A classical orchestra is a specific type of instrumental ensemble arranged into sections by the types of instruments played. A certain number of musicians make up the percussion, brass, woodwind, and string sections. These groups also have certain assigned parts in each musical performance as far as providing melodies, harmonies, and various rhythms. The first versions of the basic classical orchestra preceded the larger orchestras of the Romantic era during the nineteenth century. More musicians with a wider variety of instruments later joined each section to accommodate the artistic needs of different composers.
Early incarnations of the classical orchestra consisted of a smaller number of musicians, usually 50 at the very maximum. This type of ensemble is still frequently called a chamber orchestra in order to distinguish it from larger symphony orchestras that can sometimes include more than twice that number of players. A true classical orchestra typically has a narrower range of sound particularly in the brass and percussion sections. Much of the musical focus is on the string and woodwind sections.
The brass section of a classical orchestra often has as many as six musicians, typically two trumpets and four French horns. The keys of each brass instrument can also differ according to the pieces of music to be played. The percussion section of the same ensemble often consists of a timpanist to supply the supporting rhythm sections. Much of the difference between a classical and a large symphony orchestra lies in the numbers of musicians in each of these two sections.
Musical performances of a classical orchestra often rely heavily on the melodies that the stringed instrument players provide. Up to 12 violins are usually in the string section, and they are further divided into first and second violin sections. The first section violins usually play the most intricate and demanding melodies, while the second chair players provide a combination of harmonies and simpler melodies. Smaller groups of violas, cellos, and string basses complete the string section with backing harmony and rhythm parts.
Woodwind sections of classical orchestras are generally made up of eight musicians playing four instruments: oboes, flutes, bassoons, and clarinets. Particularly the flutes and clarinets can share parts of the melodies with the violin section, depending on the demands of the chosen musical compositions. The bassoons and oboes provide further harmony to both the woodwind section and the orchestra as a whole.