From The Album “Drumming / Music For Mallet Instruments, Voices And Organ / Six Pianos ” [1974]
info:
http://www.discogs.com/Steve-Reich-Drumming-Music-For-Mallet-Instruments-Voices-And-Organ-Six-Pianos/release/249712
Glockenspiel – Ben Harms, Glen Velez
Marimba – Bob Becker, Russ Hartenberger, Steve Reich, Tim Ferchen
Organ [Electric] – Steve Chambers
Percussion [Metallophone] – James Preiss
Voice – Janice Jarrett, Joan LaBarbara
Voice [Melodic Patterns With Marimbas] – Jay Clayton