35.1: Additive Minimalism
In Philip Glass’s version of additive minimalism as found at the beginning of his composition Two Pages (1969), he adds a repetition of a pattern but subtracts the final note in the repetition. Each addition to the pattern is another repetition with the final note of the previous repetition subtracted, as can be seen in the example below. (Note: The music notation below is a transcription and analysis meant to show the additive process and is not necessarily how the music is written in the score.)
The following example from Music in Fifths (1969) clearly displays additive process on its own, but is just one of dozens of steps in an additive process.
To hear additive process in Glass’s well-known Einstein on the Beach, listen to the following minute of music from Act 1, Scene 1, “Train.” Each chord in a five–chord cadential progression is gradually lengthened by adding to the number of subdivisions given to each chord.