Éliane Radigue’s music is like the ocean.

When she left New York, crossing the Atlantic to return to her native France, after an early 70s spent sharing a studio at NYU with Rhys Chatham and Laurie Spiegel, Radigue left something behind: the keyboard of her ARP 2500 synthesizer. She had no more need of notes. No more sharps and flats and clefs and crotchets. Only waves.

The Trilogie de la Mort, composed after her return to Paris, between 1988 and 1993, begins with no more than a ripple. But each of its three sections opens up from a simple pulsation to a vast expanse of manifoldly fluttering frequencies, all swelling and cascading together. In the right space, it is capable of a very fragile sort of magic.

Unfortunately, the Purcell Rooms is not quite that right space. It lacks the resonant liveliness of the kind of stone-walled or concrete venues that really suit the piece. Eschewing the desire to fabricate the illusion of real space built into traditional stereo, the two channels of Radigue’s Trilogie need to be activated by the acoustics of the room to bring them together, for them to rise up as one and bloom and sing. This afternoon, they kept their distance, hovering, like shrinking wallflowers, in the vicinity of their respective loudspeakers. Still a delightful listening experience, but not quite the overwhelming sonic tide it could have been.

Either that, or I was just too distracted by my neighbour in the back rows. This guy next to me, blue hoodie and chunky framed glasses, is literally stroking his Apple Watch every three fucking minutes throughout the piece. He’s checking his messages, reading the latest headlines, just idly scrolling through his apps. The Trilogie de la Mort is a long piece – three hours spent eking out the harmonics of electronically generated tones. It takes investment, concentration, a certain mindset. Not some dickhead’s wrist-torch glaring in your face every few minutes in the darkness of the room. At one point the guy actually started drumming his hands on his lap. Éliane Radigue’s ocean of sound was for a few brief seconds accompanied by the patty-pat-pat of this chump’s thigh-bongo session.

But I don’t know. Maybe it’s weird that I got so worked up about this. Maybe there is something about this particular performance situation that makes me a twitchier, more intolerant person. The room is dark, there is nothing on stage, it’s three hours long. That’s about the same length as Avengers: Endgame but suffice to say there are significantly fewer explosions in La Trilogie de la Mort. Radigue seems to ask us to be an ear and nothing more. Perhaps no real human person is good enough for her music.

About six years ago, I met the American composer Tom Johnson at a brasserie in the eleventh arrondissement of Paris. As a music critic for the Village Voice in the 70s, he was one of the very first people to refer to “minimalism” in music. As he sees it, he told me back in 2013, there is not one minimalist music – but five different kinds: repetitive music, drone music, music of limited means, music of minimal differences, and silent music.

At the time, with Another Timbre’s compilation of still, quiet sounds, Wandelweiser und so Weiter just recently released, it was this last category that Johnson was the most excited by. But for some years now, as far as London concert programmers have been concerned, ‘minimalism’ has almost exclusively meant just the first of Johnson’s categories. We have been fed an almost endless diet of dull Steve Reich and boring Philip Glass and their even more tiresome contemporary imitators like Max Richter and Nils Frahm. A wall to wall parade of over-lauded ‘menimalists’ (a felicitous coinage that I owe to Jennifer Lucy Allen). In the face of that, the Southbank Centre’s Deep Minimalism 2.0 festival is far more than welcome. It is an urgent necessity.

Here we have the drawn out drones of Radigue’s Trilogie. We have the ‘limited means’ of Kathryn Williams’ works for a single breath, a performance which saw the flautist subjecting her instrument to whispers, taps, screeches, and roars. She played lying down, stomping on the floor, and partially submerged in water. A catalogue of inventive ideas, delivered with singular wit and dedication. We have the minimal variations of Hanne Darboven’s ‘mathematical music’, in the form of her Requiem, played on the organ by James McVinnie, and Wunschkonzert, a work for cello performed by Oliver Coates, each one a rich exercise in spirals of arpeggios. Always different but always the same. And then we have the super-soft pianissimos of Morton Feldman’s Triadic Memories, a work so tenderly knitted as to almost evanesce. So still, it’s like a sculpture that we can walk round and observe from every angle.

There were other treats on the weekend’s menu, too. Mary Jane Leach’s Trio For Duo, in which fragile voice and bruised flute seemed to melt into each other, conjuring the resonant spectre of an absent third party. A tender tapestry, always in subtle flux. There was the quasi-medievalist minimalism of Laura Cannell’s instant compositions for recorders and slack-bowed fiddle that breathed and sighed with ancient energies. There was the lush expansiveness of John Luther Adams’ Canticles Of The Sky, played with verve and sensitivity by the massed cellos of the London Contemporary Orchestra.

There were also things that seemed to have very little to do with minimalism at all – like Tod Dockstader’s Luna Park and Traveling Music, chirruping and bubbling electronic menageries that swam gleefully about the space of the Queen Elizabeth Hall. I’m not sure what Tom Johnson would have made of Dockstader’s music here (nor, for that matter of Cannell’s – Johnson seemed to have little patience for any sort of improvisation when I met him), but you know what? I’m totally fine with that. If the years of endless Reich and Glass have all been preparatory to creating a situation whereby programmers can now use minimalism as a hot brand with which to sell all sorts of weird shit, then I’m all for it. It’s wonderful to see the likes of Mary Jane Leach and Hanne Darboven getting an airing in big institutional concert halls like this. London doesn’t see nearly enough of this. I, for one, cannot wait to see what they try and get away with under Deep Minimalism 3.0.