Doom metal moves slowly; that’s its calling card. For London death/doomsters Indesinence, it’s also a career dynamic. Though this band formed in 2001, they’ve produced just three LPs in their run, including the upcoming III and 2012’s underappreciated Vessels Of Light And Decay. That’s a little better than one album every five years on average. Perhaps Indesinence’s output suffered in earlier years because of the lineup’s busy schedules — between current and former members, this band has ties to Code, Binah, Pantheist, Esoteric, Fen, Cruciamentum, and Grave Miasma, among others.

Whatever the cause, Indesinence’s patience has paid off. As good as Vessels Of Light And Decay was, III improves upon it substantially. Though the lugubrious lurching and cavernous tones that characterized Indesinence’s past work still constitute the core of this album, the band has paired them with ambitious song structures and smoky, psychedelic textures that reach far beyond the constraints of their home genre. “Mountains Of Mind” is an excellent example of this dynamic. It opens with a squelching crawl that gradually builds to a death metal sprint, which in turn segues into a synth-led prog metal jam that reminds me of nothing so much as Edge of Sanity mastermind Dan Swanö’s short-lived Moontower project. And then, without missing a beat, Indesinence bust out a full cover of the Third Bardo’s ’60s psych rock gem ““I’m Five Years Ahead (Of My Time).” These guys are crazy enough for even thinking to try this stunt, but it’s even crazier that the results actually work. Somehow, this 15-minute exercise in idiom-hopping feels like a single, cohesive experience. Experiments like this one take major balls to try, and even more skill to pull off. See for yourself.

III comes out on 7/21 via Profound Lore. Preorder here.