Frank Bretschneider — Kippschwingungen

If you wondered what made the juddering behemoth of an engine sound that opened Frank Bretschneider's last album, Komet, before it was nimbly deconstructed into the kind of pointillist teutonic techno you'd expect from the Raster-Noton label co-founder, then that's the Subharchord synthesiser. It was developed in East Berlin at the start of the 1960s influenced by Oskar Sala's Mixturtrautonium that gave Hitchcock's birds their threatening and malevolent air by dealing in electronic tones whose timbre could be changed through subharmonics - blends of synthetic 'undertones' as opposed to naturally-occurring overtones. But, despite an enhanced interface that afforded greater opportunities for unnaturally manipulating sounds, only eight were made before the increasing pace of progress confined it to history's cabinet of musical curiosities.

Just three Subharchord's are believed to have survived, one of which was offered to Bretschneider in June 2007 as part of a program of events in Berlin highlighting the city's rich heritage in electronic music and musique concrète through pairing largely obsolete technology with modern day practitioners. And, aside from some additional overdubs, editing and mixing, this new release - Kippschwingungen (Sawtooth waves) - was the full result.

Instead of alluding to cold war technologies and the oppressive environments that could hamper their emergence, the 37-minute work is a fully-formed contemporary study from within Bretschneider's customary 'audio cleanroom'. The first three parts take us on a smooth but stealthy surge through a labyrinthine air conditioning unit navigated by distant pulses, the atmosphere getting denser as a deep click regularly knits the air. But such regularity never lasts for long, surprisingly denying itself the opportunity to form anything approaching a funky beat, before the strength of the pulses describe a rolling fan-engine smoothly rising and falling in a controlled environment from which Bretschneider teases out complex Moiré-patterned rhythms.

The sixth and seventh parts (of eight) house Kippschwingungen's most climactic manoeuvres: menacing lo-end pulses build to an acidic trance before acceleration shifts the illusion once more to suggest shimmering voices culminating in an intense sonic strobe effect. Part eight concludes matters as the fan's power is cut and the pulses take their time to come to a glorious rest.

The whole piece feels like a gyroscopic ballet that places the listener centre stage as the waveforms dance around them. Indeed, Bretschneider's visualisation of the piece (a still from which is used for the front cover), used on the few occasions he has performed it live, features three-dimensional wireframes of circular shapes that act like a post-rationalised score, throbbing, spinning and morphing to highlight the subtlest of modulations in the complex mix. As such, it is the only element that feels lacking from an otherwise immersive and imaginative flight that brings new perspectives to old machines.