When choosing strings, one of the most obvious questions you’ll be faced with is what material you want the string to be made out of. The reason materials matter is because each will be different in terms of elasticity, stiffness and weight/density, and thus influence how waves travel through the string.
As we mentioned in our first article, the shape, speed and pattern of thesewaves is what differentiates the sound between different strings. And so it makes sense that different materials will influence how those waves move through the string and thus impact the sound we hear.
Unless you’re a historical performer and are buying gut strings, you’re likely considering a synthetic core or a steel core, wound with different kinds of metals such as tungsten, steel, aluminium or silver. The windings can themselves be plated in other metals such as chrome or gold.
Understanding precisely how these different materials might impact the sound is a hugely complicated subject. Something a professional material scientist would be better placed to attempt to explain. But to give you feel for what can change, the introduction of tungsten winding is a good example.
Different metals have varying densities. Tungsten is almost twice as dense as silver, meaning that half as much can be used in order to maintain the same overall string weight and thus tension. Tungsten strings are thus thinner, and thinner strings generally have less stiffness, which from an acoustic point of view means a greater harmonic content. From a playing perspective thinner strings are also easier on your fingers and can have a quicker response from the bow.
Materials and practical considerations
The elasticity of the string refers to how much the tension (and so the pitch) changes when you tighten or loosen your string. Steel core strings are approximately three times more elastic than a synthetic string, which means that steel strings may be slightly more difficult to tune (since the tension responds rapidly to small changes at the peg or fine tuners).
However, steel strings are a bit more stable than synthetic core strings; just a few minutes after putting them on to your instrument for the first time, they’ll settle into their stable pitch, while a synthetic core string might require several hours to settle (and gut strings far longer).
Materials also react in different ways to the environment they are in. Heat and changes in humidity effect steel core strings less compared to synthetic and gut. So keep in mind even the moisture from your hands and fingers, and moving between dressing room and auditorium can have an impact.