An orchestra is a large group of musicians that plays music typical of classical music. It includes instruments from different families. There are usually four main groups of instruments:
Other instruments, such as the piano, harpsichord, pipe organ, free-bass accordion, and celesta, may sometimes be part of a fifth group or play alone as solo instruments. The concert harp, electronic instruments, and guitars may also be used in some performances.
A full-size Western orchestra is sometimes called a symphony orchestra or philharmonic orchestra. These names come from Greek words meaning "loving" and "harmony." The number of musicians in an orchestra can vary from about 70 to over 100, depending on the music being played and the size of the performance space. A chamber orchestra is a smaller group, usually with no more than about 50 musicians. Orchestras that play music from the Baroque period, like that of Johann Sebastian Bach or George Frideric Handel, or Classical music, like that of Haydn or Mozart, are usually smaller than orchestras that perform Romantic music, such as the works of Ludwig van Beethoven or Johannes Brahms. Over time, orchestras grew larger during the 18th and 19th centuries, reaching their largest size in the works of composers like Richard Wagner and Gustav Mahler, who sometimes used as many as 120 musicians.
An orchestra is usually led by a conductor, who uses hand and arm movements to guide the performance. A conductor often uses a short wooden stick called a baton to help musicians see the movements more clearly. The conductor unites the orchestra, sets the speed of the music, and shapes how the music sounds. Before a public performance, the conductor leads rehearsals and gives musicians instructions on how to play the music.
The leader of the first violin group, called the concertmaster, also plays an important role in leading the musicians. In the Baroque music era (1600–1750), orchestras were often led by the concertmaster or by a musician who played the basso continuo parts on a harpsichord or pipe organ. Some modern ensembles still follow this tradition.
Orchestras perform many types of music, including symphonies, opera and ballet overtures, concertos for solo instruments, and pit ensembles for operas, ballets, and some types of musical theatre, such as Gilbert and Sullivan operettas.
Amateur orchestras include youth orchestras made up of students from elementary schools, high schools, or universities, and community orchestras, which are usually made up of amateur musicians from a specific city or region.
The word "orchestra" comes from the Greek word "orchestra," which was the name for the area in front of a stage in ancient Greek theatre where the Greek chorus performed.
History
During the Baroque era, there were no set rules for the size or makeup of an orchestra. Orchestras varied greatly in size, the instruments they used, and how they played, leading to different sounds across Europe. Some orchestras were small, with only one musician per part, while others were large, with many musicians playing the same parts. For example, Johann Sebastian Bach’s orchestra in Köthen had up to 18 players. In contrast, Antonio Vivaldi’s orchestra in Rome had between 35 and 80 players for regular performances, and could grow to 150 players for special events.
In the Classical era, orchestras became more consistent in size and structure. They typically included a small to medium group of string instruments, such as violins, violas, cellos, and double basses. The wind section usually had pairs of oboes, flutes, bassoons, and horns, and sometimes included percussion instruments, clarinets, or trumpets.
By the late 18th century, a standard orchestra setup was developed, which became more common in the 19th century. This model is often linked to the works of Ludwig van Beethoven, who followed the traditions of Joseph Haydn and Wolfgang Amadeus Mozart. Beethoven’s compositions usually included pairs of flutes, oboes, clarinets, bassoons, horns, and trumpets. However, in some works, such as his Symphony No. 4, Violin Concerto, and Piano Concerto No. 4, he used only one flute. Beethoven carefully added new instruments, like the piccolo, contrabassoon, and trombones, to create unique sounds in his symphonies. For example, the third horn in his "Eroica" Symphony helped produce a richer sound, and the piccolo and trombones added dramatic effects in his Fifth and Sixth Symphonies. His Ninth Symphony required a second pair of horns and included a chorus and vocal soloists, showing how he expanded the range of orchestral music. For many years after Beethoven’s death, orchestras followed his model closely, with few changes.
In 1815, Heinrich Stölzel and Friedrich Blühmel, both from Silesia, invented the piston and rotary valve, which improved the design of brass instruments. This innovation, along with Theobald Boehm’s improvements to the flute and Adolphe Sax’s creation of the saxophone, influenced how orchestras were built. These changes inspired Hector Berlioz to write a detailed book about using instruments to express musical ideas, which became a key reference for composers.
The next major change came with Richard Wagner’s Bayreuth orchestra, created to support his operas. Wagner’s scores required more instruments than ever before, such as six harps in his opera Das Rheingold. His ideas about conducting and orchestral performance changed how music was written and played for many years. Wagner emphasized the importance of tempo, volume, how string players used their bows, and the roles of individual musicians in the orchestra.
At the start of the 20th century, orchestras became larger, better funded, and more skilled. This allowed composers like Gustav Mahler to write ambitious works, such as his massive Symphony No. 8, which used very large ensembles. By the late Romantic era, orchestras had expanded their string and brass sections and added more percussion instruments. As recording technology advanced, musicians were held to higher standards because even small mistakes in recordings could be heard clearly. Over time, audio editing allowed errors to be corrected, leading to a focus on excellence in performance and the rise of famous conductors who could meet these high standards.
Instrumentation
A typical symphony orchestra includes four main groups of musical instruments: woodwinds, brass, percussion, and strings. Sometimes, other instruments like the piano, accordion, and celesta are grouped into a fifth section, such as a keyboard section, or may be used alone. Instruments like the concert harp and electric or electronic instruments may also be included. The size of the orchestra determines how many instruments are used, but it usually includes most standard instruments from each group.
Over time, the types of instruments in orchestras have changed. By the classical period, the setup became more standard, partly because of Ludwig van Beethoven’s influence. In the 20th and 21st centuries, new types of music required more instruments, leading to a mix of traditional and new electric or electronic instruments. In the mid-20th century, some efforts in Germany and the United States aimed to limit orchestras to one instrument per group. In these cases, modified free-reed chromatic accordions were used to create sounds similar to traditional orchestral instruments during performances of Western classical music.
The terms "symphony orchestra" and "philharmonic orchestra" are sometimes used to describe different ensembles from the same city, such as the London Symphony Orchestra and the London Philharmonic Orchestra. A symphony or philharmonic orchestra usually has more than 80 musicians, though the number can vary depending on the music being played and the size of the performance space.
A chamber orchestra is smaller than a symphony orchestra. A large chamber orchestra may have up to 50 musicians, while some are much smaller. Another term for a similar group is "concert orchestra," as seen in ensembles like the BBC Concert Orchestra and the RTÉ Concert Orchestra.
In addition to the main instruments, orchestras sometimes include other instruments. These may include the flugelhorn, cornet, saxophone, classical guitar, euphonium, Wagner tuba, and others. These instruments are often used as solo performers in specific pieces or as part of the ensemble. For example, the saxophone appears in works like Maurice Ravel’s Boléro and Sergei Prokofiev’s Romeo and Juliet Suites. The euphonium is featured in pieces like Gustav Holst’s The Planets. The Wagner tuba appears in Richard Wagner’s Der Ring des Nibelungen and other works. Unless musicians are playing multiple instruments, orchestras often hire additional players for these roles.
The 20th-century orchestra was more flexible than earlier ones. In the time of Beethoven and Felix Mendelssohn, orchestras had a standard set of instruments that composers rarely changed. During the Romantic period, composers like Berlioz and Mahler used more instruments, including multiple harps and special effects like wind machines. By the 20th century, orchestras had a standard setup, but composers later had more freedom to choose instruments, including electric guitars, synthesizers, and non-Western instruments.
The history of the orchestra can be divided into five time periods: the Baroque era, the Classical era, the early/mid-Romantic era, the late-Romantic era, and the Modern/Postmodern era. The Baroque orchestra, such as those led by J.S. Bach or Handel, had fewer performers and included a group called the basso continuo, which played the bassline using instruments like the harpsichord or pipe organ. The Classical orchestra, like those of Mozart or Beethoven, had a smaller group of players and a more standardized setup. The early/mid-Romantic orchestra, such as those of Schubert or Berlioz, used more instruments. The late-Romantic orchestra, like those of Wagner or Mahler, included even more instruments. Modern orchestras today, such as those led by John Adams or Penderecki, use a mix of traditional and modern instruments.
Other percussion instruments include sound effect instruments (such as crotales, waterphone, sleigh bells, and vibraslap) and folk or world music instruments (such as taiko drums, tabla, steel drums, and maracas). Composers may also include unusual instruments like the slide whistle, Aztec death whistle, or Acme siren in their works.
Organization
In orchestras, there is a clear order of importance among different groups of instruments and within each group. Each group has a leader called a "principal," who is responsible for guiding the group and playing solos during performances. The violin section is split into two parts: first violins and second violins. Second violins usually play lower notes, support the melody, or harmonize with the first violins. The leader of the first violins is called the concertmaster (or "leader" in the U.K.) and is the most important person in the string section, second only to the conductor. The concertmaster helps tune the orchestra before performances and decides how the violins should play. They sit to the conductor's left, closest to the audience. Each section also has a principal for the second violins, violas, cellos, and basses.
The principal trombone leads the low brass section, while the principal trumpet leads the entire brass section. The oboe often starts the tuning process for the orchestra, following a tradition from 300 years ago. However, there is no single leader for the woodwind section, though the flute is often the main player in woodwind ensembles. Principals in different sections usually work together as equals when making musical decisions. Many sections also have an assistant principal, who helps the principal and may play parts when the principal is absent.
In string sections, players usually play the same notes together, unless the music is divided into parts for upper and lower voices. In such cases, players seated closer to the audience play one part, and those further back play another. If a solo is needed in a string section, the section leader plays it. The section leader also decides how to hold the bow, often following the concertmaster's guidance. In some cases, the section leader may choose a slightly different bowing to suit their instrument, like the double bass. Principals lead their sections by signaling when to start playing, ensuring the group stays together. Wind and brass players in the "tutti" section play parts that are not solo but unique to their group. Percussionists follow directions from the principal percussionist.
Today, orchestras are usually led by a conductor, but earlier orchestras did not have conductors. Instead, the concertmaster or a harpsichordist (a type of keyboard instrument) led the group. Some modern orchestras, especially smaller ones or those performing older music, do not use conductors.
Symphony orchestras most often play Western classical music or opera. They are also used in popular music, like rock or pop concerts, and in film, television, and video game music. Orchestras are also found in symphonic metal music. The word "orchestra" can also describe a jazz group, such as a big band.
In the 2000s, professional orchestras require musicians to audition for positions. Auditions usually include playing solo pieces, such as parts from a concerto or a Bach movement, and difficult excerpts from orchestral music. These excerpts are listed in advance so musicians can prepare. Auditions are judged by a panel that includes the conductor, the concertmaster, and the principal of the section the musician is applying to, among others.
Top candidates from the first round of auditions may return for more rounds to compare performances. They might also be asked to read music they've never seen before. Some orchestras have a final stage called a "test week," where musicians perform with the orchestra for a few days to show they can work well in rehearsals and performances.
Orchestras offer different types of employment. The best positions are permanent, long-term roles. Musicians may also be hired for short-term contracts, such as for a single concert or to replace a member who is sick. A musician hired for one concert is sometimes called a "sub." Some contract musicians are hired to replace members on leave, like maternity or disability leave.
Historically, professional orchestras were mostly or entirely made up of men. The first women hired in orchestras were often harpists. For example, the Vienna Philharmonic did not allow women to join permanently until 1997, much later than other top orchestras. In 1996, the orchestra's principal flute said allowing women could harm the group's unity. After public pressure, the Vienna Philharmonic admitted its first female member, a harpist, in 1997. As of 2013, the orchestra had six women, including a female concertmaster. In 2012, women made up 6% of the orchestra's members. The orchestra now uses blind auditions, where musicians perform behind a screen to ensure fair judging.
In 2013, an article noted that while some orchestras have many women, sections like double bass, brass, and percussion remain mostly male. A 2014 article mentioned that blind auditions have helped improve gender balance in orchestras.
Repertoire and performances
Orchestras perform many types of music, including dance suites from the 17th century, divertimentos from the 18th century, film scores from the 20th century, and symphonies from the 21st century. A symphony is a long musical piece in Western classical music that usually has several movements with different keys and speeds. Symphonies are written in a musical score that includes all the parts for each instrument. The conductor studies the score before rehearsals to plan how to perform the music, such as choosing tempos or how notes are played. During rehearsals and concerts, the conductor uses the score to lead the orchestra. Each musician plays only the part written for their instrument. Some symphonies, like Beethoven’s Ninth Symphony, also include vocal parts.
Orchestras also perform overtures, which were originally the instrumental introduction to an opera. In the early Romantic era, composers like Beethoven and Mendelssohn began using the term "overture" for independent, programmatic works that later influenced forms like the symphonic poem, created by Franz Liszt. These works were meant to be played at the start of a concert program. By the 1850s, the symphonic poem replaced the concert overture in popularity.
Orchestras often perform concertos, where a soloist, such as a violinist or pianist, plays with the orchestra. The orchestra supports the soloist and sometimes plays themes or interludes when the soloist is not performing. Orchestras also accompany singers in operas, dancers in ballets, and performers in musical theatre and choral works, including sacred and secular pieces.
During the Baroque era, orchestras played in aristocratic homes, opera halls, and churches. Some wealthy families had resident orchestras to entertain guests. In the Classical era, orchestras began performing in public concert halls, where audiences could buy tickets. Aristocrats still supported orchestras, but public concerts became more common. In the 20th and 21st centuries, governments became major supporters of orchestras. Many orchestras in North America and Europe receive funding from local or national governments, along with income from ticket sales, donations, and fundraising. Advances in technology, such as recordings, radio, and online streaming, have also helped orchestras earn money.
A controversial practice in orchestras is "faking," where musicians pretend to play every note written in their part, even if they do not actually play them. This is sometimes done during very difficult passages, such as high or fast sections. Some musicians say faking is acceptable if the music is poorly written for their instrument, but not if they have not practiced enough.
The early music movement led to the creation of smaller orchestras that focus on performing music in styles from older historical treatises. Examples include the Orchestra of the Age of Enlightenment, the London Classical Players, and the Academy of Ancient Music.
In the late 20th century, U.S. orchestras faced financial challenges. The high cost of maintaining large orchestras, combined with fewer supporters and declining ticket sales, made it difficult to sustain operations. Some orchestras, like the Philadelphia Orchestra and the Louisville Orchestra, filed for bankruptcy. Others, such as the Northwest Chamber Orchestra and the Honolulu Orchestra, closed permanently.
High salaries for music directors in the U.S. also drew criticism, leading some conductors to reduce their pay. Music leaders like Michael Tilson Thomas and Esa-Pekka Salonen suggested that new approaches to music, performance, and community engagement could help orchestras survive. Critics like Greg Sandow argued that orchestras must change how they present music and interact with audiences to meet modern expectations.
Some contemporary composers use unusual instruments, such as synthesizers, to create unique sounds. However, many prefer traditional orchestral setups for richer musical effects. Composers like John Adams often use large orchestras, as seen in his opera Nixon in China. Philip Glass and others may use smaller ensembles but still follow certain size limits.
Due to financial cuts, some U.S. orchestras have reduced their number of musicians, especially in the string section, where multiple players often share the same part.
Role of conductor
Conducting is the skill of leading a musical performance, such as an orchestra or choir concert. A conductor's main job is to set the speed of the music, make sure each musician starts at the right time, and help shape how the music is played. They use hand movements, often with a baton, and may also use eye contact or other signals. Before a performance, they often give verbal instructions to help musicians understand how to play.
During a performance, the conductor usually stands on a raised platform with a large music stand that holds the full score, which includes all the music for every instrument and voice. Since the mid-1700s, most conductors do not play an instrument while leading, though in earlier times, musicians often led ensembles by playing their instruments. In Baroque music (1600–1750), the leader was often the harpsichordist or first violinist, a role now sometimes used again for Baroque pieces. In musical theater, conductors may also play a piano or synthesizer while leading. Most communication during a performance is non-verbal, though some jazz or pop groups may use spoken instructions. During rehearsals, conductors often give verbal directions to help musicians prepare.
Conductors guide orchestras or choirs by choosing which pieces to perform and studying the music. They may adjust the tempo, phrasing, or other details and share their ideas with the musicians. They also handle tasks like scheduling rehearsals, planning concerts, and promoting their group. Large ensembles, such as orchestras, choirs, and big bands, are usually led by conductors.
In the Baroque era (1600–1750), orchestras were often led by a musician, such as the concertmaster (the lead violinist), who used bow movements to set the tempo. Sometimes, a harpsichordist or other musician played the basso continuo part, which was central to Baroque music. They might lead by moving their head or lifting their instrument. In some pieces, two leaders were used: one for the instrumentalists and one for the singers. By the Classical period (around 1720–1800), the use of basso continuo declined, and conductors became the main leaders of orchestras. The concertmaster still played a key role, especially for string musicians.
In 1922, the Soviet Union created a conductorless orchestra called Persimfans. The founders believed that all members should be equal, so they used a committee instead of a conductor to decide tempo and style. However, this approach had challenges, such as difficulty changing tempo during performances. The orchestra lasted ten years before being disbanded. In Western countries, some groups like the Orpheus Chamber Orchestra have successfully used conductorless models, relying on leaders like the concertmaster. Others have returned to using a principal musician as the artistic director. Some modern ensembles also revive Baroque practices by using the concertmaster or a chord-playing musician to lead instead of a conductor.
Some musical pieces require instruments to be played offstage, creating special effects. A sub-conductor may be placed offstage to help the offstage musicians stay in time with the main conductor. For example, in the ending of "Neptune" from Holst's The Planets, a sub-conductor relays the main conductor's cues. However, using two conductors can cause problems if they become out of sync. Some orchestras now use cameras and monitors to help offstage musicians follow the main conductor's movements.
In the 20th and 21st centuries, some composers have written music for multiple orchestras or ensembles to perform at the same time. This has led to "polyconductor" performances, where separate sub-conductors lead each group. A main conductor often oversees the sub-conductors. For example, in Percy Grainger's The Warriors, three conductors lead different sections of the orchestra. Karlheinz Stockhausen's Gruppen uses three orchestras placed around the audience to create spatial sound effects. The piece was first performed in 1958 by Stockhausen, Bruno Maderna, and Pierre Boulez, and later by Simon Rattle, John Carewe, and Daniel Harding.