The borders between prog and metal have always been porous, as Massachusetts-formed (and now Berlin-based) quartet Elder clearly understand. They began their own migration from craggy, red-eyed stoner-rock to proggy nirvana with 2015’s latently sophisticated Lore. Their sixth album, Innate Passage, strikes their most polished and satisfying balance yet between ground-shaking heaviness and lofty ambition.

The magic of Innate Passage lies in how lightly the group wear their instrumental mastery. There’s precious little showboating or self-indulgence, the wild flourishes always in service of the drama, the moment. The expansive playing of Nick DiSalvo (vocals/guitar) and Mike Risberg (guitar/keys) is anchored by a sensitively virtuosic rhythm section as capable of deft complexity as pulverising heft. And while all five of the album’s tracks are epic in length and aspiration, they also share a taut focus, a restless energy. Something is always happening, be it the serpentine groove and electrifying guitar crescendos of Endless Return, the elegant tidal force of The Purpose or the ever-shifting rhythms, mellotron textures and wild, synth-driven math-rock of Coalescence.

DiSalvo’s harmonious, high-register vocals are a key element of Innate Passage’s characteristic graceful power, though the lyrical concepts are vaporous to the point of being superfluous. However, the group’s riffs offer a lucid narrative of their own. The epic Merged in Dreams – Ne Plus Ultra morphs from trancy, quasi-ambient synth reverie to post-rock colossus and back again several times across 15 majestic minutes, its masterful, slow-building might recalling forebears and fellow-travellers Mastodon and Cave In. Throughout Innate Passage, Elder prove themselves those bands’ equals.