By the time they were booked to perform at the Wiener Festwochen Alternativ in Vienna in 1980, Cluster had boiled down to the duo of Dieter Moebius and Hans-Joachim Roedelius; for this concert, the two were joined by percussionist Joshi Farnbauer. By this point the group had also passed through several stylistic phases, having helped to pioneer Krautrock and dabbled in prog rock and ambient sound sculpture. In Vienna they flexed their avant-garde muscles, and the results (as documented on this two-disc set, issued here on CD for the first time) were not exactly a total success. The opening track, a half-hour-long excursion titled "Service," starts out with the floating sounds of an electronic tambura and bells (which may have been acoustic and may have been synthesized; there are no liner notes and no explanation of any of the instruments used); the sound throughout this track is wide open and nearly pointillistic. About halfway through, a guitar starts up and you think that the texture might start filling in -- but no. At the end you're left with what is essentially 32 minutes of pointless noodling. "Kurz" is more conventionally musical, incorporating sounds of piano, gentle percussion, and quiet synthesizer chords; this track segues seamlessly into the sonically similar "Piano." "Drums" opens the second disc, and consists (as one might expect) mainly of percussion sounds, starting out loosely and then tightening up into a somewhat tribal groove about halfway through. "Metalle" and "Ausgang" are drone-heavy and ambient, shifting from more shapeless twiddling into a slowly loping groove with dubwise effects. Hardcore fans will welcome this long-awaited addition to the Cluster CD catalog, but those whose interest is more casual will probably want to start with the band's more conceptually tight studio albums.