Guitar strings - Core materials

Core materials

Steel forms the core of most metal strings. Certain keyboard instruments (e.g., harpsichord) and the Gaelic harp use brass. Other natural materials, such as silk or gut?or synthetics such as nylon and kevlar are also used for string cores. (Steel used for strings, called music wire, is hardened and tempered.) Some violin E strings are gold-plated to improve tone quality.

Steel

Steel or metal strings have become the foundation of strings for the electric guitar and bass. They have a nice, bright tone when compared to nylon string guitars. Their metal composition varies greatly, sometimes using many different alloys as plating. Much of the history about metal strings evolved through innovations with the piano. In fact, the first wound metal strings ever used were used in a piano. However, when it came to getting super small diameter strings with good elastic properties, the electric guitar took the metal string to the next level adapting it for the use of pickups.

Because of the higher tension required for steel strings, steel strung guitars are much more robustly made than 'classical' guitars which use synthetic strings. Most jazz and folk string players prefer steel-core strings for their faster response, low cost, and tuning stability.

Nylon

Nylon string, traditionally used for classical music, has a more mellow tone and the responsiveness of it can be enjoyed typically for folk but other styles of music use it as well (Willie Nelson performs on a nylon string guitar). Note that nylon strings don't work with magnetic pickups, which require ferrous strings that can interact with the magnetic field of the pickups to produce a signal. Nylon strings are made of a softer, less dense material and are under less tension than steel strings (about 50% less). This means they can be used on older guitars that can't support the tension of modern steel strings.

Currently, stranded nylon is one of the most popular materials for the cores of violin, viola, cello, and double bass strings. It's often sold under the trade name of Perlon. Nylon guitar strings were first developed by Albert Augustine Strings in 1947.

Gut

The intestine, or gut, of sheep, cattle, and other animals (sometimes called catgut, though cats were never used as a source for this material) is one of the first materials used to make musical strings. In fact, the Ancient Greek word for string, "khord?," has "gut" as its original meaning.

Animal intestines are composed largely of elastomers, making them very flexible. But they are also extremely hygroscopic, which makes them susceptible to pitch fluctuation as a result of changing humidity. Exposure to moisture from the sweat of a musician's hands can cause plain (unwound) gut strings to fray and eventually break. This is not as much of a problem with wound gut strings, in which the gut core, being protected from contact with perspiration by the metal winding (and underlayer, if there is one), lasts a much longer time. Nonetheless, as such a gut string ages and continually responds to cyclic changes in temperature and humidity, the core becomes weak and brittle, and eventually breaks. Furthermore, all gut strings are vulnerable to going out of tune due to changes in atmospheric humidity.

However, even after the introduction of metal and synthetic core materials, many musicians still prefer to use gut strings, believing that they provide a superior tone. Players associated with the period performance movement use wound and unwound gut strings as part of an effort to recreate the sound of music of the Classical, Baroque, and Renaissance periods, as listeners would have heard it at the time of composition.

For players of plucked instruments, Nylgut strings are a recently developed alternative to gut strings. They are made from a specialty nylon and purport to offer the same acoustic properties as gut strings without the tuning problems.

Silk

Silk was extensively used in China for traditional Chinese musical instruments until replaced by metal-nylon strings in the 1950s. Only purely silk strings used for the guqin are still produced, while some silver-wound silk strings are still available for classical guitars and ukuleles. The quality in ancient times was high enough that one brand was praised as 'ice strings' for their smoothness and translucent appearance.