It's hard to describe Heiner Goebbels' homage to the Austrian writer Adalbert Stifter (1805-1868), whose descriptions of the natural world have been admired by generations of writers – from Rainer Maria Rilke and Thomas Mann to WH Auden and Marianne Moore. When it was first presented in Lausanne in 2007 Goebbels categorised Stifters Dinge (Stifter's Things) as a "performative installation"; it came to London the following year. The "performance" comes from five grand pianos, all played in different mechanical ways and forming part of a set that, in the course of an hour, inches menacingly towards the audience across tanks of inky black liquid only to retreat again. The pianos stumble out repeated morse-like signals, Nancarrow-style cascades of notes and the slow movement from Bach's Italian Concerto, while samples of industrial noise, ethnographic recordings, interviews with Claude Lévi-Strauss and Malcolm X, and readings from William S Burroughs and Stifter himself play in the background. It's a typical Goebbels collage and typically, too, all the elements somehow cohere. Even on disc it's mysterious and compelling.