A method and apparatus for the creation and playback of music, audio and sound; such that each time a composition is played back, a different sound sequence is generated in the manner previously defined by the artist. During composition creation, the artist's definition of how the composition will vary from playback to playback is embedded into the composition data set. During playback, the composition data set is processed by a playback device incorporating a playback program, so that each time the composition is played back a unique version is generated. Variability occurs during playback per the artist's composition data set, which specifies: the spawning of group(s) from a snippet; the selection of snippet(s) from each group; editing of snippets; flexible and variable placement of snippets; and the combining and/or mixing of multiple snippets to generate each time sample in one or more channels. MIDI-like variable compositions and the variable use of segments comprised of MIDI-like command sequences are also disclosed.