section_path: Instrumentation
section_name: Instrumentation
paragraph_text: Instrumentation
  
  The typical symphony orchestra consists of four groups of related musical instruments called the woodwinds, brass, percussion, and strings. Other instruments such as the piano, accordion, and celesta may sometimes be grouped into a fifth section such as a keyboard section or may stand alone, as may the concert harp and electric and electronic instruments. The orchestra, depending on the size, contains almost all of the standard instruments in each group.
  
  In the history of the orchestra, its instrumentation has been expanded over time, often agreed to have been standardized by the classical period and Ludwig van Beethoven 's influence on the classical model. In the 20th and 21st century, new repertory demands expanded the instrumentation of the orchestra, resulting in a flexible use of the classical-model instruments and newly developed electric and electronic instruments in various combinations. In the mid 20th century, several attempts were made in Germany and the United States to confine the instrumentation of the symphonic orchestra exclusively to groups of one instrument. In this configuration, the symphonic orchestra consisted entirely of free-reed chromatic accordions which were modified to recreate the full range of orchestral sounds and timbres during the performance of orthodox Western classical music.
  
  The terms symphony orchestra and philharmonic orchestra may be used to distinguish different ensembles from the same locality, such as the London Symphony Orchestra and the London Philharmonic Orchestra. A symphony or philharmonic orchestra will usually have over eighty musicians on its roster, in some cases over a hundred, but the actual number of musicians employed in a particular performance may vary according to the work being played and the size of the venue.
  
  A chamber orchestra is usually a smaller ensemble; a major chamber orchestra might employ as many as fifty musicians, but some are much smaller. Concert orchestra is an alternative term, as in the BBC Concert Orchestra and the RTÉ Concert Orchestra.