Much of the build up to Slave Vows - The Icarus Line's fifth record - has focused on the raw nature of its inception. With the bulk of the writing process thrashed out in the studio prior to recording, the whole thing was in the can by the end of two furious months, with the bulk of the album cut live with the band in the same room. Here's the thing, though; if you go into Slave Vows expecting to hear something scratchy, lo-fi or coarse, you aren't going to get it. It's a surprisingly polished effort.

'Dark Circles' is the mammoth, eleven-minute opener; it whirs slowly into life, increasingly furious guitars crashing over screeching feedback, with Joe Cordamone's desolate vocal not breaching the noise until well past the seven minute mark. That initial maelstrom of noise is by no means an inaccurate representation of the band's frenetic live shows, but it hardly sounds off-the-cuff either; it's a calculated, measured build-up. Like the record's other lengthy cuts, 'Dead Body' and the appropriately-titled 'Marathon Man', there's obvious consideration, on the band's part, of precisely where it's appropriate to bring in a wall of guitars, or a percussive eruption. There's clearly method in the mayhem.

The Icarus Line are really at their best when they're playing around with the intensity dial in this fashion; the record's standout, 'Laying Down for the Man', makes terrific use of the loud-quiet dynamic - it's a five minute thrash of a punk song that isn't afraid to tone things down in the midsection in order to accentuate the incendiary nature of its climax, the kind of thing Refused proved so adept at on The Shape of Punk to Come.

So gripping are the bands experiments with dynamics, though, that the record can feel a little disjointed when they try to move away from that aspect of their sound; 'City Job' is probably the most melodic, hook-driven track on the LP, but ends up coming over a little bit one-track, whilst the nods to more traditional rock tropes on 'Don't Let Me Save Your Soul', particularly the solo-driven outro, are likely to prove divisive.

If you've ever wondered precisely what is meant by the term 'post-hardcore', you could do much worse than turn to Slave Vows for a definition. This is a record that's been thought through too well, that's been delivered with too much finesse to be merely considered hardcore; there's too many nods to other sub-genres of rock music on what is a genuinely progressive album. The real crowning achievement, though, is that Slave Vows has largely turned out as The Icarus Line intended it to; their live energy is faithfully reproduced, but without disregard for some of the flourishes that two months of studio time allow for - this is surely the year's most blistering rock record so far.