Crescendo (Italian for “growing”) is marked with a “hairpin” ( < ) or the word cresc. It is a tool of tension: the composer pulls the listener along, step by step.
A legendary crescendo is the overture to Rossini's The Barber of Seville, where the orchestra grows almost to frenzy. In rock music, the device is equally dominant: Led Zeppelin's “Stairway to Heaven” is a crescendo stretched across eight minutes.
A long, carefully measured crescendo is one of the hardest tasks for an orchestra: every musician must build the sound evenly, or the effect collapses. Composers of the 18th century — notably the orchestra of the Mannheim school — were the first to turn the gradual crescendo of a whole orchestra into an independent dramatic device, which later became an inseparable part of symphonic thinking.
