I’ve been eagerly waiting for James Ehnes and Andrew Armstrong to record the three Brahms violin sonatas. They’ve already recorded a good swathe of the violin-and-piano repertoire – and with impressive consistency, too – so I figured it was simply a matter of time. I wasn’t expecting them to tackle the pair of late viola sonatas (originally for clarinet) first, but I’m delighted they have.

Ehnes is a natural Brahmsian. His playing is richly expressive yet also completely without affectation. His is the kind of music-making that the critics I grew up reading might describe as aristocratic. And lest you worry that he’s a violinist merely dabbling on the viola, I find his rich, tightly focused tone to be a model of its kind. In every way, in fact, Ehnes is very much the equal of the greatest viola players on record, from Tertis and Primrose to Tamestit and Ridout (though, of course, Ehnes’s superb recordings of viola concertos by Bartók and Walton have proved that already – Chandos, 11/11, 6/18).

What I admire most about these new interpretations, perhaps, is their tonal range. Listen, say, to the beginnings of each of the four movements of the F minor Sonata. Ehnes is so intense in the first (I don’t quite care for the way Armstrong takes his opening four-bar intro in a slightly slower tempo, but it’s the only detail on the disc that sticks in my craw), then sweetly tender in the second, songfully grazioso (as Brahms asks) in the third and heartily robust in the finale.

The Allegro amabile of the E flat major Sonata is marvellously relaxed, and note how both musicians phrase more generously here than in the more dramatically concentrated world of the F minor Sonata. There’s an abundance of passion and fire in the central Allegro appassionato, certainly, but here, too, Ehnes and Armstrong phrase in expansive paragraphs.

The programme opens with a refined yet sharply characterised account of Schumann’s four brief Fairy-Tale Pictures and closes with Brahms’s famous lullaby, the latter played with touching sincerity. Onyx’s production team flatter both players and get the balance between the instruments very close to perfect. Now, please, bring on those violin sonatas!