"The scale of electronically produced timbres contains familiar tones, sounds and noises, and mediates between them (metallic, skinlike, woodlike etc.); it allows for the transformation of timbres from each of these categories to any other, and for their mutation into completely new and unfamiliar sound events.
 
"The title refers both to contacts between electronic and instrumental sound groups and to contacts between self-sufficient strongly characterised moments. In the case of four-channel loudspeaker reproduction, it also refers to contacts between various forms of spatial movement."
 
"Nearly all the electronic sounds were produced with an impulse generator (the speed of the impulses could be varied continuously between 16 and 1/16 impulses per second, the duration of these impulses being variable between 1/10000 and 9/10 seconds). I also used a tuneable selective amplifier (used as a fairly narrow filter) with continuously variable band-width and correspondingly variable decay periods. A scaled band filter was also used. A few isolated sound events were produced by sine wave generators and a square wave generator.
 
"Most of the sounds, sound-noises and noises were produced by multiple acceleration of rhythmic impulse sequences. For some sounds an echo-plate with continually adjustable echo-lengths was used."
The multiple acceleration of rhythmic impulse sequences is explained in the Kurtz Stockhausen biography (publisher Faber & Faber, p. 100; composer's comments between quotation marks):
Rhythms were spliced together from pulses, and loops from the rhythms. These were allowed to run for hours and the entire result was recorded. In a neighboring room a new loop was prepared, and also in a third.
 
"So there were loops running everywhere, and you could see it through the glass windows between the studios. Finally I used the fast-forward on the tape recorder to accelerate the tapes so they were already four or five octaves up, then the result went up another four octaves – so then I was up eight octaves – until finally I got into an area where the rhythms were heard as pitches and timbres."