The eighteenth century technique of gradually changing levels was called the mannheim crescendo.

The eighteenth century technique of gradually changing dynamic levels was called the Mannheim Crescendo.

Explanation:

Mannheim School refers to the orchestral techniques introduced by the orchestra of Mannheim in the second half of century XVIII, as well as to the group of composers who wrote music for this orchestra, adopting the sonata form.

Composers of the Mannheim School include Johann Stamitz, Franz Xaver Richter, Carl Stamitz, Franz Ignaz Beck, Ignaz Franzl and Christian Cannabich. The School had a direct influence on many symphonists of the time, including Joseph Haydn, Wolfgang Amadeus Mozart and Leopold Hofmann.

The composers of the Mannheim School introduced a number of innovative ideas for the orchestral music of their time: a more independent treatment of the wind instruments, a crescendo and a decrescendo developed through the whole orchestra; the "rocket of Mannheim," a melodic line arpeggio in rapid ascent over a line of ostinato bass; the "sigh of Mannheim", placing more emphasis on the first of a couple of linked descending notes; the "gorgeio de Mannheim," an imitation of trills of birds in solo passages, and the "great pause", when all the instruments abruptly shut up and then resumed the music vigorously.

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