An orchestra is a group of musicians playing together under the direction of a conductor. The musicians perform music specially composed for specific instruments in an orchestral performance. They play as soloists, in small groups, and all together, which creates a tremendous sound.
A full-scale orchestra playing a symphony includes at least 90 musicians, while a smaller orchestra playing a chamber piece ranges from 15 to 45. Sections of the orchestra can perform separately—a string orchestra, for example, includes about 60 musicians.
The musicians are arranged into four sections. The strings—such as violins and cellos—sit at the front. The woodwind—such as oboes, clarinets, and bassoons—and brass—such as trumpets and French horns—sit in the middle. Percussion—such as kettledrums and a xylophone—sit at the back.
A conductor’s job is to make sure that the musicians play perfectly together. A conductor keeps time using a baton (stick) to clearly count out each individual beat in the tempo (speed) the music is to be played.
The gamelan orchestras of Bali in Indonesia use a wide range of percussion instruments, such as gongs, chimes, marimbas, and drums, as well as strings and woodwind. They create an amazing rhythm-driven sound totally unlike that achieved by Western symphony orchestras.