String instrument
In musical instrument classification, string instruments or chordophones, are musical instruments that produce sound from vibrating strings when a performer plays or sounds the strings in some manner.
Musicians play some string instruments, like guitars, by plucking the strings with their fingers or a plectrum (pick), and others by hitting the strings with a light wooden hammer or by rubbing the strings with a bow, like violins. In some keyboard instruments, such as the harpsichord, the musician presses a key that plucks the string. Other musical instruments generate sound by striking the string.
With bowed instruments, the player pulls a rosined horsehair bow across the strings, causing them to vibrate. With a hurdy-gurdy, the musician cranks a wheel whose rosined edge touches the strings.
Bowed instruments include the string section instruments of the orchestra in Western classical music (violin, viola, cello and double bass) and a number of other instruments (e.g., viols and gambas used in early music from the Baroque music era and fiddles used in many types of folk music). All of the bowed string instruments can also be plucked with the fingers, a technique called "pizzicato". A wide variety of techniques are used to sound notes on the electric guitar, including plucking with the fingernails or a plectrum, strumming and even "tapping" on the fingerboard and using feedback from a loud, distorted guitar amplifier to produce a sustained sound.
Some string instruments are mainly plucked, such as the harp and the electric bass. Other examples include the sitar, rebab, banjo, mandolin, ukulele, and bouzouki.
In the Hornbostel–Sachs scheme of musical instrument classification, used in organology, string instruments are called chordophones. According to Sachs,[1]
In most string instruments, the vibrations are transmitted to the body of the instrument, which often incorporates some sort of hollow or enclosed area. The body of the instrument also vibrates, along with the air inside it. The vibration of the body of the instrument and the enclosed hollow or chamber make the vibration of the string more audible to the performer and audience. The body of most string instruments is hollow, in order to have better sound projection. Some, however—such as electric guitar and other instruments that rely on electronic amplification—may have a solid wood body.
In musicology, string instruments are known as chordophones. It is one of the five main divisions of instruments in the Hornbostel–Sachs scheme of musical instrument classification.
Hornbostel–Sachs divides chordophones into two main groups: instruments without a resonator as an integral part of the instrument (which have the classification number 31, also known as 'simple'); and instruments with such a resonator (which have the classification number 32, also known as 'composite'). Most western instruments fall into the second group, but the piano and harpsichord fall into the first. Hornbostel and Sachs' criterion for determining which sub-group an instrument falls into is that if the resonator can be removed without destroying the instrument, then it is classified as 31. The idea that the piano's casing, which acts as a resonator, could be removed without destroying the instrument, may seem odd, but if the action and strings of the piano were taken out of its box, it could still be played. This is not true of the violin, because the string passes over a bridge located on the resonator box, so removing the resonator would mean the strings had no tension.
Curt Sachs also broke chordophones into four basic subcategories, "zithers, lutes, lyres and harps."[2]
String length or scale length[edit]
The length of the string from nut to bridge on bowed or plucked instruments ultimately determines the distance between different notes on the instrument. For example, a double bass with its low range needs a scale length of around 42 inches (110 cm), whilst a violin scale is only about 13 inches (33 cm). On the shorter scale of the violin, the left hand may easily reach a range of slightly more than two octaves without shifting position, while on the bass' longer scale, a single octave or a ninth is reachable in lower positions.
The string instruments usually used in the orchestra,[25] and often called the "symphonic strings" or string section are:[26]
When orchestral instrumentation specifies "strings", it often means this combination of string parts. Orchestral works rarely omit any of these string parts, but often include additional string instruments, especially the concert harp and piano. In the Baroque orchestra from the 1600s–1750 (or with modern groups playing early music) harpsichord is almost always used to play the basso continuo part (the written-out bass line and improvised chords), and often a theorbo or lute or a pipe organ. In some classical music, such as the string quartet, the double bass is not typically used; the cello plays the bass role in this literature.