Transposition is the moving of a musical work or a fragment of it up or down by a certain interval, that is, into a different key. In doing so, all the relationships between the notes are preserved, and the melody remains recognizable — only its absolute pitch changes.
Transposition is of great practical importance. It is used to adapt a song to the comfortable range of a particular singer, to simplify the chords for a guitarist, or to adapt a part for another instrument. There are also transposing instruments (clarinet, trumpet, French horn, saxophone) whose parts are written not at the sounding pitch, so the musicians constantly transpose “in their heads.” The ability to transpose quickly is an important professional skill of an accompanist, conductor, and arranger. Transposition shows that the essence of music lies in the relationships between notes, not in their absolute pitch.
