Great sketches (via Triangulation Blog) from one of the first sound projects called Soundcube, made in 1969 by Bernhard Leitner:
"Bernhard Leitner is considered a pioneer of the art form generally referred to as “sound installation.” He introduced sound to the installation space, allowing the installation space to emerge through the sound. Leitner, who actually studied architecture, has been a visionary ever since the very start of his artistic career. His sculptures—which he refers to as “sound-space objects”—and installations are the result of long, complex processes of development. In precise sketches and workbooks, he first approaches the sculptural, architectural qualities of sound in theory"
Find out more about Leitner's installations:
Bernhard Leitner: Sound Spaces | ArchDaily