try: (events (loop repeat 8 APPEND (list (jazz-high-hat 120 .99) (jazz-drums 120 .99))) "jazz.mid" '(0 2 4 6 8 10 12 14)) or if you prefer: (events (loop repeat 8 collect (jazz-high-hat 120 .99) collect (jazz-drums 120 .99)) "jazz.mid" '(0 2 4 6 8 10 12 14)) or even: loop with procs = {} repeat 8 set procs ^= list( jazz-high-hat(120, .99), jazz-drums( 120, .99)) finally sprout procs, {0 2 4 6 8 10 12 14} end