The principal elements of Honegger's style are: Bachian counterpoint, driving rhythms, melodic amplitude, highly coloristic harmonies, an impressionistic use of orchestral sonorities, and a concern for formal architecture. His style is weightier and more solemn than that of his colleagues in Les Six . Far from reacting against German romanticism as the other members of Les Six did, Honegger's mature works show evidence of a distinct influence by it. Despite the differences in their styles, he and fellow Les Six member Darius Milhaud were close friends, having studied together at the Paris Conservatoire . Milhaud dedicated his fourth string quintet to Honegger's memory, while Francis Poulenc similarly dedicated his Clarinet Sonata .