Qua

Forty years young as a band next year, Cluster's venerability is not unique in terms of the movement they are most often associated with - the Krautrock scene of 1970s Germany, which was footloose, sincerely experimental and in many cases highly influential. Yet their synthesiser-driven approach to avant-garde rock, sometimes ambient and abstract to the point of being beyond 'rock' as it is generally understood, was at one time like pretty much nothing else in existence. Small wonder that Brian Eno, who also developed radical concepts of 'ambient music' in the 70s, sought out the duo of Hans-Joachim Roedelius and Dieter Moebius for a series of collaborations.

All of which is a lofty legacy to live up to as Cluster, both members now of pensionable age, release their first studio album since 1995. Seventeen tracks long and requiring a hardy level of concentration, it won't change the face of music, but given that these fellows have already played a part in doing just that, such a request would be unseemly. Qua is timeless in its lack of concern for the world outside the studio; save perhaps for some minor details regarding electronic technology, this could have been made at any time in the last two decades at least, and is no worse for that.

Pieces like Na Ernel recall, in circular fashion, the ambient/dub techno types whose ancestry lies in Cluster themselves; other tracks such as Putoil or Albtrec Com (the songtitles on Qua appear to be largely words of their own creation, as if the hermetic feel wasn't already emphasised enough) are more playful, employing near-comedic burps of synthesised sound or chubby, lolloping rhythms. Percussion is often employed less as a rhythmic device and more as a kind of musical analogy for tolling bells, with the portent and unease that implies.

New arrivals at the gates of Cluster would probably be most sensibly directed to 1974 album Zuckerzeit, or more meditative turns like 1979's Grosses Wasser. Time spent with this band in general, however, will make the contents of this worthy - if likely to be impenetrable for some - comeback album fall into place.