Pandiatonicism
Free use of diatonic notes without functionality.
What it means
Pandiatonicism designates a treatment of the diatonic scale in which its notes are freely combined with one another without following the rules of functional harmony. The music remains entirely within the scale — there is no chromaticism — but the sonorities are not connected according to the principle of tension and resolution. Dissonances such as seconds or sevenths stand without being resolved.
Musical use
The term was coined in the twentieth century to describe a sonority that deliberately opposes the chromaticism of late Romanticism. Instead of stretching tonality through ever more notes foreign to the scale, pandiatonicism returns to a plain stock of notes but releases it from the customary bonds. The result often sounds bright, open, and clear, yet at the same time unfamiliar, because the expected goal direction is absent.
Typical features are layered sonorities with added notes, chords that contain several functions at once, and closes that come to rest on an extended sonority. The tonic usually remains as a reference point but is confirmed not through cadences but through repetition and weight.
Related phenomena are found in film music and in popular music, where sonorities within the scale with added notes are used as colour.
Pandiatonicism is to be distinguished from the cluster, which likewise forms dense combined sounds but is not limited to the scale, and from quartal harmony, which layers sonorities according to a particular interval.
The term was coined by the musicologist Nicolas Slonimsky. Pandiatonic music uses only the notes of a diatonic scale but combines them freely, so that chords of seconds, fourths, and sevenths arise that are not resolved functionally. This technique is found in Stravinsky, Copland, and in many works of neoclassicism.
Performance practice
Treat dissonances in pandiatonic music as colour, not as tension — they are not meant to be resolved. Watch balance and register, for with dense sonorities the distribution decides clarity. And do not phrase toward cadences that the music does not provide for.