A concert to set the mood for the evening’s largely Francophone programme from the BBC SO: two generations of Paris’s most influential composers writing for massed voices and creating sonorities that could come from no other country but . Ravel’s diaphanous vocal writing is interleaved with the richer, darker colours of Franck’s three works. Franck’s offertory, Quae est ista, bursts into life with heart-stopping rapture and glorious melody.