As part of their Breaking Free season on Radio 3, on Essential Classics I’m presenting, on weekday mornings, the complete run of Schoenberg string quartets, from the Dvorakian D major of Schoenberg’s youth to the gnarled but often beautiful last quartet, a serial masterpiece rarely heard. But has the 12-tone method had its day, now that the new ‘melodic’ phase seems to have taken over? What nowadays constitutes a listening challenge? Is dissonance, of whatever kind, a bar or a stimulant? Please discuss.