Dynamics is the emotional amplitude of a work. The scale runs from ppp (pianississimo — softer than soft) to fff (fortississimo — stronger than strong), with a full palette of shades between them.
Masters of dynamic contrast include Beethoven, Berlioz, and Mahler. Beethoven's sudden subito piano after forte became his signature device: the listener is startled, and that jolt is part of the design.
Until the late 18th century, dynamics were often left to the performer's discretion; the very invention of the piano (full name gravicembalo col piano e forte, “harpsichord with soft and loud”) made a smooth change of volume possible on a keyboard instrument. Besides level markings, there are signs of gradual change (crescendo, diminuendo) and sudden contrasts (sforzando, subito piano), with which the composer sculpts the emotional relief of a work.
