The short, simple answer to ‘what instruments make up an orchestra?’ is: ‘Whichever instruments a composer wants to play the piece he or she has written’. However, there are a few basic trends.
In the late-Baroque and early Classical periods (from, roughly 1700-1800), orchestras tended to be of a comparatively small size – no more than 30-or-so players – and would consist of a basic core of stringed instruments, wind instruments, brass and timpani.
Over the course of the 18th century, the harpsichord accompaniment that was a feature of Baroque orchestras disappeared from the scene, while the clarinet, a new invention, increasingly became a part of it. By 1800, when Beethoven embarked on his symphonic journey, the standard symphony orchestra could be expected to consist of two sections of violins, violas, cellos, double basses, flutes, oboes, clarinets, bassoons, trumpets, French horns and timpani.
The orchestra really started to grow in size and variety from around the 1830s, when Berlioz, and then later Liszt and Wagner, wanted to increase its scope to meet their grand ideas. Brass sections welcomed heavyweight new additions such as trombones and tubas, instruments such as piccolos, cor anglais, contrabassoons and harps added different colours, and all sections of the orchestra increased in size in general.
This expansion continued in the early 20th century under the likes of Mahler and Richard Strauss, who added an elaborate array of percussion into the mix. By now, it was not uncommon to see up to and even above 100 players trooping onto the stage at the beginning of a concert.
Since then, it has been a case of anything goes. Though the core of the orchestra remains roughly the same today as it was in Beethoven’s time, there are no hard and fast rules, and all manner of other instruments – pianos, saxophones, pipe organs – regularly feature too. It’s all down to the composer…
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