"At the heart of this album is a magical new recording of Karlheinz Stockhausen's Kontakte, music that makes 'contacts' between sounds from the past and sounds made now. From February 1958 until May 1960 Stockhausen worked in the Elektronische Musik Studio of Westdeutscher Rundfunk, analysing instrumental sounds, making technical experiments that he documented in over 600 pages of sketches, and eventually generating, recording and processing the sounds that make up the electronic music of Kontakte. Stockhausen's original conception was that the performers would respond to this soundworld as the tape was played back through four loudspeaker groups surrounding the audience. He imagined a performance with three percussionists and a pianist, each of whom would control the sound level of a channel in the tape part while also reacting freely to what they were hearing in the tape part. But as he later told Robin Maconie, 'I started to rehearse this and it was a real disaster. The musicians did not know what to do.' Instead he made a score, for a single percussionist and pianist, that showed them what to do.

When it reached its first audience, premiered by the pianist David Tudor and percussionist Christoph Caskel at the ISCM Festival in Cologne on 11 June 1960, Kontakte was immediately recognised as a bright new star in the expanding universe of electronic music. The tape part was bolder, grander and more technically sophisticated than any previous electronic work and the interchange of sonic textures between recorded sounds and live instruments had a sense of liveness never heard before. Stockhausen's score offered Tudor and Caskel, and all the musicians who have subsequently played Kontakte, the possibility of making magic: to create the illusion that the electronic and instrumental music is being invented in the moment of performance.

Stockhausen's musical world is made up of opposites - long and short, high and low, loud and soft, dense and singular - but all these opposites are linked by scales of connection along which the music of Kontakte travels in every direction. Continuous electronic tones turn into pulses, noise-rich sounds emanate from the percussionist's cymbals and then fly between the loud-speakers, each of these contacts reminding us that this music is also making connections in time. The music travels across time, bridging the years that have passed since Stockhausen spent all those hours in the WDR studio to our moment of listening now, and between different types of time, combining the fixed time of the tape with the flexible time of live performance. And Stockhausen would want us to go further still, to try and imagine what lies beyond the perceptible limits of these scales of connection: that beyond the longest sound there is a sound that lasts for all eternity, or that there are sounds that inhabit dimensions beyond our human perception. The end of Kontakte seems to suggest that this music is on its way to just such a space.

If Kontakte is the star of this musical universe then the other two works on the album, Spiegelung and Geschichten der Gewalt, are perhaps planets in its orbit, owing their existence to the energy it emits but quite distinct in the sorts of musical life they support. Spiegelungen is an improvisatory, exploratory prelude, music to prepare us, opening our ears for what is to follow. The three elements that will combine in Kontakte - piano, percussion, electronics - are introduced, first in intimate close-up - we hear the grain of piano strings, noises from the instrument's frame, the surface of drums and gongs - then in the middle distance, the electronic processing always selectively amplifying, echoing and looping the acoustic source sounds.

Improvisatory exploration is also important in Geschichten der Gewalt, by the Swiss saxophonist, sound artist and composer Antoine Chessex, although its descent through three 'frequency zones' traces a far more singleminded trajectory than either Spiegelungen or Kontakte. The pianist's repeated rising four-note figures are to be played 'as fast as possible' but the score suggests that 'slowing and accelerating' will help her 'to engage with the frequencies of the piano's resonant body'. The percussionist is also asked to 'slow or accelerate' the continuous rolls that he plays on three large ride cymbals, each with a different resonance to match the three frequency zones; the result should be 'a carpet of sound' into which the frequencies of the piano can 'melt'. The final element of this music is a continuous frequency glissando, diffused through two loudspeakers behind the piano and cymbals, 'gluing the instruments together'.

Kontakte is more than sixty years old. Its contacts between acoustic instrumental sounds and electronic music, its multi-dimensionality and its invitation to time travel, all promised a future in which humanity might transcend the limitations of material reality. In Spiegelungen and Geschichten der Gewalt the electronic sounds emerge as transformations of that reality."-Christopher Fox, from the liner notes