Hi everyone, I stumbled upon this archived recording of a live (!) broadcast of Branca's
Indeterminate Activity Of Resultant Masses piece on July 7th, 1982 at the Navy Pier in Chicago, IL. Thurston and Lee both play guitar, as they did on the
studio recording of this piece from November 30th 1981.
The website itself is
here, but you can also download the mp3 directly
here.