Questions & Answers

The string quartet is an ensemble made up of four string instruments, two violins and viola and cello. The string quartet is the most prominent chamber music ensembles in classical music and is also seen as the most important form of chamber music. Most major composers, from the late 18th century onwards wrote for string quartets with much of the reperotire still being performed today.

Traditional string quartets usually have four movements with a large-scale structure similar to that of a symphony. The outer movements were typically fast, the inner movements in classical quartet consisting of a slow movement and a dance movement of some sort either a minuet or scherzo. Twentieth century comoposers have slowly abandoned this structure, although substantial modifications to the typical structure were already achieved by Ludwig Van Beethoven in his later quartets.

There are many other forms of chamber groups that can be viewed as modifications of the string quartet, such as the piano quintet (quartet and piano), string quintet (quartet with an extra viola, cello or bass), string trio (violin, viola and cello) and the piano quartet (violin, viola, cello and piano).

The main traditional form for the Classical string quartet was set out by composer Franz Joseph Haydn:

• 1st movement: Sonata Form Allegro, in the tonic key;
• 2nd movement: Slow, in the subdominant key;
• 3rd movement: Minuet and Trio, in the tonic key;
• 4th movement: Sonata-Rondo Form, in the tonic key.

The quartet became popular in the beginning of the Classical period and was used to exploit the varied tonal colors of the instruments. Haydn pioneered the development of the form in the eighteenth century, and since then the string quartet has been considered a true test of the composer's art. Each instrument is equal which demonstrates the importance of operating as a team in order to develop the thematic material. 

The first violinist of a quartet usually plays the melody line in the higher register and the second violin plays lower notes in harmony. The viola fills in the inner harmony whilst the cello takes the bass lines. Depending on the composer and quartet, the significance of the instruments can change. Later composers spread out the melody a little more equally allowing a greater variety of textures and colours to develop in the group. The quartet is one voice and no one instrument is more significant than the other. The four voices of a quartet correspond to the four ranges of a vocal choirs—soprano, alto, tenor and bass. "String quartet" refers not only to an ensemble of four instruments, but is also a type of music composition. 

Some famous composers of quartets include Haydn, Mozart, Schubert, Mendelssohn, Tchaikovsky, Brahms, Dvorak, Debussy, Ravel, Janacek, Bartok, Prokofiev, Shostakovich, Cater, Ligeti, Crumb, Xenakis and Vine. There are many hundreds more to discover!