Performance

Performance is the physical expression of music, which occurs when a song is sung or when a piano piece, electric guitar melody, symphony, drum beat or other musical part is played by musicians. In classical music, a musical work is written in music notation by a composer and then it is performed once the composer is satisfied with its structure and instrumentation. However, as it gets performed, the interpretation of a song or piece can evolve and change. In classical music, instrumental performers, singers or conductors may gradually make changes to the phrasing or tempo of a piece. In popular and traditional music, the performers have a lot more freedom to make changes to the form of a song or piece. As such, in popular and traditional music styles, even when a band plays a cover song, they can make changes to it such as adding a guitar solo to or inserting an introduction.

A performance can either be planned out and rehearsed (practiced)—which is the norm in classical music, with jazz big bands and many popular music styles–or improvised over a chord progression (a sequence of chords), which is the norm in small jazz and blues groups. Rehearsals of orchestras, concert bands and choirs are led by a conductor. Rock, blues and jazz bands are usually led by the bandleader. A rehearsal is a structured repetition of a song or piece by the performers until it can be sung and/or played correctly and, if it is a song or piece for more than one musician, until the parts are together from a rhythmic and tuning perspective. Improvisation is the creation of a musical idea–a melody or other musical line–created on the spot, often based on scales or pre-existing melodic riffs.

Many cultures have strong traditions of solo performance (in which one singer or instrumentalist performs), such as in Indian classical music, and in the Western art-music tradition. Other cultures, such as in Bali, include strong traditions of group performance. All cultures include a mixture of both, and performance may range from improvised solo playing to highly planned and organised performances such as the modern classical concert, religious processions, classical music festivals or music competitions. Chamber music, which is music for a small ensemble with only a few of each type of instrument, is often seen as more intimate than large symphonic works.

Oral and aural tradition

Many types of music, such as traditional blues and folk music were not written down in sheet music; instead, they were originally preserved in the memory of performers, and the songs were handed down orally, from one musician or singer to another, or aurally, in which a performer learns a song "by ear". When the composer of a song or piece is no longer known, this music is often classified as "traditional" or as a "folk song". Different musical traditions have different attitudes towards how and where to make changes to the original source material, from quite strict, to those that demand improvisation or modification to the music. A culture's history and stories may also be passed on by ear through song.

Ornamentation

In music, an ornament consists of added notes that provide decoration to a melody, bassline or other musical part. The detail included explicitly in the music notation varies between genres and historical periods. In general, art music notation from the 17th through the 19th centuries required performers to have a great deal of contextual knowledge about performing styles. For example, in the 17th and 18th centuries, music notated for solo performers typically indicated a simple, unadorned melody. Performers were expected to know how to add stylistically appropriate ornaments to add interest to the music, such as trills and turns. Different styles of music use different ornaments. A Baroque flute player might add mordents, which are short notes that are played before the main melody note, either above or below the main melody note. A blues guitarist playing electric guitar might use string bending to add expression; a heavy metal guitar player might use hammer-ons and pull-offs.

In the 19th century, art music for solo performers may give a general instruction such as to perform the music expressively, without describing in detail how the performer should do this. The performer was expected to know how to use tempo changes, accentuation, and pauses (among other devices) to obtain this "expressive" performance style. In the 20th century, art music notation often became more explicit and used a range of markings and annotations to indicate to performers how they should play or sing the piece. In popular music and traditional music styles, performers are expected to know what types of ornaments are stylistically appropriate for a given song or piece, and performers typically add them in an improvised fashion. One exception is note-for-note solos, in which some players precisely recreate a famous version of a solo, such as a guitar solo.