The term orchestra derives from the Greek ὀρχήστρα, the name for the area in front of a stage in ancient Greek theatre reserved for the Greek chorus. A full-size orchestra may sometimes be called an orchestra or philharmonic orchestra. The actual number of employed in a given performance may vary from seventy to over one hundred musicians, depending on the work being played. The term chamber orchestra usually refers to smaller-sized ensembles of about fifty musicians or fewer, the typical orchestra grew in size throughout the 18th and 19th centuries, reaching a peak with the large orchestras called for in the works of Richard Wagner, and later, Gustav Mahler. Orchestras are usually led by a conductor who directs the performance with movements of the hands and arms, the conductor unifies the orchestra, sets the tempo and shapes the sound of the ensemble. The first violin, commonly called the concertmaster, also plays an important role in leading the musicians, the typical symphony orchestra consists of four groups of related musical instruments called the woodwinds, brass, percussion, and strings. The orchestra, depending on the size, contains almost all of the instruments in each group. Chamber orchestra usually refers to smaller-sized ensembles, a chamber orchestra might employ as many as fifty musicians. The term concert orchestra may also be used, as in the BBC Concert Orchestra, the so-called standard complement of doubled winds and brass in the orchestra from the first half of the 19th century is generally attributed to the forces called for by Beethoven. The composers instrumentation almost always included paired flutes, oboes, clarinets, bassoons, horns, the exceptions to this are his Symphony No. 4, Violin Concerto, and Piano Concerto No,4, which each specify a single flute. Beethoven carefully calculated the expansion of this particular timbral palette in Symphonies 3,5,6, the third horn in the Eroica Symphony arrives to provide not only some harmonic flexibility, but also the effect of choral brass in the Trio movement. Piccolo, contrabassoon, and trombones add to the finale of his Symphony No.5. A piccolo and a pair of trombones help deliver the effect of storm and sunshine in the Sixth, for several decades after his death, symphonic instrumentation was faithful to Beethovens well-established model, with few exceptions. Apart from the core orchestral complement, various instruments are called for occasionally. These include the guitar, heckelphone, flugelhorn, cornet, harpsichord. Saxophones, for example, appear in some 19th- through 21st-century scores.6 and 9 and William Waltons Belshazzars Feast, and many other works as a member of the orchestral ensemble. The euphonium is featured in a few late Romantic and 20th-century works, usually playing parts marked tenor tuba, including Gustav Holsts The Planets, cornets appear in Pyotr Ilyich Tchaikovskys ballet Swan Lake, Claude Debussys La Mer, and several orchestral works by Hector Berlioz
The Jalisco Philharmonic Orchestra.
A modern orchestra concert hall: Philharmony in Szczecin, Poland