The Ensemble 21 is made up of students from the HEM classes. Numerous composers have honoured the young musicians with their presence and advice.
Working in regular partnership with the Archipel festival, the Geneva HEM has come into contact with composers involved in the festival. This has enabled the Contemporary Ensemble to work with many of them in workshops, including Henri Dutilleux, Sofia Gubaidulina, Maurice Ohana, Edison Denisov, Klaus Huber, Elliott Carter, Ysang Yun, Eric Gaudibert, Yoshihisa Taira, George Benjamin, Helmut Lachenmann, Michael Levinas, Toshio Hosokawa, György Kurtág and Pascal Dusapin.
The Ensemble 21 has worked with the Grand Théâtre de Genève, the Ensemble Contrechamps, la Société de Musique Contemporaine Lausanne, the Amadeus festival and the Archipel festival. Radio Suisse Romande has recorded its performances at various events.
The Ensemble 21 regularly performs work by Geneva HEM composition students, with or without a conductor.