In February 1971 empirical studies started in my New York workspace. Listening, measuring, verifying, making notes on my own, immediate ex-perience with sound lines and space. Linearly aligned loudspeakers created the laboratory for studying the characteristics of sound, movement and space: The speed of a sound-line, back and forth movements, changed tempi in repetition, staggered lines, changes in direction, angled lines. The body-space-relationship, the act of listening to space, was the central approach to artistic and empirical research.