Has anyone else directed Mahler's Fourth Symphony while singing the finale from the stage? Surely not ... but the present release, preserving a concert live-streamed mid-pandemic from Rotterdam's empty De Doelen hall, makes a different, more collegial kind of splash than fans of Gramophone's Artist of the Year might be expecting. The ensemble Camerata RCO, which previously recorded Erwin Stein's reduction of the Mahler under oboist turned maestro Lucas Macías Navarro in 2017, is helmed not by Hannigan herself but by a frequent collaborator and past member of her Equilibrium mentoring scheme, the young Dutch conductor Rolf Verbeek....