section_path: Instrumentation/Expanded instrumentation
section_name: Expanded instrumentation
paragraph_text: Expanded instrumentation
  
  Apart from the core orchestral complement, various other instruments are called for occasionally. These include the flugelhorn and cornet. Saxophones and classical guitars, for example, appear in some 19th- through 21st-century scores. While appearing only as featured solo instruments in some works, for example Maurice Ravel 's orchestration of Modest Mussorgsky 's Pictures at an Exhibition and Sergei Rachmaninoff 's Symphonic Dances, the saxophone is included in other works, such as Ravel's Boléro, Sergei Prokofiev 's Romeo and Juliet Suites 1 and 2, Vaughan Williams ' Symphonies No. 6 and No. 9, and William Walton 's Belshazzar's 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 Holst 's The Planets, and Richard Strauss 's Ein Heldenleben. The Wagner tuba, a modified member of the horn family, appears in Richard Wagner 's cycle Der Ring des Nibelungen and several other works by Strauss, Igor Stravinsky (as featured in The Rite of Spring), Béla Bartók, and others; it also has a notably prominent role in Anton Bruckner 's Symphony No. 7 in E Major. Cornets appear in Pyotr Ilyich Tchaikovsky 's ballet Swan Lake, Claude Debussy 's La Mer, and several orchestral works by Hector Berlioz. Unless these instruments are played by members "doubling" on another instrument (for example, a trombone player changing to euphonium or a bassoon player switching to contrabassoon for a certain passage), orchestras typically hire freelance musicians to augment their regular ensemble.
  
  The 20th century orchestra was far more flexible than its predecessors. In Beethoven's and Felix Mendelssohn 's time, the orchestra was composed of a fairly standard core of instruments, which was very rarely modified by composers. As time progressed, and as the Romantic period saw changes in accepted modification with composers such as Berlioz and Mahler; some composers used multiple harps and sound effect such as the wind machine. During the 20th century, the modern orchestra was generally standardized with the modern instrumentation listed below. Nevertheless, by the mid- to late 20th century, with the development of contemporary classical music, instrumentation could practically be hand-picked by the composer (e.g., to add electric instruments such as electric guitar, electronic instruments such as synthesizers, ondes martenot, or trautonium, as well as other non-Western instruments, or other instruments not traditionally used in orchestras including the: bandoneon, free bass accordion, harmonica, jews harp, mandola and water percussion.
  
  With this history in mind, the orchestra can be analysed in five eras: the Baroque era, the Classical era, early/mid- Romantic music era, late-Romantic era and combined Modern/Postmodern eras. The first is a Baroque orchestra (i.e., J.S. Bach, Handel, Vivaldi), which generally had a smaller number of performers, and in which one or more chord-playing instruments, the basso continuo group (e.g., harpsichord or pipe organ and assorted bass instruments to perform the bassline), played an important role; the second is a typical classical period orchestra (e.g., early Beethoven along with Mozart and Haydn), which used a smaller group of performers than a Romantic music orchestra and a fairly standardized instrumentation; the third is typical of an early/mid-Romantic era (e.g., Schubert, Berlioz, Schumann, Brahms); the fourth is a late-Romantic/early 20th-century orchestra (e.g., Wagner, Mahler, Stravinsky), to the common complement of a 2010-era modern orchestra (e.g., Adams, Barber, Aaron Copland, Glass, Penderecki).