It’s violinist Andreas Seidel and pianist Steffen Schleiermacher’s bad luck that their recording of Morton Feldman’s 1982 For John Cage – recorded in 2009, released now presumably as a nod towards Cage’s centenary year – had to follow in the wake of Darragh Morgan and John Tilbury’s 2010 performance on Matchless, the small Essex-based indie label that consistently punches above its cottage-industry weight. ‘Definitive’ isn’t a word to be brandished lightly but the sheer sonic loveliness of Tilbury’s softer-than-soft softs and Morgan’s salamander zigzag slide around Feldman’s self-renewing lines is, you guessed it, matchless.

Morgan opts to play with a Baroque bow, Seidel’s tone sounding businesslike and efficient in comparison, while Schleiermacher can’t match Tilbury’s endlessly malleable turnaround of pianistic colourings. MDG’s For John Cage might well be supplemented with Feldman’s early violin-and-piano miniatures – including the all-too-rarely-heard Spring of Chosroes and the rare-as-hen’s-teeth For Aaron Copland – but the main feature is a notch below Morgan/Tilbury and probably below Marc Sabat and Stephen Clarke on Mode, too. Seidel and Schleiermacher play an idea of the music; Morgan and Tilbury play the thing itself.

But every Feldmanista will want a part of ‘Crippled Symmetry: at June in Buffalo’, the debut release on the new Frozen Reeds label. Eberhard Blum, Jan Williams and Nils Vigeland were the core members of Feldman’s own touring group and cut a classic studio Crippled Symmetry for HatArt in 1990. How does this live Crippled Symmetry, recorded in 2000, compare?

That’s a tough one to answer, not only because of the music’s cosmic scale – it sprawls over a 90-minute duration – but because Feldman has twisted the usual function of notation against itself. Pitch, rhythm, dynamics, articulation are exactingly written out but each player’s part is rhythmically cut loose from the rest of the ensemble. As performers, the sense of three musicians zoning into an emerging ‘rightness’ that only their intuition about sound can define – never how the music looks on the page – makes us raise our game as listeners.

It’s an exhilarating process. Landmarks float by rather than fix points of arrival and we’re jumped into having an active, moment-by-moment relationship with Feldman’s material. As a reviewer all I can say is that this performance is exceptionally sensitively heard and expertly measured. After playing it for 10 years, I guess the music was etched deeper inside their souls too. And so we’re talking about another essential layer of jam squeezed inside the doughnut of our understanding – more important than an ‘alternative’ recording in the usual sense.