A reliable metric for measuring pop success is hard to find these days, as Michael Hann noted in these pages recently. Massaged figures for sales and streams are so opaque as to be almost meaningless. The charts are old news; social media reach wildly distorting. Bon Iver have won Grammys and released platinum-selling albums, but that was a decade ago. Such accolades feel oddly old–fashioned now.

Perhaps the most assured barometer is the traditional one of bums on seats – by which gauge Bon Iver appear to be doing just fine. Yes, they are a band lacking any semblance of a song your postman could whistle. And yes, they are fronted by Justin Vernon, a doggedly unstarry fortysomething in a rumpled T-shirt and headband.

But still. Roughly 10,000 bums are here tonight, by my reckoning, to witness Bon Iver bring a fresh twist to the choreographed arena experience. Here’s a band which understands that in the age of bedroom pop and headphone rock, you don’t always have to shout; the bold move is to sit back and let the audience inch towards you. The resulting experience isn’t so much immersive as compellingly internalised. It almost feels like each of us is privy to our own personal performance.

I first saw Bon Iver play in 2008, in a deconsecrated church in Edinburgh. Back then, the mood was snowbound Americana: bare-backed indie-folk songs, heavy on lamentation. In the ensuing 14 years, the medium by which Vernon delivers his work has radically shifted. Collaborations with Taylor Swift and Kanye West have made him pop and hip-hop literate. The songs remain soundly shipshape below the waterline, but up top they come decked out in hazy post-digital regalia, blending gospel, R&B (in the modern sense), soul, blues and rap, with a nicely disorientating glaze of experimental electronica.

What has remained constant is the music’s melancholic beauty, which finds a lightning rod in Vernon’s moonstruck falsetto. When the singer uses Vocoder to manipulate his vocals, it’s to make them rougher, not smoother. Collectively, tonight we tacitly agree that it’s not a voice you’d wish to tread upon. Unusually for an arena show, the (many) quiet parts aren’t Polyfilla-ed with whoops and shrieks. The masses are really listening. Those who are standing barely move.

Vernon wears chunky headphones throughout, for all the world like an off-duty lumberjack at a silent disco. At one point, he covers his eyes with his hand, meaning he can neither see nor hear us. At other times, he throws back his shoulders and jabs his index finger into his chest, gesticulating like a rapper. The richly textured sound and an ingenious geometric lighting rig provide the sense of a show. The six musicians focus on making the music.

Traces of Vernon’s troubadour roots poke through on ‘Skinny Love’ and an untitled new song, where his acoustic guitar is accompanied by lilting soprano saxophone. ‘715 – CR∑∑KS’ and ‘Holocene’ are quite devastatingly beautiful, but Vernon tends to challenge the natural splendour of his voice and music by throwing sonic bombs into the fray. ‘10 dEAThbREast’ is less a song than a test, punctuated with blocks of noise and distorted vocals. ‘iMi’, which starts as a gorgeous 1970s style soul ballad, is deconstructed to the point where the act feels wilfully obtuse. Just as ‘33 “GOD”’ is building up a head of steam, it crumples.

You suspect Vernon takes these steps because otherwise his songs might be fenced in by their limitations. Some of them are, anyway. The chugging soft-rock pulse of ‘Lump Sum’ and ‘Calgary’ recalls War On Drugs, U2 and Bruce Hornsby & The Range. Pleasantly sluggish, soothingly smooth. Near the end, ‘Blood Bank’ proves Bon Iver can do big-barn rock dynamics if they choose, but it’s not that kind of show. It’s not any kind of show, really, and all the more memorable for it.