Nannette Streicher’s new piano was a six-octave godsend for Beethoven. And the next year, 1808, he ran the full gamut – from the F three octaves below middle C to the one three octaves above it – in Op 70 No 2. The lowest note first appears at 1'10", three bars before the end of the introductory Poco sostenuto, but Alexander Melnikov doesn’t make much of it. Left-hand reticence? Or is he a touch backwardly placed? Either way, his bass-line doesn’t always speak clearly, but comes into its own in the C minor variations of the second movement and an authoritative finale. Otherwise his leadership varies. Often he leaves Isabelle Faust and Jean Guihen Queyras to compensate in conceptually a large-scale interpretation. Of course, changes in levels and instrumental balance even within movements don’t help.

Concept comes closer to reality in Op 97, though a piano that regularly shifts position between centre and right is an added distraction. Yet Melnikov is in greater command both of harmonic undertow and his role in the partnership. Tempi are swifter than expected in the first three movements but only in the third, Andante cantabile ma però con moto, is a shortfall in profundity really felt. If the inexplicable – and damaging – decision to omit the long repeat in the Scherzo is a lapse, the finale offers a high point in its ideally judged Allegro moderato, the coda a fierily charged Presto. In sum, a curate’s egg.