Accelerando

Accelerando, abbreviated accel., instructs the performer to increase the tempo gradually. It is the natural opposite of ritardando, and the two often appear together as structural bookends — a piece may accelerando into a climactic passage and ritardando out of it.

The device is fundamental to Romantic and post-Romantic writing. Liszt, Wagner, and Tchaikovsky use long accelerandos to push toward thematic peaks. In folk-derived idioms — Hungarian csárdás, Romanian doinas, klezmer freylekhs — accelerando is the engine of the dance: the music gets faster and faster until the final cadence cracks like a whip.

The rate of acceleration is at the performer’s discretion, but it should feel inevitable rather than nervous. A well-shaped accelerando hides itself: the listener arrives at the new tempo without quite knowing when it changed. In ensembles, watch the conductor’s beat or section leader for the curve; do not push individually, as a runaway accelerando undermines the whole effect.

Italian, present participle of accelerare (‘to accelerate’), from Latin accelerare, celer (‘swift’). In musical use from the early 19th century.

Mark the start, middle, and end of the acceleration with rough metronome targets in rehearsal. Without that map, ensembles drift apart. On solo instruments, link the acceleration to the harmonic motion — speed up into tension, not away from it.