Title of 5 perc. works by Cage in which he also developed his interest in unusual and elec. sounds. No.1 (1939), 2 variable speed gramophone turntables, frequency recordings, muted pf., cymbal; No.2 (March), perc. quintet (1942); No.3 (1942), perc. sextet; No.4 (March No.2), 12 radios, 24 players, cond. (1951); No.5 (1952) is a score for making a recording on tape using any 42 gramophone records.