Music is composed and performed for many purposes, ranging from aesthetic pleasure, religious or ceremonial purposes, or as an entertainment product for the marketplace. Amateur musicians compose and perform music for their own pleasure, and they do not attempt to derive their income from music. Professional musicians are employed by a range of institutions and organizations, including armed forces, churches and synagogues, symphony orchestras, broadcasting or film production companies, and music schools. As well, professional musicians work as freelancers, seeking contracts and engagements in a variety of settings.



Although amateur musicians differ from professional musicians in that amateur musicians have a non-musical source of income, there are often many links between amateur and professional musicians. Beginning amateur musicians take lessons with professional musicians. In community settings, advanced amateur musicians perform with professional musicians in a variety of ensembles and orchestras. In some rare cases, amateur musicians attain a professional level of competence, and they are able to perform in professional performance settings.

A distinction is often made between music performed for the benefit of a live audience and music that is performed for the purpose of being recorded and distributed through the music retail system or the broadcasting system. However, there are also many cases where a live performance in front of an audience is recorded and distributed (or broadcast).

Performance

Chinese Naxi musiciansSomeone who performs, composes, or conducts music is a musician. Musicians perform music for a variety of reasons. Some artists express their feelings in music. Performing music is an enjoyable activity for amateur and professional musicians, and it is often done for the benefit of an audience, who is deriving some aesthetic, social, religious, or ceremonial value from the performance. Part of the motivation for professional performers is that they derive their income from making music. As well, music is performed in the context of practicing, as a way of developing musical skills.

Solo and ensemble

Many cultures include strong traditions of solo or soloistic performance, 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 for one's enjoyment to highly planned and organized performance rituals such as the modern classical concert or religious processions.

Chamber music, which is music for a small ensemble, is often seen as more intimate than symphonic works. A performer is called a musician or singer, and they may be part of a musical ensemble such as a rock band or symphony orchestra.

Oral tradition and notation

Musical notationMusic is often preserved in memory and performance only, handed down orally, or aurally ("by ear"). When the composer of music is no longer known, this music is often classified as "traditional". Different musical traditions have different attitudes towards how and where to make changes to the original source material, from quite strict, to those which demand improvisation or modification to the music.

When music is written down, it is generally notated so that there are instructions regarding what should be heard by listeners, and what the musician should do to perform the music. This is referred to as musical notation, and the study of how to read notation involves music theory, harmony, the study of performance practice, and in some cases an understanding of historical performance methods.

Written notation varies with style and period of music. In Western Art music, the most common types of written notation are scores, which include all the music parts of an ensemble piece, and parts, which are the music notation for the individual performers or singers. In popular music, jazz, and blues, the standard musical notation is the lead sheet, which notates the melody, chords, lyrics (if it is a vocal piece), and structure of the music. Nonetheless, scores and parts are also used in popular music and jazz, particularly in large ensembles such as jazz "big bands."

In popular music, guitarists and electric bass players often read music notated in tablature, which indicates the location of the notes to be played on the instrument using a diagram of the guitar or bass fingerboard. Generally music which is to be performed is produced as sheet music. Tabulature was also used in the Baroque era to notate music for the lute, a stringed, fretted instrument.

To perform music from notation requires an understanding of both the musical style and the performance practice that is associated with a piece of music or genre. The detail included explicitly in the music notation varies between genres and historical periods. In general, art music notation from the 17th through to the 19th century required performers to have a great deal of contextual knowledge about performing styles. For example, in the 17th and 18th century, music notated for solo performers typically indicated a simple, unornamented melody. However, it was expected that performers would know how to add stylistically appropriate ornaments such as trills and turns.

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. It was expected that the performer would 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 jazz, music notation almost always indicates only the basic framework of the melody, harmony, or performance approach; musicians and singers are expected to know the performance conventions and styles associated with specific genres and pieces. For example, the "lead sheet" for a jazz song may only indicate the basic outlines of the melody and the chord changes. The performers in the jazz ensemble are expected to know how to "flesh out" this basic structure.

Improvisation, interpretation, composition

Main articles: Musical composition, Improvisation#Musical improvisation, and Free improvisation

Most cultures use at least part of the concept of preconceiving musical material, or composition, as held in western classical music. Even when music is notated precisely, there are still many decisions that a performer has to make. The process of a performer deciding how to perform music that has been previously composed and notated is termed interpretation.

In some musical genres, such as jazz and blues, even more freedom is given to the performer to engage in improvisation on a basic melodic, harmonic, or rhythmic framework. The greatest latitude is given to the performer in a style of performing called free improvisation, which is material that is spontaneously "thought of" (imagined) while being performed, not preconceived. Improvised music usually follows stylistic or genre conventions and even "fully composed" includes some freely chosen material (see precompositional). Composition does not always mean the use of notation, or the known sole authorship of one individual.

Music can also be determined by describing a "process" which may create musical sounds, examples of this range from wind chimes, through computer programs which select sounds. Music which contains elements selected by chance is called Aleatoric music, and is often associated with John Cage and Witold Lutos?awski.

Compositions

Musical composition is a term that describes the makeup of a piece of music. Methods of composition vary widely, however in analyzing music all forms -- spontaneous, trained, or untrained -- are built from elements comprising a musical piece. Music can be composed for repeated performance or it can be improvised; composed on the spot. The music can be performed entirely from memory, from a written system of musical notation, or some combination of both. Study of composition has traditionally been dominated by examination of methods and practice of Western classical music, but the definition of composition is broad enough to include spontaneously improvised works like those of free jazz performers and African drummers.

What is important in understanding the composition of a piece is singling out its elements. An understanding of music's formal elements can be helpful in deciphering exactly how a piece is constructed. A universal element of music is how sounds occur in time, which is referred to as the rhythm of a piece of music.

When a piece appears to have a changing time-feel, it is considered to be in rubato time, an Italian expression that indicates that the tempo of the piece changes to suit the expressive intent of the performer. Even random placement of random sounds, which occurs in musical montage, occurs within some kind of time, and thus employs time as a musical element.