A name given by musicologists to a group of innovative 18th century German composers associated with the Court of the Elector Pfalzbayern, based in Mannheim, Germany (1724-99), which had grown into a great music center. The importance of these composers (shared to some extent with the progressive composers in Vienna, Italy, and Bohemia) is in laying the foundations for the symphony as it was to be developed by Haydn and Mozart. Johann Stamitz, who became the conductor of the Mannheim orchestra, headed this group of composers. He founded a new style of performance that was suited to his works. Features of his style included the melodic prominence of violins, extended crescendos and dynamics, tremolando, and the replacement of improvised continuo with written out parts. Since musical innovation had became associated with the Mannheim school, modern musicologists named these techniques after it:
Mannheim roll (steamroller): Scale passages in measured tremolo, combined with a crescendo. (The innovative synth band Mannheim Steamroller took their name from this.)
Mannheim crescendo: Great crescendos and diminuendos that ranged from pianissimo to fortissimo.
Mannheim rocket: Rapid upward arpeggio over a large range, combined with a crescendo