Accelerando

Gradually faster

On the page Tempo it says: music rarely stays strictly the same speed. Gradually getting faster is called accelerando, gradually getting slower ritardando, both are strong means of expression. Acceleration drives and intensifies, slowing down calms or announces an ending. The same page points out that a driving rhythm, an urgent harmony or a crescendo can create the impression of acceleration without the pulse actually changing.

Speeding up and getting louder

The page Tools describes a coupling you should know: loudness and tempo couple in the body almost automatically. It gets faster when it gets louder and slower when it gets softer. The metronome makes this mercilessly audible, which is why you should practise loud passages explicitly with a click. An unintended accelerando is so common that the page names it as a practice mistake. See also Crescendo.

Accelerando in the score

Voice and piano

• Gretchen am Spinnrade Franz Schubert · voice and piano, with chords for guitar

  On page 4 “acceler.” appears under the piano part with sf, after a long “cresc.” over the chords Gm, E♭, A♭ and F, the key signature shows one flat. The increase of tempo and loudness run together.

In Schubert the accelerando is intended: it appears alongside the crescendo and leads into the climax of the song.

Common mistakes

• Getting faster unintentionally: Especially at loud passages and crescendos.
• Not taking the tempo back after the accelerando: “A tempo” means the main tempo before the acceleration.
• Equating accelerando and crescendo: One concerns the tempo, the other the loudness.