A musical transcription is musical notation for an existing piece of music that had been previously unnotated. Musicians often disagree about what should be called a “transcription” and what is an “arrangement”. Usually transcriptions are a direct notation of the source, whereas a musician who makes an arrangement may insert new interpretations into the music (i.e. changing the instrumentation, reharmonization, or even new sectionalization of the piece as with cover songs). A transcription, as Klapuri writes, would require that the pitch, timing, and instrumentation of all sound events to be resolved; difficult as this may be for some cases, this goal is usually redefined such that a transcription constitutes the notation of as many of the constituent sounds as possible or some well-defined part of the music signal (i.e. the dominant melody or the most prominent drum sounds).
Transcriptions can be created for all kinds of music in order to help the performer to learn the piece. Transcriptions are common for music such as jazz (which usually consists of improvisation) and folk, which traditionally is taught from one generation to another by listening and imitating. In the early 20th century, some composers became interested in writing down the traditional folk songs of their countries. Béla Bartók and Zoltan Kodaly in Hungary as well as Cecil Sharpe and Ralph Vaughan Williams in England notably transcribed various folk songs they heard being sung in the villages of their respective countries.
Sometimes transcriptions are made for practical reasons. Mozart made transcriptions of some music from his own operas, arranging them for small groups of instruments so that they could play it for popular entertainment. Stravinsky transcribed some of his ballet music for piano, e.g. The Rite of Spring for piano duet and some dances from Petrouchka for piano solo. These types of transcriptions are often referred to as a "reduction": the simplification of a large work to be performed by a smaller ensemble or a soloist.
- Klapuri, Anssi (20 Dec 2006). "Introduction to Music Transcription". Signal Processing Methods for Music Transcription (Tampere University of Technology): 1. https://pdfs.semanticscholar.org/7d0a/4c536065fb559a0b8d4f13ffd32b7f996ecc.pdf.
- New Grove Dictionary of Music and Musicians, edited Stanley Sadie; London 1980; vol 1 p.626