Bridge importance made simple
The bridge is not solely responsible for problems related to freedom of sound but it should not be overlooked.
I'm talking from experience. I have seen so many violins that have a fundamental problem in delivering a clear sound.
Some violins choke under bow pressure. They sing out under gentle adjusted bow pressure. Why is this?
I could offer mathemtical equations taking into account string length, string diameter, oscillation and brige position
but that might bore you. Best to use your senses. Let's look at some problems instead and see how we can approach a solution.
We have a violin which is full of promise but just can't get the words out loud and clear. In most cases the problem should be visible to any luthier. Every violin presented to me with a similar problem or same problem is established whilst I'm talking with the customer. There is no short cut to arriving at this conclusion, it's experience and a little maths.
Today I saw a young lad kicking a football in several directions.Sometimes free into the sky, other times against the gable end of the house. Let's look at the second scenario. The ball comes back and if not careful hits you in the face.
Both balls have been kicked with equal force. In the latter the ball meets with resistance and comes back in your face.
Hope you are following my reasoning, be it so simple. Lets now apply this scenario to the violin. If you apply force to anything it will go in that direction. Unless it's a lump of concrete stuck to the ground. With the violin we have a string
stretched between two points. It sits there minding it's own business untill we pull a bow across it. The bow friction on the string pulls it from side to side and the string begins to move from side to side. We term this oscillation.The speed at which the string oscillates back and forth is governed by a number of things, length of the string and it's diameter , tension and force applied.
Try stretching an elastic band from here to there and then to the bottom of your garden. The longer the elastic band the deeper the sound when plucked. The shorter distance produces a higher sound/pitch. Amazing!!!
Listen up now becuse this next bit is important. Say you have set up an elastic band or a rope to stretch between two
fixed points and you excite or pluck it to produce a noise. You will get a sound out of it. Not a particularly musical sound but hey we dont want music just yet. If you halved that string or rope you would get a different sound. Might be higher in pitch. Who cares. Now I am going to make a statement about this. When you pluck a string or elastic band fixed between two points you are going to get the best sound ever,no way can you improve it.Not a hope in hell!!
Any length of string has subdivisions, meaning it has a half way mark and that can be halved again and it becomes quarter and so on. I have to go back again, bear with me. The string stretched between two fixed points gives a perfect though dull sound. So what; we dont want music yet. The reason it gives out a dull but full sound is because of the presence of harmonics. The upper harmonics enrich the fundamentals. Best to google harmonics otherwise I'll be here all night.
Cutting my rant short, many violins are badly set up. The upper harmonics are cut off by bridge misplacement and distance from nut to upper edge of the table not to mention incorrect string length for a given size violin. There is no set measurement for this because other factors also play a part. I'm referring to the sound box, length of the back and neck. Another factor is the cutting of the bridge. The bridge is where the sound is input. Will the sound fly back like the ball against the side of the house or will it comfortably transmit. I will deal with this later.
When cutting the the bridge I would say keep the strength and get rid of the rest. Try and make some correspondence between the lower arch of the bridge and belly of the violin. Fit the feet with knife, no sand paper. Open up the, what I call kidneys and reduce the distance between kidney and heart to 3.8mm on the treble side. Try 4.5 on the bass side. Finally, make the hips of the bridge slant down, not horizontal. Below is one of my bridges, One by my teacher and one by Vatelot and one by Machold.
The styles are very much determined by the curvature of the instrument, hence the differences in the lower arch. The Vatelot bridge is very nice. My fourth bridge example is horrendous. My bridge, the first one, looks like it needs refinement in the feet area, a touch of chiropody. The Luff bridge is top heavy. Too much wood above the heart. We all have bad days! The last bridge I cannot deal with beit is so wrong in every aspect.
