Morton Feldman, the New York School composer, deliberately operated beyond the constraints of conventional concert life. His late period, extended duration works – many premiered in art galleries and loft spaces – have long presented a challenge for record labels. How best to present uninterrupted spans of instrumental music that, in extreme cases like his infamous String Quartet II, can stretch for up to five hours? Now UK-based label Matchless and New York new music label Mode have settled on the same solution, at the same time: audio DVD.

Mode’s recording of Feldman’s 1980 Trio (violinist Marc Sabat, cellist Rohan de Saram, pianist Aki Takahashi), and the first volume of Matchless’ complete cycle of Feldman’s music for piano and strings – containing For John Cage and Piano and String Quartet played by John Tilbury and The Smith Quartet – are both released this month, giving us mint-fresh insights into Feldman’s music…

…or should that be “art”? Feldman praised John Cage for shattering the narrative-driven structures that many American composers – Copland, Virgil Thomson, Roy Harris for instance – had inherited from European tradition. As Alex Ross mentioned in the April Gramophone, Feldman explained Cage’s work as an “art form” rather than a “music form”; but that distinction applies equally potently to Feldman’s own work.

The wow-factor audio DVD brings with it is, of course, hearing For John Cage and Piano and String Quartet (through your television set or computer) without needing to flip between discs, thus rupturing the culminative flow of Feldman re-configuring, re-organising, re-mixing his trademark paired-back gestures into overarching structures. Which mightn’t sound a big deal, but cutting Feldman into arbitrary slices is like waking up in the dead of night: you’ll get back to sleep, yes, but never quite as deeply. The Mode DVD is recorded in 5.1 surround sound which, technology allowing, means you could, literally, walk around Feldman’s Trio: more sound installation than piece of music. A quarter of a century after Feldman died, the recording industry has finally caught up with him.

Also on the Matchless release schedule: Sounding Music by improvisation group AMM. Again John Tilbury on piano, with Ute Kanngiesser (cello), John Butcher (tenor and soprano saxophones), Eddie Prévost (percussion), and Christian Wolff, another New York School survivor, plays piano, bass guitar and melodica. During the group’s four-decade history its obsessions have remained constant: an AMM performance, no matter who plays, generates itself by participants subsuming their personalities into collective, centred sounds. Sounding Music is stuffed with strikingly beautiful moments. Like Prévost extracting caterwauling overtones from his tam-tam that Kanngiesser’s cello echoes and develops. And like Feldman, AMM constructs a musical narrative from a tactile relationship to sound. Like Feldman, like AMM.

Philip Clark