String quintet
A string quartet with an additional viola or cello.
What it means
A string quintet is a work for five string instruments. Two scorings are common: the quartet with a second viola, and the quartet with a second cello. More rarely a double bass is added. The choice is no side issue — it decides whether the sound becomes fuller in the middle register or whether the foundation is reinforced, and composers make it deliberately.
Musical use
With the second viola, the texture gains a dense, warm middle register; the upper voice can unfold freely above it, and inner voices can be led more richly. With a second cello, the weight shifts downward: one cello can work as the bass while the other emerges melodically, so that tenor lines become possible. In both cases the fifth voice allows the section to be divided and two tonal groups to be set against each other. Mozart wrote six string quintets with two violas (K. 174, 406, 515, 516, 593, 614), as did Brahms two (op. 88 and op. 111); Boccherini composed over a hundred quintets, mostly with two cellos, and Schubert's C major Quintet D 956 also calls for two cellos. Dvořák's Quintet op. 77 uses a double bass. The string quintet is not to be confused with the piano quintet, in which a piano joins a quartet.
Performance practice
Clarify the distribution of roles first, especially with two instruments of the same kind: who leads at which point, who supports. Match articulation, vibrato, and tone colour of the two voices of the same kind to each other, otherwise the texture falls apart. Watch the balance, because the reinforced middle or bass register easily makes the sound dense. Rehearse in subgroups, for instance the quartet without the fifth voice and vice versa. Sit so that everyone hears and sees one another.
The two common scorings pose different tasks: with two violas the difficulty lies in the clarity of the dense middle register, with two cellos in clarifying which instrument carries the bass and which the melody. Clarify this for every section and check which scoring the score calls for, because editions occasionally offer arrangements for the respective other form.