"Composition" is the act or practice of creating a work of music. In many cultures, including Western classical music, the act of composing also includes the creation of an object, such as a score, which is then performed by the composer or others. In popular music and traditional music, the act of composing, which is typically called songwriting, may involve the creation of a basic outline of the song, called the lead sheet, which sets out the melody, lyrics and chord progression. In Classical music, the composer typically orchestrates her own compositions, but in musical theatre and in pop music, songwriters may hire an arranger to do the orchestration. In some cases, a songwriter may not use notation at all, and instead compose the song in her mind and then play or record it from memory. In jazz and popular music, notable recordings by influential performers are given the weight that written scores play in classical music.
Even when music is notated relatively precisely, there are many decisions that a performer has to make, because notation does not specify all of the elements of music precisely. The process of deciding how to perform music that has been previously composed and notated is termed interpretation. Different performers' interpretations of the same work of music can vary widely, in terms of the tempos that are chosen and the playing or singing style or phrasing of the melodies. Composers and songwriters who present their own music are interpreting, just as much as those who perform the music of others. The standard body of choices and techniques present at a given time and a given place is referred to as performance practice, whereas interpretation is generally used to mean the individual choices of a performer.
Although a musical composition often uses musical notation and has a single author, this is not always the case. A work of music can have multiple composers, and it can also be composed with words, images, or computer programs that form a process for creating musical sounds. Examples of this range from wind chimes, to graphic notation, to text compositions such as Aus den sieben Tagen, to computer programs that select sounds. Music that makes heavy use of randomness is called aleatoric music, and is associated with such composers as John Cage, Morton Feldman, and Witold Lutosławski.
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 such as the Ewe drummers.
https://www.youtube.com/playlist?list=PLmfH_uY2_ijJ7qdqBN0KFpikmF-NTGgtZ
