A large-ensemble work by Swedish reed player Mats Gustafsson leading his NU Ensemble, part of his ongoing Hidros series of expansive compositions. Hidros 6 – Knockin' marshals an international cast of improvisers into a powerful, structurally ambitious large-group statement, among the more monumental projects in the label's catalog and a showcase for Gustafsson's compositional reach beyond his small-group work.