Heterophony

One of various musical textures, heterophony is a kind of complex monophony - there is only one melody, but multiple voices each of which play the melody differently, either in a different rhythm or tempo, with different embellishments and figures, or idiomatically different. The term was invented to differentiate this from European polyphonic music of separate melodies; however, it can also be seen as a type of polyphony. The term heterophony was coined by Plato and is used in many areas of the world. Morton (1978) suggests, at least for Thai music, the term polyphonic stratification.

An example of heterophony is the Gaelic band The Chieftains' tune The Wind That Shakes The Barley. Each instrument plays the same melody but embellishes it slightly with grace notes, vibrato, etc. Other examples include traditional Thai music and the gamelan music of Bali.

"Thai music is nonharmonic, melodic, or linear, and as is the case with all musics of this genre, its fundamental organization is horizontal... Thai music in its horizontal complex is made up of a main melody played simultaneously with variants of it which progress in relatively slower and faster rhythmic units... Individual lines of melody and variants sound in unison or octaves only at specific structural points, and the simultaneity of different pitches does not follow the Western system of organized chord progressions. Between the structural points where the pitches coincide (unison or octaves) each individual line follows the style idiomatic for the instrument playing it. The vertical complex at any given intermediary point follows no set progression; the linear adherence to style regulates. Thus several pitches that often create a highly complex simultaneous structure may occur at any point between the structural pitches. The music 'breathes' by contracting to one pitch, then expanding to a wide variety of pitches, then contracting again to another structural pitch, and so on throughout. Though these complexes of pitches between structural points may strike the Western listener as arbitrary and inconsequential, the individual lines are highly consequential and logical linearly. The pattern of pitches occurring at these structural points is the basis of the modal aspect of Thai music." (Morton 1978, p.21)