After records of abstract experimentation for films, art installations, and theatrical performances, KTL's IV sees Sunn O)))’s Stephen O’Malley and electronic artist Peter Rehberg team up with Jim O’Rourke on production duties for what is being described as their first studio album that exists without reference to accompanying visual stimuli.

For those unfamiliar to O’Malley and Rehberg’s collaboration, KTL deal in the higher frequencies that make for the most serious assault upon your hearing. When I saw them play at the usually appalling KOKO last year, the sound was so intensely high-pitched that it was impossible to make out the shouted conversation of even the person standing next to me as the room was washed with noise. A similar effect has been achieved on KTL’s various records to date. On II, for instance, the twenty-seven minute ‘Theme’ becomes an unstoppable force without you noticing a dynamic switch, its progression from quiet murmur to monster akin to following a small stream from its trickling source high in some mountain pass, following it for twenty-seven compressed minutes until it cascades in a welter of foam and noise, each tiny drop of water intangible against the mesmerising torrent.

IV, though, presents the listener with a record of greater complexity, but just as much power to evoke as the more soundtrack-focussed work. Take ‘Paratrooper’, for instance. Its airborne cavalry pour forth what seems to be glowering and gutteral chant. At this, atonal guitars slash and swipe and a heavily processed drum sound pushes and hisses, piston-like. Somewhere, innocent bells try to ring out before being instantly suppressed - this is an album that feels heavy, dystopian.

A deep “brrrrrr” amidst the crunches and whispers of ‘Benbbet’ is akin to patrolling a misty, snow-covered landscape and hearing a heavy machine gun open up at your flank, the sound dulled by the conditions, but unexpected and terrifying nonetheless. The drones of ‘Wicked Way’ are topped by a dry, flicking pulse, a primitive waterwheel now turned only by sand after a long drought. On the 'Eternal Winter' and closer 'Nature Trouble', the most ambient tracks here, the bright glare of treble no longer obscures detail as if it were sunlight reflected off an endless glacier, but forms part of a piece where the contract comes through subtle juxtaposition of colour, form and texture.

It’s a contrast between the evocation of technology and the sublime power of nature that, to me, is the aesthetical strength of IV - and, indeed, much of KTL’s output thus far. It is on IV that the partnership between doom and industrial musics O’Malley and Rehberg have realised this to fullest, and most satisfying, effect.