‘Placid and melodious’ is how The Record Guide (1951/55) described these clarinet sonatas, the verdict of placidity contradicted by many performances on modern clarinets and pianos beginning perhaps with Frederick Thurston’s 1937 recording of No 2. In 1990 Keith Puddy and Malcolm Martineau bucked the trend by offering them on instruments of Brahms’s day, Puddy playing Richard Mühlfeld’s own B flat clarinet – closely pitched to A=440, designed by Carl Bärmann and built by Georg Ottensteiner – Martineau an 1881 Bechstein. Lorenzo Coppola plays a Schwenk & Seggelke copy of a similar clarinet, Andreas Staier an 1875 American Steinway.

Neither Coppola nor Puddy makes any claims to imitation of Mühlfeld’s style. And common instrument notwithstanding, their differences in tone are probably due to choice of reed or even individual physiognomy. Coppola, however, draws attention to Brahms’s phrasing, especially the ‘short slurs’ which exist both individually and within longer phrases. A quarter of a century ago, Puddy respected many of these details too, more so than did others. But his largely stark delivery doesn’t match Martineau’s flexibility and his blunt phrasing lacks the ductile ‘give’ of musicians such as Gervase de Peyer (1968) or Emma Johnson (2011).

Clashes of personality don’t occur between Coppola and Staier. They interpret the texts within a framework of mutually passionate advocacy, rubato expressed through an elasticity of tempo that hews closely to the pulse, clean textures achieved through playing that reflects the timbres of each instrument. And Coppola doesn’t elide slurs. He heightens their differences subtly yet markedly. Staier is every bit as artistically distinguished a partner; and soloist too in Op 118, the last piece (Intermezzo in E flat minor) exemplifying his comprehensive understanding of mood, pacing and tonal refinement. Superlatives all round.