The National are one of those top-tier indie bands who have reached the kind of sweet spot that most groups aspire to; practically unanimous critical acclaim, enough commercial viability to secure top five positions for their last two records on the Billboard chart and a global fanbase with suitable breadth to ensure they play huge venues around the world, from London's O2 Arena to the outdoor forecourt at Sydney Opera House. They've achieved all of this, though, whilst still largely being able to walk down the street without being recognised or pestered (even if the increasingly shaggy Matt Berninger looks as if he wants to stand out from the crowd) and whilst both their frontman and twin guitarists Bryce and Aaron Dessner have a certain degree of status within the alternative world, with the latter pair increasingly established as producers and composers in their own right, The National's other band of brothers have retained a degree of enigma and anonymity even within the goldfish bowl of indie rock.

Bryan Devendorf's intricate, mercurial approach to the drums, which so often has him segueing between time signatures, has long been the group's secret weapon, with Scott, his considerably less hirsute sibling, quietly crucial on bass. There's always been a suggestion that their own musical tastes might veer away from that of the rest of The National, from the atypical nature of their playing for an otherwise straightforward indie rock band to the comment in Mistaken for Strangers, the documentary by Berninger's brother Tom, that the pair seem "more metal" than their "coffee house" bandmates. Here, they go some way to proving that correct without ever breaking truly free of their day jobs; Ben Lanz, of 4AD stablemates Beirut, rounds out the three-piece lineup of LNZNDRF, a dreadful name that's at once both lazy ("Chardee Macdennis", anyone?) and unpronounceable.

Lanz puts down his trombone and picks up the guitar, providing the trio with the necessary basic components for some pulsating, unrelenting paeans to their favourite krautrock influences. Half of the album's eight tracks are instrumentals, and once opener 'Future You' finally bursts out into the open from a couple of minutes worth of tumultuous feedback, Lanz's heavy, effects-laden guitar work conjures up an oppressive mood over the top of playing that is idiosyncratically Devendorf; a churning bassline from Scott, those little hurried fills from Bryan. It's on these instrumental cuts that LNZNDRF really comes into its own; the atmosphere is palpable, especially on the airy, experimental 'Hypno-Skate', with its thumping percussion and subtle synth swirls, and the thrillingly tense closer 'Samarra', which plays like a particularly ominous six-minute Can jam, complete with clever nods to industrial touchpoints.

It doesn't feel as if there was really any need to lend vocals to most of the record's tracks, and it should be noticed that the cuts here that do have either Lanz or Scott singing over them would stand out from the others anyway; they tend to be less freeform and more rooted in traditional structure, usually referencing psych-tinged rock outfits from the eighties, with 'Beneath the Black Sea' is a case in point. The plodding 'Mt. Storm' feels stop-start - waves of reverb crashing down one minute, before dissipating the next - but, whilst the vocal turn on that effort actually helps propel it out of a rut, the corresponding falsetto on 'Kind Things' detracts from what is otherwise one of the album's most diverse efforts, from its sunny, off-kilter beat to its chiming guitar work.

LNZNDRF was turned around in two-and-a-half days flat in a church in the Devendorfs' hometown of Cincinnati; surely, then, the idea was never for the band to overthink these songs. The result is an interesting mish-mash; some stunning instrumental work in the vein of some of their heroes - Neu!, especially, spring to mind - and a mixed bag of stabs at poppier territory that nevertheless speak favourably to the trio's ear for melody. It's also a fascinating insight into what makes The National tick; they're a ragtag bunch, from their psych-leaning rhythm section to their perma-sloshed epic poet of a frontman, but the five clearly share a broad, genre-fluid musical sensibility. LNZNDRF might feel a little esoteric to fans of the Devendorfs' back catalogue, but it's a heavyweight enough effort to hopefully ensure that it won't be a one-off.