subito
An Italian musical term meaning "suddenly," indicating that a change in dynamics or tempo should occur immediately rather than gradually.
In Depth
Subito transforms any dynamic or tempo marking into an abrupt instruction. "Subito piano" (often abbreviated "sub. p") means an immediate drop to quiet, "subito forte" means an instant jump to loud, and "subito più mosso" indicates a sudden increase in tempo. The effect is dramatic and often startling, creating sharp contrasts that cut through the musical texture.
The subito piano is one of the most powerful dramatic devices in orchestral music. Beethoven was particularly fond of it, using sudden drops from fortissimo to pianissimo to create moments of shocking contrast that keep listeners on edge. Haydn employed subito forte for comic effect — his "Surprise" Symphony (No. 94) features a famous subito fortissimo chord designed to jolt drowsy audience members awake. In modern music, subito dynamics are essential to creating the jagged, unpredictable surface of much contemporary composition.
Haydn allegedly wrote the famous fortissimo surprise chord in his Symphony No. 94 specifically to wake up audience members who had fallen asleep during the quiet second movement theme.