are mostly made of spruce and maple tonewood, trees grown in the northern hemisphere. But what if native African woods from the southern hemisphere were used to create an African violin? We set about testing the continent’s native woods and found four wood species could not just work, but work well. Then we produced two complete violins from them to test their sound.
What’s the right wood for a violin?
Soundboards are part of the body of the violin. They are made of woods that must resonate by amplifying the oscillation — the vibration — of string instruments. They should be lightweight but stiff enough to resist the tension of the strings and must propagate sound well in the direction of the wood’s grain. If the wood’s density is not already throughout then the soundwaves could become distributed. This should make (sub)tropical wood species good candidates for soundboards because the without of distinct growth seasons results in wood with barely visible year rings and few density variations.
However, high-quality violins are made of the same wood species worldwide: spruce as the soundboard (top plate) and maple as the frameboard (back). While guitar makers seem to be more adventurous in using different wood species, violin makers tend to use only these traditional wood species. Good quality wood is typically from colder regions, like Canada or the European Alps, where the trees grow more slowly, which results in a uniform wood structure with fewer density fluctuations.
The soundboard on the front of the violin needs to transmit sound well, while the frameboard on the back should have a high, elastic modulus to give sustain to the soundboard, while nevertheless radiating sound well. Both parts should have a fairly low density to avoid unnecessary weight, which would make playing the instrument uncomfortable.
Based on all these requirements, our research team characterised several wood species from southern Africa to clarify possible alternatives for violin making. We ultimately decided that Yellowwood (Podocarpus latifolius) and Knysna Blackwood (Acacia melanoxylon – which is strictly speaking not native, but has been established in the natural forests of the south western part of South Africa since the early 1900s) would be appropriate as soundboards. native to West Africa, Sapele (Entandrophragma cylindricum) and Hardpear (Olinia ventosa) from South Africa were most appropriate as frameboards.
Testing the African violin
Hannes Jacobs is a specialized luthier from Pretoria, South Africa. A luthier is someone who builds string instruments. He agreed to make a complete-sized violin from Yellowwood and Sapele. We wanted to ensure that the quality of the instrument would be comparable to good-quality commercial instruments.
The sound quality of this instrument, named the “African violin,” was then compared to a violin made from traditional wood species by the same luthier, with the same methodology. Both instruments were played by the same player with the same bow.
The sound quality of the two violins was determined by recording audio frequency spectra — ranges — of various single notes to analyse the discernible overtones. This is a musical tone which is a part of the harmonic series above a basic observe. A good sound quality generally consists of many harmonics at higher frequencies.
Listen to the African wood violins here.
The African violin was played by various musicians on separate occasions, and all agreed that its sound is quite different from that of most other violins. The general assessment was that it has a very complete, powerful sound with a strong lower register that projects well by the room.
The resonance frequencies of the African violin are visibly different from those of the traditional violin. It has stronger harmonics in the low-frequency range, which consequence in a complete sound that carries well. It also shows more overtones at higher frequencies. For frequencies above 3 kHz, the African violin shows clearly higher amplitudes, which gives it a slightly harsh sound, while the lower amplitudes of the traditional violin consequence in a softer sound. The African violin may probably be better suited for modern, or jazz music.
The physical similarities of the wood used for the African violin suggested that it may radiate sound less well in the high frequency range than spruce wood. Contrary to this expectation, the African violin shows larger resonance peaks at high frequencies than does the traditional violin. Resonance peaks are at the frequencies where the soundboard oscillates most and they compose the musical notes you hear. The more resonance frequencies are audible, the fuller the sound.
To sum up
The results of our study show that African wood species are clearly appropriate to be used as tonewoods in violins. They are able to produce an instrument with a beautiful, though slightly different sound.
The African violin has a considerably stronger sound in the lower frequencies that carries very well by the room. It also showed more harmonics with higher amplitudes in the high frequencies, which gives it a harsher sound than the traditional violin. Yellowwood and Sapele can be used to make string instruments with a sonorous, strong sound.
Martina Meincken is anssociate professor at Stellenbosch University. This article is republished from The Conversation, a nonprofit news organization dedicated to sharing ideas from academic experts, under a Creative Commons license.
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