Classical guitar strings
The three treble guitar strings are made from sheep or cow intestine, referred to as plain gut, while the three bass strings are made of a silk thread core wound with gut.
Since the development of nylon guitar strings by Albert Augustine Ltd., the three treble strings are one piece plastic line, usually nylon filament, while the three bass strings are made of a core of fine plastic threads wound with bronze wire or silver plated copper wire.
Vibrating strings are the features of the guitar that allow it to produce the specific sounds required to create music. In order to understand music and how guitars produce it, it is helpful to understand the physics of sound. Sound is created when the vibration of material bodies causes energy to propagate in pressure waves through a medium, usually air. All forms of musical instruments create vibrations in order to produce the sound waves that make music. Guitars are a type of musical instrument called string instruments, meaning that they create their sound through the vibrations of a string. Vibrating strings on a guitar are fixed at both ends and are elastic. When a guitar string is either strummed or plucked, vibrations in the form of waves travel in both directions along the string and are reflected back at each fixed end. These waves do not cancel each other out as they reflect back upon themselves, but instead form a standing wave where crests and troughs remain at fixed positions while the displacement of the envelope of the wave as a whole increases and decreases.
The guitar strings act in such a way that they can satisfy the relationship between wavelength and frequency, represented by the equation v = fλ . This equation can be rearranged to f = v/λ, meaning that the frequency of a wave (f) is dependent on both the velocity of the wave (v), and the length of the wave (λ). As well, the velocity of the wave traveling on the guitar string depends on the tension of the string (T) and the linear mass density of the string (µ), in fact, “the root frequency for a string is proportional to the square root of the tension, inversely proportional to its length, and inversely proportional to the square root of its linear mass density” . This means that waves will travel faster when the tension of the string is higher and in turn means that the frequency will be higher as the tension is increased (f = v/λ, the v is increasing).
This also means that waves will travel slower on a more massive string, since if the mass is increased, the v will decrease. This relationship between the speed, tension, and mass density can be arranged into a new equation, v = sqrt(T/µ).
When a standing wave vibrates its physical components, the incident and reflected waves, interfere with each other. When this interaction occurs the medium appears to vibrate in segments separated by nodal points and it is not visually apparent that the whole wave is traveling. Since a guitar string has two fixed ends it will behave as a standing wave when either plucked or strummed. The longest wavelength that a string can produce is twice the length of the string.
Mass density is the only other factor that can be significantly and easily changed, a fact easily verified by noting the different thicknesses of guitar strings. Nevertheless guitars are constructed so that the tension of the strings, as well as their mass, are increased together. As a result, strings are made so that the higher the required frequency, the less mass the string will have, as higher frequencies require a higher tension. The less mass they have the less tension is needed to achieve the same frequency. It follows that the lower the required frequency, the higher the mass of the string, since a lower tension produces lower frequencies. The greater the mass of a string, the more tension is required. In standard tuning the strings on the guitar are a perfect fourth apart in pitch (except between G and B), therefore the change in mass required such that the tension remains constant can be calculated.
Up until the Second World War animal gut and silk were the materials from which guitar strings were manufactured. Albert Augustine, an instrument maker from New York, USA, was the first to produce guitar strings in Nylon. According to Rose Augustine, his wife, he was unable to secure source materials due to the war restrictions and happened upon nylon line in an army surplus store in Greenwich Village. When initially approached by him the DuPont company, who manufactured the material, were unconvinced that guitarists would accept nylon's sonic characteristics. Augustine staged a blind test with company representatives from DuPont, they happened to choose nylon over gut as having the best "guitar sound". The DuPont company then supported Augustine's initiative. Augustine classical guitar strings were first commercially manufactured in 1948, in conjunction with Olinto Mari, President of E.& O. Mari/La Bella Strings at their factory in Long Island City New York. When Andrés Segovia, the great Spanish guitar virtuoso, discovered Augustine's strings he was an immediate convert.
Fluorocarbon polymers have recently become an alternative to nylon treble strings. The sound is preferred by some luthiers and players, especially for the smooth transition provided by the G string from treble to bass.
- Palmer, Tony (1982). Juliain Bream: A Life on the Road. Macdonald & Co. ISBN 0-356-07880-9.
- General remarks on strings for the classical guitar, Sebastian Stenzel
List of classical guitar strings makers
- Aquila USA
- Black Diamond
- C.F. Martin
- Conde Hermanos
- Dean Markley
- DR Strings
- Ernie Ball
- Galli Strings, Since 1890, Italy
- Hannabach, Since 1869, Germany
- Hermann Hauser
- John Pearse
- José Ramírez
- Ken Smith
- La Bella Since 1640 (Salle, Italy)
- Royal Classics
- Savarez (France)
- S I T Strings
- Wyres Strings (Canada)
-  Tilman Hoppstock - 2006 Interview with lacg (Los Angeles Classical Guitar)
- How to Select the Best Classical Guitar Strings by Tom Prisloe
- The Guitar String Jungle. Are You Judging A Book By The Cover? Article about how guitar strings are marketed, written by Professor String
- ProfessorString.com Guitar string research
- Changing Classical Guitar Strings By Peter Kun Frary, Professor of Music • University of Hawaii, Leeward
- Restring Your Guitar By Frank Ford.
- Safety First! when re-stringing your guitar
-  A quick look at the composition of Strings, Frank Ford, 5/18/00.