A ‘very singular double concerto’ is how Richard Bratby described CPE Bach’s work for two keyboards in an interview in the June issue with the chief protagonists of this performance. It’s one of Emanuel’s most endearing creations: a late work, ranging wide across the many facets of its composer’s imagination, the timbrally dissimilar solo instruments here echoing, there sparring, elsewhere joining together for semiquaver passages in contrary motion purely for the purpose of making a joyful noise. It’s formally taut but effortlessly witty, and Alexander Melnikov and Céline Frisch delight in its fantasy, responding to its playfulness without ever forcing the humour. He plays a piano based on a Viennese Walter from 1795, she a harpsichord based on a Berlin instrument from the opposite end of the century.

The curtain rises with the first of four symphonies Emanuel published in 1780. Here Café Zimmermann set out their stall, their period-instrument sonorities majoring on the rasp of gut strings and the individualities of the woodwinds. Compare it with, for example, the altogether suaver Berlin Academy of Ancient Music (Harmonia Mundi, 4/14), where sustain is preferred to Zimmermann’s discontinuities, underpinned by the satisfying ‘thonk’ of Frisch’s fortepiano continuo. This sound world especially suits the third of Mozart’s ‘Salzburg Symphonies’, divesting the suspension-laden slow movement of all sentimentality and revelling in the high spirits of the faster music.

Melnikov returns in a performance of Mozart’s G major Piano Concerto that pays no heed to traditional notions of Mozartian beauty, taking each gesture as a provocation and presenting an alternative view of this wonderful work that compels from first note to last. Accents and sforzandos aren’t simply leant on but become points of disruption, sending the rhetorical tone spinning off in unpredictable directions. Legato, it says in my 19th-century edition under the soloist’s Alberti bass figures at his first entry: not here (nor, indeed, in Mozart’s manuscript), and Melnikov recreates the solo part in nobody’s image but his own. Piano, woodwind soloists and strings argue and chatter, converse and debate together to a rarely paralleled level; there’s little that’s comfortable or consoling in the central Andante or merely graceful in the finale. If one were to cavil, it might be only that the orchestra never quite manages to match Melnikov’s stilled pianissimo. Never mind: this almost unstoppable stream of melodic inspiration emerges as if from the ferment of a true operatic drama and is every bit as involving as that description suggests.