In 1968 I was ten years old - and Karlheinz Stockhausen was forty. I was in the north-east of England, living in a strange post-industrial community, and attending a difficult school. He was all over the world, a celebrity of the avant-garde.

That year, Stockhausen deleted musical notation from his musical compositions. Working with a group of improvisers, he developed a set of text instructions to inspire performance. Jazzers had been doing this forever, but Stockhausen's sound world abhorred a regular beat, or the irregular long-term rhythmic connections of free jazz. In fact freedom sounded a lot like control, from Stockhausen's mind.

In 2015 we are left with the words he wrote, From the Seven Days. His thinking would degenerate in the '60s, to produce notions of higher beings from distant stars - including KS himself. Now it feels the product of drugs and meditation.