THE BRIDGE AND ITS AFFECT ON SOUND

 

A bridge, like the instrument itself, is a delicate balance between wood and air.   If there is too much wood in either then the instrument sounds solid and dull - if the instrument is thin or the bridge insubstantial then there is not enough wood to focus the sound, which could then be weak or hollow in character.

The first known description of the effect of the bridge on sound is by Leopold Mozart, father of the more famous Wolfgang, who wrote in 1755,  "The bridge also affects the tone greatly.   For instance, if the tone be too shrill or penetrating or, so to speak, piercing and therefore unpleasant, it can be softened by using a low, broad, and rather thick bridge which has been but very slightly cut away underneath.   If the tone too weak, soft, and muffled - then one should use a thin bridge, not too broad, and as high as circumstances permit, greatly carved away both underneath and in the centre.   Such a bridge must above all be of very fine-grained, well seasoned wood, with well closed pores."

This gives a good indication of the tonal variations possible from different types of instrumental set up.   However, there is obviously a limit to how far one can raise or lower a bridge.   The height of the bridge is largely determined by the angle of the neck and it is best to reset a neck that is much higher or lower than the ideal elevation of 27 - 27.5mm.   The elevation, a crucial measurement on the violin, is the height measured at the bridge position to a straight edge laid along the top of the fingerboard.

The bridge on a violin is made of a particularly dense form of maple cut to accurately fit the front of the instrument and shaped at the top to complement the curve of the fingerboard.   Its job is to transmit the vibration from the strings to the sounding board of the violin and to raise the strings enough to allow the player to "drive" the strings with some force without them rattling.   Its role is therefore crucial both tonally and technically, and Leopold rightly stresses the need to have a bridge made from good quality strong wood.

 

The higher the bridge, the greater the tension the strings bring to bear on the bridge and belly - this can give increased power and focus but often at the expense of warmth and breadth of sound.   A low bridge diminishes the tension and can give a quieter, woody sound - perhaps at the expense of clarity.  To a certain extent it is all just personal - one person's focused is another person's edgy, one's mellow is another's muffled, one's bright is another's harsh, one's soft is another's dull and ultimately there is no right or wrong.   There is only whatever works for the player on their particular instrument.