Composed between 1968 and 1970, Acustica, for experimental sound-producers and loudspeakers, is one of Mauricio Kagel's radical and extraordinary works, in which his constant search for ways of escaping from the restraints and conventions of traditional musical performance took him into a world of exotic instruments and almost surreal invention. The instrumentation for Acustica is a huge array of sound sources: there are folk instruments collected from around the world and from different periods in history alongside a vast array of devices that Kagel invented himself - from pebbles dropped into a bucket of water to a gramophone record "played" with a penknife stuck in a tin can - all of which he notates meticulously. The order in which they are played and overlapped, however, is left entirely free - the only fixed element in the composition is a pre-recorded tape that adds more musique concrète sounds to the mix - so this disc contains two realisations of Acustica by the five players from TAM Theater, with the composer controlling the tape playback. Both broadly follow the same plan, for Acustica is essentially a musical continuum in which the structures of the sound gradually shift as different instruments join or leave it.