The nature of love as explored in the songs and duets of Brahms and Schumann was the subject of Jonas Kaufmann and Diana Damrau’s latest Barbican concert, carefully programmed by pianist Helmut Deutsch, and forming an effective sequel to their near-dramatised performances of Hugo Wolf’s Italienisches Liederbuch in 2018. Less overtly histrionic than that earlier concert, and consequently more reflective in tone, the new programme nevertheless had much in common with it, with groups of songs by each composer carefully fashioned into narratives of love, loss, desire and affirmation, all of them sharply differentiated.