Here’s a lovely recording of some early music for voices and electronics (not Early Music) called Extended Voices by a motley assortment of 60s luminaries, all conducted by Alvin Lucier. Also included are some magnificent non-electronic works by Feldman for chorus that could stand to see the light of day more often! I might also point you to the links on the left of the page to access the rest of the fabulous resource that is UbuWeb.
Tags: Alvin Lucier, David Tudor, Extended Voices, Gordon Mumma, John Cage, Morton Feldman, Pauline Oliveros, Robert Ashley, Toshi Ichyanagi, UbuWeb