How to do written justice to the delights here in hand? Artists-wise, this is a first-ever solo album from Quatuor Ébène second violinist Gabriel Le Magadure after over 20 years in the quartet. Pianist Frank Braley, meanwhile, is his longstanding personal friend, but this is their first significant musical collaboration. Then joining them for Chausson’s Concert is one of the quartet world’s very newest and brightest lights: fellow Frenchmen Quatuor Agate, pupils and mentees both of the Ébène and of former Ébène viola player turned conductor Mathieu Herzog, whose label Appassionato hosts this recording.

All of which is to say that this is an artist constellation permeated with friendship and lineage, and those themes crank up a further notch when you look to the programming, because not only are both Chausson’s Concert and Lekeu’s Violin Sonata dedicated to Belgian violin virtuoso Eugène Ysaÿe but both Chausson and Lekeu were mentees of César Franck. One final neat dovetail is that Lekeu completed his Sonata, aged 22, in 1892 – the same year that the 37-year-old Chausson premiered his Concert. Really it’s surprising that more artists haven’t recorded this pairing. Either way, Le Magadure, Braley and the Agate have set a new benchmark, because whether viewed individually or as a package, these readings are showstoppers.

Thumb through the score of Chausson’s Concert and the visual impression alone tells an eloquent story: noteyness and tight dialogue running hand in hand with ventilation; weighty power counterbalanced by utter delicacy; shapes reminiscent of long-lined rolling waves, dips and swells; all played out with constant push and pull, coloured with tremendous dynamic detail – and that is precisely what Le Magadure and friends deliver. Tempos feel spot on (the Sicilienne perfectly pas vite, the finale invigoratingly animé), with their myriad fluctuations fluidly handled. Long-view architecture everywhere. Le Magadure, on a magnificent 1729 Guarneri del Gesù, switches chameleon-like between virtuoso soloist and blending chamber musician, singing out long, supplely lyrical lines with lithe, rich, steely sweetness, vibrato sensitively attuned to the moment. Braley shapes, shades and voices with equal sensitivity and élan; he draws an especially beautiful hazy softness from his Stephen Paulello piano in the Sicilienne, where his melodic exchange with the others is one of its chief joys (if anything, I’d have liked him more clearly mf for his 1'10" exchange with the cello, but now I’m nitpicking). The Agate meanwhile are no mere accompanying force, dishing out their luminous, personality-brimming contributions to the drama thick and fast. Notice how they fuel the first movement’s euphoria – the glassy timbre of its ppp double-stops at 10'35" and the shading within its fever-pitch febrility onwards from 11'15" – or, in the tautly heart-rending Grave, the organ-like quality to some of its chordal work.

Criminally, I have left myself hardly any words to deal with the Lekeu, for which Le Magadure’s preparation extended to studying Menuhin’s annotated score. Again, though, it’s everything you could wish for. This sonata may ostensibly be from the same high Franco-Belgian Romantic, grand opéra-esque stable as the Chausson but Le Magadure and Braley’s cleanly poised reading ensures we nevertheless sense a subtly different universe. Fire and thrill, tender time-suspended serenity, it’s all to be savoured.

Add a nicely pitched natural immediacy to the capturing, and to describe this as a long-term keeper is an understatement.