The first hour of this program is a conversation with Terry Riley, outdoors on his land. The second half is performance.
More info on the series this is from, via Ubu:
Music with Roots in the Aether, an artwork by Robert Ashley, is comprised of seven two-hour programs featuring noted American experimental composers, created during the 1970’s.
Each program is two hours long and consists of one part Landscape / Interview (one hour) and one part live performance (one hour).