Orchestra - Organization

Organization

Among the instrument groups and within each group of instruments, there is a generally accepted hierarchy. Every instrumental group (or section) has a principal who is generally responsible for leading the group and playing orchestral solos. The violins are divided into two groups, first violin and second violin, each with its principal. The principal first violin is called the concertmaster (or "leader" in the UK) and is considered the leader of not only the string section, but of the entire orchestra, subordinate only to the conductor.

The principal trombone is considered the leader of the low brass section, while the principal trumpet is generally considered the leader of the entire brass section. Similarly, the principal oboe is considered the leader of the woodwind section, and is the player to whom all others tune. The horn, while technically a brass instrument, often acts in the role of both woodwind and brass. Most sections also have an assistant principal (or co-principal or associate principal), or in the case of the first violins, an assistant concertmaster, who often plays a tutti part in addition to replacing the principal in his or her absence.

A section string player plays unison with the rest of the section, except in the case of divided (divisi) parts, where upper and lower parts in the music are often assigned to "outside" (nearer the audience) and "inside" seated players. Where a solo part is called for in a string section, the section leader invariably plays that part. Tutti wind and brass players generally play a unique but non-solo part. Section percussionists play parts assigned to them by the principal percussionist.

In modern times, the musicians are usually directed by a conductor, although early orchestras did not have one, giving this role instead to the concertmaster or the harpsichordist playing the continuo. Some modern orchestras also do without conductors, particularly smaller orchestras and those specializing in historically accurate (so-called "period") performances of baroque and earlier music.

The most frequently performed repertoire for a symphony orchestra is Western classical music or opera. However, orchestras are used sometimes in popular music, extensively in film music, and increasingly often in video game music. The term "orchestra" can also be applied to a jazz ensemble, for example in performance of big band music.