Hans van Koolwijk builds musical instruments for  K l a n g M ø b i l  of Ensemble Interface  - Bettina Berger, Anna d'Errico, Andrea Nagy, Agnieszka Kropowska, and Christophe Mathias - and guest musician Roberto Dani; and three composers - Amir Shpilman, Beat Gysin and Sergey Khismatov.