How did group-virtuoso ensembles work with living composers in the 20th century?

In the 20th century, the emergence of chamber works like Arnold Schoenberg’s Pierrot Lunaire and Igor Stravinsky’s Histoire du soldat necessitated a new type of performer: the group-virtuoso.1

These ensembles, which often formed around a specific living composer or a university where they taught, functioned as active partners in the compositional process rather than mere interpreters. Their work was characterized by the following dynamics:1

• Collaborative Creation: Performers were deeply involved in the creative act, with the final musical product reflecting their unique skills, personalities, and the specific dynamics of their working relationship with the composer.1
• Realization over Interpretation: Instead of simply interpreting a score, these groups focused on realizing the work, often exploring nontraditional instrumental combinations and economy of means.12
• Specialized Training: The unique demands of these modern compositions—such as the use of Sprechstimme or unconventional instrumental blends—helped train these performers, leading to the proliferation of such groups across various musical institutions.1

This shift marked a departure from the 19th-century focus on the individual concert virtuoso, moving toward a more collaborative, ensemble-based approach to contemporary music.13