Many other chamber groups can be seen as modifications of the string quartet: The string quintet is a string quartet augmented by a fifth string instrument. Mozart employed two violas in his string quintets, while Schubert's string quintet utilized two cellos. Boccherini wrote a few quintets with a double bass as the fifth instrument. Most of Boccherini's string quintets are for two violins, viola, and two cellos. Another composer who wrote a string quintet with two cellos is Ethel Smyth. The string trio has one violin, a viola, and a cello. The piano trio has a piano, a violin, and a cello. The piano quintet is a string quartet with an added piano. The piano quartet is a string quartet with one of the violins replaced by a piano. The clarinet quintet is a string quartet with an added clarinet, such as those by Mozart and Brahms. The string sextet contains two each of violins, violas, and cellos. Brahms, for example, wrote two string sextets. Further expansions have also produced works such as the String octet by Mendelssohn, consisting of the equivalent of two string quartets. Notably, Schoenberg included a soprano in the last two movements of his second string quartet, composed in 1908. Adding a voice has since been done by Milhaud, Ginastera, Ferneyhough, Davies, İlhan Mimaroğlu and many others. Another variation on the traditional string quartet is the electric string quartet with players performing on electric instruments.
Many other chamber groups can be seen as modifications of the string quartet The string quintet is a string quartet augmented by a fifth string instrument Mozart employed two violas in his string quintets while Schubert's string quintet utilized two cellos Boccherini wrote a few quintets with a double bass as the fifth instrument Most of Boccherini's string quintets are for two violins viola and two cellos Another composer who wrote a string quintet with two cellos is Ethel Smyth The string trio has one violin a viola and a cello The piano trio has a piano a violin and a cello The piano quintet is a string quartet with an added piano The piano quartet is a string quartet with one of the violins replaced by a piano The clarinet quintet is a string quartet with an added clarinet such as those by Mozart and Brahms The string sextet contains two each of violins violas and cellos Brahms for example wrote two string sextets Further expansions have also produced works such as the String octet by Mendelssohn consisting of the equivalent of two string quartets Notably Schoenberg included a soprano in the last two movements of his second string quartet composed in 1908 Adding a voice has since been done by Milhaud Ginastera Ferneyhough Davies İlhan Mimaroğlu and many others Another variation on the traditional string quartet is the electric string quartet with players performing on electric instruments