Morton Feldman has made it to Naxos American Classics! But not with some of his more accessible pieces such as Rothko Chapel or The Viola in my Life but with the challenging late String Quartet (1979) – a single span lasting nearly 80 minutes. When I reviewed the original incarnation of this fine performance, I imagined Feldman at his piano fastidiously conceiving his sounds through some kind of psychic transmission that somehow penetrated the fog of his uniquely personal conceptual confusions.

What has changed in 12 years? With 90 works now available, that’s three times as many as in 1994, a substantial advance recognising the value of CD as a medium for Feldman. Unlike Cage he would not have welcomed background noises at a concert violating his arduously achieved sound world. There’s also more information now about Feldman with Give my Regards to Eighth Street, his collected writings edited by BH Friedman (Boston, Exact Change; London, Turnaround: 2000) and a new British anthology of interviews and lectures edited by Chris Villars (Morton Feldman Says; Hyphen Press: 2006), whose Feldman websites are most informative.

The String Quartet is long but never boring. Within the gamut of slow and mostly soft sounds there’s intriguing variety and the players often ride a high wire of demanding harmonics. The occasional loud clusters – only nine of these – are like volcanic eruptions. By the time we reach the end Feldman has taught us to listen microscopically and the stop-start of the final section seems almost agonisingly moving.