The development of the orchestra has been a long process that saw its first developments in the 1600s. The Baroque period made extensive use of several small combinations of instruments. Towards the end of the Baroque period, composers started experimenting with using standard ensembles. Starting with the Classical period, string quartets and orchestras became standardized and the development towards the current orchestra rapidly progressed. In the Romantic period, the orchestra expanded and added new instruments. Chamber music and larger full orchestras developed, as composers needed increasingly complex apparatus's to communicate their ideas.
Chamber music can be any group of smaller ensembles that composers use to express their musical ideas. Chamber orchestras generally have a single player per part. Other chamber music groups include woodwind quintets, string orchestras, brass quintets and other groups with only one player per part. These were the most common types of ensembles used in the Baroque and now Modern periods. In the Baroque period, composers used whatever instruments were available and only in special circumstances wrote for specific ensembles. In the Modern period, beginning about 1910, composers began to experiment with increasingly complex ideas. These complex ideas were well suited for simpler, smaller ensembles.
Full orchestras consist of four smaller chamber music groups including woodwinds, strings, brass and percussion. Each group includes several instruments from each ensemble. The woodwinds typically have one piccolo, two flutes, two oboes and two bassoons. In the string section, there are typically sixteen first violins, fourteen second violins, ten violas, ten cellos and eight basses. The brass section has four horns, three trumpets, three trombones and a tuba. Within the percussion section, you'll find a timpani and a bass drum. There are also several smaller percussion instruments such as triangle, bells and a cowbell.
Small chamber music ensembles are enjoyable for intimate settings, short pieces and music performed in a small music hall. These small ensembles are light, can more easily learn complicated music and do not require a conductor. This is one of the reasons many modern composers left orchestras to write for smaller ensembles. Full orchestras are extremely useful for composers with expansive ideas developed over a longer period. With the larger orchestra, composers are able to keep the interest of the music by moving the melody from one instrument to another. This helps to create a variety of timbres not possible with small chamber music.