Schubert: String quartets 13, 14, 15VirginThe difference between a good string quartet and a great one is no more than a fraction of a heartbeat. The Artemis Quartet – two Russians, two Germans, based in Berlin – have made the imperceptible upward transition in the past two years.It’s not so much how they play as how they play together – the fractional anticipations that foster an illusion of four minds thinking as one, eight arms in total cohesion. Together since 1989, their Beethoven cycle on Virgin is both the most coherent and the most integrally conceived set in decades. And that’s without saying a word about the sheer serenity of the playing.It is no easy matter to go from the high mindedness of Beethoven to the melodic allure of Schubert. The Artemis make no perceptible alteration to their approach. The tone is taut and bright, the tempi brisk and the breathing organic. In Death and the Maiden, there is none of the pathos that some quartets pump in for the third hankie effect. In the Rosamunde quartet, the symphonic sonorities point ahead to Mendelssohn and Schumann. And in the ultimate G major quartet, 50 minutes long and staring death in the eye, the Artemis present an interpretation of psychological neutrality, never second-guessing the composer’s sentiments and intentions.The cumulative effect is utterly convincing. You’d need to go back two decades to the Alban Berg Quartet for an account of comparable beauty and authority. This is a great performance by a very great quartet.Three Shostakovich CDsSymphonies 2, 15NaxosVasily Petrenko is midway through an illuminating Liverpool cycle. The short second symphony is a hair-raising piece of political exuberance; the 15th is a dying man’s exhalation. The former performance here is brilliant. In the 15th, the tempo slackens and the sound turns oddly opaque.Symphonies 9, 15HänsslerIn this captivating account of the 15th, Andrey Boreyko navigates its mysterious emptiness with a Mahlerian lexicon and a failsafe compass. His performance with SWR-Stuttgart is four minutes shorter than Petrenko’s in Liverpool. The problematic post-War 9th falls between two stools of exhilaration and fear; the solution here is not always crystal-clear.String quartets 1-4CedilleThe US-based Pacifica Quartet takes a careful, depoliticised approach to the most intimate personal utterances of the besieged composer, who did not start writing quartets until Stalin threatened his life in 1935. Sheer beauty justifies the neutral tactic, though one misses the suppressed rage that imbues Russian interpretations. That said, the interpretation is fully thought-through than the Emersons and the sound is outstanding. There is a bonus quartet – Prokofiev’s second.___Norman Lebrecht is a regular presenter on BBC Radio 3 and a contributor to the Wall Street Journal, Bloomberg and other publications. He has written 12 books about music, the most recent being Why Mahler? He hosts the blog Slipped Disc.