Rehearsal
It is undertaken as a form of practising, to ensure that all details of the subsequent performance are adequately prepared and coordinated.
Almost all mid- to large-group performances have a person who leads the rehearsals; this person may be a bandleader in a rock, country, or jazz setting; conductor in classical music (including opera); director in theatre or musical theatre; or film director for movies.
For a musical performance, the dress rehearsal does not require wearing formal concert outfits (such as, tuxedos and gowns).
Abbreviated Q-2-Qs in which only the opening and closing sequences of each act or scene are performed are sometimes referred to as "tops and tails".
They may include patrons (who pay a reduced ticket price), family and friends of the ensemble, or reviewers from the media.
A professional orchestra, choir or chamber ensemble (e.g., string quartet or wind quintet) rehearses a piece (or song) in order to coordinate the rhythmic ensemble, ensure that the intonation of pitches of the different sections matches exactly, and coordinate the dynamics (changes in loudness and softness) and phrasing.
Instead, a professional ensemble will typically review passages which pose challenges from the point of view of rhythmic or harmonic coordination.
In some orchestras, there may be a limited audience during the dress rehearsal (typically university music students or other invited guests).
Amateur orchestras or chamber ensembles, such as university or community groups, rehearse music for a number of reasons.
However, amateur musicians are much more likely to make note mistakes, transposition errors or play with incorrect intonation or rhythms; the conductor must point these issues out to the performers and give them advice on how to correct them.
In amateur groups, players may not have strong ensemble skills, so the conductor may have to coach players about how to learn to blend their sound well with other sections or how to coordinate rhythmic passages that are played by different sections, or how to mark their part after they make an error to prevent the error from being repeated.
Rehearsals assemble the elements of a musical event, offering an experimental space where sounds and rhythms are put together and taken apart, played with, argued over, and refined.
However, the purpose of rehearsals is the same: to ensure that all the band members can play and/or sing their parts with a good rhythmic ensemble, correct intonation, and the right "feel" and style.
The bandleader also typically chooses the members of the rhythm section: the instruments that provide the beat and the chord progression for songs.
Emergency-planning organizations often rehearse their preparations for responding to civil disasters; in some cases, there may even be actors playing the role of "injured people", so that emergency workers can learn how to provide assistance.
The Israeli Defence Force used this approach in planning for the Raid on Entebbe, which freed air hijacking hostages.
An accurate model of the airport building where the hostages were being held by gunmen was recreated so that the commandos could practice their attack maneuvers.
The introduction of major changes to complex industrial and technical fields, such as information systems is often rehearsed, particularly where this requires multiple activities to be coordinated and completed within time constraints.
