Funny, the unconscious prejudices one acquires. Not that I’ve ever thought of the Nash Ensemble as anything other than excellent; but perhaps the group’s elegant name and its long reputation for finesse led me to expect a particular kind of interpretation. Wrongly, as it happens: the boldness, ferocity and raw red-blooded vigour of this pairing of Tchaikovsky and Korngold string sextets comes as a bracing surprise.

But then, why not? Tchaikovsky’s chamber works aren’t exactly restrained: the dynamic range in Souvenir de Florence stretches from triple piano to quadruple forte and the Nash Ensemble make a pretty good job of hitting both. The propulsive energy of this performance hits you between the eyes right from the earthy, smudged opening chord. It’s all about rhythms – bouncing, kicking, hammered home by huge percussive spread chords. If the more lyrical melodies are never exactly lush, they’re always stylishly shaped, and the crispness and clarity with which the lower players articulate their accompaniments means that even in the grander climaxes (and it gets very boisterous indeed) there’s a sense of purpose and precision.

As for the Korngold: well, it’s as if they’ve heard the wit, warmth and ravishing polish of the Sinfonia of London’s recent account (Chandos, 5/20) and set out to offer an alternative. The virtuosity of the playing is in a similar class but this is a radically different vision: multilayered, impulsive, sometimes violent and unafraid to probe the work’s darker corners. It’s an expressionist approach, and if the Sinfonia’s recording relates this music to Brahms, the Nash Ensemble position it right next to Berg. But again, why not? If you love Korngold’s chamber music, you’ll want to hear both.