Answer: dynamic
Step-by-step explanation:
The technique of gradually changing dynamic levels was developed by the Mannheim symphonists.
The Mannheim school were composers whom were under the guidance of Duke Karl Theodor. They were good in their instrumental music, and they introduced several innovative ideas for the orchestral music.
Some of the composers in the school were Johann Stamitz, Christian Cannabich, Franz Xaver Richter, Carl Stamitz, etc