KTL formed in 2006 to specifically provide the sonic
accompaniment to Vienne and Cooper's Kindertotenlieder production, from which they took their moniker. Previously Rehberg had been Vienne's composer of choice for several years where his queasy electronics helped intensify her delirious blend of life-size puppets and live performers that somehow managed to confuse the two in the
minds of her audience. But in Kindertotenlieder Cooper's disarming dialogues wove a tale of teen murder that, perhaps, with parallels to black metal's troubled beginnings, required Sunn O)))'s O'Malley, who had arguably been making the most wayward experiments with the form, to provide additional cult dimensions. This work stretched over their first three numbered releases, then, after the pair toured extensively as an improvising unit throughout 2007 and 2008, they released their first non-soundtrack work together - KTL IV. Produced by Jim O'Rourke it was perhaps the most successful fusion of "Extreme Computer Music and Black Metal" as their first release had put it.

Yet, for KTL V's finale, instead of layers of blackened guitar noise, 'Last Spring' has a vocal performance from Jonathan Capdevielle at its centre (who can also be heard on Rehberg's excellent earlier soundtracks collected on Work for GV 2004-2008). Here he performs a French translation of Cooper's deranged dialogue between a disoriented boy and his hand puppet (both of which are 'performed' by automatons in the resultant installation). Capdevielle's strains alternate between a timid teen and his more venomous inner voices. Throughout this psychological power play creeps KTL's insidious soundcraft, this time made with just computers and contact mics, their uneasy processing subtly gilding the unnerved narration.

Even though this last track takes up over a third of the album and reunites Rehberg and O'Malley with Vienne and Cooper's theatrics, KTL V seems, on the whole, several evolutionary stages removed from such origins. Instead it brings to light the pair's passion for minimalist and avant-garde composition rooted in post-war US and European academic institutions.

Indeed, the opening piece 'Phill 1' and its companion piece 'Phill 2' were recorded in Stockholm's Elektronmusikstudion, a reknowned international hub for innovation in electronic composition, while their titles hint at both drone pioneer Phill Niblock and the City of Prague Philharmonic Orchestra that perform on 'Phill 2'. The original piece is simply guitar and modular synths unfurling extended layers of elegantly sinking tones, while 'Phill 2' sees Jóhann Jóhannsson orchestrate the original into an exquisitely simmering tension.

Perhaps more famous than Elektronmusikstudion is Paris' Ina GRM studios, whose rich history stretches back to the very beginnings of electroacoustic music. Shortly after KTL V the pair began lovingly reissuing classic GRM recordings via a dedicated sub label of Editions Mego. For KTL V though, O'Malley and Rehberg got their hands on one of its state-of-the-art recording facilities to produce 'Study A', a dense computer-only composition. Its constant but delicate morphing timbres stretch and slide to slowly stir a wide range of states, from a meditative calm through worried pastures, into a traumatic torpor and all the way back again. It is followed by a similar spread simply named 'Tony', perhaps nodding to the droneworks of US artist Tony Conrad, as it parades layers of swirling artefacts produced by the colliding harmonics of extra long guitar and computer tones.

Drone is such an awkward, limiting word though, with its old-fashioned negative connotations and the terms more modern use as a genre in its own right. But neither seems satisfactory as it feels more like a mere element that can be employed in music just like rhythm or melody or song. And for much of KTL V this elusive element is deployed to awesome effect, creating sonic sustenance that reaches far deeper into the psyche than their previous compellingly bleak and monochromatic soundtracks to feel on the whole less threatening and more refined, provoking a full spectrum of colourful emotions.