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In 'Kontakte', Stockhausen set out to prove a radical hypothesis: that rhythm and pitch are the same thing, just at different speeds. In a pivotal moment of the piece, a rhythmic pulse accelerates until the individual clicks blur into a continuous low tone, unifying the time domain. The title refers to the contact between electronic sounds and live instruments (piano and percussion), but also to the contact of sound waves in space.

To achieve spatial rotation before digital panning existed, Stockhausen built a 'rotation table' (Rotiertisch)—a spinning loudspeaker surrounded by four microphones. By recording sound through this mechanical 'helicopter,' he achieved a physically authentic Doppler effect. In concert, these swirling electronic textures aggressively interact with the live performers, circling the audience like a physical presence.