Violin typically are lower in pitch than the G-string; these strings are usually tuned to C, F, and B. If the instrument's playing length, or string length from nut to bridge, is equal to that of an ordinary full-scale violin; i.e., a bit less than , then it may be properly termed a violin. Some such instruments are somewhat longer and should be regarded as violas. Violins with five strings or more are typically used in jazz or folk music. Some custom-made instruments have extra strings which are not bowed, but which sound sympathetically, due to the vibrations of the bowed
Viol for the lowest-pitched bass strings on viols, and on many other string instruments as well. Viols are fretted in a manner similar to early guitars or lutes, by means of movable wrapped-around and tied-on gut frets. A low seventh string was supposedly added in France to the bass viol by Monsieur de Sainte-Colombe (c. 1640–1690), whose students included the French gamba virtuoso and composer Marin Marais. Also, the painting (1618) by Domenichino (1581–1641) shows what may be a seven-string viol. Unlike members of the violin family, which are tuned in fifths, viols are usually tuned in fourths with a major