STRING TYPES AND DIAMETERS

Before considering diameters and working tensions, we should give a moment's thought to the following question: why is it that so few manuals of the nineteenth and early twentieth centuries give dimensions for guitar strings, as they do for strings for the violin and other bowed string instruments (with the single exception of Pujol, which occurs well into the twentieth century)? The mystery is solved with the help of a number of documents of the time, in which we read that the first strings of the nineteenth-century guitar were identical to the first three strings of the contemporary violin, an instrument about which we know a great deal in relation to strings. The guitarists of the time probably regarded this as common knowledge, and therefore felt that it was unnecessary to discuss it in their manuals. To answer our questions fully, at least with regard to the first three gut strings, we must turn our attention to the violin, taking into consideration not only the manuals but also the information that has come down to us from the string makers of the time, principally in relation to the number of guts required for each string. It should be pointed out, however, that this number in fact determines not a precise final diameter but rather a fluctuation around an average diameter, in that guts, being a natural material, will always differ slightly in thickness (at the time, moreover, there was no mechanical means of correcting strings, the only way of ensuring a precise calibre). It is known that the first string of the violin was made from three lamb guts, which produced a diameter of between 0.65 and 0.73 mm. For the second and third strings five and nine guts respectively were used, producing a diameter range of 0.80-0.90 mm for the A string and of 1.04-1.20 for the D string. These were also the E, B and G strings of the guitar of the time of Sor, Giuliani and Coste. There were two main types of guitar string available from the beginning of the nineteenth century to the middle of the twentieth: oiled natural gut for the upper three strings and overspun silk for the three bass strings. It should be emphasised that the acoustic output of strings made of overspun silk is generally greater than that of the strings with a gut core that were used in the eighteenth century for five-course guitars and for bowed string instruments in general. After the addition of the sixth string and the elimination of courses in favour of single strings, and up to the 'enlarged' guitars of Torres (the second half of the nineteenth century), the vibrating length was stabilised at about 62-63 cm, as shown by the manual of Aguado: 27 pulgadas, i.e. around 62 cm (.9132 of an inch, see J.H. Alexandre 'Universal Dictionary of Weights and Measures Ancient and Modern', New York 1867 p. 90) and as seen in the many surviving instruments of the period, whether made in Italy or abroad.