Was this music really created to facilitate falling asleep? A popular legend has it that Count Hermann Carl von Keyserling, Russian envoy to the Dresden court, regularly called on his harpsichordist Johann Gottlieb Goldberg to play Bach for him­­­ as a barbiturate. In truth, these variations were “composed for connoisseurs, for the refreshment of their spirits” and elevated a genre - whose hitherto purpose had been to provide pleasant diversion, and which Bach had long avoided but for a few youthful works - to an unimagined, unheard-of compositional level. The thirty “changes” are interwoven with a myriad of contrapuntal intricacies that place the highest demands on listener and performer. Fall asleep? It is impossible to be awake enough to fully appreciate the Goldberg Variations. The excellent arrangement for string trio by the Russian violinist and conductor Dmitri Sitkovetsky makes it all the more palpable - and the passionate chamber musicians Julian Rachlin, Sarah McElravy and Boris Andrianov illuminate its voice-weaving with delicacy and emphasis.