Structural strength in a stringed instrument bow
We have spent some time now looking at the structure of a violinist skeleton and their playing position from the point of view of the Dynamics of playing the instrument, which is mostly dictated by the Dynamics of the bowing arm. The bowing arm, the violinist right arm, is the heavy object that gets thrown about mostly from left to right, but also quite violently in the vertical plane. It is the Dynamics of this right arm that is mostly responsible for unbalancing the musician and causing problems with the fingering of the left hand, which we will come to next. Just think of the huge forces that are applied to the bow when playing fast and furious dance music at a wedding ceilidh or birthday barn dance. The musician, an adult man or woman, applying all the force that they can muster through their hand, wrist and arm to the bow to produce the excitement and 'lift' needed to get people jigging and reeling furiously, (especially if they have just eaten a large and luxurious wedding breakfast!). Even when playing classical music for a church wedding or civil wedding ceremony, where one might have thought that everything was more genteel and civilised, the amount of pressure on the violin bow dictates the volume of sound produced. So, obviously, during the wedding recessional, when wedding guests are cheering and clapping, the violin, viola and cello players are having to excert a lot of pressure to make the music penetrate the background noise. Less obviously during the processional, as the bride enters the church during a church wedding ceremony, or descends the grand staircase at a civil wedding venue, the bride and guests may be quite some distance from the string quartet at this point in time, so again, a lot of volume has to be produced.
Going back to the ceilidh dance, the fiddle will be amplified, so you may think that a lot of pressure needn't be applied to the bow, and to an extent this is true, as the PA (amplification) System does a lot of the work, however, without extreme pressure being applied at times, the instrument doesn't produce the musical accents and tonality that is needed to drive people to have a wild and frantic time at the barn dance.
Incidentally, I'm speaking about the violinist using their right arm for bowling and their left arm and hand for the fingering.
You might ask, what about left-handed violinist? Well, left hand violinist normally learn to play a violin the same way round as a right-handed violinist. I have only seen one left hand violinist playing it left handedly, ie the other way round. This caused chaos! He got away with it just about when playing in a string quartet, because there are only four instruments that can space themselves out as they wish, but when playing in an orchestra he was a liability.
The string section in an orchestra sit close together, usually in pairs on a desk , that is per music Stand. All the bows go in the same direction, so there is no clashing of bows. The player's position themselves so they don't poke each other's eyes out with the end of the bow. (You might find this amusing, but it is a serious consideration, and new musicians i.e children learning, soon become very aware of the dangers of playing in an orchestra.) Soimagine 20 violinists sitting in pairs one behind the other, with all their bows going in the same direction except one. Chaos absolute chaos.
Anyway, back to the left hand. The left arm stretches out to support the violin as it sticks out horizontally from the violinist's chin. I said supported, but in reality as I've explained earlier, the hand is not really supporting the violin. The violin is supported by the clamping action of the musicians head on the chin rest and the supporting position on their shoulder. However the hands does provide a limited supporting and stabilisation effect to the instrument which is being bashed this way and that by the action of the bow, which can sometimes be extremely violent.
Look at a soloist playing the final movement of a violin concerto, or the leader of the String Quartet playing the fast movement off a Quartet by a romantic composer, playing with passion and energy. The violinist is sometimes putting all the force that they can onto the instrument. Even with an engineering background, I'm often quite amazed at the strength of the violin bow, the strings and the violin itself, which appears to be just a weak and flimsy wooden object. In fact things are not quite as straightforward as they seem.
The violin bow is just a thin wooden stick, but it's not just any old wood. Violin bows are generally made of pernambuco, a wood from an amazonian tree. Not only is it remarkably strong, but it is flexible. You might think that you could use a wood like oak, which is also extremely strong, but it doesn't have the flexibility of pernambuco. It is such specialised, valuable and rare wood, that I understand that it is strictly regulated in South America, where it is produced. The companies that harvest and prepare the word evidently restrict is distribution and sale, probably for the purpose of keeping the Price High, but I understand also to ensure long-term supplies of this very rare and important material. Possibly because of the rarity of good quality pernambuco, but possibly also for performance and fashion, there are companies who make violin bows out of carbon fibre composites. Bowes combine the kind of properties of Carbon Fibre composites that are used in high quality fishing rods, the flexibility with strength, together with the structural properties associated with the use of carbon fibre composites in the aircraft industry, where strength and long-term reliability and integrity are important. I've tried these bows, though I don't have one myself, and they certainly are very good. You can get the bow made in a range of stiffnesses and weight to suit your style of playing, so there is a lot of controllability in the final product provided the manufacturing process is strictly controlled. I'm told that there's a YouTube advert for one of the manufacturer's bows, where a bow is dropped on the floor and a car runs over it, then the violinist picks up the run over bow and continues to play. I've never seen that advert myself, but it sounds as if it's a dramatic demonstration. I suppose that in a viola player joke of a string quartet, it would be something like; a String Quartet being run over by a lorry, but the violinists and the cellist escape, but the viola player gets run over. The remaining members of the quartet pick up their bows and continuing playing celebrating the fact that the viola player is no longer with them. A bit mercarb, but mild compared with some viola jokes. For those who are uninitiated, the viola player in the string quartet is traditionally the butt of many jokes.
Then we come to the strings. Traditionally violin strings were made of catgut. You can still buy gut strings and they are used on baroque instruments to give the very special tone, what I consider to be a slightly acidic sound of the baroque instruments, though gut strings on a more modern violin give a very soft and gentle tone. Although catgut is a remarkably strong natural material, isn't not nearly as strong as modern strings which can be made from synthetic fibre or all steel cores. I have read that some very expensive violin strings are made with cores constructed from spider silk. Spider silk as you will doubtlessly know, is stronger than even the most advanced synthetic fibres such as Kevlar and carbon fibre.
I've no idea what synthetic material is used in the core of modern violin strings, because Kevlar which is the strongest is also relatively elastic, and carbon fibre which is almost as strong has very little elasticity, so probably would not resonate well. Indeed carbon fibre is so inelastic as a fibre that it nearly caused the collapse of the Rolls-Royce aero engine company some years ago, when they constructed the turbine fan blades of their fan jet engines out of carbon fibre composites. Although extremely strong and light, they could not absorb impact in the way that a titanium or steel blade could do. In the event of a bird strike, the conventional metal blade would bend and distort absorbing the energy of the impact. However the carbon fibre blade, though it could survive small impacts better than metal blade, if it reached a certain loading on the blades would shatter, resulting in a much more dangerous catastrophic failure accured with a distorted metal blade.
So modern day strings are extremely strong and can withstand the hammering given to them by the violinist. However, violent playing does take its toll on strings. Players in a classical string quartets change their strings very regularly, that is if they are a high quality quartet who really give their instruments some welly. Amateur player’s strings can last for years on one set simply because they are being gentle with their playing and never give it the force that a good string quartet player will produce.
Similarly, the fiddle player of a Ceilidh Band may get through their strings rather quickly. Barn dance fiddle players will sometimes use steel strings that can survive the abuse they are given, but these have the disadvantage of sounding rather harsh, which might be good for some styles a barn dance playing, but not for other styles. Modern day barn dance bands and ceilidh band use amplification on their instruments, so the fiddle player doesn't have to produce volume as such in the same way as the string players in a String Quartet have to. When playing in a string quartet, in order to get the sound volume and energy on the accents that make the music come alive, the fiddle player does have to give their insurance a lot of well.