When doom lords Sunn O))) played the basement venue of Glasgow’s Oran Mor in 2004, the sub-bass vibrations shook the lights out of their sockets in the restaurant above. ‘I remember that one clearly,’ says Stephen O’Malley, core member, alongside Greg Anderson, of the experimental metal titans from Seattle.

A Sunn O))) gig is an intense experience, with the band dressed in their trademark grim robes, cranking out slow, downtuned riffs and feedback at extreme volume. Since their inception in the late 90s, the band have experimented with their doom’n’drone template to incorporate a variety of influences, from electronic music and black metal to modern composition and jazz.

This year’s Monoliths & Dimensions is their most expansive release to date, featuring collaborations with avant-garde composer Eyvind Kang, a Viennese women’s choir, and Sun Ra trombonist Julian Priester among others. Less claustrophobic than previous releases, the album sees Sunn O))) letting the light in to their sound, culminating in the sublime ‘Alice’, which initially recalls the desert blues of latterday Earth, before transforming into a stately ensemble jazz piece complete with a gorgeously understated solo from Priester. But don’t worry doom lovers: the album still has its share of brutal riffs and unsettling noise, not to mention the black mystical croak of Hungarian vocalist Atilla Csihar.

For this tour, the core duo are joined by Csihar and Earth multi-instrumentalist Steve Moore.

Translating the complex new material to a live setting has been a challenge. ‘We don’t have a choir on stage and we’re not using a string section either, but some of the music, structurally, it comes from the songs,’ explains O’Malley, ‘We focus a lot on the melody and the harmonic aspects of that music and it’s incredibly powerful. It’s gonna make perfect sense when you hear the music live, especially if you’ve experienced a Sunn O))) live concert in relation to the records we’ve put out; it’s a different animal. In many ways it’s more powerful, demanding, but I would say that the live aspect has grown a lot from the beauty that we were able to access on Monoliths & Dimensions.’

It’ll still be heavy as hell though?

‘Oh fuck yeah. Actually, I think there’s gonna be more equipment per member than there ever has been. Our gear keeps growing incrementally. This time I’m going to have three full stacks, six amps. But there’s also quieter parts than we’ve ever had. Steve Moore is picking up quite a lot, keyboards and a little trombone. And also Atilla, he becomes a centre anchoring point for all of the music. But overall it’s a progression of Sunn O)))’s live aspect more than anything else. The music has opened up so much and we’ve played about 50 concerts this year, so I think people in the UK are really gonna get the cream of what we’re capable of right now.’

Curiously, Scotland plays a part in O’Malley’s musical development. ‘I was in a pipe band for five years when I was a teenager, I played bagpipes. We played some Highland Games,’ he laughs. ‘There was some Scottish heritage to the school. That was actually the first place I started hearing about drone intonation. So from my own foundational musical background the bagpipes are pretty heavy in there. Bagpipes and Morbid Angel. And Black Sabbath.’

Sunn O))), Stereo, Glasgow, Sun 6 Dec.